Negative effects of shorter cranks

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lighht
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Joined: Thu Feb 22, 2024 5:01 am

by lighht

I'm asking more from the perspective of someone who is over 6'2 (190cm+) since this short crank buzz seems to be for shorter people. Or is that not true?

TobinHatesYou
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by TobinHatesYou

lighht wrote:
Fri May 17, 2024 4:25 am
I'm asking more from the perspective of someone who is over 6'2 (190cm+) since this short crank buzz seems to be for shorter people. Or is that not true?

Arithmetic suggests someone with an 82cm inseam riding 140s is roughly equivalent to someone with a 93cm inseam riding 160s

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Jaisen
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by Jaisen

lighht wrote:
Fri May 17, 2024 4:25 am
I'm asking more from the perspective of someone who is over 6'2 (190cm+) since this short crank buzz seems to be for shorter people. Or is that not true?
I'm 192 cm and recently swapped from 175mm to 170mm. For the most part I haven't noticed much of a difference at all. Maybe on flats my cadence is a little bit smoother and faster (big maybe). Out of the saddle climbing feels tiny little bit different, but if I just shift one or two cogs down on the cassette, it feels pretty close to before. Whatever difference there is, it is very subtle and I am usually very sensitive to changes in equipment or fit. :noidea:

NordicSal
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by NordicSal

TobinHatesYou wrote:
Fri May 17, 2024 4:48 am
lighht wrote:
Fri May 17, 2024 4:25 am
I'm asking more from the perspective of someone who is over 6'2 (190cm+) since this short crank buzz seems to be for shorter people. Or is that not true?

Arithmetic suggests someone with an 82cm inseam riding 140s is roughly equivalent to someone with a 93cm inseam riding 160s
So if like us like +100 cm 175-180's is the place to be?

satanas
Posts: 368
Joined: Sat Jul 04, 2020 5:45 pm

by satanas

You need to figure out what's causing the knee problem and address it; this is where a good bike fitter comes in. The crank length may be totally irrelevant - the issue could be cleat alignment, leg length differences, excessive pronation or supination, etc.

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pdlpsher1
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by pdlpsher1

satanas wrote:
Sat May 18, 2024 1:18 pm
You need to figure out what's causing the knee problem and address it; this is where a good bike fitter comes in. The crank length may be totally irrelevant - the issue could be cleat alignment, leg length differences, excessive pronation or supination, etc.
You could be right but the most likely cause is simply old age. A person may still experience pain even with a perfect fit. Our bodies aren't designed to last forever, unfortunately. I have a chronic back pain. My surgeon said he could operate on my back to relieve the pain but he can't reverse the damage aging has done, and that the chance of the pain coming back is pretty certain as I age more.

satanas
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by satanas

True enough; I'd really like a few new body parts, but it's not going to happen. :-(

Having said that, a visit to Steve Hogg sorted out lots of seemingly permanent issues with some relatively small adjustments. You do need a *good* fitter though, one with biomechanical knowledge, not someone who just works off formulae and statistical averages.

charirider
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by charirider

I am 6 feet tall (183cm).
Changed from 172.5 to 170mm cranks and couldn't be happier.
2018 Cannondale SuperSix EVO 2 rim size 56 (raw stripped) 6.8kg
2014 Bridgestone Anchor CX6 Equipe size 55 (cyclocross) 9.6kg

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pdlpsher1
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by pdlpsher1

satanas wrote:
Sun May 19, 2024 1:58 am
True enough; I'd really like a few new body parts, but it's not going to happen. :-(

Having said that, a visit to Steve Hogg sorted out lots of seemingly permanent issues with some relatively small adjustments. You do need a *good* fitter though, one with biomechanical knowledge, not someone who just works off formulae and statistical averages.
I wasn't trying to devalue your suggestion on getting a bike fit. I'm a big advocate to a good bike fit. But the sad reality is that sometimes we can't cure the rootcause and short cranks can help manage the symptoms.

I have my family (three out of four people) fitted by Ivan O'Gorman at IOG. Highly recommended.

https://www.ivanogorman.com/

CR987
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Joined: Sun Jan 26, 2020 10:37 am

by CR987

It will be interesting to see how many pros move to shorter cranks by the time le Tour rolls by . The oval crank ring thing slowly died, I wonder where this will settle in the pro peleton

TobinHatesYou
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by TobinHatesYou

CR987 wrote:
Sun May 19, 2024 7:48 pm
It will be interesting to see how many pros move to shorter cranks by the time le Tour rolls by . The oval crank ring thing slowly died, I wonder where this will settle in the pro peleton

It's pointless to compare short cranks to oval chainrings.

1) There are plenty of studies supporting that aerobic efforts are not hampered by short cranks unless you go ludicrously short (as I have experimented with.) In contrast there is no credible research showing oval rings having a major impact on trained cyclists.
2) Short cranks have obvious real-world benefits. They allow for more aero positions, they reduce thigh/tummy interference at the top of the stroke. They lower the chance of pedal strikes. Oval rings on the other hand make for less reliable front shifting, and it might overwork the clutch on an AXS FD.

CR987
Posts: 180
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by CR987

I don't understand the aero benefit, your seat height is higher so you're bent over more to get to the bars. This can be achieved by lowering your bars, either by removing spacers or a negative stem.
Also, the same 'research' showed plenty of benefits to oval rings (that's why so many people bought them).
Research on crank length is also inconclusive. That's why I made the comparison. Froome did ok on oval rings and Poggy is doing ok with 165's

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cyclespeed
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by cyclespeed

CR987 wrote:
Mon May 20, 2024 2:59 pm
I don't understand the aero benefit, your seat height is higher so you're bent over more to get to the bars. This can be achieved by lowering your bars, either by removing spacers or a negative stem.
Also, the same 'research' showed plenty of benefits to oval rings (that's why so many people bought them).
Research on crank length is also inconclusive. That's why I made the comparison. Froome did ok on oval rings and Poggy is doing ok with 165's
Imagine drawing a straight line down the torso of a cyclist. Commuter will be at about 75' or 1130h on a clock. Amateur cyclist maybe 45' or 1030h on a clock.Pro cyclist maybe 30' or 10 o'clock.

As the angle drops, so your back flattens.The 'V' between your torso and your waist/legs, which traps a lot of air, starts to close. So that is all good for aero.

Raising the saddle achieves this. So does dropping the handlebar, but most pro racers already have it slammed. So raising the saddle helps flatten your back and reduce the frontal area that your torso presents to the oncoming air.

toxin
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by toxin

Eh thats a bit overstated unless your mobility is truly awful, just being lower and redung the frontal area of your legs is generally more advantageous. That's why keeping your saddle height the same or even lowering it slightly, as tobin suggests, isn't the worst idea. Look at bigham's track position. Even ganna has relaxed his position slightly in recent years

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pdlpsher1
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by pdlpsher1

This article has some animations to show the effects of short cranks on a rider's position. The pelvic/hip rotation is key. The position changes might seem small on the animation but the 'as felt' effect on the bike is huge.

https://www.applemanbicycles.com/resour ... nk-length/

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