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27 mm seatpost for a 27.2 mm bike?

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27 mm seatpost for a 27.2 mm bike?

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Old 08-14-08, 02:55 PM
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snot69
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27 mm seatpost for a 27.2 mm bike?

Will it be a big deal? I know trying to squeeze a 27.2 into a 27 is a bad idea, but what about the opposite - I have a 27.2 mm bike and an extra 27 mm seatpost would it be a monumental mistake to use it?
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Old 08-14-08, 03:15 PM
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no it should work. you may want use a shim
(a coke can) for a fit. other wise it will work.
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Old 08-14-08, 03:16 PM
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ooops

if its campy italian no---- if its jap yes- stick it in
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Old 08-14-08, 03:16 PM
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not with a shim. use a coke can for the shim, and it should work.
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Old 08-14-08, 03:18 PM
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Get a pair of calipers! invaluable devices!
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Old 08-14-08, 05:34 PM
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1. 27.2 is one of the most common sizes, so why bother?

2. they (used to) make seatposts in 0.2mm increments for a reason
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Old 08-14-08, 05:42 PM
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Originally Posted by snot69 View Post
Will it be a big deal? I know trying to squeeze a 27.2 into a 27 is a bad idea, but what about the opposite - I have a 27.2 mm bike and an extra 27 mm seatpost would it be a monumental mistake to use it?
Do NOT use a 27.0 post in a frame desinged for 27.2

Sell your 27.0 and buy the correct size post.
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Old 08-14-08, 06:13 PM
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Originally Posted by operator View Post
Do NOT use a 27.0 post in a frame designed for 27.2

Sell your 27.0 and buy the correct size post.
I agree. You could try to tighten the clamp enough to hold the undersized post but it will likely slip anyway and won't be supported properly. Buy the right size.

As mentioned above, there is a reason seatposts are made in 0.2 mm increments.
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Old 08-14-08, 06:17 PM
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As mentioned above, it will most likely slip. Maybe even so slowly that you don't notice until your knees are hitting your chest and people have already been snickering behind your back for weeks.
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Old 08-14-08, 07:17 PM
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+1. Buy the right size. You will not be happy with your post dinging around in your frame with that extra 0.2 mm. of slop as you hit rough terrain.
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Old 08-14-08, 08:16 PM
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It'll wiggle around and walk down in the frame as you pedal. It'll be almost impossible to tighten it hard enough to avoid that. Even then it'll only slow down the walking effect. It'll also be very likely to make odd noises in protest. Either shim it with some popcan metal or bite the bullet and get the proper size.
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Old 09-15-08, 01:27 PM
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Ok I have the same problem. I have a 27.2mm bike. I have a 27.2mm post to test, and it's quite the tight squeeze. Bianchi RC frame. I have the choice of a brand new ultegra post 27.0mm for $45 or the same post in 27.2mm for $65. BOTH brand new. 20 dollars really worth it?
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Old 09-15-08, 02:43 PM
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Yes. My experience with shims was a PIA.
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