Current Projects chat and miscellany

Spotter is the go to guy for bar inspiration.

Too kind

That^ needs qualifying slightly- "Spotter is the got to guy for modern bar inspiration"

I give up trying to understand crank length as I've been thoroughly confused and slightly pissed off over being treated like an idiot.

I'll possibly change my cranks down to 167.5mm Omniums when I next have some money just to negate toe overlap.

Least then I'll be able to test it out using the same gearing and by personal experience.

I give up trying to understand crank length as I've been thoroughly confused and slightly pissed off over being treated like an idiot.

There is nothing to understand, just remember that it doesn't matter (unless you have very short legs) which length of Omniums you buy. I'd actually suggest getting 165s, just because that avoids argument if you go to one of the indoor velodromes which needlessly insist on them. Plenty of people here have a range of cranks lengths on different bikes and don't even notice when they switch. Reading left to right in my bike park at moment, I have 175, 170,175,170,175.170,165,175,177.5

If it's any consolation, you came out of the discussion looking much less idiotic than some other people.

I always buy track cranks in 165mm as you can always sell them for "good price"- have a look on eBay, there is a significant discrepancy in price between the "everyone wants them" 165mm and the unfashionable 170mm ones.

As I've said before, I've gone round Herne Hill on my road bike, with 175mm cranks and been nowhere near grounding a pedal.

Of course, I have no experience of other tracks- but then my "track" bike is used to commute in London, so it's not that relevant really.

I do always buy 175mm cranks for my geared bikes, force of habit there really- plus the size of frame I buy is always specified with 175's

I've gone round Herne Hill on my road bike, with 175mm cranks and been nowhere near grounding a pedal.

Of course, I have no experience of other tracks

I've been round Calshot, slowly, with 175s. It is possible to ground them, but only if you turn right on the steep bit of the banking with the drive side pedal down.

I always buy track cranks in 165mm as you can always sell them for "good price"- have a look on eBay, there is a significant discrepancy in price between the "everyone wants them" 165mm and the unfashionable 170mm ones.

Oh, and ^this^ is easily the most compelling argument for selecting crank length.

I used to ride with 175 cranks on steep tracks. It gave me a good guide of how slow I could go on the track. All I ever did was scuff the edge of the shoe.

^ Cowley Road?

... Reading left to right in my bike park at moment, I have 175, 170,175,170,175.170,165,175,177.5
...

That has to be quite a niche length doesn't it.

Yes I did read your post, but as I was still trying to understand, I asked for clarification.

Sorry, that statement needed a smiley or something, I wasn't actually irritated or anything.

beagle smiley

Glad we got that sorted. You're both wrong.

If gain ratio is held constant, crank length is irrelevant over a wide range. It's irrelevant to acceleration rate, and irrelevant to constant speed.

The problem I have with this statement is that various people have done supposedly scientific tests and come to a different conclusion to this.

They may well be wrong, but you're not providing any evidence to back up your assertions. I don't expect you to do your own tests, although I'm sure they would be interesting, but you could at least provide some basis for your assertions. Otherwise it's just someone on the internet telling people they're wrong, which I tend to be wary of.

However, you have convinced me it's not worth worrying about too much and I will just go for 170mm for the new road bike and save fifty quid, I'm quite happy with that outcome so thank you for that...

Found a 167.5 here. exotic

I did an eBay oops. One more week and it'll have a more HHSB build.

off to a good start.

found a 167.5 here. Exotic

167.5 ftw!

Sorry, that statement needed a smiley or something, I wasn't actually irritated or anything.

Fair, thats why I tend to use lots of them, the finer points of expression being quite difficult with the written word, at least without being a poet, which I won't kid myself I am. :P

The problem I have with this statement is that various people have done supposedly scientific tests and come to a different conclusion to this.

They may well be wrong, but you're not providing any evidence to back up your assertions. I don't expect you to do your own tests, although I'm sure they would be interesting, but you could at least provide some basis for your assertions. Otherwise it's just someone on the internet telling people they're wrong, which I tend to be wary of.

However, you have convinced me it's not worth worrying about too much and I will just go for 170mm for the new road bike and save fifty quid, I'm quite happy with that outcome so thank you for that...

As far as I have ascertained so far (I think) as long as the gain ratio is constant crank length doesn't matter too much, as the leverage is in effect the same as is foot speed and movement.
But, cadence is a factor, smaller cranks can get upto speed quicker and spin easier at a higher RPM, but longer cranks make it easier to maintain a lower but more stable RPM cadence?
Which was kind of what I was getting at with the diesel Land Drover and nippy hatch back analogy.
Could also be referred to size of spinning tops, smaller tops can go very fast and accelerate quickly, but are innately unstable, whereas a table sized (I know the scale is wrong!) spinning top will be stable for far longer but at a slower speed and rate of acceleration.

How am I doing so far?

The question is - will you notice the change? or will it be a placebo effect?

I'm starting to see why Tester says its pointless with regard to power output, as there would be no difference.

But power output can be used in different ways, and for someone constantly stop/starting in a city, 165mm cranks might be a help as its literally moving less weight each rep, but you'd probably have to cycle going on a century a day for it to be of any noticable benefit, and likewise for someone touring, or spending virtually all day at a constant cadance with few stops, the additional weight would act a bit in principle like a fly wheel.

Might be a help, but it's the equative of eating half a polo mint expecting it to give you 5% extra power on the Col du Pentonville.

Will you feel it?

Exactly.

Seriously of all the bicycle adjustment (saddle height, angle & fore and aft positon, bar angle, cleat position, gear inches, stem length, saddle to bar drop, etc.), the crank lengths is the least of your concern.

Going from 165 to 170 made big difference in comfort for me.

No where near as tight or restrictive in rotation.

So does lowering the saddle 5mm.