Assembly Tech

[325racer]

Let's start a discussion about assembly tech.  Everything from tricks and tips to specs and how to.

I'd like to start off with a couple questions of my own.

When assembling, are people using Carbon Paste and if so what brand?

What torques are people using and what torque wrench are you using?

[carbonazza]

I used the VENZO Torque wrench, $56 on cyclingdealusa.com(by eBay)
It comes with most hex and torx keys I needed.
It stops at 24Nm so you don't have the 40Nm for the crank arm.

And no carbon paste.
Gently tightening the carbon parts(bar, stem, seatpost), and nothing moved so far.

Good luck for your build!

[Sussed.]

Similar to Carbonazza !

Mighty torque wrench with misc bits.  Didn't use carbon paste until I swapped out my Seat Post clamp from a Hope Qr to a Mt Zoom lightweight collar.  Experienced a bit of slippage after that so I have used some paste and a little over torque. 

[Vipassana]

Carbon Paste:

Carbon paste really should be used in areas where two carbon parts are in close contact and experience cyclic loading.  I have seen several instances seat posts and frames bonding/seizing together on bikes after long periods of riding without adjustment.  I'm not sure the exact reason for this, but I think that the resins may bleed together with time and pressure.  This has been a problem on road bikes of the past.

For the paste, you should really avoid anything petroleum based as this can degrade the resins using on the parts.  Instead look for a non-petroleum grease or paste.  Many of the pastes have a grit in them to help with grip. 

I use a carbon paste on my seat post only as it is the only carbon-carbon joint on the bike.  I also had some issues with the seat post dropping with time and this paste cured that right up.

[Vipassana]

Torque Wrenches:

As for torque wrenches, I have several, but I only used two for my build.  Prior to the build, I brought them to work and checked their calibration. 

1. VENZO 1/4" Torque Wrench - 2-24 Nm Range:

I purchased this wrench from Amazon for $59, but it is sold under other brands as well, including NASBAR.
http://www.amazon.com/VENZO-Bicycle-Torque-Wrench-Socket/dp/B00811WQT8

It comes in a nice case and with a great selection of bits that cover about 99% of what you may need for a bicycle.  I was impressed with everything about the wrench except for two things: accuracy and the marking for the settings. 

The markings for each torque setting are printed on a sticker and then stuck to the wrench.  This seems not very robust to me as it could easily be damaged by a chemical or the sun or it might move.  Any of these occurrences would result in an unusable/unreadable wrench. Why are these not laser etched onto the metal?  They took the time to laser etch their damn logo...

The second issue was the accuracy.  The instructions claim that the wrench is accurate within ±4%.  According to my ISO certified calibration lab an its multi thousand dollar test equipment, this is a lie.  Here are my results:

Setting: 10Nm -> Reading: 9.3Nm - Result: -7%
Setting: 20Nm -> Reading: 19.0Nm - Result: -5%
Setting: 24Nm -> Reading: 21.9Nm - Result: -8.8%

So the gage is clearly not linear.  And it is not within ±4% as claimed.  But it was repeatable on repeated measurements, so that's something.  What we can conclude is reading consistently low.  You will be under-torqueing a fastener if you use this wrench.  Since I needed it in a hurry for the build, I kept this in mind and used it anyway figuring it was in the ball part.  But make no mistake, this is sloppy for a measurement device.  We would throw this in the garbage at work or send it out for a rebuild, which I may do with this one in the future if the price is reasonable.

2. Craftsman  Micro-Clicker Torque Wrench 1/2'' Drive - 20-250lb-ft (27-340Nm)

I bought this one from Sears several years ago.  This one below is the newer version of mine.  I also bought the Craftsman case and both have served me very well for years and years.  That said, they are much cheaper now at Sears which makes me question where they cut costs to bring the price down.  This might not be the same wrench I have in practice; YMMV.
http://www.craftsman.com/craftsman-micro-clicker-torque-wrench-1-2inch-drive/p-00931425000P?prdNo=1&blockNo=1&blockType=G1

I have literally zero issues with this wrench in use over 6 years.  My results:

Setting: 30 lb-ft -> Reading: 27.5lb-ft - Result: -8.3%
Setting: 50 lb-ft -> Reading: 46.9lb-ft - Result: -6.2%
Setting: 75 lb-ft -> Reading: 66.5lb-ft - Result: -11.3%
Setting: 100 lb-ft -> Reading: 97.9lb-ft - Result: -2.1%

As with the VENZO, I wasn't thrilled with the results, but the wrench was repeatable and was erring on the under-torqued side of things so at least you wouldn't crush your parts using this.  I will definitely be sending this one out for a rebuild.  I ended up using it since I was using it in the 45 to 55 Nm range for the crank and it was decently accurate in that region.  I just kep in mind that it was performing a bit low and aimed for the upper end of the torque spec by SRAM.

[Vipassana]

Headset Install:

I also wanted to add my experiences with the headset install.

I ordered the "FSA" headset with the IP-256SL frame from Iplay.  Everything assembled fine and I used the top cap to draw the stack together and tighten the assembly until there was no axial or radial play between the fork and the frame.  My general test for play is to put the bike on the ground and lock the front brake.  Then I rock the bike back and forth and feel for a click or general movement between the fork and the frame.  On some bikes, the movement of the brake pads in the caliper or the fork stanchions in the fork lowers can feel like headset movement.  So rule those items out, I always press my thumb between the headset and the frame and feel for movement.  If there is play, losen the stem and use the top cap to draw everything together further.  If turning of the bars becomes too difficult, back it off, you've tightened it too much.  This is sometimes an iterative process.

The first time I assembled everything on this particular bike, I did so dry.  That is to say, I used no grease anywhere in the assembly.  Everything went together perfectly, however, after about 100 miles (45 on the trail), I started to get creaking and popping from the headset area.  It was very apparent when I hit the front brakes or pulled/pushed on the handlebars hard.  It got louder and louder.

I checked everything for tightness and everything was sight with no play.  If I tightened the top cap further, the assembly would bind and steering would become tight.  I assumed that this clicking/creaking must be a result of micro movements between the bearings and the carbon frame.  Disassembly of the bike confirmed this.  See below.



The black particles everywhere appeared to be overspray from the bear seats in the frame.  The seats were now nice and smooth and shiny indicating that the bearing was moving and had polished/cleaned the seats of manufacturing debris.  Additionally, you can see the "hot spotting" on the bearing (brown marks).  This was another indication of play between the two.  My solution was to reassemble the system, but with grease between the bearings and the frame's bearing seats.  For the grease I used a waterproof, super long-lasting, silicon based, suspension grease that I also use on my race car's suspension bushings.  This is the stuff:

http://www.amazon.com/Energy-Suspension-9-11104-Formula-Prelube/dp/B000CN7B4I

Warning: This stuff is sticky.  Insanely sticky.  It can really only be cut with a solvent so apply with care and a q-tip and gloves.  Don't slop it on, much isn't needed.

I should also note that I removed the rear drop-outs and put this stuff between them and the frame to avoid any issues back there with noise.  Preemptive maintenance.

[Vipassana]

Internal Cable Noise:

My last tip for today is how to prevent noise from internally routed cables slapping on the inside of the frame tubes.

My build suffered from this issue and after my first long offroad ride, I almost threw the bike off a cliff because the rattling noise was so loud people were staring at me as I bounced by.  That's not the feeling you want from a bike you have thousands of dollars into.  I first thought this may be the result of a poorly designed Chinese frame.  But after reading, I found that this was a common problem with many name brand frames as well.

Here is a solution my buddy came up with on his Chiner and it worked well for me.  First, go to the hardware store and pick up some of the foam used to cover water pipes to prevent freezing.  It should cost you less than 5 bucks.  Next, remove your fork and stem so that you can see down the down tube.  Cut a 2-3" section of the foam and wedge it into the down tube.  Orient it so that the cut section (pacman's mouth) clears the shifter cable.  You don't have to do this as the foam really doesn't seem to impact the shifter cable.  Then use a long rod to push it down the tube.  I got to the water bottle mounts and stopped.  Then I repeated the process again, but only pushed it down a couple of inches.  Looking in the tube you can see the break line pressed up against the sidewall of the tube.  It cannot slap around now.  Reassemble the headset and enjoy a silent bike.  Cheap and effecting fix.

An acquaintance with an IBIS said that IBIS told him to put zip ties on the brake line with long tails and do not cut the tails.  They claim the tails wrapped up in the down tube prevent the cable from moving as well.  I have not tired this, but it seems like another good option.

[Vipassana]

Also, I think this should be moved to a more general area than the 29er subforum.  These tips apply to most every carbon bicycle regardless of wheel size or road or MTB.  Good idea for a thread.   

I'll have a few more to add in the future.

[outriding9800]

I did the same as Vip.. but I found there was still some "release agent" on my stem and carbon steerer. It cause a bit ofcreaking.  I cleaned it with some rubbing alcohol. I did put some grease on te headset bearings   I used this.

http://www.belray.com/bel-ray-waterproof-grease

I have used for years on other things and it has never failed me...

[Carbon_Dude]

For quick jobs or to take with me on the trail to adjust a seat post, bars, levers, etc.  I have a Ritchey 5N-m torque key.  It comes with 4 bits.  At home I have a craftsman torque wrench but am thinking it might be nice to have the Venzo Kit that Vip mentioned.  Park Tools Polylube grease for metal components, Finish Line Fiber Grip between the carbon bits.  I use the paste mostly to prevent and wear or creaking, I like a quiet bike.