The other day I was stopped at a traffic light when I felt my bike moving slowly forward. Did not pay really attention, thought there was a slight slope, so hit the brake and voila. But it did not stop moving and I realized an idiot in his car was pushing me!! I should have gone and yell at the guy but I freaked out: he is enough of a psycho to push a cyclist, who know what he can do... So I deflected to the sidewalk to check the bike... He was pushing on the rear mudguard and on the rack... the mudguard was bent just behind the crankset so I straightened it and it looked like the bike was fine so hopped on and finished the ride.

Only later I noticed that the contact of the mudguard on the tyre while being deformed left a "wound" on the side of the tire. Cannot post a picture, sorry, but it looks like the integrity of the side of the tyre was compromised and one can see the fibers inside. It does not "leak", the tube cannot be seen or anything but I hate it... Is the tyre fragilized enough to increase significantly puncture risks? could it "explode" and cause a more serious accident? Does it need replacing? I hardly think so,... but well...

  • Yeah, if cord is showing the tire should probably be replaced. But you can take it to a bike shop and ask the mechanic -- some lightweight tires have the cord virtually on the surface and a little fraying wouldn't indicate serious damage. Nov 16, 2012 at 12:51

3 Answers 3


I would ask myself the question: "Even if it looks like the tyre is ok, do I really want the hassle of the thing blowing 10 miles from home - even if there's only one chance in a hundred - and then having to change the tube, hoping it doesn't re-puncture, all the while freezing your ** off? And probably in the dark too. And even then, when you get home, having to replace the tyre in any case."

Compared to the price of a new tyre I know what my answer would be. (I should probaby add that tyres in general are more susceptible in thev walls, which would sway me even more.)

Congratulations for keeping your cool by the way. Your logic seems totally sound in terms of this guy being a psycho but very often adrenaline wins hands-down over rationality.

  • 1
    Yeah, thanks! As it turns out, I might change the tyre but the other "problem" is that the wear of my rims is kind of advanced, so I had planned to change the whole wheels either way in the future months, and had planned to go for thinner rims (allowing a range of 23-32mm wide tires) so I don't feel like buying a new tyre just for that little time... I guess I will get my wheels sooner that I wanted, and will keep those tyres only an extra week or two instead of the foreseen month or two... Thanks for the answer!
    – ptpdlc
    Nov 16, 2012 at 13:03
  • @tisek..so it's all an opportunity then ;-)
    – PeteH
    Nov 16, 2012 at 14:04
  • Yes, I suppose it is... but this made me wonder about one more detail about those wheels which led me to ask that new question: bicycles.stackexchange.com/questions/13245/… to know whether any 700c wheel will fit in my fork and on my frame overall...
    – ptpdlc
    Nov 16, 2012 at 14:13

If any of the fibers are torn or frayed, you should definitely replace it. Even if they're not, it's still a good idea. Those fibers are what give your tire its strength. If any of them tear, your tube is likely to push through the tire. If this happens, it will pop because the tube is not strong enough to contain the air pressure inside of it without the reinforcement of the tire.

If all of that happens and you get a flat, you'll have a hard time repairing it on the road since a new tube will just push through the hole and pop again. You could boot it, but I've never had a whole lot of luck with that.

Since it's the rear tire, it's not likely to cause a serious accident. But it's always a possible, e.g., if it pops while you're cornering hard.

  • Re: booting - it's a temporary measure to get you home. If it's a bad puncture (hole or slice in the tire) and all you've got is a spare tube, use a bank note, candy wrapper, or similar folded up and properly fitted between the tire and tube. Otherwise the tube will protrude from the hole in the sidewall and if it doesn't pop, something will puncture the protruding tube.
    – Duke
    Nov 21, 2012 at 7:44

I would probably replace it. most tire walls are not made to withstand a lot of stress.

I had a wheel with quite a wobble in it (maybe 4mm to the side) and kept riding it. this stressed the tire wall constantly until it disolved and the tire blew out quite explosivly.

So keeping in mind that tires does not nedd to be that expensive, I would not risk it.

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