Bicycle Mechanics - Changing my stem from threaded to "less

Hey yall, I just got a sweet set of oversized (31.7 clamp diameter) Deda bars and want to put 'em on my ride. Of course I have a threaded headset and the only stems that fit these bars are threadless. I am planning on buying the adapter and a new stem but I was wondering first of all how do I find my steerer size? I think its 1 inch but I'm not sure if I'm even mesuring the right thing. Will a 1 1/8th inch stem fit a 1 inch adapter at all? Also my crappy wrenches dont even get "big" enough to remove my headset. What kind of wrenches (inexpensive a +) should I be getting? Thanks peops for any help.

Hey yall, I just got a sweet set of oversized (31.7 clamp diameter) Deda bars and want to put 'em on my ride. Of course I have a threaded headset and the only stems that fit these bars are threadless. I am planning on buying the adapter and a new stem but I was wondering first of all how do I find my steerer size? I think its 1 inch but I'm not sure if I'm even mesuring the right thing. Will a 1 1/8th inch stem fit a 1 inch adapter at all? Also my crappy wrenches dont even get "big" enough to remove my headset. What kind of wrenches (inexpensive a +) should I be getting? Thanks peops for any help.

Most threaded headsets are the 1 inch size. Nothing you can actually see measures 1", that's the outer diameter of the fork steerer, which is not visible.

What you can see is the stem quill that fits into the fork steerer. This will be 1/8" smaller than the nominal headset size, so for a 1" setup, it's going to be 7/8" (22.2 mm.)

To make this modification, you do not do anything to the existing headset, the headset stays unless you replace the fork for some reason (not usally a good idea.) The adaptor goes in place of the quill stem.

I've got a similar setup on one of my own bikes, using a 1" threaded type stem raiser as the adaptor. This has a 1" O.D. on the upper section, and I've clamped a 1 1/8" threadless stem to it using a shim to make up the difference. (1 inch threadless stems are very uncommon, but the shims to permit a 1 1/8 stem to clamp onto a 1 inch tube are quite common, in fact they come with many 1 1/8 stems.)

Sorry this sounds complicated, but that's the way it is.

Sheldon "Fractions" Brown

thanks so much. Thats exactly what I needed. And as far as shims go... can I use anything thats "weatherproof" or should I seek out a secific substance? thanks again.

thanks so much. Thats exactly what I needed. And as far as shims go... can I use anything thats "weatherproof" or should I seek out a secific substance? thanks again.

The shims I've seen/used were aluminum.

See: http://harriscyclery.net/page.cfm?PageID=49&action=details&sku=SM5320

Sheldon "Shims" Brown

Many stems come with a factory shim included which as Sheldon points out is usually AL. If you don't have one it's a super cheap part at many LBS or mail order. I would advise against the "beer can shim" approach since the money you save isn't worth it.

Great, I'll get straight to work then. thanks for all the help.

Look at Easton stems, they come with a shim. I recently did a build with a 1 in. steerer and the 31.8mm Deda Newton bars (was 1 in threadless, but with the adapter for a threaded headset, you can attach in the same way.)

Look at Easton stems, they come with a shim. I recently did a build with a 1 in. steerer and the 31.8mm Deda Newton bars (was 1 in threadless, but with the adapter for a threaded headset, you can attach in the same way.)
The house brand 1-1/8" stem I just got from Nashbar also came with the proper shim to use with a 1" steerer.