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Who are the brain police?
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Are you sure about the higher quality rubber thing? Can you cite a specific example?

Kevlar is lighter and thus more expensive than the wire version. And heavier tires have more rolling resistance. I thought that was it.
 

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Domestic Fowl
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I'm sure there are other more significant advantages, but tires with a kevlar bead can be folded. Wire bead tires cannot. This particular difference doesn't mean poo when the tire is on the rim, but you can fold up a kevlar bead tire and throw it in your tool box. Makes it easy to carry a spare.
 

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Administrator
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I must say that the main reason for the kevlar beads on tires is three fold:

1: they are lighter. By using woven strands of kevlar they can make a tire lighter than a comparable woven strand of steel.

2. Kevlar does not stretch. Kevlar beads will not stretch no matter how many times you remove or change the tire. This guarantees that as the tire ages the tire will always remain on the rim whereas the steel bead will stretch ever time you work them over the bead. This amounts to a looser and looser fit, generally on one side since most people will undo a tire from the same side, creating a situation where the tire can pop off the bead under hard corners.

3. This is also related to the shipping methods, kevlar will not hold the shape of the shipping state where as the steel bead can bend and create a spot on the bead where a kink can affect the tires ability to seat and hold on a rim. This can translate into a wobble in a tire to a tire that will pop of the rim under heavy load.

This is all academic. I suspect that this is a hold back from the early era where some rims were handmade (cut down bontrager's) and some where offshore (araya RM20's) and thus there was a greater variance in the diameters of the rims and some tire that were made were popping of rims. I haven't seen a tire pop in forever and find that WTB and Bontrager make large wheels that prevent popping on any type of tires. The other factor that makes this a moot topic is that tires now do not last as long as older tires, kevlar (read $$$) tires usually have a shorter life span and many DH/FR tires use steel beads because the weight concept is not as important and the casing is so stiff that popping a tire off is a rarity.

You can find the tire differences in kevlar vs steel as varied as the type of tires there are out there.

Generally steel bead OEM tires will be different rubber compounds than the aftermarket tires with steel beads (tioga DH2.1)

Rubber comps will generally be better with kevlar beads because of the premium charged for the tire anyway. Steel beads will be more of the work-a-day versions and usually be $10-15 less than the Kevlar versions.
 

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Premium Member
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Locoman said:
Are you sure about the higher quality rubber thing? Can you cite a specific example?

Kevlar is lighter and thus more expensive than the wire version. And heavier tires have more rolling resistance. I thought that was it.
It varies from brand to brand. Some companies have no difference in the tires other than the bead material (Panaracer is one). Others (Bontrager, Michelin, others) use cheaper, lower TPI casings and sometimes different rubber in the wire bead tires. All wire bead Hutchinson MTB tires, except for the Python, are made in Taiwan instead of France.

I have also never seen a wire bead tire stretch/relax any more than a Kevlar bead tire. The difficultly or ease in mounting is not so much whether it is wire or folding bead. I have had wire bead tires that are very easy to mount and folding tires that are very hard to mount. Just depends on the specific tire/rim combo.
 
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