Reynolds top cap on a 1" carbon steerer

[DRZRM]

OK, question of the day. I have a Serotta F-3 fork incoming for my older Legend with a 1" HT (thanks Oliver1850 and Gothard). Resale is so bad on these frames--and the ride is so awesome--I figured that I'd modern it up a bit and keep it forever. I'm going to use a 1 1/8" Moots Open Road stem on it with a Thomson 1" to 1 1/8" adapter. In the past I have put a spacer on top of the stem, and used a 1 1/8 topcap, but that was on steel bikes with steel steerers like my Zanc. In this case I need a compression plug for the carbon steerer, but can I expect a 1" top cap to work on a 1 1/8 stem? I'm not going to have much extra steerer and I don't know if I'll have room for extra spacers on top (though I guess I can flip the stem to positive rise if I have to). Anyone done this before? The fork is coming with one of these (http://www.chainreactioncycles.com/Models.aspx?ModelID=18344) in 1".

[GregL]

...can I expect a 1" top cap to work on a 1 1/8 stem?
It should work fine. I had a bike with a 1" steerer tube that used a very similar setup (1" steerer Reynolds Ouzo Pro fork, 1 1/8" Ritchey WCS stem with shim, and 1" Reynolds compression plug). No problems, and the compression plug had plenty of coverage for the top of the stem.

- Greg

[eddief]

so don't the combo of stem and shim need to stick up about 3mm above the steer tube so you can preload the bearings? seems like if the combo is above the steer tube by a bit, then it would depend next on if the top cap is flat on the bottom or if it had a knobbish that sticks down into the steer tube. If it is flat then seems like the diameter needs to be equal to the diameter of your stem. If it is knobbish, then the knob would need to fit into the 1 inch hole of the steer tube. does that make any f-ing sense at all?

or you could put a 1.125 spacer on the top and then put 1.125 top cap on top of that..without other factors to be worried about.

[DRZRM]

Yeah, that sounds right, something will need to stick up past the top of the steerer, either the shim/stem or a spacer. I guess a 1" spacer on top of the stem/spacer should work to get it to the right height, assuming that everything is flush. Given what GregL said, I figure this is flat on the bottom.

http://www.chainreactioncycles.com/Images/Models/Original/18344.jpg

so don't the combo of stem and shim need to stick up about 3mm above the steer tube so you can preload the bearings? seems like if the combo is above the steer tube by a bit, then it would depend next on if the top cap is flat on the bottom or if it had a knobbish that sticks down into the steer tube. If it is flat then seems like the diameter needs to be equal to the diameter of your stem. If it is knobbish, then the knob would need to fit into the 1 inch hole of the steer tube. does that make any f-ing sense at all?

or you could put a 1.125 spacer on the top and then put 1.125 top cap on top of that..without other factors to be worried about.

[oliver1850]

Top cap must be Reynolds to work with the Reynolds plug. It doesn't use a screw to hold it on, the threads are on the bottom of the cap itself.

[GregL]

Yeah, that sounds right, something will need to stick up past the top of the steerer, either the shim/stem or a spacer. I guess a 1" spacer on top of the stem/spacer should work to get it to the right height, assuming that everything is flush. Given what GregL said, I figure this is flat on the bottom.

Yes, the compression plug is flat on the lower surface that touches the top of the stem. IIRC, Reynolds specifically stated that there should be NO spacers above the stem. This was to ensure that the top of the compression plug was inside the part of the steerer tube covered by the stem, ensuring that compressive forces did not crush the steerer. That is how my bike was configured and I had absolutely no problems. The top of the steerer tube was approximately 3mm below the top of the stem/spacer per Reynolds instructions (http://www.reynoldscycling.com/uploads/documents/OuzoProInstallation.pdf).

- Greg

[DRZRM]

Awesome Greg (and Mark) just what I needed to know. I should be all set.

Edit: Everything came today and it all works perfectly, the cap fits right onto the stem, now I just need to have my cups pressed in.