Coker handlebar woes

I just received the new Coker handlebar and am having trouble with installing the thing on my Coker Big One that I bought earlier this year. Here’s the handlebar…

The problem is that the inner diameter of the clamp that goes onto the seatpost is slightly smaller than the seatpost itself. I have the aluminum seatpost from Coker, rather than the steel version. Has anyone else had this problem? I tried to force it on, but you can see the results below. In the process of trying to get it to fit, both the clamp and the seatpost were damaged. I tried prying the clamp open, but any attempt to do this just damaged it more by gouging the aluminum through the painted surface. It springs open and then immediately back again, so there is no point were I am able to slide it cleanly onto the seatpost.

Has anyone successfully installed the handlebar on an aluminum seatpost from Coker?


Hmm, that’s strange indeed! The OD for the coker seatpost, whether alum or steel is purporedly 25.4mm. They should be identical OD. The only thing I found different with the big one, compared to my radial in that area, is that the big one’s Seat tube OD requires a seatpost clamp that is 27.2mm!

This is because the alum seat tube’s OD is significantly thicker than the radial’s steel tube. But again, the seatpost OD 25.4mm should fit the ID of the coker handle, but apparenltly there is a discrepency between the alum and the steel seat post OD’s, which should not be-if they are both 25.4mm. (I guess I’ll have to find out for myself as I just got a call from Jamey of uniproshop, informing me that my coker bar has been delivered!)

Thanks Terry. I look forward to hearing how yours fits. Do you have a steel seat post, or alum?


It’s a KH rail type and I think it’s chromo.

I’m a bit confused. So, the new coker handle is designed to fit over a 25.4mm seatpost? So I could buy one and put it on my Nimbus fr ame? I’ve been wanting a handlbar, and this one looks better for my uses than the T7.

Also, does the coker handlebar act as the unicycle’s seatpost clamp? Or is it supposed to slide up under the saddle?

Sorry haha I guess I should not have confused the issue by mentioneing the seat tube, lol.:o

But yeah, both the new coker, the nimbus and the radial all use the same size seatpost: 25.4mm. So it shouldn’t matter whether the post is alum or steel. As long as its OD is 25.4mm.

Take out the bolts and then get a long metal file or something strong with leverage and stick it inbetween the opening slot and pry open the clamp a little bit. This technique always works for me when trying to get bar ends or brake levers onto posts. Make sure you grease the seatpost as well.

Hope that helps.

I would recommend doing this:

Look at the bottom of your seatpost where you probably cut it to fit your height. File around the edges on the outside because sometimes when you cut the post a very small ridge appears, even if you can’t see it. Grease the post. Remove the bolts on the handle clamp. Pry the clamp(it is alright if paint chips) a small amount and slide it on. This should work fine.

Hope that helps.

Hi siafirede,
Yes, that’s exactly what I already attempted, but it just binds up when I attempt to slide it over the post. The clamp is springy and fairly stiff, so it doesn’t open enough to slide over the post, even with lots of effort, prying, etc.


  1. Contact the folks at Coker, if you haven’t already, to find out their recommendation. It may turn out to be a slight defect in one part or the other (though if your post fits in your Coker, it sounds like the flaw would be in the new clamp)

The aluminum post has kind of a krinkly silver finish which, though it may increase the tube’s size a tad, still has to fit in the same frame so it probably doesn’t. Again if your tube fits your frame well, the problem would appear to be with the new clamp.

Yes, it’s made to fit on the seat post. Unfortunately my older Coker has a 7/8" post, so it won’t fit there. :frowning: I’m hoping it will fit on the seat tube, which appears to be 1" (25.4). It could replace my aging Wyganowski handle.

  1. While waiting to hear from Coker, since you’ve already marked up the inside of the clamp, you could try “customizing” it with a file, to make the hole a tad bigger. This is much more easily done with the correct size drill bit or reamer, but if you don’t have that you could try a fat rat-tail file. Take your time.

It’s also possible that somehow the clamp got squeezed or crushed somewhere along the line, so it’s not opening up like it’s supposed to. Not sure how knowing that would help, but it’s another possibility.

  1. Hopefully Coker will send you a new one straight away, once they’ve determined if this (possible) flaw doesn’t exist in more of them.

I just got mine and it doesn’t fit either.

…of course that’s probably because they didn’t include a clamp at all.

Here’s an idea that worked for me when I was cobbling together a temporary brake-handle post on a muni (I put an old bar end from a MTB on the seatpost, and the fit was even tighter than you’re describing).

If you have a set of either brake spring or circlip pliers–these are pliers that instead of closing together when you grip them, they spread apart–put them in the gap in the new handle, and use them to spread it open while you put the seatpost in.

If you don’t have these kind of pliers, then use a flat-bladed screwdriver, and put it in the gap, and twist it so that it will pry open the gap in the handle. Then slide the post in.

It will probably help, with either of these methods, if you have somebody there to maneuver the seatpost for you while you’re propping open the handlebar’s gap.

The good thing about your situation is that your handlebar will, once mounted, stay in place really well.

Addendum to my previous:

Perhaps some emory cloth (or sandpaper) on a piece of dowel would be a smoother way to file down a bit from the inside of the clamp.

Also, if you work on the pry method as suggested above, in the past I’ve had success with a pair of screwdrivers, one pointed each way to balance each other out. Crank on those a bit and see if it’s gotten any looser. But at this point you really should at least sand down all the scratches in there no matter what.

Remove each of the bolts, screw them in from the other way, jam two pennies in the slot so the end of each bolt presses against them. Now do up the bolts and it will wind the clamp open for you, and hold it open while you slide it on.

I just got my handles in and will go try and put it on right now and report back…

I like kingstons idea ^

Pretty clever.

To help us get to the bottom of this, how about someone measuring the clamp, so we know how far it is off ?

Yes, you have to use this trick to get it to fit. I just put my handles on 2 different Cokers and both of them would not fit unless I did the above method. Thanks for the very helpful advice!

Use some oil on the seat post, the only thing I had handy was motor oil, but it did the trick.

Then what? I think I’d rather have my handle stay in the front, if you know what I mean. :slight_smile:

Sounds like the bolt-into-the-penny trick is the way to go! I’ll have to remember that for stubborn clamps in the future. Great tip!


Thanks for the help guys. This morning I tried the penny method and it did the trick! Pure genius. The handlebar slid onto the seatpost with no resistance.

I had contacted Coker yesterday, and they said that this is the first they have heard of the problem. They are sending a new clamp, seatpost and “instructions”.

Thanks again,