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I've just got my first ever carbon fibre MTB frame and am a little paranoid about damaging it.. So, after spending many hours swearing and chasing tiny bubbles from the underside of frame protection film last night.. the next thing I'm worrying about is torquing up stuff like the seat clamp..
The free torque wrench from YT seems a bit ropey.. and the recommended 5nm "feels" different each time.. I have a decent teng torque wrench from years ago that probably needs calibrating but local firms seem to charge £30-40 which seems a bit steep (unless I'm underestimating what is involved?)
Any advice/tips for a noob spannering a CF frame for the first time?
Thanks
Any advice/tips for a noob spannering a CF frame for the first time?
In my experience, got a torque wrench you trust and use that. The preset ones tend to be OK, you could try comparing it to your Teng on something else and see if it's consistent or not maybe?
Thanks Lunge - good shout, I'll compare the two on something a bit cheaper than my new frame. Might be worth getting the Teng one calibrated after all.. will help me sleep at night!
Carbon Jeffsy here.
I now have 2 torque wrenches. Large one for high torque stuff and small one for everything else.
If it's just the carbon you are concerned about, just get a small one for lowish torque stuff.
I will admit there is a satisfaction of reasonably knowing that all the bolts on the bike are at the correct tightness. Torque wrench accuracy allowing.
Cheers PS, aye there is definitely satisfaction involved in doing a job right! Mine is a Capra and I've never had a full brand new bike since I was a kid (34 now...) so I'm wanting to look after it as best I can. Think I'll end up just buying a small one or getting this teng one sorted.
Thanks
I bought a norbar torque wrench when I got my first carbon frame. £70 I think (0-25nm or maybe 20nm) it was but I have used it loads and there is no need to worry when tightening bolts. Would be worth while getting your one calibrated IMO. Frames are not cheap to fix!
I will admit there is a satisfaction of reasonably knowing that all the bolts on the bike are at the correct tightness.
Until you start throwing threadlock/grease/whatever into the equation
I've recently brought myself a decent torque wrench (brought it back from the US, tools seem a lot cheaper over there than in the UK) as I've always got by on 'calibrated hands' before. 'Two knuckles white tight' just doesn't cut it with many components these days.
From what I remember of my time in the measurements department in my apprenticeship we had a machine that calibrated the torque wrenches. You basically tightened up a 1/2" drive socket that was attatched to a NM readout and that told you if you were at the correct torque when the wrench snapped. There was then minor adjustments on the wrench. If they let a 17 year old at it im sure it's not too difficult.
I still rely on my calibrated hands, none of my carbon frames have died as a result.
Carbon assembly paste wherever needed, and just go easy.
What will you do if you need to adjust things out on the trail?
not paranoid. just sensible imo
im the same.
Until you start throwing threadlock/grease/whatever into the equation
This. However good your wrench is, once you add some threadlock, copperslip or whatever, all bets are pretty much off as to whether you're at the torque the manufacturer intended. Calibrated hands are a useful thing anyway, but there is some common sense involved (size of fastener, function etc) because not everything really needs to be as tight as you can get it. I think even on carbon between your brain and your hands you should be able to do a pretty good job of not ruining it if you're sensible.
The other reason is that even with a good torque wrench, you should be aware if there are signs that it's not working - I've seen people blindly cranking them with no awareness that things aren't seated right or there's something wrong with a fastener.
Also makes me laugh when you check a newly built bike against the manufacturers own torque specs...
After having some stem bolts fail, and having a bit of a think about how they're loaded under fatigue, I realised that over-torquing a lot of bolts can have a negative effect on their fatigue life.
I therefore use a torque wrench for pretty much all of them these days. If the frame came with a torque wrench, I would use it on the basis that if it's wrong it's not your fault.
As an aside, I took a length of steerer tube offcut and an old stem and tightened it as much as I dared (I was worried about bolt heads flying off at high speed when I stopped, it was prettty much as tight as I could get), to no ill effect. I still never reached the recommended torque (13Nm on an M5 bolt) for the steerer clamp on another set of carbon forks, but that was more out of concern for the stem than steerer (things felt like they were getting a bit yield-ey). Obviously metal will generally bend a bit where your carbon frame will go crunch so I understand the will to be a bit careful.