Beggars Would Ride
The Backfoot
(Header image here graciously provided courtesy of Rob Wilson, via Grant Lestock Kay's tale of his '41 Schwinn cruiser over on the blog of his bike shop, Cowichan Cycles)
Last Saturday I sat down to breakfast with Cameron Falconer. We were overdue for catching up. Life has been trucking along for both of us, and I happened to be passing through his town. As can happen when one sits down to breakfast with a framebuilder, the talk eventually turned to bike geometry.
Cam has been recovering from a broken leg, and is back to pedaling around in the woods. He has also pretty recently picked up a new Transition Smuggler. To paraphrase why a talented framebuilder would buy someone else’s full suspension bike rather than build his own; suspension is hard to get right, carbon fiber is similarly challenging if you don’t have a ton of experience modeling with fancy computers or access to big factories and really expensive molds, and it’s way more fun to ride than it is to toil away “iterating” all the various incarnations of the learning curve between “sorta rideable” and “good enough.”
His Smuggler is a thoroughly modern geometry bike. Not to say that the steel hardtails Cam crafts are not modern, but they are generally more conservative in geometry than the newest of new school FS bikes. Cam is not conservative in his own thinking when it comes to geometry, and will adapt whatever he feels makes his bikes perform at their best, but he has a large brain and always strives to fully understand the “why” of any given trend before implementing it into his repertoire.
With modern bike geometry, there is a lot of “why” to unpack. If this column now devolves into a familiar sounding inquiry into the current state of mountain bike design, written by a probably out of touch old kook, well, you have been warned. Not the first time I’ve tilted at this windmill.
Cam was pointing out a couple things he was noticing with regard to adapting to the Smuggler. One, he was working his way through some knee pain. Surgery in the past, now recovery from a broken leg, a lifetime of miles and miles, plus a new riding position. Bingo. And two, he was noticing the saddle poking him in the ass whenever he was standing and climbing anything but super steep pitches. The ass poking, I agreed with some resignation, just kinda comes with the territory when it comes to 77+ degree seat angles. Proponents of modern geometry will question why someone would stand when climbing anything but super steep pitches in the first place “because suspension only really works when you’re sitting down anyway and standing is for old burnout onespeeders who are too fossilized in their muscle memory habits to adapt.” Or something like that. Fair point.
But then we got into talking about knee pain, the “begat” aspect of design philosophy, human adaptability, and whether or not we can really trust what we think our bodies are telling us.
Last year, when I was testing the Kona Honzo, I kept running into a “new” knee pain sensation on longer rides. I ascribed that at the time to lack of fitness, or maybe not being able to reconcile my knee over pedal relativity with the steeper seat angle. So when Cam mentioned his own knee discomfort, my ears pricked up. Our conversation then veered into the begats.
Begat number one: Full suspension seat angles needed to get steeper. Mirroring the traditional road and mtb 73-degree standard, or in some cases going even slacker, was not helping anyone once rear travel started climbing north of 150mm. A modern 160mm bike will sag anywhere between 40-55mm when a rider sits on it. There will be some corresponding front sag, but that will be substantially less. So, it makes perfect sense to compensate by ratcheting seat angles a degree or two steeper. Boom. Happy old school riding position nirvana is restored.
Begat number two: Crank the seat angle up a couplefew degrees, leaving all else the same, your bike will end up with a longer wheelbase. A steeper seat angle pushes rider weight forward AND moves the front of the bike forward. This brings up Begat one point five. Moving rider mass forward is a good thing when design trends also dictate slacker head angles. If the rider mass stayed back in the old 73 degree (sagged out to 71 or so) zone, then that radical new sub 67-degree head angle would cause the front to push like crazy in the corners, especially with all that fork offset.
Begat number three: It turns out that riders in general really like long slack bikes. They are more stable. Shredders can push them way harder, and less experienced riders feel “safer” almost everywhere, and nobody rides switchbacks anymore anyway. So, since the majority of riders are okay with this, fronts keep getting slacker, seat angles keep getting steeper, and wheelbases get longer.
Begat number four: Riders with flat pedals are positioning their feet over their pedal spindles with the arches, rather than the balls of their feet. Progressive riders who are still clipping in are running their cleats as far back as possible, sometimes even dremeling the slots in their shoes to allow for more rearward cleat placement, effectively putting feet farther forward on pedals as well. This relaxes the knee angle at forward – 3-o’clock – position. Now, does this happen as a result of steeper seat angles causing riders to push their feet forward to retain a “good” knee flexion, or does this happen because riders feel more planted on the pedals in techy terrain, and therefore defining yet another contributing factor toward the steepening of seat angles? Because if a rider’s feet are moving forward to find a better position to ride the tech stuff, then it makes total sense to skooch the seat angle steeper in order to feel less recumbenty. This also contributes to a change in rider mass centering, effectively moving the rider forward relative to the front and rear axles/contact patches. Whether this is something worth splitting hairs over in terms of overall bike dynamics is way above my pay grade.
And here, mid-begats, is where Cam began to interrogate his knee discomfort. Rather than it being something that he felt was emanating in the usual pressure point beneath the kneecap, where most of us get knee pain when pushing too hard on the power phase of our pedal strokes, he felt like maybe this particular sensation was being generated at the rear of his pedal stroke, from the 6-o’clock zone, up to top dead center. That maybe, just maybe, his knees were not happy with a relatively deeper bend at the rearmost, most “bent” part of his pedal stroke.
Which, inadvertently, brings us to begat number five: Shorter cranks. I have not personally been interested in shorter cranks because a) I don’t find myself experiencing a lot of ground clearance angst, b) I don’t ride ebikes, and c) I want to preserve every sad little scrap of torque I can muster. I have, for the most part, thought that short cranks are best left to the winch and plummet set, since even in spite of the increasing experiential database suggesting that there are zero drawbacks associated with shortening cranks, I tend to believe that the old 170-175mm crank, 73-degree seat angle relativity is not accidental. It is biomechanically what most average shaped humans adapt most readily to when it comes to spinning circles with our legs while propelling a bike forward for hours at a time.
But wait! What if, in the modern bike design reality, short cranks also help alleviate some of that rear-to-top of pedal stroke acute knee angle twinge potential? That might be a validation, right there. Shorter cranks dictate that a knee will experience less flexion/extension overall during a single rotation. Multiply that by several thousand, and it stands to reason spinning smaller circles might, in the long run, result in happier knees. Until breakfast the other day, this was not something I had ever thought about.
As the coffee flowed, Cam mentioned something about how humans are incredibly adaptable creatures. We can get used to almost anything. So, we are getting used to long and slack bikes, and this is then sets the table for us to experiment with steeper seat angles, and get used to that as well. And then we can shorten our cranks, and get used to that. Whether any of this is biomechanically “better” is up for debate. It definitely makes it easier to rip downhill. The current geometry also lends itself well to winching big heavy bikes up super steep climbs, but I will still put it out there that none of this steep seat angle, short crank malarkey is of any help in grinding out miles of shallow grade climbing (unless my knees hurt less. In which case, game on!). Cameron would point out that "we're just old men yelling at clouds at this point."
Shallow grade climbing isn’t what sells bikes. It’s not very aspirational. Nobody wants to buy a bike to get mellow on. We want the rad shit.
Shaking out stiff joints on the sidewalk after breakfast, squinting in cold bright winter sunlight, we hugged and said our goodbyes. I was set to drive all day (talk about finding new ways to make knees and hips hurt), and Cam was gonna sneak a ride in. I’m now wondering which of us will cave in first and buy some shorter cranks.
Comments
mikesee
5 months, 1 week ago
Where are all of the switchbacks being stored?
You know -- until we collectively realize how much we miss them.
Reply
Justin White
5 months, 1 week ago
My chosen trail bike has grown 3+ inches in reach and almost 5 inches in wheelbase, (and perhaps 2" in ETT) in the past two decades, and I'm still riding the same switchbacks as ever, up and down. Maybe even riding more of those same switchbacks since there is way less walking down them, and even a bit less walking up!
Reply
Kerry Williams
5 months, 1 week ago
They're on some of the trail in the Okanagan. Some are ludicrously tight. And, by the way, my longest and slackest bike I've ever owned naviagates them easier than any old school, over the bar sending, bike I had in the good ol' days, LOL.
Reply
Justin White
5 months, 1 week ago
Agree. I actually like a longer and slacker bike for faster and steeper tight switchbacks, and especially for off-camber ones. You can get in so much more steering angle before the front tucks or slides, and a much bigger window to shift your weight around to load the front just so. I find it actually easier to load up and swing the big bike around than trying to nurse something with a too short front-center through without accidentally applying half a degree too much steering input and losing the front in a hurry.
Reply
Hawkinsdad
5 months, 1 week ago
Travellin Man (Smith Creek), West Kelowna.
Reply
rolly
5 months, 1 week ago
Did an Okanagan bike trip last June. Smith Creek Friday afternoon/evening. Three Mice Saturday. Osoyoos Sunday. Fun factor went in that order too. Osoyoos has lots of potential, but reward on the downs doesn't quite match the suffering on the climbs yet. Yet. The trailbuilders there are putting in the time though.
Reply
NealWood
5 months, 1 week ago
Sawblade.
Reply
bushtrucker
5 months, 1 week ago
You're onto it with this one. I reckon the biggest reason a lot of older cyclist prefer 73deg STA's and 170-175mm cranks has gotta be because they've been riding bikes with those numbers for decades. Yes the human body is adaptable but over time you also get very used to the way things are. If ya new to riding or younger and more flexible it's easier to make changes to ya setup. Especially when the changes lead to a more rad bike!
I used to think 73 degrees was the sweet spot too. It took 5 months of solid riding on a Surly Big Fat Dummy with a crazy high Q-factor and a saddle slammed all the way forward to make me realise that 75ish degrees might just be more comfortable for me. I got a Norco Torrent on the way with a 77 deg STA and I'm keen to see how that goed. It still comes with 175mm cranks but hey one thing at a time right.
Reply
Mike Ferrentino
5 months, 1 week ago
I think it is all conjoined. We are super adaptable creatures, but younger versions of us are probably more adaptable than older versions. I DO think that the static/hardtail 73 degree STA and the 170-175mm crank length exists for a reason, though - and I suspect that people who pedal a whole lot, like, hundreds of miles a week, would have something to say about the relative pedalability of steep STA over old skool STA when it comes to crunching huge hours in the saddle. At that point I am not sure if the perceived choice for tradition over evolution is failure to adapt or if there is a biomechanical sweet spot that had seat angles on hardtails eddy out at 73 degrees for a hundred and twenty years. I know for myself, that steeper STA bikes feel fine when climbing really steep pitches, but generally do not feel great for long flat/shallow grade grinds. But I am old, and I don't commit enough hours a week to really investigate how much worse I can make my knees feel...
Reply
Justin White
5 months, 1 week ago
Don't kid yourself, the market kept STAs at 73 degrees forever. No one could sell something different until recently, and no one really tried anything different until recently, because it wouldn't sell in the mass market. An influx of mountain bikers with disposable income, and the love of little niches in the industry, allowed experimentation outside of the pressure of mass-marketability. As more and more people tried, and easily adapted to, radically different geometries, the middle-ground shifted. Indeed, some might say it "progressed".
Well, actually some did try to mess with STA before mountain bikes did: triathlon bikes have long used very steep effective STA, whether from steep steep STA, big forward offset, long seat rails, or just seats designed for a very forward position, and those course aren't exactly full of steep climbs. I originally heard it was to engage different muscles than used in the running portion, but I personally feel more of the same running muscles in use as my seat goes forwards.
Reply
taprider
5 months, 1 week ago
It seems every generation, riders play around with frame dimensions and crank lengths as if it is a new thing.
Since the 1890s (Eighteen Nineties), track riders have been playing with crank length and in the 1980s (Nineteen Eighties) an aggressive crit bike had steep head and seat tube angles. What goes around comes around and in another decade, riders that actually pedal a bike will probably be using 170mm cranks.
Reply
Andy Eunson
5 months, 1 week ago
I heard the same from a few sources. I think Steve Hogg (sp?) from Australia said that. The UCI doesn’t allow that forward position for road racing tts. I think it’s more of a hip angle thing while being aero. If one is too folded over it’s harder to really push hard. Too upright is similar. When I watch riders when I’m guiding, all riders new and experienced all bend over when climbing a steep bit. And they pull back on the bars. These loonies are all bobbing I think to get some power down. https://youtu.be/QvloKB9Fg58?si=RpR-DxVtVH1kn-8r If they are just trying to be aero they should just stay down. Someone told me ages ago that the old guy in the London fog trench coat on the Raleigh 3 speed would bob like that to engage the glutes. Kind of fits with what I see guiding.
Reply
NealWood
5 months, 1 week ago
I think you are right when you suggest that winch and plummet vs more xc up, flat, down, flat, up, flat, down….. oriented riding has differing needs.
Reply
Blofeld
5 months, 1 week ago
I really enjoyed this little journey over coffee and looked up some photos of your Falconer for reference.
There was some discussion of Begat 4 in and under one of Andrew Major’s articles a while back. It’s interesting to think about moving foot position forward as effectively shrinking the bike when standing. The why of how this innovation was established is a little tricky. For myself, I’ve always ridden DH on flats with my arch over the spindle. Assuming the same position on an enduro bike seems to make sense now, as their capabilities have become very similar.
Reply
JT
5 months, 1 week ago
Will not pontificate my opinion on short cranks. Will not pontificate my opinion on short cranks. Will not pontificate my opinion on short cranks. But yes, my knees hurt less since the switch.
Reply
Brad Nyenhuis
5 months, 1 week ago
Since no one else has mention this, am I the only one who thinks Cameron Falconer is the coolest name ever?
I immediately assumed it had to be made up or stolen from a James Bond movie.
I'd buy a bike from him for that reason alone.
Reply
Cooper Quinn
5 months, 1 week ago
Porn. It belongs in porn.
And I mean that not in a bad way, but in a "no one's name is actually that cool" way.
Reply
Mark
5 months, 1 week ago
For my two cents seat angle is the wrong measurement/parameter we should worry about, it should be seat position. Obviously seat position is different for up and down, both vertically and horizontally. It seems that the critical question is where the seat should be in relation to the BB if pedaling efficiency and comfort are to be maximized. The problem we have as mtb'ers is the optimal seat position is in conflict with itself when it comes to the up and the down. Products like the Aenomoly Switchgrade help, but fore/aft adjustment is also needed. Imagine some sort of electronic seat post and clamp gizmo that offer 3 or 4 settings you can manipulate so the seat is always where you need it when you need it. Something for flat/mellow, steep ups, crazy downs and maybe something in between the flat and steep settings for those short little pedally sections that show-up on descent every now and then. Would you pay for such a thing?
Is it possible to have all the adjustments necessary for optimal up and down riding positions or do we just need to accept that because we do two very different things on an mtb that we simply have to make compromises? All day pedaling comfort means we'll need to sacrifice downhill munching capabilities. There may very well be some magic design where most riders can find they can get pretty close to having it all, but that probably means getting a custom bike made by someone who knows how to take an individual's unique physical measurements and translate them to the bike's geometry. Even then, there are going to be some compromises to be made such as amount of travel, weight and cost.
I think the solution has always been n+1, horses for courses. And maybe, recognizing that we all have some limitations we just have to deal with.
Reply
Justin White
5 months, 1 week ago
This. Actual saddle position is the metric, not the angles. Yes the angles limit the position, but the same way that frame stack limits bar height, and seat tube length limits saddle height: there is a range to many (most?) bike fit metrics for a given frame, but seat tube angle is always compared by the single number, which is kind of silly.
(And we can get into actual, and effective, and "effective at what saddle height for which size", and all those seat tube angle things, another time).
Reply
fartymarty
5 months, 1 week ago
https://theradavist.com/measuring-mtb-seat-tube-angles/ was a good read. This was discussed a bit further on the MEATengines thread.
Edit - I've just seen the same article posted below.
One thing I added on the MEAT thread was Tippability (Bum Reach / CS length). This will give you an idea of how the bike will climb.
Reply
ZigaK
5 months, 1 week ago
This passage:
...and nobody rides switchbacks anymore anyway.
reminds me of the line in the 2014 article
[
](https://nsmb.com/articles/2014-specialized-stumpjumper-fsr-evo-29-review/)
https://nsmb.com/articles/2014-specialized-stumpjumper-fsr-evo-29-review/
Tight and awkward? Not where this bike shines – but who wants to ride that shit anyways?
and I find it hilarious almost 10 year on
and also a little bit sad
Reply
Kerry Williams
5 months, 1 week ago
All this time, I thought I was the only older fart thinking about geometry way too much, LOL. But I love to think about how fit can make or break the love of a bike.
Reply
TristanC
5 months, 1 week ago
I'm in the midst of ordering a custom frame, and I've found myself agonizing over things like STA now. I think it's going to end up at 73°, because that hasn't let me down in the past and the bike is already ridiculously long without moving the rider even further forwards. And I am a pedal masher, not a spinner.
I checked the geometry of my current bike, though, and found that the STA is 70° (overforking a 73° nominal). I've been riding it for months and didn't die, and my knees didn't explode. I have tried 165mm cranks too, and they made my knees hurt (on top of the knee, which is a new one) so I swapped back to 175mm and they felt better. Maybe I'm just in that sweet spot of 73° STA, 175mm cranks.
Reply
Justin White
5 months, 1 week ago
Try looking at Effective Top Tube Length (especially if the seat height it's measured at is provided, for even better comparison to your current) instead of STA. STA alone doesn't really tell you where your seat will be in relation to the bars or BB. ETT at least tells you bars to seat much more effectively.
Also try to find and compare the Effective STA at your seat height. With weird seat tube offsets and slack actual STA for clearance, the ESTA can sometimes change fairly drastically as the seat height changes.
Reply
Kos
5 months, 1 week ago
Bang on, par usual, Mike.
The majority of riders are not winch and plummet, but most bike's geo keeps trending further and further that way. Bah! Humbug!
Also, your editor called, and noted that Begat Number 1.5 should technically be 2.5.
Let it snow, dammit!
Reply
Mike Ferrentino
5 months, 1 week ago
No, I meant it as begat 1.5, as in; steeper STA brings rider mass forward and this is also a good thing with regard to slacker head angles pushing the front of the bike farther out, and this is BEFORE we really get to begat 2. I think. All those begats. So much math. Early morning. Need coffee.
Reply
Cam McRae
5 months, 1 week ago
Phew! I looked at that and pondered for a moment and realized it was likely intentional.
I'm not really worthy of being Mike's editor, and he rarely has a letter out of place, so I'm glad I left that one.
Reply
Cee Cee
5 months, 1 week ago
Obvs Falconer needs a shorter, flatter saddle, footbeds with met support, and -9mm max saddle height...not enough data. This could be fun if it were a reader contest to solve the rider's knee/s pain with a pair of NSB cranks for a prize. Odds of winning are fair for entering with 'degenerative condition'
Reply
Andy Eunson
5 months, 1 week ago
I was pushing weights the other day on the 45° inclined leg press thing. Have one unhappy knee I don’t go past 90° lest it collapse and I’m in a world of hurt. I’m pushing a little over double my weight but I seem to make max power at 100° or so. Linking this to pedalling I’m think a crank length that puts your knee under 90°, more flexed, isn’t so good. So a crank length should be selected that accounts for that knee angle. Maybe?
Seat position includes height, angle and fore aft. The fore aft affects balance and how much weight is on your hands. Steep seat tube angles encourage a more upright position which can be less efficient in terms of ergonomics and making power. There seems to be three ways manufacturers deal with steep seat angles. One pushes the bb back under the butt, two the seat goes forward over the bb and three some of each. Many frames in my alleged size, small, have short effective top tubes. Too short and my knees will hit my grips on steep uphill switchbacks where this steep seat angle thing is supposed to be better. Get the bigger size and now I’m leaning on the bars a bit more than I like. And my cleats are pretty Mach as far back as they go on my shoes. If I’m on flats I don’t have my arch over the spindle but I am further forward than on cleated shoes.
I think steep seat tube angles have something to do with keeping costs down by using the same rear triangle in all sizes when larger bikes need longer rear ends. A small bike with 435 stays will ride differently than a XL with the same stay length. Different fore aft balance. Is my small bike perfect balance and everything bigger off? Or the XL perfect and smaller bikes are off?
I dunno. It’s a complex web. I’m having issues with a trigger thumb and two fingers on the left and three trigger fingers on the right. Doc thinks it might be neck issues affecting forearm muscles being tight causing the trigger issues. The only thing that has changed is I have a fuel ex with a 78 seat angle. I’ve been futzing with bar heights and saddle tilt trying to get comfier. Fucking old age
Reply
fartymarty
5 months, 1 week ago
Andy - are your fingers numb? If so it sounds like Carpel Tunnel. I changed to 12-16 degree backsweep bars and it helped. Also a steeper STA puts more weight on your hands making it worse. Higher rise bars with more backsweep help.
Reply
Andy Eunson
5 months, 1 week ago
No. Not numb other than parts of a ride which has always happened. The doc asked me that too as did the physio. Doc sent me for a ct scan of my neck in case that was the proximate cause. Neck isn’t too bad. Physio thinks it’s the tight muscles in my forearms. Which might still be neck related. There is a good sized bump on the inside of my thumb where the tendon runs through the pulley. Getting shock wave therapy on that. Going tomorrow. It’s not getting worse but neither is it improving. Could be worse. A friend has Dupuytren’s Contracture and has had two surgeries. Ended up having his pinky finger amputated because they couldn’t fix it. Another friend is or just had the surgery. Hopefully his was successful.
Sometimes the cause of trigger fingers is unknown. I’m hoping the end riding season may offer relief or at least information that it’s not riding related.
Reply
Justin White
5 months, 1 week ago
"Is my small bike perfect balance and everything bigger off? Or the XL perfect and smaller bikes are off?"
Pick one:
More than likely the Medium or Large is "perfect" and everything else is off.
Don't forget that seat tube angle and fore-aft are connected, as far as seated weight distribution is concerned. A steeper ESTA is the same as making a forward slide on the rails, slacker ESTA is a backward slide. It's just a matter of how far you can slide: a slack ESTA means fore slide is more limited, and steep ESTA means aft slide is more limited. This is part of why STA is a semi-useless metric: because every size of every bike really has a range of ESTA: driven directly by saddle height, but adjustable at the saddle clamp. The measurements that actually matter for bike to bike comparison for an individual rider are: bar-to-saddle length at preferred saddle height, and reach, neither of which can be derived from STA without much much more data.
Reply
Pete Roggeman
5 months, 1 week ago
This isn't talked about enough but I've seen it first hand: many brands' bikes are tuned for the PM and/or the loudest or most respected voices in the test squad. Some brands have gone past that and tune suspension and other things (chain stays and other dimensions if you're lucky) for various sizes, and Specialized for example actually engineers different carbon layups and/or tube sets for each frame size in order to get the ride quality the way they want it for each size.
If you care more about the rear derailleur spec than the tech and design that goes into the frame, just shop by price and spec sheet. But if you want a frame that rides near the top of the heap, you gotta understand those R&D costs are higher. Not everyone cares, but it's good to know what you're getting.
Reply
Velocipedestrian
5 months, 1 week ago
>I think steep seat tube angles have something to do with keeping costs down by using the same rear triangle in all sizes when larger bikes need longer rear ends.
Someone posited steep seat tube angles are a result of long travel + bigger wheels + short stays = contact. The designers steepend the STA and the marketers had to sell it to us.
Reply
Flatted-again
5 months, 1 week ago
I’ve heard that before, but I’m not so sure about it. It seems we’re finally approaching 2015 Geometron geometry, and I’m doubt those had steep STA for any other reason than it worked. Heck, the pictures here seem to indicate 77* wasn’t steep enough: https://m.pinkbike.com/news/nicolai-mojo-geometron-first-ride-2015.html
Also, the causality could have gone the other way: steeper STA allowed for bigger wheels/travel etc, rather than bigger wheels/travel needed steeper sta. I’d argue this directionality, mainly because I remember so many bikes with saddles slammed all the way forward. It’d be an interesting analysis to do for a bike historian
Reply
Velocipedestrian
5 months, 1 week ago
My bike...
Saddle's still slammed forward on the rails.
Reply
Flatted-again
5 months, 1 week ago
Nice rig! I’m not going to lie, I’m quite jealous of Geometron owners.
Reply
Velocipedestrian
5 months, 1 week ago
Until recently I was too.
Mark
5 months, 1 week ago
If most people on the new geo frames are having to push their seat all the way forward then that tells us that either the front ends are too long OR the seat tube is in the wrong position relative to the length of the front end. Steeper seat tubes simply seem to be the way to compensate for longer front ends (reach). The thing we can't escape though is that the length from the BB and seat to the head tube is limited by the human piloting the thrill craft. So even though a longer front end might be good for descending, it's not necessarily good for pedaling. I think the new geo bikes are good, not because they are optimal in terms of riding/pedaling biomechanics, but because the old geo was just so bad and we didn't know any better. Things are better now, but we're still chasing problems. MTB bike geo is like a game of chess on a sound mixer - move one slider (dimension) up and you have to compensate by changing something else.
At the end of the day unless people are riding something horribly mis-sized or have had the chance to ride a lot of different bikes/setups to be able to understand how fit matters, I think they're not realizing how wrong their bike fit might be simply because they're having too much fun on the trails.
Reply
Velocipedestrian
5 months, 1 week ago
>the seat tube is in the wrong position relative to the length of the front end.
Personally I feel the front end length is good, and I slammed the saddle forward to get the Bum Reach in a happy place.
Justin White
5 months, 1 week ago
"Crank the seat angle up a couplefew degrees, leaving all else the same, your bike will end up with a longer wheelbase."
No it won't.
Or rather, you can't leave "all else the same". If you leave reach the same, cranking the seat tube angle changes nothing about the wheelbase, and shortens the effective top tube. If you keep the effective top tube the same, then both reach and wheelbase grow.
Reply
a.funks
5 months, 1 week ago
I don’t believe most quoted effective seat angles because they’re measured at too low a saddle height with offset/bent seat tube that have slacker actual angles.
On my singlespeed hardtail (quoted ESA 77.5 deg) I usually drop the saddle for standing climbing (most of it!) That bike also has 165mm cranks…
Reply
93EXCivic
5 months, 1 week ago
Maybe I am weird but when I moved from 175mm to 165mm cranks I noticed the following things, 1) less pedal strikes, 2) needing to raise my seat and handlebars a little. I didn't notice any change in my power tbh.
Reply
Cam McRae
5 months, 1 week ago
I must be weird then too.
When I went to 145s I noticed more things though.
Shorter Cranks or DH Performance
Reply
Cr4w
5 months, 1 week ago
That's a very interesting analysis. This squares with my recent experiences. I've already switched my primary bike to 170s (which is short for me at 6'6") and it's so consistently good that I'll do my other bike too.
Reply
Justin White
5 months, 1 week ago
"I tend to believe that the old 170-175mm crank, 73-degree seat angle relativity is not accidental. It is biomechanically what most average shaped humans adapt most readily to when it comes to spinning circles with our legs while propelling a bike forward for hours at a time."
That's correlation, not causation. Through out the history of bikes, most average shaped humans have only ridden bikes with close to those measurements, so of course they've adapted to the only environment they've experienced. Yet, the majority of people who try shorter cranks, or steep (-ish, not as much for the crazy steep 80+ stuff) seat tubes, easily adapt to those.
One more re: shorter cranks, I'd argue the greatest loss that comes with shorter cranks is not absolute max torque* but reduced time in the the (relative) max torque zone. Stomping squares up rough stuff does become slightly harder because you have slightly less time per stroke in the most advantageous portion of the pedal stroke. However, spinning just a bit higher cadence is so much easier (more clearance, and less leg speed for a given cadence) and gets you back to that advantage portion faster. You get the same power output in the end, and power is really what keeps you moving up a hill, it's just delivered differently.
* (If you truly need max torque on 175s to ride stuff right now, you're already screwed if you ever try to ride anything slightly bigger without also embiggening your cranks)
Reply
JT
5 months, 1 week ago
I liken it to motos. Sure, a Harley generates a shite tonne of torque due to the throw each cylinder has. Very big uppy downy forces at play. Compare it to near any 4- or 6-cylinder moto and there's less throw per rev, which means the system can redline at MUCH higher RPMs. What it lacks in all out torque it makes up for with consistent power delivery. The engine isn't gonna try to throw a piston or rod through the case near as bad.
Reply
Kos
5 months, 1 week ago
I also despise moto engines that demand high rpm for power, so maybe that's why I gave up on shorter cranks, after two separate 30+ hour trials.
Reply
Justin White
5 months, 1 week ago
Preferences are preferences, but I don't think the moto pref has anything to do with your mtb pref. Your legs are not a motor, and your body has no clutch to slip and smooth the rougher power delivery of a long-stroke thumper or v-twin, or the uneven power delivery of a long pedal stroke. No matter how good you are at spinning circles instead of stomping squares under high load on 175s, you'll be even better with a shorter crank, which equals enhanced traction, like being good with the clutch.
Reply
Kos
5 months, 1 week ago
"No matter how good you are at spinning circles instead of stomping squares under high load on 175s, you'll be even better with a shorter crank"
Yet, as noted above, my two lengthy experiments with shorter cranks (tried both 165 and 170) were decidedly negative.
To each their own.
Reply
Marc Pfister
5 months, 1 week ago
Coming from 175s and 180s I absolutely hated 170s every time I tried them. 165s were strangely OK, anything shorter felt totally crazy until I radically changed my position and then 160s and 155s felt crazy good. Unfortunately that position requires basically custom frames, so my only conclusion is "ride what works best for you".
JT
5 months, 1 week ago
Bikes are for the most part fun. I don't mind what anyone has brung to run as long as they're smiling. Different (pedal) strokes for different folks and all that.
Marc Pfister
5 months, 1 week ago
"Through out the history of bikes, most average shaped humans have only ridden bikes with close to those measurements, so of course they've adapted to the only environment they've experienced. "
I assume the formal "fit rules" of published books like the CONI Manual all lined up to place the "average" rider with KOPS and calculated seat height rules on a 73d seat angle. Since cranks weren't scaled, shorter or taller riders got their seat angles tweaked to maintain the KOPS rule.
But of course "average" (as well as "biomechanically optimized") has a heaping dose of survivorship bias. If you didn't fit the accepted geometry, you didn't make it to pros, and the circular logic repeats itself.
In the golden age of safety bikes, cranks varied from 6"-8", though most bikes came stock with 6"-7" cranks. The optimal length was heavily debated and tested at that time too, but with all bikes being single speed the lengths those riders preferred skewed the gearing baseline towards higher sprocket to cog ratios. These days with more gear selection it's much easier to experiment with finding a length that works for you.
Reply
Justin White
5 months, 1 week ago
If you first accept that KOPS even matters, then, yeah, you still have to navigate the survivorship bias.
Though, KOPS doesn't apply so much for MTB. Evidenced by contemporary STAs, and slammed forward saddles before the great steepening: people care about weight distribution in climbing position more than getting a precise leg alignment measure on flat ground. And less sitting and spinning for extended periods when trail riding: if half your ride is out of the saddle, is the biomechanics of the saddle position only half as important?
KOPS makes so many other assumptions about the rest of the body being in a good position anyway, I never understood it as a goal rather than a starting point, much like suspension sag.
Reply
Marc Pfister
5 months, 1 week ago
I don't have to accept KOPS, I'm just saying it could explain the dominance of the 73 seat angles for road racing. I'm not making the argument that 1970s road racing positions are relevant to modern trail riding.
Reply
Alec Barron
5 months, 1 week ago
The Ripmo v2 was my first bike with the steeper STA and slacker head tube. I ordered my typical 175 cranks and kept getting persistent knee pain. I moved to 165 cranks and it solved all my woes. Talking about STA seems complicated. I really like Travis Engel’s write up on this here: https://theradavist.com/measuring-mtb-seat-tube-angles/
I’d love to hear you two discuss this fully into the weeds.
Reply
Justin White
5 months, 1 week ago
Wow, that was a lot of words... (the linked article, not the comment, duh)
From the Ibis guy: “That’s when I started measuring horizontal distances from the seat, but I was actually measuring distance to the rear axle, not the bottom bracket.”
They got it right. Bum/butt reach as an offset from the BB doesn't tell you enough without also knowing chainstay length. "Seated rear-center" (as I call it) as a measurement from axle to seat (at climbing height) is the real key to keep geo consistent among sizes.
Travis also kind of missed the factor of slack actual STA vs matching or even steepening effective STA through the size range. A slack ASTA is always going to cantilever a rider on the taller side of a given size further out the back, drastically decreasing ESTA at the upper seat heights, even if they're measuring ESTA at some idealized average seat height. And vice verse for riders on the short side of a size.
Matching ESTA through the sizes goes some of the way making geo feel consistent through the sizes, but getting ASTA closer to ESTA goes even further. And might avoid the need for steepening the "average/middle" ESTA through the sizes, since that can end up screwing the riders on the short side of a size with a very very steep ESTA, exactly the opposite of Travis's complaint that measuring ESTA from the headtube screws tall riders.
Reply
Cr4w
5 months, 1 week ago
The guy who posted 9 different comments (nearly 80 lines) on this article thinks this 4 line comment was too verbose everybody.
Reply
Mark
5 months, 1 week ago
I think he was referring to the article - in a good way?
Reply
Justin White
5 months, 1 week ago
Yes, I was referring to the Radavist article.
Mike uses lots of words to build context, Travis used a lot of words to build... flavor?
He mentions "Dutch angles", which is not a type or measure of an angle like acute or steep which would make sense in the context of bikes, but a tilting of perspective used to increase tension and anxiety in cinema, which makes no sense when talking about actual angles in an item, not even as flavor.
Reply
Joseph Crabtree
5 months, 1 week ago
It's what I call irony.
Reply
fartymarty
5 months, 1 week ago
Justin - they didn't quite get to "Tippability" as I have described above.
Reply
JPR
5 months ago
I don’t know about knee pain, but I know my back pain went away when I went from a 73 seat tube hardtail to a 77. I’m 6 foot and convinced the taller you are the steeper the seat angle needs to be so you’re over the bb and not excessi hinged at the lower back.
Reply
Justin White
5 months, 1 week ago
"If the rider mass stayed back in the old 73 degree (sagged out to 71 or so) zone, then that radical new sub 67-degree head angle would cause the front to push like crazy in the corners, especially with all that fork offset."
Except the rider mass doesn't "stay back" in situations where you have to worry about the front pushing "like crazy" in the corners since you're probably not (arguably should not be) sitting on the seat in those situations. So seat position* is kinda moot there.
*(as Mark pointed out above, the actual position fore-aft matters more than the numbers of the actual or effective seat tube angles, though the angles do limit the range of positions)
Reply
taprider
5 months, 1 week ago
Except riding on flat or less-steep-uphill trails and roads and cornering hard while seated pedalling keeps the weight back. I have crashed in such situations when I tried an angle adjust headset, even after giving it a good try for 10 months, and have since gone back to a neutral headset.
DownCountry originally meant an XC bike for RACING with some extra downhill ability without compromising flat trail agility and uphill speed. Looks like the newer DC bikes are more and more Down and less and less Country (No DownCountry for Old Men)
Reply
Justin White
5 months, 1 week ago
"extra downhill ability without compromising flat trail agility and uphill speed"
And how were they accomplishing that holy grail? More suspension for the DH side and super light and fragile components for the uphill side? More suspension alone doesn't help DH that much, and fragile race-day-only stuff doesn't help the average rider that needs to pay for replacement parts.
Newer DC bikes come from the realization that slackening the head tube angle a bit does not drastically change the climbing experience: that's all from the rear-center and saddle position. Nowadays, we know you can slacken a bike a bit for DH capability without touching climbing, add a little suspension without minimal weight penalty for both DH and keeping climbing as it is, and also add lightness with minimal durability penalty for climbing and keeping the wallet heavy.
Reply
taprider
5 months, 1 week ago
Current XC race bikes pretty much fit the description of the original downcountry bikes
Reply
Pete Roggeman
5 months, 1 week ago
Which is why they should just be called "(modern) XC bikes". All DC does is confuse people because it's a poorly defined category that means different things to different people.
Reply
Kos
5 months, 1 week ago
Nah, the whole DC critique is just internet angst. It makes perfect sense, whatever name the sport wants to choose. XC for 100 mm pure race whips, DC for 115-ish bikes, Trail at about 130, etc., etc..
Gotta call them something. XCM used to seem fine, too.
Justin White
5 months, 1 week ago
"a poorly defined category that means different things to different people"
DownCountry is just another attempt to narrow down the always ambiguous middle ground between the established-but-still-fluid categories. And it helps: DC is generally more relaxed than XC Race whippets, but probably a lighter build than a typical Trail weapon, and people are obviously looking for that. Has also been called:
* (maybe comes with coupons for pumpkin spice lattes, a black fleece pullover, leggings, and a pair of Uggs)
Pete Roggeman
5 months, 1 week ago
I can't reply below both of you, but: I agree that Enduro is also a shitty category name. And that Trail is vague. The problem is over reliance on categories and buzz words and a lack of proper language to describe a bike's intended use. Marketing copywriters in this business are extremely lazy and usually just revert to hyperbolic, unoriginal language. Game changers and 'fire' descenders and 'literally' all over the place. Anyway, a 130mm bike that works on the shore may or may not be the same 130mm bike that works in Colorado. Overlap? For sure. Relying on category markers is risky for an under informed consumer.
The problem with DC is that it blurs the line between light duty trail and XC. We've had at least one test bike come in that was marketed as a DC bike but rode like an (non-race) XC bike, and many more have been offered and declined (partly because DC bikes for other parts of the world just don't work on the Shore).
The concept of DC is fine, it's just that the definition of it doesn't work, because the modern incarnation of it (Levy did not invent the term) was tongue in cheek and basically meant better rubber and brakes on an XC bike. Yet Justin is introducing geo into the conversation about it (obviously a fair evolution of where DC would go after being around awhile now.
Mark
5 months, 1 week ago
@Pete
Yup, people need to ignore all the marketing categorization BS. Talk to people who know bikes really well (not necessarily the sales guy at your LBS) and know how/what you like to ride in order to figure out what will probably work well for you.
I love bikes, but I tend to loathe what the bike industry has become in terms of how it presents itself.
Please log in to leave a comment.