I realise that i'm not the most gentle on wheels but HOW THE HELL?!
Second ride out on my fancy new (carbon) wheels and i've just noticed two large cracks in the rim, pretty much exactly opposite each other.
is one likely to be the cause of the other or am i looking at some sort of rim/building defect?
Tyres were over 20psi and still inflated when i got back to the van
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Gonna be fun 'ard rocking on a hard tail tomorrow
The god of carbon has done that to you for buying ghastly weaved rims
Don't worry.
Someone with the all the engineering expertise of a dead tench will be along to blame something in a minute.
😀
Clumsy git. 🙂
I'm going to guess its due to logo/valve misalignment.
Admit it, you just prefer riding your on-one.
How much over 20 psi? Unless by 10 psi or so I would suggest that is your issue.
That doesn't look like a crack to me - can you actually feel a crack with your finger nail?
It does look like a discontinuity in the carbon-fibre weave. So long as the resin over it isn't cracked or damaged I'd carry on riding them.
They're definitely cracks, both of them :/
was running 25/28 F/R by the way but didnt check the pressure before i popped the tyre off to change it. Still felt firm though
Spec me a bombproof wheel?
I guess it depends on what you riding but if I had carbon rims I don't think I would run under 30psi (I run more than that anyway).
If you are hard on rims then I would check out nukeproof. They are about £15 on crc. No rims bombproof but it won't hurt the wallet as much!
Assuming you dont want to go full on DH weight then a DT EX471 32h rim on whatever hubs are going with decent quality spokes built by someone who knows what they,'re doing.
Seemed to work for Gwin last year, tyre or no tyre.
What rims [s]are[/s] were they?
What wheels are they? I beat the bejabbers out of my original LB rim, it took a long time to die... Massively tougher than any equivalent-weight metal rim... I reckon anyone who found that one delicate would just need to be getting a full on dh rim tbh
I reckon carbon could be more bathtubby in failure rate than metal though- more liable to manufacturing defects which'll often show up as failures in the first few rides...
It was a LB 32H, I've pinged them an email to see what they say.
I was just surprised at the double failure opposite each other (give or take an inch) and interested if one could lead to another or if indeed it's indicative of a manufacturing defect
That sort of opposite fail is a little bit like how compressed tubes buckle at 90 degrees to the forces applied... But I really can't see how that makes sense in a wheel, unless it's been somehow compressed when unbuilt.
*[i]checks weight thread to see if Scaled has posted[/i]*
Great thread title BTW...
If the scuff on the sidewall of the tyre in the first picture is anything to go by looks to me like you thwacked the rim when the tyre bottomed out! Are they tubeless tyres or tubeless ready or non tubeless? Is your pressure gauge accurate?
I agree that mark on the tyre probably indicates something happened at that side.
+1 I reckon someone is telling porkies and that an impact has occurred.
Some steel / alloy wheels are 'pinned'
As everyone knows, Carbon Fibre wheels are 'spooned', that is to say they are joined via spoons wrapped in carbon fibre. just re-wrap then and slap some resin one and they'll be fine
I agree that mark on the tyre probably indicates something happened at that side.
That tyre has never turned in anger, I'd only just put it on when I noticed the damage. the 'scuff' is sealant.
And i'm under 12 and a half stone ya cheeky sods
Those rims have plenty of usage marks on them (and mud).....only saying what I'm seeing.........
Those rims look like I've made them. With a blue peter build your own carbon wheels set, involving sticky back platic and cornflakes packets. What on earth are they?
No Less than 30psi? Why? Northwind, what did you run yours at for all those years?
Running less than 30 makes the bike feel sluggish and make damaging rims too easy also if tubeless you can roll the tyre off the rim.
Might just be me though?
I see rims as disposable items like tubes though so perhaps it's just me
If it's holding air tubeless just ride it.
Might as well finish it off properly!
damascus - MemberWhy? Northwind, what did you run yours at for all those years?
Allsorts, but I'm light. Probably 25 most of the time, sometimes less with a stronger tyre
Have to consider rider weight as well. I'mabout 75kg geared up and will ride low 20s front high 20s rear.
I have had two LB 35mm AM rims go like this both times tubeless at approx. 26-28psi. Both times I was descending fast rocky trails and felt the impacts, but if I had been running tubes & alloy rims then I would have expected a pinch flat, and maybe a small rim dink, but nothing more.
The first was similar to what you show in your photo and when you take the tyre off you could see delamination in the rim wall. LB replaced it under warranty.
The 2nd time the crack was bigger and when I sent the photos to LB they said 'you've hit a big rock very hard haven't you?' to which I cannot deny - needles to say not replaced under warranty.
Have now realised carbon rims are not for me (85kg & ride lots of very rocky trails), at least not on the rear.
If they're useless and have no value, you've nothing to lose by doing a repair yourself.
Hmmm looks like you parked it in a field full of cows!
They look really cheap.
They do look cheap-talked me out of buyin some if a 12 stone weakling can snap em so easy, so thank you Sir!
PS, breaking bike bits does feel actually quite good doesn't it?