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Latest Bike Material Evolution!?!?(11 posts)

Latest Bike Material Evolution!?!?wasabekid
Jan 6, 2003 5:23 PM
I've recently heard that some manufacturers are now experimenting with Kevlar fiber reinforced bike frames and forks. This might be the next evolution to the Carbon Fiber tubes.

Anybody heard of this?

No sites to post so far but if you have info please share.

Thanks,

W.
It's been going on since the 80'sDave Hickey
Jan 6, 2003 5:47 PM
Vitus and LOOK used Kevlar in their frames since the 80's.
It's been going on since the 80'swasabekid
Jan 6, 2003 6:06 PM
If that's the case I wonder why didn't it catch on? In theory the kevlar polymer is stronger than the carbon.

If this catches on this time, we will be faced with another debate regarding it's merits and demerits.

W.
I think this has been done a few timesKerry
Jan 6, 2003 6:12 PM
over the past several years. However, it hasn't seemed to catch on, though it seems like it should. It may just be that no one is offering CF/Kevlar pre-preg and so there's no base for it (you have to make your own pre-preg, which adds cost and reduces consistency). Alternatively, it may be that the cost/benefit isn't there, or that there's just no benefit. Kevlar is not nearly as strong in tension as CF, so it may be that it provides impact resistance more than the characteristics desired in bike frames.
KevlarFez
Jan 6, 2003 6:26 PM
Kevlar use seems to be ideal for things where durability and light-weight are important.

Bulletproof vests, and motorcycle clothing/protective gear come to mind. I think you can get it on the trim of some saddles so that if you wipe out your saddle is still in OK condition.

My guess is if we see it in bikes, it would be combined with other materials like carbon fiber and not used by itself.
I think this has been done a few timestoomanybikes
Jan 6, 2003 8:05 PM
One other point - re cost.

I have a client that uses a lot of Kevlar in their product. Cost of Kevlar has gone through the roof the last few years because they use in manufacture of Fiber Optic Cables, to sheild the cables before they ae buried.

Why sell the stuff to bike builders when you can get premium price (and then some) by selling to people who want to bury it in the ground!
Some problemsspeedisgood
Jan 7, 2003 7:05 AM
I don't claim to be someone who does a lot of work with the stuff but I did some research last year on CF/aramid applications for a bike frame I had to repair (see pic). BTW, it's aramid generically cuz Kevlay is Dupont's trade name for aramid. Anyhoo, I had to reinforce the front of the seat tube on my TT bike as the bar holding the set screws holding the seat post was herniating the seat tube skin.

The problems with aramid as I recall is that it's super hard to cut (that's why it's bulletproof) so much that you have to use special ceramic scissors. It's also denser than CF (I think) which makes it less than ideal for a complete bike to be made out of it. And the main issue is that aramid is not really stiffer than CF. Aramid is best used as a tensile load bearer (loaded in stretch) as opposed the compression (like a pillar). I think the blend idea is good, to give a frame more impact resistance, but the stuff is REALLY a pain in the ass to cut so it's probably more of an economic consideration to not use it more.

My $0.02.
It makes a sweet chainstay protector thospeedisgood
Jan 7, 2003 7:12 AM
I guess boat builders use aramid matting as skid plates for small boats.

Merckx has CF wrapped chainstays. I say aramid makes more sense!
sounds good for spokes thofractured
Jan 7, 2003 7:44 PM
I believe there are a few manufacturers exploring kevlar spokes, although nothing i'd trust yet... Could prove lighter and stronger and more aero than the best metal spokes.

There are also some tensioned kevlar disks out there. Accel makes a very light one.
Perfect for Spinergy's IMHO [nm]speedisgood
Jan 7, 2003 7:55 PM
Giant MCMJowan
Jan 7, 2003 11:04 AM
Don't know for sure, but I think the Giant MCM composite MTB frame's are kevlar re-enforeced. You can see a yelowish thread in the tubes.