True Temper Head Tubes

[John Clay]

The TT 31.7 HT (VERHT1) has a 0.9mm wall which I just discovered is essentially the same ID as the OD of my HT reamer, i.e. the bore cutters only engaged part of the ID, maybe 75% of the circumference. I haven't pressed the cups in yet but I find that to be irksome. Is that normal, OK? Deda and Columbus are 1mm wall.

Thanks,
John Clay
Tallahassee, FL

[Jon Norstog]

John, list:

This is an issue with 1 1/8" steertube frames, especially if you fillet braze using a lightweight HT.  I have gone over to using machined head tubes for bikes that are going to take hard use.  I still use Columbus HT stock for bikes that are going to be ridden sitting down.  On bikes with 1" steer tubes I find that 1.25" x .035" works pretty well, gets a good cut.  I use reinforcing rings top and bottom.

If you are building for yourself, you may be able to use a little loctite to bed in the cups.

Good luck there! 

jn

"Thursday"

[Andrew R Stewart]

I agree with this observation. My recent two touring bikes have only 1/2 to 2/3 of the HT ID machined by the reamer (a Cobra 1.125 for a campy pilot). The cups slide in with no slop, but also no press fit. I figure after paint takes some space I can fall back on LockTite if needed. Andy.

 

Andrew R Stewart
Rochester, NY USA

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[John Clay]

Jon and Andy,

Thanks for the reality check. 

I've never had this happen before and when I initially saw the results of the boring operation I was horrified, thought I'd used part of a butted tube; quite a shock at that point in a frame's construction! Then I checked the specs of TT, Deda, Columbus and others and saw a mix of 0.9 and 1.0  for 31.7 HTs and felt a little better. I'll find the cutoff and check the wall; I wonder if it was under spec? I know this much; never again will a 0.9 wall HT enter my shop as raw material. Yet another lesson learned! 

John Clay

Tallahassee, FL 

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John

[Jim Adney]

Sounds like the ID really doesn't need to be reamed. Could you make a
smooth pilot for your chaser, to replace the ID cutter, to allow the
end to be faced, and then press the headset into the unreamed bore of
the tube?

Try a headset on a bit of scrap tubing to see if it presses in okay.

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Jim Adney, jad...@vwtype3.org
Madison, Wisconsin, USA
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[Mark Hall]

I noticed this same issue on a batch of 36mm PlatOX head tubes purchased two years ago.  I found that brazing in 2 pins through the lug reinforcing ring works great.  Three would be better.

The wall of the Zona 36mm head tube is 1.1mm so it's a good alternative when a heat treated head tube is needed.

Mark Hall

mahallbikeworks

[Cliff McLeroy]

The one experience I had with a TT head tube was with the 37 x 1.6 and I had the same problem. Since then I have only used the 36 x 1.1 or 31.8 x 1 from Columbus and have not had a problem. That particular tube from TT should have had the same i.d. as the Columbus but obviously it didn't. With the Columbus HTs I end up having to ream out more material than I'd prefer, but that's better than a loose headset cup. You may be able to carefully lay in some silver in that gap.

-Cliff