Why no light, carbon, hardtail MTBs?

[Renard]

Extra layering where its needed.

 

[mr Mag00]

yeah, than extra layering is gonna add milligrams to the weight , mnot like gussets that used and are still welded to metal frames, it will still be lighter than the equivalent trad materials. and if you are racing them it is unlikely that you will be training on it too. so far less wear and tear

 

[roadjunkie]

They do (did in 2007) a Giant XTC SX (hardtail) with a carbon frame..

 

[bike_the_planet]

Lots of R&D money has been spent developing superb, smooth-riding carbon road frames, which weigh less than anything ever before, but how much effort has gone into developing really fast, comfortable, lightweight XC MTBs? Does such a thing exist? Am I missing something?

The problem is carbon's poor impact strength and strength in compression.

When you're flying downhill on an MTB you're far more likely to meet unforseen stresses, bumps, obstacles etc.

Materials like steel and ti are equally strong in compression and tension. But carbon isn't. It's great in tension but poor in compression and impact. And compression/impact are exactly the stresses that MTBs are more likely to encounter.

Also, Carbon's failure mode is different to steel and ti. The latter have a failure stress point significantly higher than their yield point. Carbon doesn't have a separte yiels/failure stress point - they're essentially the same thing meaning a sudden or 'catastrophic' failure.

You can get carbon MTBs - but you have to be alot more careful with the way you handle them.

Cheers,