I’m looking for a new steed to replace my Spec Stumpy 07. Most of the bikes I’m looking at are carbon frames. My concern is how will they last. My Stumpy is 5 years old and still riding well but showing the scars of battle. I’m a heavy rider (108kg) and am have been told I’m an aggressive rider, although I don’t get off the ground much. I will chuck it in rock gardens, boulder strewn decents etc and seem to regularly get strikes from pebbles/stones etc.

So will carbon last as well as my stumpy, even if it gets dropped occasionally.

If I were you I would stick with aluminium, IMO carbon isn’t for mtb. I had the same predicament last year and went the carbon route. I’m on my second frame now and my new one is making creaking and cracking noises.

It look the muts nuts but am probably going to change back to aluminium next year.

A well made carbon frame is stronger than an aluminium one.

every person I know with a carbon frame has had it fail in some way or another, take of that what you will.

I dont know anyone with a carbon MTB frame that has failed
Take of that what you will

TBH I think we are all bit resistant to a newer material when it first comes into use but look at all the stuff they use carbon fibre for.
Now it would neither be a plus or a minus for me just like other materials.

Mine has failed in no ways, and it’s not been babied. However, i’ve broken alu frames and steel frames, and I own a broken titanium frame. I think just about everyone I know with a non-carbon frame has broken one.

I’ve broken 5 or is it 6. My riding Buddy has just had his top of the range Trek replaced.

Stay clear.

I ‘ve also broken two Alloy frames but that still make it 5 / 6 to 2 in favour of carbon.

Have you seen this vid of a Santa Cruz carbon vs alu test? Changed my mind about carbon mtb frames completely…

http://www.pinkbike.com/news/santa-cruz-bicycles-test-lab.html

i can’t promise a carbon frame won’t break but it’s a lot tougher than most people realise. I’ve broken lots of carbon fibre in material tests and it never fails to amaze.

Just buy one built for the purpose you intend. ie if you go jumping a lightweight XC frame it will fail just like an aluminium one will.

Composites are used for hockey sticks and axe handles – you don’t get stuff abused much more than that.

Indeed! A carbon road frame is built to be light and is significantly weaker than a carbon MTB frame. So long as you buy one for its intended purpose you shouldn’t have any problems

if I may correct a little..

a carbon road frame will be built stiff and strong in the directions it needs to be – ie to transfer the most power and to be able to withstand massive loads from the rider and harsh jolts transmitted from high pressure tyres and no suspension. It will have a great deal of optimisation for this purpose to give the lowest weight possible for the required stiffness and strength (but still allowance for mishaps)

A carbon mountain bike has a lot more variables to deal with – more impacts, jumps, crashes, suspension mounts etc etc and will be built with these in mind and a higher redundancy to allow for impact – ie less optimised for the pure cycling loads. If you gave me a set of frames out of every material that were all the same weight I would trust the carbon one the most.

That video changed my mind about Carbon when I saw it. My next steed will be carbon and made by Santa Cruz.

Thanks for all your replies – interesting reading and the SantaCruz testing doesn’t surprise me. F1 cars wouldn’t use the stuff if it wasn’t strong.

BUT the SantaCruz pictures above only proves to me that the frame is designed to take frontal stresses through the front forks. I’d be shocked if it couldn’t cope with that. My real concern is when I stack and leave the bike, the bike then bounces on taking side forces impacting with the terrain including rocks. And what about chainsuck. On my stumpy this has all lead to small nicks into the paintwork and into the aluminium. I know from fishing if I’ve damaged my pole, when I put it under stress it will then break.

Its ok for sponsered riders to use as if it fails then they get another one, but for me I wouldnt buy one for AM/ Downhill use as there are too many variables, XC maybe and for road probably
Too many frames seem to fail in one way or another

Mine’s almost four years old & faultless, a good friend of mine still regularly rides one that’s eight years old & I still service one from 1996 that’s in weekly service. All mountain bikes.

BigSteve – you’ve asked a question and received a number of responses, some of which confirm your concerns. Regardless of the facts, would you ever be fully relaxed riding a carbon frame? If not, just buy aluminium or steel and ride on.

carbon frame owner here (ibis mojo hd) – no problems to report, bike has been dropped, crashed, and generally ridden fast over rock strewn descents, had rocks bounce hard off the downtube (with no protector in place) , no issues. A friend with another carbon frame but a bit lighter (titus FTM) has also had no issues with similar riding.

My previous bike, an aluminium specialized enduro , failed when it cracked at a weld.

make of that what you will.

I’d have no qualms about using carbon fibre in mountain bike frames

I’ve got a 3yo carbon frame that’s still going strong. Suffered countless offs, rock strikes, small jumps, etc. I’ve punctured a hole in the downtube of an alu frame from a similar crash to those I’ve had on the carbon bike, and seen a Ti seatstay snap just from the strain of braking.

My personal experiences suggest that I’ll die a fiery death on a metallic frame about 3 times more often than I will on a carbon frame. Doesn’t make me more or less comfortable riding either though, because it’s all just stuff that happens. Just buy whatever you like the look/ride of, and ride it within its design parameters.

I use carbon to protect my alu frame.

Carbon can be repaired far easier than alu

I wouldn’t be put off at all.

I have my Spesh SL2 carbon now for 3 years without a hint of an issue. I have had my Felt Edict LTD carbon frame for 6 months and TBH I have no issues with it at all – I don’t see (unless you going to hammer it way beyond its function that its really an issue – not “Many” people keep a FS frame for more than >10 years? Other things fail more than the frame components?

My real concern is when I stack and leave the bike, the bike then bounces on taking side forces impacting with the terrain including rocks.

They seem to have cut that Santa Cruz video short as when it was first released the last segment showed them hitting that white nomad frame onto the corner of some concrete as hard as they could (on the top and down tubes) and not one of them could get it to break I seem to remember!

My Madone SL road bike is now 9 years old and still fine, that was a pretty light frame back in the day too.

I’ve ridden carbon MTBs for 10 years (at least 10 of them) and never broken one. I’d not have any qualms at all about carbon. As Druid said though, if you do, don’t buy one, it’s simple! But the facts are that it’s stronger.

No more carbon frames for me.

I’ve got a carbon zesty, 20 months old and the press fit bottom bracket spun round in the shell wearing the carbon and trashing the frame. Lapierre told me it was my fault…

No more carbon frames for me.

I’ve got a carbon zesty, 20 months old and the press fit bottom bracket spun round in the shell wearing the carbon and trashing the frame. Lapierre told me it was my fault…

No more food for me.
Went to Tunisia and got gastroenteritis from a dodgy salad.

🙄

Carbon is obviously rubbish as a frame medium, proven by the fact that no manufacturer uses it any more. 😉

ps. My only MTB is Carbon, cost £300 for the frame and is, so far, as hard as nails.

I bought a Whyte 146s. Some of my concerns are because of that bike. But it was as useful as a chocolate fire guard and after having the frame replaced and the 3 set of brakes that failed it went back to the shop. It also suffered severe cable rub to the frame in 3 rides. Now that was through the paint down to the carbon.

And the other problem is the bike I’m looking at only seems to be in Carbon.

I tape up carbon and alu against cable rub

I have broken aluminium, carbon and titanium frames (check the forum name).

The alu frame got bent in a crash and was junked.
The Ti frame snapped at the rear triangle after a week and was replaced immediately under warranty.
The carbon (1999 Scott Strike) snapped the little sticky up bit holding the front mech in place. It was replaced without question and is still going strong.

I am a heavy, aggressive, clumsy, accident magnet. I have crashed the Scott regularly and it has chips and scars to prove it.

I would recommend a carbon Scott to anyone who will listen

Arguments about the ‘strength’ of carbon v aluminium are a bit of a red herring.

All frames be they carbon or Al with have been designed and stressed to cope easily with any expected loads from riding.

The main concern really is the same as with aircraft which is called BVID – Barely Visible Impact Damage. You can impact a carbon laminate and it may look perfect from the outside, but the laminate itself can be badly internally damaged. In this state it will no longer necessarily be able to cope with the design loads. Then it fails catastrophically rather than warning you with deformation.

There’s a YouTube clip of Niner battering their carbon forks with a lump hammer that pretty much shows how good carbon copes with direct impacts rather than stress loads and it’s pretty convincing.

I’m not sure eBay carbon frames would fair the same but you get what you pay for.

I would recommend a carbon Scott to anyone who will listen

+1

I have a Scale and whilst my riding style may best be described as jey-boy lite, I’ve ridden it (badly) all over the shop, off drops, jumps, rocks and even crashed it a few times. Tough as old boots. Plus stupid light.

BVID – Hmmm, My frame has a Big Visible Impact Damage where I hit a tree at about 20 mph totoally out of control and about 8 feet in the air. the main thing i noticed was it went Clack! instead of Clang!!!!!!. Different noise and much shorter ringing than when I killed the Alu frame.

Just to put the proper STW view forward : You ARE going to DIE!

Just possibly not from riding a bike

Well i had a pro-caliper Gary Fisher OVLC carbon 1996 used it to race few years then fun riding.Still going strong my Dad has had it for years no problem.

Just to show I’m not talking bs

Coincidence , but the lad who owns this bike is also called bigsteve

anyone ever ridden steel?

gb1m – is that a Whyte as well?

nathaneddy – yup – I have a cotic soul – steel bike.

And I’ve realised that I’ve been riding with Carbon Forks on the road bike for the last 3 years. And I haven’t died yet 😀

yep it is Steve.

If I would buy another carbon bike I would go for a specialized or a giant because from what I’ve been told are well made and have a good warranty.

A mate of mine is on his 6th or 7th Sworks frame but all have been replaced within a week which is reassuring if nothing else. I waited 6 months for my 146 to be replaced which has left me with a bad taste .

“Carbon can be repaired far easier than alu”

You hear this a lot, but would anybody seriously do this and then ride it? I would even question whether welding up a steel or aluminium frame is a good idea. Depends on the damage I guess.

The strength of the carbon itself shouldn’t be questioned, more the design and quality control of a particular frame. There’s a big element of trust in the manufacturer!

I am definitely buying a carbon frame soon, but still deciding what to go for. For now I’ll just keep on riding my steel hardtails!

I have ridden a Mojo SL for the past 3 years and just recently the frame failed. Not due to the numerous offs or rock strikes but by an aluminium insert within the carbon frame, which housed the front pivot bolt, unbonding from the frame. Replaced without a quibble as was the rear triangle that was also showing some wear at the pivot bolt.

For comparison, i rode a Marin for three years – cracked one frame and three swingarms before being told to sell it and get something stronger. I then rode a Heckler for two years before cracking the downtube nearly all the way round – luckily I found it before it failed completely.

I’ve no worries about the strength and longevity of carbon frames and their ability to soak up trail riding and its associated crashes 🙂