Seat Post Collar Size.
 

Need Seat Post Collar Size. The seat post says it's 31.6 mm, So a 32.0 collar should work? Cannondale Beast of the East 3.
Thanks.

Seat post collars are sized to match the outside diameter of the seat tube, not the seat post.

You are going to have to buy measuring tools.

ID + 2 x the tube wall thickness is the OD of the tube..


generally tubing uses inch sizes, but are spoken of in metric ..numbers..





;)

A 32.0mm will not work since the seat tube is certainly thicker than 0.2mm (~0.008"). You will need to measure.

Harbor Freight sells a perfectly OK digital caliper for not much.

You'll need a 34.8 (35mm) seat post clamp.

So does Radio Shack...

Thanks guys, didn't think about adding the frame too.

IMHO this is one of those questions with "go to your LBS" as the correct answer. Buying a caliper good enough to measure to the nearest tenth of a millimeter is going to cost more than the markup a decent LBS will put on the collar.

Except afterwards you will own the caliper and have it available whenever you need to accurately measure something else. Going to a bike shop only gets you the need to do it again the next time you need similar help.

I know, he who dies with the most toys and all. But let's get real about cost and savings. I've only replaced one seat post collar, and it cost less than $25 at the LBS. Where can you get a decent caliper for anywhere near that? A really good mechanical one (if you can still find such a thing) is upwards of $75. The electronic cheap caliper from Harbor freight was $30, IIRC, and it took another $10 of batteries to get it working again within two years. Cheap plastic mechanical junk cost me more in ordering the wrong size part than either of the other two. So where's the savings again?

It's not a matter of "toys", it's having a useful tool when you need it. You can get a really decent dial-type stainless steel caliper for $35 or less from several sources and they are both accurate and durable and need no batteries. Since most are in inch calibration you do need to know how to multiply by 25.4.

Yes, "name brands" such as Starrett and Mitutoyo cost much more but are not needed unless you work in a machine shop.

Current online price for HF digital caliper is $19.99. Looks like the one I have. Functional.