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Hairline split in rear tire. Reparable or replacement required?

9K views 38 replies 20 participants last post by  Lombard 
#1 ·
Hi Guys- I was out for a ride today and had a rear flat. When changing the inner tube, I noted that there was a hairline split on the sidewall of the rear tire (pic below). The inner tube suffered a puncture at this location. I put on my spare inner tube, pumped up to about 70% of my normal 110 PSI, noted that it was not bulging through too badly, and safely finished my ride back home.

A couple of questions:

1) Is the side wall hairline split something I can somehow fix (no ideas here, except I read that I could fold a dollar bill on the inner wall to prevent the inner tube from protruding).

2) If replacing is required, I'm certain I should replace both front and rear tires. Any recommendations for brands/models? Current tires are Continental Grand Prix 4000 25 mm and I've got about 4500-5K miles on them thus far. I'd likely like to go back to 23mm, if replacement is recommended.

Cheers!

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#2 ·
Hi Guys- I was out for a ride today and had a rear flat. When changing the inner tube, I noted that there was a hairline split on the sidewall of the rear tire (pic below). The inner tube suffered a puncture at this location. I put on my spare inner tube, pumped up to about 70% of my normal 110 PSI, noted that it was not bulging through too badly, and safely finished my ride back home.

A couple of questions:

1) Is the side wall hairline split something I can somehow fix (no ideas here, except I read that I could fold a dollar bill on the inner wall to prevent the inner tube from protruding).

2) If replacing is required, I'm certain I should replace both front and rear tires. Any recommendations for brands/models? Current tires are Continental Grand Prix 4000 25 mm and I've got about 4500-5K miles on them thus far. I'd likely like to go back to 23mm, if replacement is recommended.

Cheers!

View attachment 319523
Would also need to see the inside.

However, it looks more than just a wee hairline crack.

I would say bin it and stay away from Continental in the future. They are prone for failure like you have experienced. The only Continental that will last are Gatorskins everything else from Continental is Micky Mouse.

You don't need to buy 2 new tyres if you stay with the same brand.

I would only buy 2 new ones if you change brand for aesthetic reasons (although even in that case you can ride different brands front and rear).
 
#5 · (Edited)
I'll ride it if there's no bulging. But that doesn't look good. Scrap it. At 100 psi, there's a huge force on the tire fabric, and that cut won't hold it for too many more miles.

Continental tires have wear indicators, two small pits an inch apart on the tread. When they are worn away, the remaining tread is paper thin.

Yes, put the current front on the rear, and buy a new front tire. Otherwise, the front won't wear out for years, accumulating cuts and cracks.

I don't see any reason to go back to 23mm since your frame allows 25mm. Your 25mm GP4000 are just as fast as the 23mm, and can be run with about 10 psi less pressure. That's a lot better on rough roads.

Lower the front pressure 10 to 15 psi below the rear, since there's less weight on the front. At 170 pounds, I use 85-90 psi front, and 100-105 psi rear. It's fast and comfortable.

Would also need to see the inside.

However, it looks more than just a wee hairline crack.

I would say bin it and stay away from Continental in the future. They are prone for failure like you have experienced. The only Continental that will last are Gatorskins everything else from Continental is Micky Mouse.

You don't need to buy 2 new tyres if you stay with the same brand.

I would only buy 2 new ones if you change brand for aesthetic reasons (although even in that case you can ride different brands front and rear).
I've kept using GP4000S tires for 6 or 7 years now. They have very good grip in the corners, a smooth ride on rough roads (due to the very flexible sidewalls) and long life, at least 3500 miles.

In past years, I've had a few bad sidewall cuts in the same year. One, a sharp piece of metal, and later, a sharp edged pyramid shaped rock. But since then, nothing other than a thorn and a small piece of glass in the last 10,000 miles.

It's kind of bad luck, getting a series of cut tires. I reduce my chance of a flat by staying mostly in the right tire track, where cars kick any debris off toward the side of the road. I rarely ride on shoulders (and even avoid dedicated bike lanes, since they don't get swept very often.)
 
#4 ·
No way I would ride that - the dollar bill thing I would use to get me home and then change the tire. At 4500 miles, it's probably close to shot anyway. You could move the front to the rear and put a 23mm on the front if you want to save some cash right now.

On tire choice, I love the conti 4000S, they work well for me and rarely flat + never had a sidewall cut like that (knock on wood)
 
#12 ·
I greatly appreciate everyone's input. Clearly, the consensus is to toss the rear tire. The current wheel set is a set I built, but I have the stock wheel set in the basement. I could swap on those tires for now (the bike came stock with Continental Ultra Sport 23mm), as they are just doing nothing and may as well get some use (I think they have maybe 1000 miles on them). I suppose this is a no-cost solution for now. I can take my current 25mm front tire and put it to use on the bike trainer cycle.
 
#13 ·
+1 for replace. I've run 23 and 25 GP4000s tires and tbh haven't noticed much difference (and I have reduced the pressures on the 25s). I normally get about 5000 miles with the rear and it is usually replaced because it has squared off rather than hit the wear marks. My current bike was supplied with Conti Ultra Sport wired on tires and they were the tightest fitting tire I've encountered. I don't even have them on a spare set of wheels because there is no way I would want to face having to fix a flat with them out on the road.
 
#15 ·
Hi Guys- I was out for a ride today and had a rear flat. When changing the inner tube, I noted that there was a hairline split on the sidewall of the rear tire (pic below).
Definitely not a hairline split. Tire is ruined.


I put on my spare inner tube, pumped up to about 70% of my normal 110 PSI,
OMG, why are you pumping 25's up to 110PSI?? And you want to go to 23's? What will you pump those up to?
You're losing all the benefits of the awesomeness of GP4K's at those pressures.



I have never seen a Continental 4000 II, however, I know for a fact the sidewalls are paper thin.*
Definitely obvious you've never seen one. So you should be a LOT careful with anecdotes on the internet.

You could be living in wonderland with perfect roads and no rain and will never experience problems with that tyre. I am always a little bit carefull with anecodotes on the internet.
I live in PA. Ride GP4K's year round. Potholes galore, s#ity roads, chipsel and I've never had a sidewall cut.
 
#16 ·
Unsafe at any speed. Pitch that tire! A dollar bill may get you home, but it's still a time bomb. Any sidewall cut is a game ender.

My suggestion would be to take your existing front tire and put it on the rear. Then put a new tire on the front. You always want your newest (safest) tire on the front.

And as TLG said, why are you pumping 25s up to 110PSI. How much do you weigh?
 
#19 ·
Definitely not a hairline split. Tire is ruined.


OMG, why are you pumping 25's up to 110PSI?? And you want to go to 23's? What will you pump those up to?
You're losing all the benefits of the awesomeness of GP4K's at those pressures.



Definitely obvious you've never seen one. So you should be a LOT careful with anecdotes on the internet.

I live in PA. Ride GP4K's year round. Potholes galore, s#ity roads, chipsel and I've never had a sidewall cut.
Are you guys stating I'm having too much pressure at 110 psi? I don't know any better and I was told this was the pressure. I'm 6'1" and about 163 lbs. What pressure would you suggest for 25mm and what pressure for 23 mm? Guidance is most appreciated!
 
#24 ·
That is certainly your privilege, but it's totally unnecessary. But hey, if you like riding a bucking bronco, who am I to judge?
 
#30 ·
Hi Guys- I was out for a ride today and had a rear flat. When changing the inner tube, I noted that there was a hairline split on the sidewall of the rear tire (pic below). The inner tube suffered a puncture at this location. I put on my spare inner tube, pumped up to about 70% of my normal 110 PSI, noted that it was not bulging through too badly, and safely finished my ride back home.

A couple of questions:

1) Is the side wall hairline split something I can somehow fix (no ideas here, except I read that I could fold a dollar bill on the inner wall to prevent the inner tube from protruding).

2) If replacing is required, I'm certain I should replace both front and rear tires. Any recommendations for brands/models? Current tires are Continental Grand Prix 4000 25 mm and I've got about 4500-5K miles on them thus far. I'd likely like to go back to 23mm, if replacement is recommended.

Cheers!

View attachment 319523
Gp4000s are great tires. I use them myself for everything. Now they have some setbacks. The sidewalls are weaker than other tires. I used to run at 90psi 23s and I was destroying the sidewalls on the back. I'm 205lbs. I did some research and they recommend 110-120psi for the 23s. If you go 25 then you can do lower. 90-95psi.
After a flat or running them at low air after a slow leak I usually have to toss them out or move it to the front. The problem is the same as with car tires and a flat. The rim border cuts into the tire and destroys the side wall. You will start noticing strands of thread falling and getting stuck in your hubs. What happens next is that the weak sidewall will separate when the bead meets the tire and you will have a catastrophic failure that will send you home walking. Happened to me 2 times after I learn my lesson.the tire was ran at low pressure because it was a slow puncture. So I didn't noticed after a while when I was probably at 60psi or so. Next ride I went out my front tire blew from under me. If I would have been going fast it would have been a messed up move.
So when this happens you either move the tire to the front and risk getting a blown tire or throw it out. The key here is the amount of time you run at low psi. To prevent these things from happening I installed Mr tuffy light and my flats decreased significantly although the gp4000s are really good with flat protection. You start getting flats when they are worn out. Mr tuffy allows me to ride them a couple more months w/o flats.
Good luck.


Sent from my iPhone using Tapatalk
 
#31 ·
...Next ride I went out my front tire blew from under me. If I would have been going fast it would have been a messed up move.
So when this happens you either move the tire to the front and risk getting a blown tire or throw it out....
I personally would never put a damaged tire on the front. A front blowout at speed can be a heck of a lot more risky to deal with than a rear blowout. You seem to even acknowledge that prior to recommending moving a damaged tire to the front. If a tire is unsafe to use as a rear tire, then time to toss it.
 
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