Steerer cap

[TPMB12]

Stupid question but what is best to plug the gap on my recumbent steerer. The plastic cap came out mid ride so now I have the top of the steerer with an open end right down to the allen bolt. It's fire USS and looks messy plus it's inches from part of my body that could get hurt more by an open tube than a blocked one (my perception at least). It's quite a narrow tube to block off.

What's it called. Steerer bung? Steerer cap? Told you it's a stupid question.

[Brucey]

it sounds as if it may be a quill stem you are looking at rather than an A-head setup. If so the stem may have a cap that is a specific design that fits that, and that only. They are not easy to track down especially if they are angled in any way.

A photo of the parts might help. This is a photo of a welded steel stem with an angled plug, half-way out



cheers

[TPMB12]

It's round and a straight tube, with what on a normal bike would be a stem welded to it just below the top. The "stem c is welded to the bars (under seat steering on a recumbent).

I think I need to measure the ID.

This link has a side photograph of it and you can just see a black cap.

http://www.hpvelotechnik.com/produkte/sm/gt/details_lenker_e.html

[fuaran]

Stick a cork in it.
Or a bar end plug?

[Samuel D]

And what is “fire USS”?

[TPMB12]

It's a Chinese phone's autocorrect for the word "for".

[Kim]

My USS Streetmachine has a perfectly normal 1" Aheadset with a fairly long stem that achieves the funny angle between the steerer and bars by being upside-down and backwards compared to how you'd expect to find one on a DF bike.  The only unusual thing about to top cap^[1] is that it's the older 1" type, rather than the more common 1⅛" type.

TPMB12's bike is older, so may do things differently.  It certainly looks like a quill stem in the photo.


_{[1] To use the magic word.}

[LittleWheelsandBig]

For Under Seat Steering

[Brucey]

it looks as if it is constructed similarly to a welded quill stem to me, angled plug and all.

I suggest you contact the manufacturer, and that you glue any replacement in the hole so that it is less likely to come out accidentally.

cheers

[mzjo]

it looks as if it is constructed similarly to a welded quill stem to me, angled plug and all.

I suggest you contact the manufacturer, and that you glue any replacement in the hole so that it is less likely to come out accidentally.

cheers

This would seem to be the best solution.
 I have known a similar arrangement on cheap mtb stems but with the stem expander bolt passing through the cap and holding it in place.

Failing all else a look through your local DIY store may yield a variety of rubber and plastic bungs and caps for going on the feet of stools and masking screws and all that sort of thing which can be diverted to bicycle use (with a cunning bit of use of a suitable blade and glue).

[TPMB12]

I've seen expander bolts / plugs /bungs. Could they be suitable? They look like a cap with an allen bolt to tighten it by expanding to clamp on. I've seen something similar for up to 22mm for ends of drop bars. But they're too small or 1 1/8.

[RichMoss]

Large wine cork, suitably sculpted to fit

[Si S]

Sugru?

[TPMB12]

Sugru?

Doesn't that set hard making it difficult to get to the allen bolt to work on the headset?

[Si S]

Sugru?

Doesn't that set hard making it difficult to get to the allen bolt to work on the headset?

Sets hard, yes, I've used it to make a plug for the allen bolt bolt in the top of a steerer cap to prevent water running down the bolt, I've removed and replaced it a couple of times and its started to crack, I'll have to make another at some point but it does the job.

[Paul]

Bar end cap fettled to fit? You might need to pack it with tape or something.

If (because of the angle of the cut) the hole is oval rather than round, the overhang of the cap won't, erm, overhang all of the hole, but it might be enough to stop you getting cored.

[TPMB12]

I don't think mine is oval. It looked round to me.

1 1/8" steerer means the diameter of the outside right? What would the inside diameter likely to be? I'm guessing 25 - 26 mm. IIRC bar end caps fit 22 - 25mm.

[fuaran]

If it is a 1 1/8" headset, you could use a headset expander bung, with a regular stem cap on top.
eg Hope Head Doctor. Or a cheaper equivalent. Or even hammer a star nut in.
http://www.wiggle.co.uk/hope-head-doctor-expander/

[Brucey]

no need to guess the size of the hole, just measure it. The ID of the hole will vary with the wall thickness of the tube, even if the OD is known.

There are, of course, any number of round things that will fit into the hole. But the problem is that the top is sloped, so any normal thing will leave an exposed edge, right in the worst place.

If you cannot get the right thing, I agree with a post upthread; try a cork; jam it in place then whittle it so that it protects you from sharp edges whilst not sticking up too far (which will lead to it being damaged or displaced). BTW if the cork is not a tight fit, you can wind a few turns of tape around it until it is.

cheers