Tyre cracks

drumon

Hi

I have Continental Sport Contact tyres on a spare mtb for the road.

Both tyres are showing cracks in the tyre wall around the circumference on the diamond (dynamo?) strip, and a line/crack by the rim.

Is this superficial wear/ageing or does it make the tyre unsafe? I was considering using them for a 50 mile road ride. Hopefully the picture shows the cracks clearly.

keef66

As long as there's no sign of the tube appearing through any of the cracks I'd say it's probably safe to carry on riding those.

marcusjb

Not sure I would be quite so keen.

That looks like the tyre has been run underinflated for some time and caused that cracking?

At some point, the top part of the tyre may make a break for freedom from the carcass of the tyre - particularly on the front tyre, that may have some consequences that are reasonably unpleasant. Trouble is, you just don't know - they could last for many miles like that, or not very many miles.

keef66

OK, I'll qualify my earlier advice. Keep riding them but keep an eye on them. Don't do any white-knuckle descending or sign up for the Fred Whitton.

drumon

marcusjb wrote:

Not sure I would be quite so keen.

That looks like the tyre has been run underinflated for some time and caused that cracking?

At some point, the top part of the tyre may make a break for freedom from the carcass of the tyre - particularly on the front tyre, that may have some consequences that are reasonably unpleasant. Trouble is, you just don't know - they could last for many miles like that, or not very many miles.

Thanks for the advice. They haven't been ridden under inflated but bike has been unrridden for a while with tyres below recommended pressure. Recommended pressure is 80psi. Will keep an eye on them.

bikes`n`guns

Bin

I wouldn`t ride those

Schoie81

I wouldn't ride on them either. Its ok saying they're fine if the tube isn't appearing through the cracks but that would be true 1second before the crack goes through the tyre and the tube IS appearing through. As Marcus says, might last the 50miles, might not last 5... The tyres are the one thing that keeps you on the tarmac

Out of interest, if the tyre drops to bits 25miles in to your 50mile ride - do you have a back up plan to get home?

Matthewfalle

Wouldn't touch them. In the bin and replace.

apreading

If I had an event tomorrow then I would probably chance it and ride them and replace as soon as practical, but would not be keen to advise someone else that is the correct course of action or in any way sensible. I think if you feel the need to ask on a forum then you already know the right answer - doesnt cost much to replace and needs doing soon anyway. But you make your own choices regards how much of a risk you want to take.

IShotYou

Better to take a trip to buy new tyres, than a trip to A&E because you didn't.
Cost of new tyres Vs Cost of time off work/new lycra/and new tyres! etc etc. Simples.

rolf_f

keef66 wrote:

As long as there's no sign of the tube appearing through any of the cracks I'd say it's probably safe to carry on riding those.

I guess though there is no reason to assume that the tube will appear through any of the cracks. The fabric under the rubber is keeping the tube in rather than the rubber coating to the sidewall. Posh tyres don't even have rubber on the sidewalls.

The issue here is perhaps that the rubber is probably brittle and probably won't grip too well. I ran (for several hundred miles - I come from an age when we didn't scare so easily!) my Record Ace with the old Michelin Grand Tours it came with. They were pretty hard and the back just locked up everytime I used the back brake (which was impressive as I was using Weinmann calipers at the time! )

I wouldn't fear death on that tyre but you could get a nicer tyre to ride for about £6 so why not?

keef66

My advice was based on my recent experience with some GP4Seasons which I ran till the carcass was appearing where patches of the, admittedly very thin, remaining tread started to delaminate. Impressively they still didn't puncture. For the OP I hadn't considered that the hardened rubber might not give the expected level of grip, especially in the wet.

If you're absolutely skint, keep riding and watching them. And go carefully in the wet.

drumon

Thanks

Will keep riding them for short rides and watch how they go. I'll replace them in due course, sooner than later.
Appreciate all the points of view

Matthewfalle

drumon wrote:

Thanks

Will keep riding them for short rides and watch how they go. I'll replace them in due course, sooner than later.
Appreciate all the points of view

Seriously? They're funked dude. Chuck them away. If you're skint get some Vittoria Zaffiro slicks at £6 each - slick, roll really well, last for eons.

Hey ho, its you and your bike though ..........