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Sidewall cut - Grand Prix 4000s

15K views 33 replies 19 participants last post by  dcgriz 
#1 ·
Rather than hijack the recent thread on the gatorskin sidewall failure, I’ll start my own.

I hit something yesterday which put a cut in the side wall of my rear tire. A few of the casing treads are cut and it looks fairly deep considering how thin the sidewall is. Can this tire be considered safe to ride or do I face a potential blow out at some point? Whatever I hit didn’t fully penetrate the tire as there is no puncture to the tube. There’s no bulge in the sidewall either which is why I’m asking the question. If there was, I wouldn't even ask, I'd just trash it and move on.

What say you more knowledgeable than I?
 
#3 ·
Thanks ghost. What tires do you ride now? I've been considering Gatorskins as my next tire for their stronger sidewall.

I actually believe this cut is from a walnut. With autumn in full swing in the midwest, there are plenty of walnuts on the rail-trail I was riding yesterday.
 
#4 ·
I suppose it's a hit or miss with tires. I had too many sidewall problems with 4000s and Gatorskins. It seemed like their sidewalls dry out prematurely, crack and burst. I switched to Schwalbe Ultremo ZX about a year ago and haven't had any problems. This was a surprise considering the Ultremo is a 180 gram race tire.
 
#6 ·
What's it look like from the inside? When you flex the tire along this area does it show any obvious signs of weakness? I've been running a 4000s for 1k+ miles with a sidewall cut that's only in the rubber. I put it on the rear just in case. Your cut looks worse than mine, though.
 
#13 ·
I second that. but if you're still worried, put this tire on the rear... so if you have a blowout it is least catastrophic.
 
#17 ·
It's BS. Sidewalls on the GP4000 are at least as tough as anything else in its Crr range... and it has better treadlife and puncture resistance. No fast tire is going to have tough sidewalls. Unless you want to go to slow heavy duty tires, there is no better option.
 
#20 ·
I've mostly ridden the Conti GP4000 and Supersonics the last ~30k miles, but the times I tried different tires they were worse for sidewall cuts. Veloflex Corsa, Vittoria Corsa CX, Challenge Criterium, Michelin Pro3.

How are you getting 3 sidewall "failures" in 100 miles? What does it look like?
 
#21 ·
It looks like a hole with a tube bubble coming out of it.

After all those problems I tested the strength compared to a spent Vit Corsa out of curiosity but poking holes in each by hand and it was amazing how much easier it was for me to cut a GP4000s.

The thread is about GP4000s but the way.......not GP4000.
 
#22 ·
But you must have hit something sharp enough to cut the sidewall? I have a lot of experience bombing down gravel roads, and that doesn't bother them.

The GP4000 with black tread is the same as the 4000S. The colored ones have a different tread compound. Actually all the top Conti clinchers have the same casing and sidewall...
 
#23 ·
But you must have hit something sharp enough to cut the sidewall? I have a lot of experience bombing down gravel roads, and that doesn't bother them.

The GP4000 with black tread is the same as the 4000S. The colored ones have a different tread compound. Actually all the top Conti clinchers have the same casing and sidewall...
Yes, I must have. If you want to think it's just coincidence that I hit something sharp enough to cut a side wall 3 times in less than 100 miles with GP4000s tire and 0 times in over 21000 miles with other tires is just a coincidence I'm not going to argue with you.
 
#24 ·
The sidewall doesn't contact the ground when riding on pavement... unless you run over or into something that sticks up. That "something" must be sharp to cut the sidewall.

3 times in 100 miles leads me to suspect something very odd. Were the cuts vertical or horizontal? All the same wheel or different ones?
 
#25 ·
Pedro;

I don't think you mentioned nor has anyone asked.....how many miles do you have on your Conti's?

Perhaps if you have a bunch of miles on them, then change them out and cut your losses.

You should be able to see the small holes in the black riding surface around the tires. These are you wear indicators.

Without seeing the tires in my hands; I can't recommend you keeping it or not. Having said that, I run the 4000s without any sidewall issues so far(@2000 km).
 
#27 ·
Pedro;

I don't think you mentioned nor has anyone asked.....how many miles do you have on your Conti's?
These tires have been mounted for 6 months and are just short of 1000 miles. The wear indicators show plenty of tread life left. In fact the molding ridge in the center of the tread is still barely visible on the front tire. It too has the same deteriorated look to the sidewall but without any cuts or scuffs. The tire with the cut is on the rear.

I really love the way these tires roll, grip, etc. but my sidewall experience as well as others have given me cause for serious concern about their safety. Unfortunately the cooler weather and shorter days are beginning to cut into my cycling time, I guess I'll have to consider possible replacements before spring.
 
#28 ·
I had a flat with my front tire of my 4000s after about 1500 miles and realized I went thourgh some broken glass. At the time didn't realize it was the sidewall and just changed the tube. After noticing the bulge of the tube coming through I just put an inner patch on and have put another 1000 miles on the tire. So with 2500 miles on these tires and still plenty of wear left, I just ordered two more from Prokit at $40 a piece since I figure I only have another 1000 (?) miles left. Love these tires.
 
#34 ·
Are you both seriously expecting replies to your questions from a thread dead since 10/19/2012?

It would be best to start a new thread asking your questions.
 
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