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2 points: I have seen guys with shorter cranks clean sections because they didn't spin out (less torque). Also, you comment that their bottom bracket is obviously too low, but they may view yours as being too high, and suffering handling because of it. You could lower it a little if you didn't use the long crank arms. :p

Everything is a compromise.


I employ long cranks and have noticed that I clean steep up sections that riders on shorter length cranks don’t.

I’m not saying the longer lever saves energy, just that it metes that energy out differently. Personally I like the longer lever but like I said before, in the end it all comes down to personal preference.

I will voice one more opinion about crank length. If someone turns to shorter cranks to avoid pedal strikes, that may be a bandaid instead of fixing the root problem. The truth may be their bottom bracket is too low. Bike fit should trump everything else. Right-size your cranks, then get a frame that accommodates that length crank. Proper length cranks are a matter of bike fit. Just as wheel size, handlebar width, even grip diameter and brake lever size are matters of bike fit. Why should the frame be the only thing that gets larger for taller riders or smaller for shorter riders? Everything should change.

But everything doesn’t change on production bikes because it would too expensive for bike companies to change everything throughout the size lineup of the bikes they offer. That’s one reason I build up my own bikes.

These are my opinions. We each have to make our own way. Everybody do as you will.
=sParty
 

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Everything is a compromise.
Agreed. One of the things I love about cycling is we each get to decide what works best — for us. We’re free to prioritize our choices when building up the machine we want to ride. Cheers!
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No strong opinion about the superiority of proportional cranks (having owned long cranks i think they're a waste of mental energy), but i'm positive that it's less important than BB height and ground clearance. I don't know if i'd want longer cranks if they came with a higher BB........ I certainly wouldn't want longer cranks if the BB height wasn't adjusted accordingly, and the FC wasn't being scaled up with my own height.

I think for production complete bikes it makes more sense to stick everyone on 170s and tune the suspension (and geo) so we're all experiencing the same clearance and travel use. Like all you shorter folk, i'm perfectly fine with turning circles with 165s.
x2....tried 185-165mm cranks and the one thing I didn't see mentioned here is downhill fatigue in the legs (mostly front quad), longer cranks can put more of a strain on that front leg....I definitely don't have to switch my front leg as often w/ the shorter cranks due to less leg burn
 

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I have seen guys with shorter cranks clean sections because they didn't spin out (less torque).
Counterpoint: I see guys trying to spin too low a gear up tech sections and fail (wheel spin, bounced off line, etc) where a bigger gear/lower cadence promotes less wheel spin and the ability to lurch up over obstacles with precisely timed half cranks etc.

To each their own.


Everything is a compromise.
Agree. Seems to apply to pretty much everything in life...
 

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I don't like this game of "longer is better" or "shorter is better" and people going too far with it. Going as long as possible before it becomes too much of a problem seems to be too simple-minded of an action. Enduro racers were cutting back to 740mm bars this year, prompted by some challenges in some courses, and some just kept 'em without moving back to longer ones. Surely, one can learn of this sweet spot without experiencing going too far in either direction? I personally recently learned that 30mm stems compromises a lot in terms of handling on my current bike, and that the sweet spot is around 45-50mm. Someone mentioned that Greg Minnaar said to match your stem length to fork offset, and I wonder if that's just coincidence... technically, 10mm of stem length is worth 20mm of bar width in leverage.

People talk about spinning vs mashing, and relating it to crank arm length... can't you just shift gears if one pedaling strategy doesn't work in a particular section? xD
 

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People talk about spinning vs mashing, and relating it to crank arm length... can't you just shift gears if one pedaling strategy doesn't work in a particular section? xD
Go get a road bike. Put on 170 cranks. Go climb, ride the flats, etc. Then with the same bike and gear ratio, put on 175 cranks and repeat. Report back.
 

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I don't like this game of "longer is better" or "shorter is better" and people going too far with it. Going as long as possible before it becomes too much of a problem seems to be too simple-minded of an action. Enduro racers were cutting back to 740mm bars this year, prompted by some challenges in some courses, and some just kept 'em without moving back to longer ones. Surely, one can learn of this sweet spot without experiencing going too far in either direction? I personally recently learned that 30mm stems compromises a lot in terms of handling on my current bike, and that the sweet spot is around 45-50mm. Someone mentioned that Greg Minnaar said to match your stem length to fork offset, and I wonder if that's just coincidence... technically, 10mm of stem length is worth 20mm of bar width in leverage.

People talk about spinning vs mashing, and relating it to crank arm length... can't you just shift gears if one pedaling strategy doesn't work in a particular section? xD
Solid post.

Can you clarify how running the ultra short stem negatively affected your bike handling? I've been trying to understand what people are so adamant to run ultrashort stems. I run a 60 personally but I did it to extend my effective reach. Are you saying that when you have a longer stem, it gives you more leverage over the bars, and therefore makes the bike more twitchy? Trying to understand.

I'm 5-11 and run 740mm bars, I think it's a perfect fit I've tried the longer bars I just don't get it. I even have a spare set of carbon fiber 740 bars on the shelf and I can't sell them because people seem to think they are too short.

Also I did another ride on my slightly shorter cranks, and I'm a huge fan. It's not that this is the only change, but over the last 6 months I went from being a pretty weak climber to a darn strong climber. The 170 cranks was certainly part of the puzzle for me. It was a big part actually.

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Buy a High engagement rear hub and practice when to not pedal. This will let you run whatever crank arms you like.


I have always run 170s because I have a 29 inch inseam. Also, moving up to 175s would put my Thighs 1CM higher into my stomach and make. No thanks.
Me, too, 29" inseam. But I have relatively longer torso so I'm actually on a medium Yeti (felt better than the small).

I just had my second ride on 170 cranks after years on 175. I'm never going back. And I'm not a short guy. I'm just clearing stuff that I've been trying to clear for 2 years and I could not do it, I thought I needed to be more fit but I'm going right up the same stuff with just a crank change.
It felt a little funny on the first ride at first, it's all completely normal on this ride, I couldn't even tell that the circle was slightly smaller.

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How tall are you @Suns_PSD? Think I will start with 170s as that's what I have on my road bike. My knees do hurt with the 175s but thought it may be other things...
 

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Solid post.

Can you clarify how running the ultra short stem negatively affected your bike handling? I've been trying to understand what people are so adamant to run ultrashort stems. I run a 60 personally but I did it to extend my effective reach. Are you saying that when you have a longer stem, it gives you more leverage over the bars, and therefore makes the bike more twitchy? Trying to understand.

I'm 5-11 and run 740mm bars, I think it's a perfect fit I've tried the longer bars I just don't get it. I even have a spare set of carbon fiber 740 bars on the shelf and I can't sell them because people seem to think they are too short.

Also I did another ride on my slightly shorter cranks, and I'm a huge fan. It's not that this is the only change, but over the last 6 months I went from being a pretty weak climber to a darn strong climber. The 170 cranks was certainly part of the puzzle for me. It was a big part actually.

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There's many types of turns. There's quick banked turns, longer high speed bermed turns, sharp 90d turns in soft dirt, sweeping flat turns, long arcing turns, chicanes (zig-zag turns), uphill switchbacks, downhill switchbacks, off-camber turns with deadly exposure, etc. and a skilled rider has a large pool of various skills that they can opt to use for each based on the circumstances. Twitchy might compromise with stability in long arcing turns, while it can help with flat ground turns where you're upright and in the saddle, squeezing between trees and boulders, or getting your tire to thread some needle-like line. Going too far put me out of the comfort zone for certain types of turns, and decided I'd rather have a compromise that wasn't biased more to one type. I was "understeering", going wide off of the trail, on bigger sweeping turns, possibly due to correcting my angle from being too tight. Even putting over 100 miles to adjust my steering sensitivity didn't really do much to correct it. Going to back to 45mm (was using 50mm before 30mm) and pretty much I don't think about steering*, and instead think about refining my technique for different entry speeds, to push for even more speed to connect one turn to the following section. *no longer have probs going wide off the trail

There's also an issue with knee pad clearance with stems. On banked uphill switchback that is fast and sort of flowy, my kneepads were banging into the bar's controls as I was pedaling with my bars turned a little past 45d. This was the clinching factor in deciding that 30mm wouldn't work on my current bike. The bike has 20mm more ETT/reach than my last bike. My last bike I ran with 50/60mm.
 

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Me, too, 29" inseam. But I have relatively longer torso so I'm actually on a medium Yeti (felt better than the small).



How tall are you @Suns_PSD? Think I will start with 170s as that's what I have on my road bike. My knees do hurt with the 175s but thought it may be other things...
I'm 5'11" with I think a 31.5" inseam.
Check out the Bike Dynamics UK website. They have some pretty sophisticated formulas for calculating the correct crank length for your body. It put me at about a 171-172 crank as being ideal for me.

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As far as why the shorter cranks are working well for me, I'm just guessing that for your feet to move the same speed you're carrying a little faster cadence because the size of the circle is a bit smaller. It doesn't feel like I'm spinning faster. I think that extra cadence just carries me over stuff, that's my guess. It honestly feels like I have additional torque like I have more power but I know that's not the case with a shorter lever.

I rode out at a place today, and granted I haven't been there in a long time. But there's a long series of climbing switchbacks that go on for 10 minutes or so, and I recall I could never even come close to making it in the past. I was dabbing getting stuck on the switchbacks, feeling exhausted. Well twice today I just motored right up it. Now for certain cranks are not the only thing that has changed about my mountain biking. For the most part other people are slowing me down on climbs lately, including riders that are just better all-around riders than I am . This part is pretty significant to me, because I was just always the poor climber, I was always the guy having to walk. It's just not the case anymore.

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I'm 5'11" with I think a 31.5" inseam.
Check out the Bike Dynamics UK website. They have some pretty sophisticated formulas for calculating the correct crank length for your body. It put me at about a 171-172 crank as being ideal for me.

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Thanks, will take a look.
 

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Can you clarify how running the ultra short stem negatively affected your bike handling? I've been trying to understand what people are so adamant to run ultrashort stems. I run a 60 personally but I did it to extend my effective reach. Are you saying that when you have a longer stem, it gives you more leverage over the bars, and therefore makes the bike more twitchy? Trying to understand.
There's three components that I can think of, effective lever length(ELL), fore/aft weight position and hand position along the steering arc. A setup with long stem/short bars and a setup with short stem/long bars where the ELL (distance from your hands to steering axis) is equal, should be about equally twitchy (same 'steering speed'). One advantage of short stem/wide bars is that you can keep your body center of mass nearly the same as with long stem/short bars by keeping the effective reach the same but when you are applying force to the bars it's easier to lift the front end (you're more in a deadlift form with the short stem) and you're less likely to go OTB since the bars you're putting your weight on are further behind the front wheel. The last thing, which I don't see mentioned much, is hand position along the steering arc. Ever see a modern race car steering wheel? Most are not wheel shaped anymore because racing drivers always position their hands at 9 and 3 o'clock for the greatest control. You're not going to see a racing driver with their hands positioned together at the top of the wheel (i.e. long stem/short bars) for the same reason you wouldn't position your hands that way to open a wheel valve, you'd put your hands opposite of each other. With a given ELL wider bars give greater control. That of course doesn't mean everyone should run 1000mm bars, it has to work ergonomically too. Also, stems can get so short that the backsweep of the bars causes your hands to move behind the steering axis with increases ELL just like running a longer stem would.
 

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Me, too, 29" inseam. But I have relatively longer torso so I'm actually on a medium Yeti (felt better than the small).



How tall are you @Suns_PSD? Think I will start with 170s as that's what I have on my road bike. My knees do hurt with the 175s but thought it may be other things...
I do too. I'm barely 5'9 and my wingspan is a lil over 6'. (34 sleeve) I typically ride smalls that come in 16" with a setback of 25mm on the seat. Mediums always feel boarderline too large.

I'm curious which Yeti you are on. I may build a 4.5 this year, and I think I could go either way. When I sit in the small, it feels like my current bikes which is pointing me towards a small again. But that's with wide bars and I know when I go down to a narrow bar, things could get more cramped.






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There's three components that I can think of, effective lever length(ELL), fore/aft weight position and hand position along the steering arc. A setup with long stem/short bars and a setup with short stem/long bars where the ELL (distance from your hands to steering axis) is equal, should be about equally twitchy (same 'steering speed'). One advantage of short stem/wide bars is that you can keep your body center of mass nearly the same as with long stem/short bars by keeping the effective reach the same but when you are applying force to the bars it's easier to lift the front end (you're more in a deadlift form with the short stem) and you're less likely to go OTB since the bars you're putting your weight on are further behind the front wheel. The last thing, which I don't see mentioned much, is hand position along the steering arc. Ever see a modern race car steering wheel? Most are not wheel shaped anymore because racing drivers always position their hands at 9 and 3 o'clock for the greatest control. You're not going to see a racing driver with their hands positioned together at the top of the wheel (i.e. long stem/short bars) for the same reason you wouldn't position your hands that way to open a wheel valve, you'd put your hands opposite of each other. With a given ELL wider bars give greater control. That of course doesn't mean everyone should run 1000mm bars, it has to work ergonomically too. Also, stems can get so short that the backsweep of the bars causes your hands to move behind the steering axis with increases ELL just like running a longer stem would.
Yep, steerer to grip length is the measurement that matters. Every 10mm of stem is worth 20mm of handlebar.

What problem does having hands behind the steering axis cause? I've tested this, not with a 0mm/10mm stem like Mondraker testers did, but with a stem pointing backwards, and didn't really notice any steering issue besides the one caused by new body positioning.

Do race car drivers twist their arms in sharp turns, or is their steering sensitivity turned up? I can't even manage turning the wheel any more than 2/3 of a revolution. xD

OTB is caused more by lag in the front end, from flexy parts. The force of a wheel suddenly stalling in a nook, and having all that force wound up in fork flex, tire and wheel flex, and handlebar and headtube flex, will give enough time for your body's inertia to continue moving forward. People back then countered it by just getting low and behind the bars. New XC bikes with stiffer parts do a lot better than bikes with the same geo back in the day, less punishing to casual upright position.
 

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Seriously? You beleive that "flexy parts" are the cause as opposed to weight bias?
Yes, more of a statement than a belief. Ride a cheap bike with the same technique as you ride a modern stiff bike, and you'll see what I mean. Care to challenge it with some science? Newton's First Law is a solid place to start, but I'm open to hearing some quantum theories which seem to contest such laws...
 

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Yes, more of a statement than a belief. Ride a cheap bike with the same technique as you ride a modern stiff bike, and you'll see what I mean. Care to challenge it with some science? Newton's First Law is a solid place to start, but I'm open to hearing some quantum theories which seem to contest such laws...
Whoa that's a crazy misdiagnosis! OTB is all about your center of mass relative to the fulcrum... err, front axle. Move the center of mass past the tipping point and you tip over.
 

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Do race car drivers twist their arms in sharp turns, or is their steering sensitivity turned up? I can't even manage turning the wheel any more than 2/3 of a revolution. xD
The steering ratios are such that they don't have to turn the wheel more than a max of about 180* (if that).
 

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Yes, more of a statement than a belief. Ride a cheap bike with the same technique as you ride a modern stiff bike, and you'll see what I mean. Care to challenge it with some science? Newton's First Law is a solid place to start, but I'm open to hearing some quantum theories which seem to contest such laws...
It's caused primarily by weight distribution.

Adaptive Map - Slipping vs. Tipping
 
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