Cycling UK Forum

Hi,
What do you think the cause of failure is likely to be
And whats the line above writing?
The vid on the link shows more, clik youtube and 30 seconds in.

http://bicycletouringpro.com/warning-ab ... try-tires/

I read that page a couple of weeks ago when I was looking at tyres, from memory doesn't he say that the sidewalls are quite thin?

I ended up with Conti Grand Prix 4 Season tyres which I'm very happy with.

Hi,
The town and country is a mtb size tyre only, your grand prix is a all season road bike tyre?

My point is that a failure like the cracked line above writing where tread meets canvas which he makes little reference too, and the perish at around bead which you get to a lesser extent anyway points too under inflation?

In his blog he says the bike shop suggested underinflation and he countered it with being an experienced tourer and knowing how to keep his tyres inflated.
I would be interested in what he thinks is the right pressure for these tyres and how it matches the weight distribution on them.
The symptoms fit with underinflation, as he normally rides much thicker sidewall tyres he may be used to riding with tyres that can take lower pressures than these thin sidewall ones can.

Hi,
Yes,
As bicycle tyre walls are thin any way a thicker wall will go the same way I would of thought in time.

I use the very same tyre touring over Dartmoor all up bike 70 Ibs plus off road and I don't see the need for under inflating tyres

Pinch flats and bent rims abound.........................

In my green lanning days you would run rear at 5psi and 2 if you needed more grip only in deep mud / on wet grass................but flats and damaged rims run high.....................

I think he needs more air.

Hi,
https://www.google.co.uk/url?sa=i&rct=j ... 0579987856

That one was surely driven while flat or it was touching something while driving.

Hi,
Yes, first pic I found but similar place on tyre.

Where's Brucey

Probably got the day off.

About 15 years ago Contis were notorious for sidewall failure when there was still plenty of tread left.

I stopped using them for that reason.

30 days is a bit quick though.

Hi,
I was using conti's about 30 years ago, grand prix supersport etc, never had a problem at all, used grand prix 25mm on my 200 k audaxes.

When I started up cycling after a layoff about 6-7 years ago I rekindled my cycling interest by going camping with my bike, and started using mtb conti trail master IIRC (now discontinued) I replaced with town and country and used it for the same, off road railway tracks etc.

I know that some conti that roadies use have had problems, from reports here on forum.

http://road.cc/content/feature/180830-h ... e-pressure

That graph is a good illustration of the relationships, but not a good graph of facts.

Strange - for instance - that a Conti GP 28mm tyre has recommended max pressure at 110psi, and a Conti Sport Contact 28mm tyre has a max pressure of 85psi.
Does this mean that with you can be a MUCH heavier rider with the GPs than the SCs?
Somehow, I doubt that very much indeed.

A more supple tyre needs more air in to support it for the same load,and a bigger air chamber needs less air than a smaller one for the same support.

IMHO the tyre in the OP looks as if it's a victim of underinflation for load and has taken a stone hit or pothole where the tyre's been nicked in the first photo.

meic wrote:That one was surely driven while flat or it was touching something while driving.

I wonder; if I saw that (failure at the inside edge of the tyre) I would assume that the toe setting and/or the camber was miles out. You can see that the tread is entirely worn off the inside shoulder only, over a wide area; this pattern of damage is inconsistent with either rubbing or low pressure. I would suppose that the carcass shoulder became exposed through wear and then failed.

Diagnosing bicycle tyre failure is often more difficult than that; the Conti in question could have been badly made, badly treated, or both.

I'd have to say that I have had carcass failures in Conti MTB tyres (that were not underinflated) and I have also seen Conti MTB tyres fail by perishing prematurely. I'm not overly impressed with them just now.

cheers

blackbike wrote:About 15 years ago Contis were notorious for sidewall failure when there was still plenty of tread left.

I stopped using them for that reason.

30 days is a bit quick though.

Quite correct. I started using Conti Top Touring 2000 tyres, they were superb, great supple ride, good grip and noticeably low rolling resistance. Can't remember what I was using before.

However I never went close to wearing one out, the reinforcing tape on the bead chafed through leading to sidewall failures. I was only cycling locally and would not have used them on long trips. Why didn't I stop using them? Because the distributor replaced them and so this kept me in tyres for many years.

More recently the Town & Country tyres that were on my mum's bike handed down to one of my daughters have lasted incredibly well, not used hard but now the treads are so cracked and perished I have a pair of Marathon Supremes waiting to go on. 15 years old at least!
Also the Travel Contacts have served me well on my old MTB used on the road commuting and touring, so much so that I brought a new pair, which do seem a touch lighter weight and with less tread thickness possibly.

Having suffered a couple of sidewall failures on Conti high performance road tyres I am wary, but not sure if this was bad luck or anything else.