Crank length

[mickle]

Centre to centre. The difference between 170 & 175mm is minimal. You won't notice it.

I bought a Saracen Conquest many years ago which had been fitted with a 175mm and a 170mm crank from the factory. I noticed. It took me a while, but I noticed. It's 10mm across the diameter of the circle described by the pedal axle, which is no small amount in terms of saddle height.

But you're probably right that it would be very difficult to tell the difference in a blind test between a bike fitted with a matching set of 175s versus 170s.

 

[Yellow Saddle]

I bought a Saracen Conquest many years ago which had been fitted with a 175mm and a 170mm crank from the factory. I noticed. It took me a while, but I noticed. It's 10mm across the diameter of the circle described by the pedal axle, which is no small amount in terms of saddle height.

But you're probably right that it would be very difficult to tell the difference in a blind test between a bike fitted with a matching set of 175s versus 170s.

Now there's an interesting one. If it wasn't for the saddle height problem it would be interesting experiment but alas, you noticed because of that. Years ago we had a guy on one of these forums who had a leg length discrepancy and the discussion was about shims under his shoes and all that. I suggested two different crank lengths and that was discussed up and down, left and right, with no formal conclusion. Then a (claimed) orthopaedic surgeon climbed in and pee'd all over my battery and said it wouldn't work. I asked why, and he disappeared from the thread. I still wonder, why won't it work? He with the 10mm leg discrepancy never experimented with it and went the appeal-to-authority route. To this day I still want to analyse this but on the internet, everyone can be an othopaedic surgeon.

 

[cyberknight]

Centre to centre. The difference between 170 & 175mm is minimal. You won't notice it.

oddly i do notice it , mind you i notice if my saddle drops 2 mm

 

[Paulus]

I have 175mm cranks on all of my bikes, except a Raleigh Royal which I bought and fully refurbished. That has 170mm cranks and although it is only a 10mm difference a full rotation of the cranks I can notice the difference in cadence in all the gears.

 

[Deleted member 89023]

I bought a Saracen Conquest many years ago which had been fitted with a 175mm and a 170mm crank from the factory. I noticed. It took me a while, but I noticed. It's 10mm across the diameter of the circle described by the pedal axle, which is no small amount in terms of saddle height.

But you're probably right that it would be very difficult to tell the difference in a blind test between a bike fitted with a matching set of 175s versus 170s.

That is what I meant. I recently replaced a 175mm with a 170mm crank and couldn't tell any difference. I await more clever dick responses.
With attack and counter attack this is becoming more like X/Twitter every day. Any idea how to delete an account?

 

[mickle]

That is what I meant. I recently replaced a 175mm with a 170mm crank and couldn't tell any difference. I await more clever dick responses.
With attack and counter attack this is becoming more like X/Twitter every day. Any idea how to delete an account?

Chin up mate.

 

[Dogtrousers]

Off topic but this reminds me of a rather weird cycling program that was on TV a while ago. In it two italian ex-pros (Paolo Savoldelli and Massimo somebody) cycled up famous climbs chatting to each other aimlessly about this and that. It was in Italian (naturally) and dubbed on the cheap, so one bloke did both voices, which was a bit odd.

Anyway, in a desperate attempt to keep the conversation going, at one point they spent around ten minutes rambling on about the preferred crank lengths of different riders from back in the day, with special reference to Miguel Indurain (very long cranks apparently). It was dull, but in a hypnotic way. I watched it a lot.

I also recall a story about a mechanic getting into deep doodoo for fitting the wrong length cranks to Mark Cavendish's bike. Whether he fitted odd lengths or just matching cranks that were not of Cav's preferred length I don't recall. I imagine that the professionals probably can notice such things.

 

[Sharky]

Leverage on a bike has many variables.
Wheel size, crank length, chain ring, sprocket.

If you change any of these, you automatically compensate by changing one of the others, so that the perceived effort is the same.

Changing crank length also can change the knee and hip angles and can be beneficial to some.

 

[Ajax Bay]

Any idea how to delete an account?

Looks like they got the idea they sought.
@nmfrb70's wisdom lost to the chat. Though a discussion about whether some riders can or can't tell a 5mm difference in crank length does seem a low threshold.

 

[presta]

Of course, there has been the view that if you're serious, even 5mm. can make a lot of difference in spinning comfort & efficiency.
Personally I can't see it, but there are those that claim it does - !

I very much doubt I'd notice the difference in feel, but my toes just touch the mudguards with 170mm, so I'm not about to try 175.

 

[C R]

Looks like they got the idea they sought.
@nmfrb70's wisdom lost to the chat. Though a discussion about whether some riders can or can't tell a 5mm difference in crank length does seem a low threshold.

Poor flounce technique, if you ask me, 4 out of 10, could do much better.

 

[twentysix by twentyfive]

Whatever happened to 172.5 mm cranks?

 

[Dogtrousers]

Poor flounce technique, if you ask me, 4 out of 10, could do much better.

I think flouncing over something as obscure as crank length is pretty stylish.

 

[C R]

I think flouncing over something as obscure as crank length is pretty stylish.

I would have expected at least one glancing mention to GDPR.

 

[Ian H]

I used to race tandem on 175s. 170s everywhere else except for a brief flirtation with 165s on fixed. The hire bikes at Newport track are 165s. Put me on any and I doubt I'd be able to identify which.
But anyway, the French System of measurement (described in 1907) -