cracks in tyres

Chris S

Legendary Member
Location
Sparkhill
There are cracks running around the edge of my rear tyre rim.

This would be an MOT failure point on a car but I've been told that on a bike the forces are much less and at the spped I cycle at (fast walking) they're not going to make any difference.

Is this correct please?
 

rusky

CC Addict
Location
Hove
There are cracks running around the edge of my rear tyre rim.

This would be an MOT failure point on a car but I've been told that on a bike the forces are much less and at the spped I cycle at (fast walking) they're not going to make any difference.

Is this correct please?
I would say it depends on how bad the cracks are. My M+ have small cracks & are only a few months old
 
OP
Chris S

Chris S

Legendary Member
Location
Sparkhill
[/quote]

I would say it depends on how bad the cracks are. My M+ have small cracks & are only a few months old
[/quote]

I can see something light brown underneath them - is this an internal tyre wall? (as you've probably guessed I'm new to cycling)
 
C

chillyuk

Guest
If it is bothering you then change your tyres. However over the years I have ridden hundreds of miles on tyres with cracks in them. Just ensure you can recognise the difference between a few cracks in the rubber and the rubber perishing, or when the tyre internal wall is failing.
 

gbb

Legendary Member
Location
Peterborough
Just had this Chris...old tyres with cracks running with the tread. As soon as i put decent pressure in one, i noticed it started deforming the tyre....replaced pronto.
Reminds me a good few years ago...riding with similar tyres, BANG, instant deflation. Went like a gunshot.
 

Davidc

Guru
Location
Somerset UK
Decent tyres don't do this. If this happens the tyre is well old and should be replaced.
Agree with you.

If the tyre's perishing there's a danger of a burst, and bike tyres have high pressures so the bits of rubber will fly well. That's in addition to the dangers if the burst is while you're moving.
 

AlanW

Guru
Location
Not to sure?
Decent tyres don't do this. If this happens the tyre is well old and should be replaced.
Even modern tyres will split if you leave them inflated to maximum pressure for any length of time. Which is why after a ride/race you should really deflate them to avoid it happening. From my experience Pro Race 3 tyres are prone to this happening.
 

andrew_s

Guru
Location
Gloucester
We'd need to see a picture of the cracking to give a proper judgement, but...

Usually cracking isn't a problem.
The tyre pressure is retained by the fabric body of the tyre and the rubber tread is just there to provide grip and protect the fabric from the road surface.
There's also a thin skin of rubber on the sides that's similarly there to protect the fabric from stones or any kerb edges you may run against, and a stuck on fabric chafing strip to protect against wear from the hooked edges of the rim. Often you get what looks like a crack when the chafing strip starts to lift at the edge.

It's the first time I've heard of any problem with tyres splitting from being pumped up for too long. I've a Conti GP4S that was sitting for about a year with 160psi in it and which showed no sign of splitting. (It was an excessively tight fit, so I was giving it a bit of a stretch)
 
OP
Chris S

Chris S

Legendary Member
Location
Sparkhill
I've now noticed a crack on the shoulder of the tyre as well. It's likely that this will come into contact with the ground when I'm cornering so I'll definitely replace it.
 
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