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Discussion Starter #1
Hi !



Could you pls let me know the seatpost clamp size, that I should buy for a 29.8 Seatpost. Unfortunately the availability in india is nil, I would have to go online for a purchase. I have already tried a 31.8 clamp and been unsuccessful.
If possible could I have a table for all the compatibility like : SeatPost size---- Seat post clamp. This would certainly help !





Pls advise



rgds
 

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It's hard to say without measuring. If the seatpost is 29.8, then 29.8 is the inside diameter (ID) of your seat tube. What you need to know is the outside diameter (OD) of your seat tube. That's dependent on the wall thickness of the seat tube. If you have metric calipers you can simply measure it. I have a 29.4 post and use a Thomson 31.8 collar.
 

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Merlin is correct, that you need to know the size of your frame tubing, Steel will generally be thinner than aluminum, so it's possible for two frames to require different sized clamps, even if they both use the same size post. What size is your front derailleur clamp?
 

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The only other alternative would be to check with the bikes manufacturer. Have the model and serial numbers, and ask them. With luck they might still sell you one. With some luck but a little less, they may be able to give you the size they used during production.. With no luck you are no worse off though. Granted this is a bit of a long shot, but it might be worth a try.
 

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Discussion Starter #5
Thank you so much for your replies, yes the 31.8 clamp was too small for the particular seattube. And yes it is an alloy frame, I have bike with a 34.9 quick release collar and tried it on, the fit was marginally on the larger side( ie the collar is slightly loose on the seattube). Is there a DIY shim that I could make for this little gap. Over tightening the quick allen after turning the key does solve it , but I am not in the comfort zone.
 
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