lee_rimar

Short version: Lighter and stronger than steel, carbon fiber, kevlar, and even spider silk.

Long version: ... a very tough material ... highest impact strength of any thermoplastic ... highly resistant to corrosive chemicals ... extremely low moisture absorption, self-lubricating, low coefficient of friction (comparable to Teflon), better abrasion resistance than carbon steel ... odorless, tasteless, and nontoxic. ...

Source: https://en.wikipedia.org/wiki/Ultra_high_molecular_weight_polyethylene


Why aren't more bike components made of this stuff? Cables? Tire belts/beads? Spokes? Sprockets and chains? Forks?

Siu Blue Wind

Is it costly to do the Gel spinning? Production costs perhaps.

Retro Grouch 

What does "impact strength" mean?

BarracksSi

Check the section about hip & joint replacement. Every other application is basically a rope or a coating; the hassles of making it a structural material seem like reason enough to not use it in a cycling application.

The spinning manufacturing process is like how a spider spins its thread (the early fishing & kite lines that used this material were even called Spiderwire). The molecules are already long & narrow, and the intent of the process is to align them as parallel as possible. That's where the high strength & low friction come from.

I've only used it in kiteflying, and it kicks Kevlar's ass as a kite line, being very light & thin for its strength, with very little stretch (about 4%, last I heard) and exceptionally low friction against itself (important when doing spins with a kite) -- but it needs to be tied with a protective sleeve, or else the knot will either slip or melt. I imagine that it would need the same reinforcement as a shifter or brake cable, and I don't think that its low melting point (MUCH lower than Kevlar's) would inspire confidence as a tire bead. It's still polyethylene, after all.

Bekologist

I don't know the why, but Dyneema has been developed with properties that make it a great spun or laid fiber. I've got Dyneema webbing and Dyneema woven into lightweight yet tough backpacks.

It is tough and light.

womble

AFAIK, dyneema is basically a very slippery fabric (at least, that's what it is in my backpack and in my climbing gear. They make sails and cords out of it). You can't make things like chainrings or forks out if it because of this. Or even softer things like cable housing. Bike stuff needs to be stiff, if not completely rigid. If you want to make it rigid, you could probably impregnate it with resin, but that's the domain of CF.

Bekologist

I suspect Vectran fabric and Dyneema are very similar.

You could be riding a Dyneema like materiel in your tires...