That is one of the big issues with carbon. Often there are no signs of stress fractures prior to destructive failure. My thoughs about the high modulous as opposed to woven (again this is MY thought, not based on any science)...is that a woven carbon structure will possibly fracture, but the weave of the fabric may have a chance to sort of hold things together. I have seen this on impact destruction as well as as over stress failure (impact on frames, stress on carbon weave fishing poles that cracked but helt together by the weave).
Every point to create a ridge is bad for any handlebar, or steer tube. Now, if you look at my BigOne Stem, you can see there are three potential ridge points, one on each side of the clamp area, one at the closure area....same with the steer side of the stem. A BIG thing that many folks may look past...sand and other pollutants. If you have sand, metal shavings or any other crap that is common in a shop get under a clamp - it will cause a defect in the material and possibly a wonderful start to a future failure.
Now, how many potential areas are there for crushing damage on this stem? This is other than the fact that the rider has a VERY small area of contact for the stem to secure the bar...or transfer the stress load. One thing you cant see here is the rubber insterts that ship with the F99 that go between the stem and bar (could get a photo from my Bianchi though). Also, the F99 stem REQUIRES a special "lube" that has "grit" in it to keep the bolts torqued (got me, I got the packages of the goop)
Now then there are stems like this super nice Thompson. I have seen bars carbon and Alu very damaged by this stem but not with out allot of help from a mechanic who has no clue or torque wrench for that matter. This stem also leaves the steer tube open to the same crushing damage as the bar...again, with a bad mechanic.
This is the stem that is currently on my Litespeed road bike with a TTT Prima220 (NOS) bar. As you can see, there is a solid clamp for both the bar and steer tube. On the other side what is nice is the torque spec is etched right onto the stem next to each bolt.
But, as you can see here http://www.biketechreview.com/...links/bigonefail.htm the ITM can also be broken (this example was broken on a machine).
----------------------------------------------------------
What if the Hokey Pokey is what it is all about?
Every point to create a ridge is bad for any handlebar, or steer tube. Now, if you look at my BigOne Stem, you can see there are three potential ridge points, one on each side of the clamp area, one at the closure area....same with the steer side of the stem. A BIG thing that many folks may look past...sand and other pollutants. If you have sand, metal shavings or any other crap that is common in a shop get under a clamp - it will cause a defect in the material and possibly a wonderful start to a future failure.
Now, how many potential areas are there for crushing damage on this stem? This is other than the fact that the rider has a VERY small area of contact for the stem to secure the bar...or transfer the stress load. One thing you cant see here is the rubber insterts that ship with the F99 that go between the stem and bar (could get a photo from my Bianchi though). Also, the F99 stem REQUIRES a special "lube" that has "grit" in it to keep the bolts torqued (got me, I got the packages of the goop)
Now then there are stems like this super nice Thompson. I have seen bars carbon and Alu very damaged by this stem but not with out allot of help from a mechanic who has no clue or torque wrench for that matter. This stem also leaves the steer tube open to the same crushing damage as the bar...again, with a bad mechanic.
This is the stem that is currently on my Litespeed road bike with a TTT Prima220 (NOS) bar. As you can see, there is a solid clamp for both the bar and steer tube. On the other side what is nice is the torque spec is etched right onto the stem next to each bolt.
But, as you can see here http://www.biketechreview.com/...links/bigonefail.htm the ITM can also be broken (this example was broken on a machine).
----------------------------------------------------------
What if the Hokey Pokey is what it is all about?
Last edited by:
Record10Carbon: Feb 2, 08 19:36