Carbon fibre rear ends
Discussion
Your call...I saw a 2nd hand Scott Spark the other day for 2k, my dream bike, bike shop was saying that it had just had a new back end too! The man maths was running at full speed (sell the fuel, sell my pet cat) until I thought about the two times I dropped my fuel on rock gardens at CYB and put a tiny dink in each seatstay and I started to think better of it, and especially as it was a shop team bike that had done a year, it had probably been ridden by someone with infinitely more talent than me...
Chrisga on here is building a project bike from a hardtail carbon frame, also with seatstay damage, it can be repaired with CF that we use in sailing, however it won't be pretty and will probably be more of a bridleways/greenlane bike.
Tricky one really...
Chrisga on here is building a project bike from a hardtail carbon frame, also with seatstay damage, it can be repaired with CF that we use in sailing, however it won't be pretty and will probably be more of a bridleways/greenlane bike.
Tricky one really...
Absolutely fine, buy a reputable brand, and check like you would any frame for cracks and damage, however I've ridden several carbon rear ended frames in my past and all have been no problems at all.
In some ways they will suffer from less issues as they're usually bonded putting the lugs under less heat stress making the frame stronger.
Obviously impact damage is worth taking care over, but hit a frame hard enough to damage carbon, and you'll have dented a normal frame anyway.
Advantages of a carbon rear end (aside from lightness) include quite a significant trail buzz removal at the back.
ETA this assumes you're talking about hardtails.
As for full suss, the same applies, by in large.
In some ways they will suffer from less issues as they're usually bonded putting the lugs under less heat stress making the frame stronger.
Obviously impact damage is worth taking care over, but hit a frame hard enough to damage carbon, and you'll have dented a normal frame anyway.
Advantages of a carbon rear end (aside from lightness) include quite a significant trail buzz removal at the back.
ETA this assumes you're talking about hardtails.
As for full suss, the same applies, by in large.
Edited by neil_bolton on Wednesday 11th February 09:12
smifffymoto said:
I was thinking full sus but the problems are the same.If you ding alu. it's just a dent but carbon suffers from structural weakness I would of thought,then again I could be talking rubbish
Don't forget that alumninium is a much softer material, so will dent more easily and suffers more from stress fracturing that an equivilent carbon tube will.The sort of damage required for a catastrophic failure of carbon is the sort that would kill aluminium also.
My mate's carbon Scott Genius has a metal rear end. They've apparently designed it like that as it's the rear which takes a lot of the stress.
The way I figure things, they make F1 cars out of Carbon Fibre, so a mountain bike isn't going to be a big deal. Its impacts at right-angles to the weave that bother me.
The way I figure things, they make F1 cars out of Carbon Fibre, so a mountain bike isn't going to be a big deal. Its impacts at right-angles to the weave that bother me.
I've got carbon stays on my RM Slayer. I was a bit worried at first, but saying that, I've never held back on it. It's taken some good punishment and been fine. As with most things I've heard some stories about snappage, but it seems to be limited to the earlier stuff, the latest models using carbon should be sorted.
Although I have to admit I was too scared to get a Scott Spark
Although I have to admit I was too scared to get a Scott Spark
Unfortunatley when I stack it my bike is way down the list of bits to protect.I know carbon is strong but "hit" it right and it can be quite weak.As bikes have not been made of carbon for very long do we really know the durability and longevity of it?Remember,a bikes for life not just Christmas.
smifffymoto said:
Unfortunatley when I stack it my bike is way down the list of bits to protect.I know carbon is strong but "hit" it right and it can be quite weak.As bikes have not been made of carbon for very long do we really know the durability and longevity of it?Remember,a bikes for life not just Christmas.
"Hit" it in the right way? You're talking about impact damage of a level of which that would cripple any tubing.The only way you will make carbon fail is to bend the tube past its design limits: The carbon is laid in such a way in order to make the tube stiff in places and flexible (to a finite degree) in others - this is what 'dials' out the trail buzz. Treks OCLV is specifically designed in this way: think butting in metal tubing.
You have to remember this: Helicopters (especially Westland) have been using carbon composite baldes for years and years and led no fatigue failures beyond their deisgn limits - and bear in mind the stresses that they are put under.
Many of the scare stories we hear are just that; stories of people who have been either unlucky or have abused thier carbon frame. I've never seen a carbon frame go in such a way that I think "I'm never riding THAT again" - I've damaged a Trek Y frame by letting the shock smash into the frame when a bolt fell out, and it was fine. We had to get the frame repaired (by Westland no less) but it came back perfect and as strong as it was before.
Remember, aluminium frames are just as liable to go: I've seen a Speicalised rear end snap for no other reason that we believe that the metal wasn't heat treated correctly and it gave up the ghost - so it can happen to either material.
Just get it brought and stop trying to talk yourself out of it: even better stop listening to that mate who keeps talking b
ks about carbon. There are people out there who really know their stuff and wouldn't ride bikes unless they trusted them.
I think what it boils down to is how you hit it. A carbon frame will take big landings all day long no problem at all, but they are not designed to take a sharp point/puncture loading, and that's when things can go wrong. I mentioned chrisga's project carbon hardtail...and spookily enough that's a Giant XTC as mentioned elsewhere in the post.
Depends on the layup too, a UD layup will usually fail over a larger area, ie the crack will spread along the fibres more easily than on a twill or weave layup. We use carbon in racing sailboat building and it's as strong as fook but in any areas that are likely to come in contact with sharp point/puncture loadings such as the cockpit floor or bottom, we tend to put a layer of glass or kevlar in there too for puncture resistance. I know the guy who makes Ben Ainslie's tiller extensions and they also lay up a layer of aramid fibres so that a small failure does not result in a total failure of the stick.
So cane it flat out all day to your heart's content but don't drop it on a rock!
Depends on the layup too, a UD layup will usually fail over a larger area, ie the crack will spread along the fibres more easily than on a twill or weave layup. We use carbon in racing sailboat building and it's as strong as fook but in any areas that are likely to come in contact with sharp point/puncture loadings such as the cockpit floor or bottom, we tend to put a layer of glass or kevlar in there too for puncture resistance. I know the guy who makes Ben Ainslie's tiller extensions and they also lay up a layer of aramid fibres so that a small failure does not result in a total failure of the stick.
So cane it flat out all day to your heart's content but don't drop it on a rock!
PomBstard said:
I'd seriously consider a carbon bike - had a go on a Carbon Giant XTC and its still on my wish list. Just seemed so much more nimble and 'flingy' than even the XTC Zero I've got.
As for carbon breaking, not heard too many stories about frames. Bars, yes, but frames, no.
Those carbon XTC's are superb and very rideable, I miss mine, but it was a very minor crash that finished it.As for carbon breaking, not heard too many stories about frames. Bars, yes, but frames, no.
My good friend has just lost a £4.5k carbon yeti frame (£6.5k bike). I would not touch carbon on a mountain bike. Mountain bikes by their very nature take knocks, carbon doesnt deal with dings very well. This is dependent on your use. If your idea of off road mountain biking is a tow path then go ahead. If it isnt then I suggest you look at different materials.
no tow paths near me. Downhill legend Brian Lopes uses Ibis Mojo frames with no problems http://www.ibiscycles.com/lopes/.
Stif in leeds sells Mojo SLX for £2.6k which is still the same frame as the more expensive ones for not alot of money.
Stif in leeds sells Mojo SLX for £2.6k which is still the same frame as the more expensive ones for not alot of money.Gassing Station | Pedal Powered | Top of Page | What's New | My Stuff