# Sidewall cut - Grand Prix 4000s



## Pedro S (Mar 28, 2011)

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?


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## ghost6 (Sep 4, 2009)

I wouldn't consider that tire safe to ride unless you stay below 10 mph. Ongoing sidewall problems made me stop buying the 4000s and gatorskin.


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## Pedro S (Mar 28, 2011)

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.


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## ghost6 (Sep 4, 2009)

Pedro S said:


> 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.


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.


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## Pedro S (Mar 28, 2011)

ghost6 said:


> It seemed like their sidewalls dry out prematurely, crack and burst.


That is exactly what I've noticed about these tires. The pictures really show how the sidewalls appear to be well on their way to dry rot in the short 6 months they've been on the bike. How else would a glancing blow with a walnut do this kind of damage...


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## springs (Jun 26, 2011)

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.


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## matfam (Jul 13, 2012)

The risk of a blow out at speed would be unacceptably high for me. I would not ride far or fast on a tire with sidewall damage.


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## rruff (Feb 28, 2006)

Just in case, put a patch on the inside of the tire in that spot... no worries.


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## kbiker3111 (Nov 7, 2006)

You're fine.


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## JokerSeven (Jun 15, 2010)

Slap one of these on the inside of that tire. If you have a blow out, it won't be in that spot.

http://www.biketiresdirect.com/product/park-tool-tb-2-emergency-tire-boot

a $1 bill works equally as good, plus its cheaper


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## c_h_i_n_a_m_a_n (Mar 3, 2012)

So far I have been using the GP4000s and the GP 4 seasons ... fingers crossed :wink:


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## Pedro S (Mar 28, 2011)

The tire looks fine on the inside. I took it to the LBS for expert opinion and they said it's ok to ride but to keep an eye on it. "Any sign of bulging, junk it." I think I'll slap a Park boot in it and see what happens.


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## CleavesF (Dec 31, 2007)

kbiker3111 said:


> You're fine.


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.


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## twinkles (Apr 23, 2007)

That's why god put that one HUGE patch in patch kits.


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## Jay Strongbow (May 8, 2010)

Any other tire I'd just put a boot inside of the area of concern and feel confident.

But as someone who's had multiple side wall failure with that brand/model.....there is no way in heck I'd let that tire any where near my bike.


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## Pedro S (Mar 28, 2011)

Where were the reports of sidewall failures when I was reading all the reviews touting the GP4000s as the holy grail of bicycle tires?


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## rruff (Feb 28, 2006)

Pedro S said:


> Where were the reports of sidewall failures when I was reading all the reviews touting the GP4000s as the holy grail of bicycle tires?


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.


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## ghost6 (Sep 4, 2009)

rruff said:


> 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.


No better option? At $60 a tire, and riding 10,000 miles per year, I had way too many sidewall problems with GP4000's. I've had zero sidewall problems with Schwalbe Ultremo ZX, which is a lighter, "faster" tire. I've also never had sidewall problems with Hutchinson Atom Comps and Michelin Pro 3. For me, there's plenty of better options.


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## Jay Strongbow (May 8, 2010)

rruff said:


> 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.


My experience is:

Vittoria Corsa (similar or better Crr): About 17,000 miles, 0 sidewall failures.

Mich Pro Race (also low Crr): About 4,000 miles, 1 sidewall cut (I'll stock short of calling it a 'failure')

GP4000s: Less than 100 miles, 3 sidewall failures.

The odds of that being 'bad luck' are pretty slim and I'm not the only one with similar reports. I think everyone understands you won't have 'tough' sidewalls with any light racing tire. Defective is an entirely different matter and if someone wants to reduce their chance of defective tires I'd suggest that GP4000s is a very poor choice.


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## rruff (Feb 28, 2006)

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?


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## Jay Strongbow (May 8, 2010)

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.


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## rruff (Feb 28, 2006)

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...


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## Jay Strongbow (May 8, 2010)

rruff said:


> *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.


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## rruff (Feb 28, 2006)

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?


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## bikerjohn64 (Feb 9, 2012)

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).


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## scottma (May 18, 2012)

FWIW I have over 5000 mi on my current set of Conti 4000s tires. I've had one flat in that period. No sidewall issues.


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## Pedro S (Mar 28, 2011)

bikerjohn64 said:


> 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.


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## Ruby13 (Aug 11, 2011)

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.


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## Kerry Irons (Feb 25, 2002)

*Bad luck or bad batch*



Jay Strongbow said:


> 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.


My wife and I together have put well over 20,000 miles on several GP4000S tires with only one sidewall nick (didn't cause a flat but booted it anyway). You either had bad luck or got a bad batch of tires. There are way too many satisfied GP4000S users for your experience to be "typical."


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## brewster (Jun 15, 2004)

This is why I don't think I'd get GP4000 again. I've had the same experience. An otherwise great tire is ruined by sidewall cuts. Mine cut all the way through. Not really what you want to see on a fifty dollar tire.


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## ghost6 (Sep 4, 2009)

GP4000s might be the best tire ever made, but after 12 tires with sidewall problems, I lost interest. Every sidewall prematurely dried out then quickly tore, split open or burst. I've never had this problem with any other tire.


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## framesti (Jan 26, 2009)

*gp4000s*



ghost6 said:


> GP4000s might be the best tire ever made, but after 12 tires with sidewall problems, I lost interest. Every sidewall prematurely dried out then quickly tore, split open or burst. I've never had this problem with any other tire.


what pressure did yo uuse?


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## SauronHimself (Nov 21, 2012)

ghost6 said:


> GP4000s might be the best tire ever made, but after 12 tires with sidewall problems, I lost interest. Every sidewall prematurely dried out then quickly tore, split open or burst. I've never had this problem with any other tire.


Do you live in a very dry climate?


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## dcgriz (Feb 13, 2011)

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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