175 mm to 170 mm chainset?

[lingus75]

I have finally found a suitable square taper chainset for my trusty Orange clockwork. Only trouble is that it's 170mm as opposed to 175mm currenltey on the bike (and totally worn out LX so no repacement rings).

What, if any difference will this make. I only use the bike as a commuter so I guess I will notice very little in terms of gearing or will it make a substantial differnece?

Also, what would this mean?

• Q-Factor: 169mm.
• BCD: 104/64mm.
• Chainline: 50mm.

I currenltey use old LX, the ones which had the fixed to the spider outer ring.


Can't wait to get it back on the road.

Edited by lingus75 on Wednesday 2nd September 21:56

[R.P.M]

What length leg do you have, if you are particularly tall I would say forget it.
In theory you will loose a little leverage on the shorter cranks, but it will also affect you leg posture which is more important.

I have just made the change from 175-170mm, the main reason was that I was keen to reduce pedal strikes (full susser) and I have a perhaps shorter than average inside leg.

I cannot tell any difference in pedalling efficiency/gearing, but I prefer the 'fit'.

HTH

[Disco You]

I originally had a 175mm on my bike. I had a problem with the left hand pedal arm, so it needed replacing. My LBS couldn't get another 175mm arm, but they did have a 170mm crankset. So I just replaced both arms with 170mm arms. I noticed no difference between the 170 and the 175.

[hughjayteens]

Unless you have particularly long legs I don't think you'd notice. I have a 32" inside leg and have ridden both comfortably.

[lingus75]

Thanks, ordered the 170mm FSA V drive square taper from chainreaction with a sram pc-850 cassette and they told me I needed a 9 speed chain, so ordered a pc-951, I think. All in £75, got to be a bargain?

[AbarthChris]

lingus75 said:

Thanks, ordered the 170mm FSA V drive square taper from chainreaction with a sram pc-850 cassette and they told me I needed a 9 speed chain, so ordered a pc-951, I think. All in £75, got to be a bargain?

Sounds alright to me!

Also, Q-factor is the distance between the pedals - so a larger q factor would mean your legs/hips are further apart.

BCD is bolt circle diameter, basically the distance between the bolts on the chainring. most are 104mm

Chainline im not so sure what it exactly means