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Hello everyone,
I'm currently planning to buy a new groupset for one of my bikes. It's a road bike and I'm going to buy Shimano 105.
I'd normally just pick 175mm crank length. But a friend has recently had a bike fit and the guy told him that crank length is related to leg length and Knee articulation.
So how do I choose WITHOUT getting a bike fit session???
how big are you?
Which ever is cheaper out of 175 & 172.5 when I order! I have a mix of both on MTB and on road bikes, no ill effect from either. Not sure I notice the difference tbh.
5' 11" tall - so somewhere between the 172.5 and 175????
Depends on leg length, really. I went for a bike fit and he dropped me from 172.5 to 165 and the difference was amazing. More power, easier to keep a higher cadence and more comfortable on long rides.
I’m 5’10” but with short legs (29” trousers). My MTBs still have 175mm that they came with but I’m going to swap them out.
Ride til you clip a pedal and have a massive crash
Blame the crank length not your own stupidity
Get 5mm shorter, as if it makes any difference
Repeat until you have 5mm long cranks
If in doubt, go for the shorter option. 170mm
Interesting to read that you think that going to a shorter crank gives you more power (I'm assuming you're using a power meter and have done back to back power tests to back this up?)
[url= https://www.trainingpeaks.com/blog/the-benefits-of-reducing-your-crank-length/ ]This[/url] is an interesting read on the effects of crank length.
TL;DR crank length won't increase your power biomechanically although if it fits better then you can potentially output more power. In short, get a proper fit or just get the length that feels comfortable.
If in doubt, go for the shorter option. 170mm
+1
I've gone shorter over the years. A lot of it is flexibility and personal preference. The power thing is a red herring.
I have found I'm more comfortable with 170mm your mileage, knees and [i]Powah[/i]! May vary...
The pro tour are getting shorter and shorter
"sort by cost:low to high"
I have to say I don't actually know the crank length of any of my bikes. I am average size tho so I suspect average sized cranks are just fine
I'm average sized (well, slightly over i think) and average sized cranks are too long. Going down from 170 to 165 on the road bike has improved everything, starting with comfort. Finishing with speed. Having passed through power output and aerodynamics. I know a few other guys local to me are experimenting as well. No one has said it's caused a problem, a couple have found it more comfortable. One (a triathlete) is using 150 or 155s on his race bike and 165s for everything else (i guess 3 sets of short cranks were even too expensive for a triathlete!)
Most of the trend for longer cranks is either misplaced fashion sense, or bad engineering. You just have to look at Adam Hansens interview/comments, he, and his engineering buddy have made some fairly significant errors in calculation, and physics, to get to his 180mm crank length. It might be comfortable for him, and not cause him any issues, but his reasoning is pretty crap.
As above, it's not about power but bout comfort.
There really should be crank length options from 150mm to 180mm, but industry standards and economics resist this. So most cranks at 175mm are for someone around 5'11" tall.
Weeeeellll....
Everyone on a velodrome rides with 165mm cranks and the big riders don't seem to suffer a disadvantage.
I'm 6'0" (with short legs), and I'd run 165mm across everything if it wasn't going to cause a massive faff/expense.
If in doubt, go for the shorter option
I have some [b]155mm[/b] cranks. They are dreadful 😀
Interesting to read that you think that going to a shorter crank gives you more power
It might do. Power is a combination of how hard you push on the pedal and how fast you can turn the crank. If you can turn the crank faster with a shorter crank then you may very well generate more power. Depends how quickly you can move your legs while maintaining the pressure on the pedal. If you struggle to achieve high cadences then a longer crank would be more beneficial, but if you are able to achieve and maintain higher cadences then a shorter crank might work better for you.
For the majority of us I don't think we're that sensitive to crank length within the 10mm - 15mm variation of commonly available standard crank lengths.
Im 5'7" and have found that shorter cranks work better for me, especially climbing. I can definitely feel the difference between 165mm and 175mm on the same bike.
Makes sense. shortarses need short cranks for their wee diddy legs. Normal sized folk are fine with normal sized cranks, giants need giant cranks.
have some 155mm cranks. They are dreadful
I found 155mm pretty good for my arthritic knees, although they felt decidedly odd when out the saddle. So they're now on my recumbent. On the upright bikes, I reckon 160mm is about optimum for me, although I have 165 on the best bike as quality 160s are hard to get. I'm 6ft, for the record.
For road go smaller it allows you to be more comfortable down on the bars. Also short leg here. 170 on road bike, just right for me and Id be tempted lower next time. Riding down on the bars not the hoods saves a huge amount of power. Get comfortable there and you will save a large amount of energy. You can google for results. Don't ride on the hoods kids!
Whichever is on sale
It's not just about pedalling either, I went to 165s on the dh bike for fitment reasons mostly, but it always felt really weird to me with flat pedals, just because my stance was shorter.
I made the initial comment about power above and this was whilst on a bike fit. I was keeping a constant cadence and had to up the resistance once the bike fit guy had adjusted the cranks to 165mm to maintain the same cadence, otherwise it was just spinning out. We actually looked at the power data and it was up quite a bit with the shorter cranks.
I’m not saying that is best for everyone, it is for me though.
leg length / 5
we can buy all sorts of bike parts, in all sorts of sizes.
you can buy XS frames, all the way up to XL frames. even smaller/bigger if you want.
stems? 35mm to 150 and beyond!
tyres? 22mm to 5" monsters.
all good, choice is good.
cranks? 165-175mm. a whopping 5% difference.
if bike-fit is important, and it is, then surely crank length plays a huge role in that?
fwiw, MsWife has (modified) 140's on her tiny bikes - that came fitted with 175's...