Hi there, I'm working on a recumbent that uses a Long John-style steering linkage to turn the front wheel. Right now it has a threaded headset (I think). It's important that the headset be flush with the head tube, or else the rider's legs will bash into it.

I'd like to upgrade it to a fork with a 1-1/8 threadless steerer tube, and I'm happy to replace the headset if needed.

The problem is that on threadless headsets, the stem clamp bolts are what's holding the fork and bearings together. So if the bike doesn't use a stem, wouldn't all the tension be put on the top preload screw? Is this OK?

Is it possible to buy a tiny fake-stem-clamp to properly hold the fork steerer tube in place?

The pre load is just that. You can't secure a fork, stem, and bars with just the top cap screw to hold them all together. You need the stem clamp or some substitute clamp. Don't attempt it. There may be stemless clamps. Don't know.

You can use a clamping type of collar, similar or identical to a seatpost clamp, to hold the stem preload adjustment. Look in the "Threadless without Spacers) section of this article: Hands Up (Or Down)! Adjusting Handlebar Stem Height on Your Bicycle

You could also use spacers like those used under a threadless stem to give the top cap a surface to pull down on and the clamp-type collar to hold the adjustment.

Right, but the top cap isn't made to hold up the fork, just to preload it.

I think he'd be OK with a suitable clamp as a stem replacement. The fork, bearing and frame carry all the load, and are held in plce by gravity. All he needs is good quality 1 1/8" ID clamp to hold the fork in place once the adjustment is made. Basically just something to prevent the fork from falling out when the bike is lifted. Thinking about a threaded headset, it is never 'tight', as it has to be 'loose' enough for the bearing to roll freely.

OP, why do you want to switch and what is the inside diameter of that frame tube?

Thanks for the replies! I get it now. Hopefully I can find a nice tidy 28.6mm clamp.

I'm trying to find out the inside diameter of the frame head tube on the manufacturer's forum. The bike is on loan right now so I can't measure it myself. I found a photo on the internet that is identical to my bike, here.

I fear that might be impossible to use a fork with 1-1/8" steer tube. Which is surprising, since the frame head tube is super wide! I guess it's just very thick-walled to hold the tandem weight.

My reason for wanting to convert is that the (crappy) stock suspension fork is almost toast, and finding 20" suspension forks that are good quality and reasonably priced is very hard. Finding the above in a 1" steerer....

Yeah, I know which is why he'll need the clamp to hold the adjustment. The spacer is just a place holder while the top cap is adjusted and the clamp tightened.

There are clamping spacers but in your case a 28.6 seatpost clamp should work just as well

I can't tell from your photos, but that tube you're trying to fit the headset into looks pretty huge, almost like a Cannondale.

I think you really ought to wait until you can pop out the old one and measure what's going on before you attempt this switch. One guy's opinion.

Once you loosen the stem it's just a spacer .. no stem add a spacer to fill in the gap ..


I bought a Locking spacer A thin version of a band clamp and it would hold the preload .. Problem Solvers

NB: there is this https://problemsolversbike.com/produc...headset_spacer

Have a one of these 'WC' in 9/8" another clamp around the steerer , with a built in 2nd function... a bottle opener.

Now, discontinued .. the 27.2 continues to be sold. ,as do the non locking spacer .. ones for threadless forks.

The One and Only WiseCracker

Yeah, fair enough - I should have measured it before loaning the bike out. The frame head tube is the same width as the stoker boom (50-60mm), but it also seems very thick-walled.

That looks great. Once I hear back from the manufacturer about the head tube ID, should be able to get started.

With the really fat walls, and your desire to change steerer ODs, I'd check to make sure you can find a headset that is compatible before you buy a fork too....just to be sure.

only a CF fork steerer would be thicker wall than a 16th of an inch

Mine : steel . ID is 1" ... OD is 9/8"

Never heard back from Hase, so I went ahead and pulled it. Went better than expected. A Problem Solvers stem collar is now holding the preload tension on the new 1-1/8" steerer tube.