31.8 Stem on 1" steerer - headset top cap issue?

You need to post a picture of the adapter and the stem.

Quoted post said:

My problem is the 1" headset top cap falls inside the stem.

Sounds like the steerer tube has been cut too short for the current setup?

cyclepunk said:

I have forks with a 1" steering tube, and I bought a 31.8mm handlebar stem with an adapter to fit the fork. My problem is the 1" headset top cap falls inside the stem. What options do I have in fitting a 1-1/8" headset top cap on my 1" steering tube? Do they make wider top caps for 1" steering tubs?

Just buy/use a 1-1/8" top cap (i.e., match the top cap to the STEM and not the steerer) & your problem will be solved.

+1 😉

alfeng said:

Just buy/use a 1-1/8" top cap (i.e., match the top cap to the STEM and not the steerer) & your problem will be solved.

cyclepunk said:

I have forks with a 1" steering tube, and I bought a 31.8mm handlebar stem with an adapter to fit the fork. My problem is the 1" headset top cap falls inside the stem. What options do I have in fitting a 1-1/8" headset top cap on my 1" steering tube? Do they make wider top caps for 1" steering tubs?

You need a large cap. The cap needs to be big enough to cover the stem. Another option would be to put a headset spacer above the stem and then the top cap should cover that fine.

alfeng said:

Just buy/use a 1-1/8" top cap (i.e., match the top cap to the STEM and not the steerer) & your problem will be solved.

Thank you for confirming this. My concern was the ID of the top cap would not fit in a smaller steering tube. That it would be a bit larger to fit a 1-1/8 steering tube.

I do have one in the mail, so I feel better about that.

If not I was thinking similar to what Peter suggested. Except I was going to cut the steering tube down and fit the top cap in the stem adapter. I thought that would be a more positive connection.

art, the stem adapter looks like this.
[img]nexternal.comadapter.jpgOpen ↗[/img]
The 1" steering tube fits inside and the stem fits over the top.

And I'm using it on this stem.

FYI. As designed, the top cap has two functions:

[indent]1) to seat the fork

[/indent]After that,

[indent]2) the only real function is to keep crud out of the steerer.[/indent]It could be suggested that a questionable third function is the BLING-factor -- e.g., a carbon fiber top cap ... MTBers seem to buy/use colored/anodized after-market top caps.

The SHIM you are using should NOT extend above the actual steerer ... the steerer should be between 1/16"-to-1/8" below the top of the stem OR a stacked spacer above the stem.

alfeng said:

The SHIM you are using should NOT extend above the actual steerer ... the steerer should be between 1/16"-to-1/8" below the top of the stem OR a stacked spacer above the stem.

Just so I'm clear...

The shim should be flush with the steerer?

And the stem 1/16" above the shim & steerer?

Or...

If the top of the stem is below the top of the steerer/shim the difference can be made up with a spacer? So from top to bottom - top cap, spacer, stem, spacers, headset?

Thanks again for your input.

cyclepunk said:

Just so I'm clear...

The shim should be flush with the steerer?

And the stem 1/16" above the shim & steerer?

Or...

If the top of the stem is below the top of the steerer/shim the difference can be made up with a spacer? So from top to bottom - top cap, spacer, stem, spacers, headset?

The shim should be flush-OR-below the upper edge of the steerer:

top cap
stem ... 1/16"-to-1/8" gap visible INSIDE the stem between the top of the steerer & the top of the stem
spacer
headset

Add a spacer below OR above the stem to create the "gap" which will allow the top cap to snug up the steerer ...

Snugging up the fork is most easily done (particularly with a suspension fork, BTW) if the bike is inverted & the head tube is vertical (let gravity do the work) -- I refer to this as the "French method" ... but, it was undoubtedly the way it was universally done 35+ years ago.

alfeng said:

Snugging up the fork is most easily done (particularly with a suspension fork, BTW) if the bike is inverted & the head tube is vertical (let gravity do the work) -- I refer to this as the "French method" ... but, it was undoubtedly the way it was universally done 35+ years ago.

You're a value and a resource. Thank you!