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175 vs 172.5 mm cranks(7 posts)

175 vs 172.5 mm cranksNew Steelman
May 2, 2001 10:01 AM
Just took home a new bike. New cranks are 175mm vs 172.5 on my old bike. What will the difference be? Thanks.
crank length formulaET
May 2, 2001 10:14 AM
"According to Hinault and Genzling, those with an inseam from 74-80cm should use 170 mm cranks; from 81-86cm inseam 172.5mm cranks and inseams from 87cm to 93cm 175mm cranks."

That is a quote from the Feb '01 issue of Cycling Plus. So, what is your inseam? BTW, if you keep your handle as a permanent one, expect some flak (see another thread). I presume your bike is a custom. If so, wondering why you didn't clarify this before you bought the bike.
The difference will beSteeve
May 2, 2001 10:20 AM
about 2.5mm per crank. All you have to do is subract the lengths.
The difference will benew steelman
May 2, 2001 11:47 AM
I have to clarify. The bike is custom and I did get fully measured for it. The thing fits like a glove. My question is how much of a difference in feel will the extra 2.5cm make? Are you all of a sudden producing more torque per revolution? Sorry, I'm a geek at heart. Can't wait to get on the bike this weekend. SR 525, Daytona group, Ozuo Pro.
The difference will bemmaggi
May 2, 2001 11:54 AM
2.5mm = .25cm

1.0 inches = 2.54cm

.25cm = .1 inches or 1/10 of an inch

Therefore, the difference between 170mm crank and a 172.5 crank is 1/10 of an inch.

I really don't think that it could make that much of a difference.

The difference between 170mm crank and a 175mm is 5mm or .5cm or 1/5 of an inch. You might feel a difference there.
Hec, I don't even think you'll realize a difference.
re: dont worrycyclopathic
May 2, 2001 12:00 PM
you wouldn't feel it, just lower seat by 2.5mm

I have 170mm road and 175 mnt. shorter cranks, spin faster? not so my mnt cadence is higher due to lower gearing/wider gear spacing.
re: 175 vs 172.5 mm cranksWoof the dog
May 2, 2001 4:06 PM
Beware the knee pain. Get 172.5 mm cranks. Lighter (psychological edge), better in sprints, better clearance in crits, saves your knees.