New to building on carbon!

Herbie153

I'm the proud owner of an Argon-18 Krypton frame, however before I can show the world I have to build the bike!

Being new to carbon,I'm petrified I'm going to crush or crack the frame whilst building. Any hints and tips to avoid such a traumatic event would be most welcome!

Fulcrum racing 3 wheels, mechanical Ultegra 6800 groupset and fizik (Alu) finishing kit!

Thanks in advance

meanredspider

A couple of things that will help:

1. Buy/borrow a torque wrench - something reasonable in the £30-£50 range normally - this will give you the confidence to apply the correct torque (else you will probably under-torque things in your anxiety)
2. Get some carbon assembly paste (Tacx and others make it) and use it on seat post, stem clamp etc - this will allow you to apply the low end of the suggested torque range.

That said, carbon is pretty tough - it's just that, when it fails, it's hard to fix.

mikenetic

Presuming you have a workstand, use an old seatpost as the clamping point when you're assembling the bike. Don't clamp directly onto the carbon tubing.

ayjaycee

What meanredspider said ^^ and ignore the ones on here who tell you that you really don't need to use a torque wrench on a carbon bike and should just 'use the force' when tightening. There was another thread in workshop a little while ago where a few contributers aired such views but, rightly or wrongly, I was unconvinced by their arguments and prefer the imaginary comfort blanket of a decent torque wrench.

If you do decide to get one, search on BR for recommendations as there are loads of threads on the subject. Personally I use a Park Tools wrench and regard it as cheap in comparison to the price of the bikes it's used on.

Mike talks sense as well.

meanredspider

Good sense about workstand - better still, issue a BB & fork stand.

The risk with torques is that you're more likely to under-torque without a torque wrench and you'll have a slipping seat post and twisting bars.

Herbie153

Superb, thank you all for the advice. Quick and knowledgeable as always.

I do have a workstand and will get myself a suitably cheap alu seat post for the job. I've also got to get a high Newton torque wrench. I think mine tops out at 5N. I'll think of that purchase (persuade the wife); it's an investment!

I've already got a bottle of fixing paste.

Can't wait for the spring!

Thanks again

Monty Dog

A 5Nm torque wrench is probably all you need IME for stem / seat clamp. Higher settings like BBs / lockrings are 40Nm which is actually a pretty firm heave - a decent sets of metric, hardened steel hex-bits and 12" breaker bar will be a far better investment as it reduces the chance of slippage / damage to parts.

meanredspider

Yes - if you have 5Nm, that will probably cover you - especially for those items you're likely to break if hamfisted.

Hand tools are often of a size that naturally limit the torque you can apply - a 10mm spanner is pretty short, for instance. Where people go wrong is fitting a 10mm socket to 1/2" drive ratchet and then swing on it - surprised when the bolt sheers or threads.

That's where torque keys are quite good - the Ritchey 5Nm key is a size that actually make it quite an effort to apply 5Nm - you're unlikely to exceed it by any margin (unless you're built like an out-house).

lesfirth

Watch" Pinkbike Visits The Santa Cruz Test Lab Video " on youtube .This will stop you being frightened of your new carbon frame .
I think a 12in breaker bar in the wrong hands is asking for trouble and is not needed.
Has anyone ever damaged a carbon frame with a bike stand clamp or is this another forum myth? I have been clamping on the top tube for years on several bikes. I have been" holding" the frame with the clamp and not trying to squash it but I do not think I could squash if I tried.
Just my opinion.Have a nice day guys.

meanredspider

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19760563#p19760563]lesfirth[/url] wrote:

Has anyone ever damaged a carbon frame with a bike stand clamp or is this another forum myth? .

Funny you should say this - only 10 days ago I sent back an ex-demo carbon bike because the top tube was cracked and it looked all the world like it had been done in a bike stand - even the place was exactly where I'd expect a bike to balance in a stand. Of course, the crack could have happened otherwise. It was however a crack.

He great thing about carbon is that it can be designed to the loads in the directions you expect to see them without the need for additional material. This is also its downside. They make propshafts out of carbon for powerful sports cars - the loads they can transmit in the designed axis are incredible. It's wonderful stuff - but you do also need to treat it with care.

Barbarossa

Stop worrying - get on and build it.

Think it through and there are very few bits that bolt to the frame in a way that you would damage the frame - any worse than an aluminium or steel frame - if you over-tightened them. The thing to be careful about is don't drop the frame onto hard edges and don't drop heavy things - like torque wrenches :-) - onto the frame.

Herbie153

All great stuff. Thanks again. You're right, just got to get on and build it now. I'm still going to go with clamping on an old seat post, but as for the torque, those compopens that need large torque eg bottom Bracket are screwing into metal threads anyway so shouldn't cause the same grief as carbon on carbon clamps like head tube and stem/handle bars.

svetty

Just a note of caution re seat-post. Is it proposed that you have a cheap alloy seat-post and fit this each time you wish to place the bike in the workstand? If so I think this increases the likelihood that you will eventually cause damage - simply through fitting and re-fitting the seat-post until the seat-post clamp breaks or cracks the seat tube.

If the work stand is a reasonable quality one, with soft jaws, you should be fine clamping the frame - or invest in a front fork - BB style design stand...

keef66

Horses for courses:

My CR1-SL has a top tube I can compress visibly with my fingers, so I'm not going to be clamping it there however gently. Alloy seatpost is the only bit I'm clamping.

The alloy top tube on the Racelight Tk seems pretty robust, so that's fair game; the downtube though sounds paper thin so I'm careful with that.

Things like pedals and BB cups that require a bit of grunt, I do with the bike standing on it's wheels

mikenetic

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19761299#p19761299]Svetty[/url] wrote:

Just a note of caution re seat-post. Is it proposed that you have a cheap alloy seat-post and fit this each time you wish to place the bike in the workstand? If so I think this increases the likelihood that you will eventually cause damage - simply through fitting and re-fitting the seat-post until the seat-post clamp breaks or cracks the seat tube.

If the work stand is a reasonable quality one, with soft jaws, you should be fine clamping the frame - or invest in a front fork - BB style design stand...

That shouldn't be the case if the carbon frame is built to acceptable tolerances. I have seen frames with oversized (i.e. out of tolerance/specification) internal seat tube diameters crack close to the clamping point, but that's not a failure of the process, it's a failure of manufacture.

You can clamp on your 'final' seat post obviously, but there's less chance of decal damage/scuffing if you use a dummy post. You should be pulling the post out every now and again to make sure there's no seizing. Less of an issue with carbon/carbon, but not a bad idea if it's an alloy post in the frame.