3T Rotunda LTD installation issues

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theStig
Posts: 421
Joined: Mon Aug 06, 2007 1:22 am

by theStig

Excuse the carbon paranoia here...

Was installing a set of di2 shifters into these bars. Since the clamp mounting surface has that rough sand-paper like coating, I didn't use any carbon assembly paste.

Put everything together and start tightening the clamps. I would tighten it finger tight, and then try rotating the shifters. If they still moved, I would tighten some more - each time a tiny bit incrementally.

After not all that much torque and with the shifters still moving if I twisted them hard enough, I tighten it a bit more and I heard a "crack" sound come from the bar.

So I take everything apart, inspected with a flashlight and magnifying glass and could not find a crack or scratch on the bar. Put everything back together. Grab both sides of the bars and try to flex them as hard as I could. No creaks, no sounds. Put the front wheel between my ankles, grab the bar ends and tried twisting it from side to side. Nothing.

What does everyone suggest? Put some miles on it and see if anything turns up? Or toss them (brand new bars :( ) and not risk it?

How strong are these bars anyways? for those of you who have actually cracked a handlebar by overtightening the shifter clamps - how hard were you tightening them before something broke?

thanks in advance

thisisatest
Shop Owner
Posts: 1980
Joined: Sat Jun 13, 2009 4:02 am
Location: NoVA/DC

by thisisatest

1. I've tightened lever clamps pretty hard before on many, many 3t bars and have had no failures.
2. Sometimes the T-bolt at the lever clamp is turned from the clamp itself and will slide into place after a lot of torque is applied, making a "pop" or "crack" sound. It's definitely a different sound than carbon cracking, but I wouldn't be surprised if one mistook it for that.
3. Use grip paste no matter what.

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itsacarr
Posts: 1012
Joined: Fri Nov 14, 2008 4:55 am

by itsacarr

Use a torque wrench!!

Carbon paste for sure but especially if you are using the LTD bars use a torque wrench. Yes carbon can generally take quite a bit of force but the tolerances with the LTD plastic are pretty refined. It's easier to go past 5 or 7nm than you realize.

I would agree the ti bolts can ping and make noise as well while tightening if you have those.
Just ride ..

RudyMontana
Posts: 65
Joined: Fri Dec 14, 2012 4:17 am

by RudyMontana

I too would recommend use of a torque wrench for installation of carbon parts.

A respectable torque wrench can be had for ~100 USD new. A fraction of what 3T Ltd bars cost.


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