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Carbon Steer Tube Help(10 posts)

Carbon Steer Tube Helpgabaguy
Sep 10, 2003 8:33 PM
Can someone give detailed instructions on installing a carbon fork with CARBON steer tube. I hear there are some differences compared to aluminum
re: Carbon Steer Tube Helpclintb
Sep 10, 2003 10:20 PM
What particular questions do you have? Besides material, there's really not much difference in the installation. They both have to be measured the same. Both will also need to be cut to a height within manufacturers guidelines. Not a heck of alot more than that.
re: Carbon Steer Tube Helpgabaguy
Sep 11, 2003 4:00 AM
someone told me you have to cut the steer tube 3 mm above the stem (rather then below as on an aluminum tube) and must have spacers above the stem as well.
about the cut..C-40
Sep 11, 2003 5:38 AM
You don't have to cut the steering tube longer than the stem, it's just an idea that some think will reduce the chances of cracking the steering tube from over-tightening the stem. I've done all mine in the conventional manner, with no problems.

Be sure to mark the length correctly. Install the headset, the desired spacers and stem, then scribe a line at the top of the stem. Make the cut just below this line, or above if you choose to use a top spacer.

As others recommended, use a new 24T hacksaw blade. You don't need to "cut quickly". The best way to avoid fraying is to cut GENTLY, with light pressure. I prefer to cut AROUND the entire perimeter of the tube, rather than through it, to be sure that I'm following the line. After the steerer is cut, use fine sandpaper or a file to dress the edges of the tube.

The fork will come with a special expanding plug to reinforce the top of the steering tube. A star-fangled nut is never used on a carbon steerer.

It doesn't take a lot of force to hold the stem in place. Don't get carried away tightening the steering tube clamp bolts, especially the top one.
I've used a carbide blade (I think that's what it's called). Itbill
Sep 11, 2003 5:56 AM
makes a very smooth cut. It's not a blade, really, at all, but a cable coated with . . . something -- carbide? . . . that kind of sands it's way through the carbon fiber. They're about $5-$7 at any hardware store -- expensive relative to a hacksaw blade, but not in absolute terms, and they do a nice job.
To guide the blade, I've used hose clamps.
I've also always cut the steerer on the bike, whether from laziness or whatever. It just made sense to me to do it that way, gripping the bike between my knees as a way of holding the thing in place rather than putting the fork into a vice. I then sand the cut smooth and flat with very fine sandpaper wrapped around a flat piece of wood.
Noooooooo, the BEST way to avoid fraying is.....................Synchronicity
Sep 11, 2003 5:23 PM
to use the proper blade!

A tungsten carbide blade, like bill said. A wire coated with chunks of the stuff. I know it costs more, but do it properly. Consider it an investment. There is no need to tape the tube while you cut it.

CF is quite brittle. An extreme example: would you cut a brittle floor tile with the same 24T hacksaw blade? No, you neeeed something hard to actually cut the material. These special "blades" are meant to cut very hard & brittle materials & will slice through that CF steerer tube with ease. :-)

Spread the word, dudes. 'Cause most people do it wrong. Hell, I can't monitor this board all day long acting as the "carbon fiber steerer-tube nazi" can I?

My, this is one of those things that needs to be in the FAQ section.
re: Carbon Steer Tube Helpasphalt assault
Sep 11, 2003 4:02 AM
With carbon steer tube, you do not use a star fangled nut as you would an aluminum or steel steer tube. A special expanding plug is used instead.

Also it's generally not recommended that you use any more then 20mm of spacers under your stem.

When cutting to size, use a NEW hacksaw blade and saw through the diameter quickly without stopping. This will reduce the chance of fraying the weaved fibers.

Other then that, all is about the same as with an AL biggie.
re: Carbon Steer Tube Helpdivve
Sep 11, 2003 5:39 AM
My fork and some others that I've seen also include an extra tall top cap which inserts about 30mm into the steerer. I don't know if it's included with all carbon steerer forks. It allows you to tighten the stem really well and prevents it from crushing the steerer.
Yep...asphalt assault
Sep 11, 2003 9:34 AM
That's the expandable plug that is used instead of a star fangled nut.
typical for Mizuno forks...C-40
Sep 11, 2003 2:20 PM
The extra-long top cap is used on Mizuno forks (like the one on my Forndriest). Seems to work OK.