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From 170 to 175 crank

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Road Cycling “It is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle.” -- Ernest Hemingway

From 170 to 175 crank

Old 06-03-17, 04:12 PM
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seanandnik
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From 170 to 175 crank

I ordered a new ultegra crank and didn't realize i went to 175mm from the170mm I now have. Will I notice a big difference?
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Old 06-03-17, 04:48 PM
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Originally Posted by seanandnik View Post
I ordered a new ultegra crank and didn't realize i went to 175mm from the170mm I now have. Will I notice a big difference?
You tell us. We are interested. Better yet, cancel the transaction.
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Old 06-03-17, 04:54 PM
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You might notice a difference in the hip area, make sure you adjust your seat height if you keep it. I went the opposite way intentionally from 172.5 to 165 and noticed a huge difference in my hip pain/angle on my messed up hip flexor. My change was at the recommendation of a bike fitter and I'm glad I did it.
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Old 06-03-17, 04:56 PM
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You will notice it.
Faster/slower/more power/less power - maybe no difference.
Seat is typically a wee lower on longer cranks. Some debate about that, and I'm not sure I agree, but that is the prevailing view I have heard.

Last edited by Doge; 06-03-17 at 06:38 PM.
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Old 06-03-17, 05:18 PM
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Small difference. Do you know your cycling inseam measurement?? If not, what size frame?
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Old 06-03-17, 07:03 PM
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Originally Posted by Doge View Post
Seat is typically a wee lower on longer cranks. Some debate about that, and I'm not sure I agree, but that is the prevailing view I have heard.
How could anyone dispute lowering the saddle with a longer crank? Changing crankarm length won't magically make your leg extend more so unless you had your saddle lower than necessary to begin with (and thus giving up some power) you'll need to lower the saddle height by at least the change in length of the crank arm. You may need to go even lower to offset the increase in knee/hip flex you'll have at the top of the stroke.

I say this as someone who went from 175mm cranks to 172.5mm and have happier knees for it.

Also watch for decreased pedal clearance in turns.
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Old 06-03-17, 07:07 PM
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If you're used to 170, and happy with it, you should probably just cancel/change the order.
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Old 06-03-17, 07:08 PM
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Originally Posted by joejack951 View Post
How could anyone dispute lowering the saddle with a longer crank? Changing crankarm length won't magically make your leg extend more so unless you had your saddle lower than necessary to begin with (and thus giving up some power) you'll need to lower the saddle height by at least the change in length of the crank arm. You may need to go even lower to offset the increase in knee/hip flex you'll have at the top of the stroke.

I say this as someone who went from 175mm cranks to 172.5mm and have happier knees for it.

Also watch for decreased pedal clearance in turns.
The 3:00 position is exactly the same. The 6:00 lower the 12:00 higher. And as most power come 3:00-6:00 I understand the argument. Why?

Because of the purpose of the cranks for the type of riding.

If going to longer cranks you are also going to lower cadence.
Climbing might be a good reason for higher seat, lower cadence, longer cranks. Lower seat is used for longer rides, but if rides are shorter, a higher seat is fine.

If now the bike is going to have say 175 for climbing and 172.5 for RR (as in the case here), I like a higher seat for climbing and a more extended leg than for road riding.

Last edited by Doge; 06-03-17 at 07:13 PM.
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Old 06-03-17, 07:51 PM
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I went from 172.5 to 165. I can't tell a difference performance wise, and am not sure I'd be able to tell a difference if I hopped on the same bike with 172s. Just raised my seat a commensurate amount. Did increase my overall drop, though.
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Old 06-03-17, 07:57 PM
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your inseam probably matters. Mine is 30" and I can't ride 175 very well at all. My max cadence is ~10rpm lower than with 170s i usually ride and it just feels off.
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