This became very apparent as I struggled up the Tournmalet in the summer at about 3rpm. Would a more open knee angle through the dead spot at the top of the stroke and maximum torque further down the stroke reduce the sheering stress and the amount of force required to move the pedal? We based our calculations on the average saddle height of average sized riders who would normally use mm or It is not fool proof because femur length and foot size also get involved but the actual difference of 1.
See table below:. Unfortunately I have had the opportunity to ride up any mountains yet, Mallorca will be the first climbing test and in the mean time I will get some 'power' data.
The handlebar drop is reduced as the bike travels up hill and this combination results in a reduced angle at the hip; shorter cranks help maintain an open hip angle which aids leg tracking integrity for riders with a limited hip inflexion range. Well there is less torque generated by a shorter mm crank so I'm told but more force is required to drive a mm crank for two reasons: shorter levers i. I can subjectively say that one balances out the other.
Riding over wet grass for instance at a lower cadence is no harder than with longer cranks. Where the shorter crank is noticed is when a surge is required to increase speed, where in the past I would click up a couple of gears and push down hard I now increase cadence before changing up, but there is less need to get out of the saddle.
Steep seat angles and forward saddle positions are it seems improving pedalling bio mechanics for triathletes and David Green of Elite Cycles has always advocated shorter cranks for triathletes 'Pedal fast, run fast' he would say - a shorter crank encourages use of a lower gear and higher cadence. The other advantages such as better bio-mechanical efficiency, open up more hip angle for more aero position etc.
I think you can read everywhere. Post by TobinHatesYou on Tue Dec 31, pm I'm cm and use mm cranks and would consider mm cranks if more options were available. In addition to what's already been mentioned, I can pedal through corners at slightly more aggressive angles which is a huge boon when trying to be as efficient as possible in crits. Post by wheelsONfire on Tue Dec 31, pm Perhaps it's a learning curve, i tried mm and mm. But i sometimes think that when on the, upstroke, it would be a great advantage.
All my cranks are Post by dudemanppl on Tue Dec 31, pm I'm the same height and went from First ride on it will feel weird but afterwards feels just like riding a normal bike. I have a slight hip inpingement issue and cranks are great and I'm still able to hit the same max power, although you have to focus on pedalling technique more with a short crank while sprinting.
Post by RossLB on Tue Dec 31, pm I'm a similar height and recently went from mm to mm cranks on all my bikes. The main reason was to try to prevent some intermittent knee pain, and that seems to have been successful. I now prefer the mm cranks, and have found no real difference in power output, but it does feel more comfortable for my relatively shorter legs.
Remember to raise your saddle 5mm to compensate. I'm about cm I don't know much about using a longer crank on the ROAD, but my Fatbike has mm and use it primarily on a flat gravel trail.
Take me out on a hilly route and my cadence decreases heavily. On road I'd average about 90rpms and have built my power with high cadence. That's the benefit for me primarily. Con for me: I cant produce power at a lower cadence. But there is more to cycling than simply generating power.
There is the demand of maintaining a highly repetitive activity for long periods in the context of fluctuating loads. The bicycle itself is a highly symmetrical machine while the human body is typically asymmetrical, so the potential for uneven loading is enormous and injuries are common.
In fact, a high proportion of cycling injuries relate to overuse for both recreational and professional cyclists. This is where the optimisation of crank length becomes important. While the position of the saddle can be adjusted to suit the overall reach of the legs, the length of the cranks largely dictates the range of motion. As a result, bike-fitters have come to view crank length as an important parameter that can be optimised for every individual, regardless of whether they own a factory-built bike or are selecting the parts for a custom road bike build.
The current market offers a pretty generous range of crank lengths, starting as short as mm and extending to mm, often in 2. In addition, there are a few manufacturers offering custom-built cranks outside this range, so it is possible to fit significantly shorter e. Thus, there are plenty of products available for optimising crank length, but how does a rider to decide on a specific length in the first place? While it is generally acknowledged that crank length should increase with the height and leg length of the individual, the exact association remains vague at best.
A variety of other formulae have been proposed over the years ranging from simple equations to more complicated approaches. Each formula is an attempt to describe an association between measurable parameters e. Nevertheless, they have found favour because of the ease they offer, but in strict terms, they do little to settle the matter.
Most of these formulae fail to consider this at all, effectively isolating the issue from all other considerations, and for this reason, it is probably best to view any result as theoretical at best. While any of these formulae might provide a starting point for further investigation, it makes more sense to get some advice and direction from an experienced bike-fitter, if only because cranksets tend to be quite expensive.
Stewart Morton has over 10 years experience as a bike-fitter and he still considers crank length a can of worms. Cranks are measured from the centre of the pedal axle to the centre of the bottom bracket spindle. Lengths most often range from mm up to mm, in 2.
Yet, thinks Phil Burt, we should consider challenging this status quo. And he should know, having spent 12 years as head of physiotherapy at British Cycling and five years as lead physio and consultant to Team Sky.
He was on similar for his Hour record.
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