Hi,

I have a zoom brand threaded to threadless adapter on my fixed gear bike, and my lbs noticed that there is play in it when it isn't all the way down. I liked that it pushed up my handlebars a bit, and am wondering if the solution is to get a better quality one like a Deda or Nitto? Maybe it is a manufacturing defect? I want to measure the diameter and see if it is uniform all the way down, but am wondering if something else could be causing the play? Ideas anyone?

Dave

A better one might solve the problem. But it also might not. It's also possible that the steerer ID is just a billionth too big.

I was wondering the same thing, maybe its a tolerance issue and just a tad on the smaller side. Maybe the thing to do is to buy different ones and see which ones fit best :-p

Dave

A threaded-to-threadless adapter is basically a quill stem with a cylindrical head instead of a neck.
Don't quite see how one could develop play as long as it's properly tightened.

Use a caliper to measure the OD of the stem and ID of the fork steerer. Maybe try shimming it with a slice of aluminum can.

I'll have to try the aluminum can idea. Thanks! It almost seems like there is a slight taper on the adapter as it is raised, and gets a little thinner. Going to check it out with a caliper tonight.

Dave

Just measured the adapter with a caliper. It is roughly 22.2mm (with a non-digital caliper) all the way down. The steerer is also 22.2mm. The only thing I can figure is that maybe the wedge isn't engaging when the adapter is raised? Below is a pic. Not much room in the headtube for the clamp to engage since the top tube and bottom tube have an opening inside the headtube. See the pic below.

https://www.pedalroom.com/bike/1986-...eedfixie-32051

Dave

The top tube and down tube have nothing to do with it, since the wedge is inside the steerer.

Oh, and MAKE SURE the wedge isn't inside the threaded part of the steerer. It MUST be completely below the threads.

The wedge can't clamp to an open hole from the top tube! :-p

It's definitely because your head tube is so short. I doubt getting another brand adapter would help. There's probably a "sweet spot" where you could tighten it down without play.

Agreed. I will probably take the adapter out and hold it next to the tube. I wonder if it is as simple as making the clamp engage the front of the tube instead of the back?

Dimension makes an adapter with 118mm distance from min insertion to the top. My current adapter is 63.5mm. It probably won't be a precise solution, but might work. Here's a link:

https://dimensionbikeproducts.com/pro...teerer_adaptor

Dave

Check inside the steerer, It's likely butted down the bottom and the adaptor isn't far enough in. That being said, I've always had a bit of slop in ones I've used in the past.

Are you inserting it past the adapter's minimum insertion/ max height line?

The adapter's wedge might not making complete contact with the inside of the steerer tube.

that has nothing to do with it.

The stem was at the minimum insertion. My LBS couldn't find a point where the adapter would fully engage except when it is all the way down. I found a cross-section picture of a threaded stem. I'm guessing this wouldn't work since the wedge isn't contacting the bottom of the stem? Just trying to get a better understanding on how exactly this works, then I can make some measurements and figure out what the handlebar height would be with the Dimension adapter.



Dave

Except that a quill is inserted into the steerer tube, not the head tube.

Yeah, I gotcha.. let me try to explain this differently. If I take the adapter out of the steerer tube, there is an opening where the top tube meets the steerer tube (the tube is hollow).

Dave

Yeah, whatever. I quit. Best of luck to you.

I won't believe that unless you post a pic.
Again, inside the headtube there is the steerer tube, the top part of the fork.
You won't see the inside of the head tube unless you remove the fork.
I have never seen a steerer tube with holes in it.

Wow, my bad. Now that I think about it, there aren't any cutouts in the steerer. That doesn't make any sense Back to square one I think. Is it possible the steerer tube is slightly tapered? Not as much as a Bombtrack frame, but enough to throw off the threaded adapter?

Dave

Makes perfect sense. Cutting holes in something meant to take an internal expander seems rather risky.



The steerer began as a tube.
It might be widened in spots, by enthusiastic tightening of previous quill stem wedges.
But an accidental taper - not very likely.
Maybe the ID is overall a little wide, and maybe the OD of the adapter is overall a little narrow.


I'd still start by Another look at the headset, a far more common cause for play in this area.

Last night I adjusted the adapter again and got it to go up about 1/2". There's no play, and it was comfortable for the 10 miles I rode last night. Going to leave it alone for now... Thanks!

Dave