# Flat spot on tire -- rotating tires?



## tystevens (Jul 10, 2008)

I have about 1k miles on my Conti Gatorskins. I've started to get a lot of flats on the rear after virtually none for about 700 miles (no flats on the front yet). The rear tire has a noticable flat spot on it -- the LBS commented on it when I had the bike in this afternoon. Should I be rotating the tires to avoid this? Or do I just replace the rear twice as often? I would hope to get more than 1k miles out of these tires, but at 225 lbs, maybe that is just somthing I'll have to live with until I lose more weight?

If it is time to replace, can I run a 28 on back and a 25 on front? Any ideas? Thanks!


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## PBike (Jul 6, 2007)

It isn't recommended to rotate tires usually. If you ever do, you would get a new tire and put it on the front, then put the old front on the back. Never put an old back tire on the front. The rear will wear out more quickly.


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## kfurrow (May 1, 2004)

tystevens said:


> I have about 1k miles on my Conti Gatorskins. I've started to get a lot of flats on the rear after virtually none for about 700 miles (no flats on the front yet). The rear tire has a noticable flat spot on it -- the LBS commented on it when I had the bike in this afternoon. Should I be rotating the tires to avoid this? Or do I just replace the rear twice as often? I would hope to get more than 1k miles out of these tires, but at 225 lbs, maybe that is just somthing I'll have to live with until I lose more weight?
> 
> If it is time to replace, can I run a 28 on back and a 25 on front? Any ideas? Thanks!


As has been said, rotating tires is a bad idea... you'd be putting a worn rear tire onto the front, and the front needs traction or you're going down.

You can run a 28 on the back if your bike supports it (i.e., the tire needs to be able to clear the frame and the brakes). A lot of modern road bikes don't.have enough clearance for tires wider then 25. What brand / model bike do you have?


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## Kerry Irons (Feb 25, 2002)

*No rotation*



tystevens said:


> I have about 1k miles on my Conti Gatorskins. I've started to get a lot of flats on the rear after virtually none for about 700 miles (no flats on the front yet). The rear tire has a noticable flat spot on it -- the LBS commented on it when I had the bike in this afternoon. Should I be rotating the tires to avoid this? Or do I just replace the rear twice as often? I would hope to get more than 1k miles out of these tires, but at 225 lbs, maybe that is just somthing I'll have to live with until I lose more weight?
> 
> If it is time to replace, can I run a 28 on back and a 25 on front? Any ideas? Thanks!


By "flat spot" I assume that you mean the tire has started to square off? The wear indicators on Conti GP4000 disappear just before the casing threads start to show through the tread, so Conti basically recommends that you wear a tire down to the casing. I'd be surprised if your batch of flats is due to thinner tread, because the casing is so much thicker than the tread. If you decide to replace the tire, put a new one on the front and move the front to the back.


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## waldo425 (Sep 22, 2008)

PBike said:


> It isn't recommended to rotate tires usually. If you ever do, you would get a new tire and put it on the front, then put the old front on the back. Never put an old back tire on the front. The rear will wear out more quickly.


Who says that? Putting the old rear tire (not very old 1000 miles or so but still something on there) makes sence and Ive done it many times. Many people here do this and noone complains. The rear tire wears out much faster then the front since theres much more weight and force applied to it. The front wears out very slowly. So taking a slightly worn rear tire and putting it on the front is best.


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## jmlapoint (Sep 4, 2008)

Flats are usually more frequent on the Rear.
From the OP, still not sure why the 'Flat-Spot"?
A new GatorSkins should last a lot longer than 1000 miles.


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## waldo425 (Sep 22, 2008)

Sounds like you did some skids.


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## jmlapoint (Sep 4, 2008)

+1
Skids would be my thought as well.


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## Blue CheeseHead (Jul 14, 2008)

Agreed on the mileage. Gatorskins should get you closer to 3,000 miles. I suppose sharp chip sealed roads could cause that to go down a bit but 700 miles waaaay low.

I replace the rear tire when needed. Rotating is NOT a good idea.


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## PBike (Jul 6, 2007)

waldo425 said:


> Who says that? Putting the old rear tire (not very old 1000 miles or so but still something on there) makes sence and Ive done it many times. Many people here do this and noone complains. The rear tire wears out much faster then the front since theres much more weight and force applied to it. The front wears out very slowly. So taking a slightly worn rear tire and putting it on the front is best.


Your front may not wear much since it isn't the drive wheel, but it needs good tread for a very important reason. Since you asked who said this, I'll give you a respected source.

http://www.sheldonbrown.com/tire-rotation.html


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## tihsepa (Nov 27, 2008)

Best tire always goes on front. I do rotate though. Here is how. I only by one tire at a time. I put the front on the rear and replace the front with the new one. Have a front washout at 30 mph and you will agree, the front needs to be the good one.


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## waldo425 (Sep 22, 2008)

PBike said:


> Your front may not wear much since it isn't the drive wheel, but it needs good tread for a very important reason. Since you asked who said this, I'll give you a respected source.
> 
> http://www.sheldonbrown.com/tire-rotation.html


Hmm, well damn; I just got told. Thats a very respected source indeed.


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## tystevens (Jul 10, 2008)

kfurrow said:


> You can run a 28 on the back if your bike supports it (i.e., the tire needs to be able to clear the frame and the brakes). A lot of modern road bikes don't.have enough clearance for tires wider then 25. What brand / model bike do you have?


It is an '08 Jamis Ventura Race. I've got 25's on there now, seems to be enough clearance for those.

Regarding the skids, you mean I'm not supposed to lock up the back tire and do a slide out in front of my best friend's house? I thought that is what the back brake was for?! Just kidding ... no, I don't think I did many skids -- although I'm somewhat new to road biking, I've been mountain biking for years and know how to handle a bike w/o skidding the tires.

As far as the wear goes, I thought it seemed premature, too. Like I said, virtually no flats for about 700 miles with the Contis. After that, flats have been increasing up to about 2 per week now on the rear, about where they were with the stock Vittoria 23s when they reached about 1000 miles or so. So that's been frustrating. The Contis now have between 1000 and 1100 miles on them. Anyway, I had the bike in the LBS yesterday and he had it up on a stand in the middle of the sales floor looking at my rear der. A salesman happened to be showing a woman tires close to where my bike was, and he told her "when the tire starts to look like this, with a flat spot in the middle (rubbing his finger across my rear bike tire), you need to start thinking about replacing it." Then he had her feel my tire to see what he was talking about. So I guess it was a textbook example of a worn rear tire.

Well, any other ideas would be appreciated. I am heavy (225 lbs or so right now), and do a fair amount of climbing as I live and ride in Utah, so I know I'm not going to get a rear tire to last forever under those conditions. I don't know what to compare to, but perhaps I push pretty hard on the pedals -- the tech said the chain was severely stretched after 2000 miles, which was contributing to my shifting problems -- but I don't think I'm really a masher. By the way, I didn't know you could stretch a chain in 2000 miles -- is that normal, or was the LBS feeding me a line? Whatever it was, the bike shifts perfectly now with the new chain on it, so that is nice.


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## tystevens (Jul 10, 2008)

Kerry,

Yes, I mean the tire is starting to "square off" -- a better way to put it. In other words, the middle of the tire seems flat, and equally so all the way around the tire.


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## mohair_chair (Oct 3, 2002)

tystevens said:


> Yes, I mean the tire is starting to "square off" -- a better way to put it. In other words, the middle of the tire seems flat, and equally so all the way around the tire.


That's not that big a deal. It's very likely that you have plenty of wear left on that tire.


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## fast ferd (Jan 30, 2009)

I rotate my tires and this never ever caused a problem for me. Naturally, you don't put a worn-out rear tire on the front, but a slightly squared-off rear will not cause any issues whatsoever to the front.

Odd that so many are against this practice here. Who wouldn't want to get max mileage out of their $50 apiece tires?


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## JCavilia (Sep 12, 2005)

fast ferd said:


> I rotate my tires and this never ever caused a problem for me. Naturally, you don't put a worn-out rear tire on the front, but a slightly squared-off rear will not cause any issues whatsoever to the front.
> 
> Odd that so many are against this practice here. Who wouldn't want to get max mileage out of their $50 apiece tires?


False dichotomy. You can get maximum mileage out of the tires with the front-to-back rotation method people here are recommending. You just leave the back tire on until it's ready to toss, then do the switch. The back tire wears out sooner than it would with your rotation method, but the tire that goes on the front new lasts longer than it would. In the long run, the net tire use is the same.

And while you may be right that there are no issues with a slightly squared-off tire in the front, I think the reasoning is that the more worn the tread, the more likely the tire is to suffer a puncture, and we'd rather have the lowest risk tire in the front, where the handling issues are more serious.

It's not a huge deal, but when I'm descending at 45 mph I want my best tire on the front.


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## fast ferd (Jan 30, 2009)

JCavilia said:


> False dichotomy. You can get maximum mileage out of the tires with the front-to-back rotation method people here are recommending. You just leave the back tire on until it's ready to toss, then do the switch. The back tire wears out sooner than it would with your rotation method, but the tire that goes on the front new lasts longer than it would. In the long run, the net tire use is the same.
> 
> And while you may be right that there are no issues with a slightly squared-off tire in the front, I think the reasoning is that the more worn the tread, the more likely the tire is to suffer a puncture, and we'd rather have the lowest risk tire in the front, where the handling issues are more serious.
> 
> It's not a huge deal, but when I'm descending at 45 mph I want my best tire on the front.


Okay, maybe you get the same mileage with this type of rotation method. However, it presumes you stick with the same brand/type/color tire throughout the process. I prefer to change in pairs and make a color swap at the same time. In fact, that's when I change my bar tape, too.

IMO, even a front tire with some squaring off is not much more prone to puncture. It scarcely shows any wear during the next 1,000 miles on the front. My best habit is to closely inspect my tires after each ride. Speaking from experience (70k miles rotating tires), my practice has never increased the frequency of punctures.


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## JCavilia (Sep 12, 2005)

Whatever works for you, Ferd. Since there's a vast amount of randomness in puncture-frequency, no one rider is a good statistical sample. You're obviously careful, and even if you weren't, you could be lucky and ride a lifetime without ever getting a front flat in a dicey situation.



> However, it presumes you stick with the same brand/type/color tire throughout the process. I prefer to change in pairs and make a color swap at the same time. In fact, that's when I change my bar tape, too.


Well, it doesn't necessarily presume that. It could be (it is, for me) that you don't care much whether your tires match in brand/type/color. My rims don't even match ;-) They work, though.


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## fast ferd (Jan 30, 2009)

fast ferd said:


> Okay, maybe you get the same mileage with this type of rotation method. However, it presumes you stick with the same brand/type/color tire throughout the process. I prefer to change in pairs and make a color swap at the same time. In fact, that's when I change my bar tape, too.
> 
> IMO, even a front tire with some squaring off is not much more prone to puncture. It scarcely shows any wear during the next 1,000 miles on the front. My best habit is to closely inspect my tires after each ride. Speaking from experience (70k miles rotating tires), my practice has never increased the frequency of punctures.


Quote:
Originally Posted by JCavilia
_False dichotomy. You can get maximum mileage out of the tires with the front-to-back rotation method people here are recommending. You just leave the back tire on until it's ready to toss, then do the switch. The back tire wears out sooner than it would with your rotation method, but the tire that goes on the front new lasts longer than it would. In the long run, the net tire use is the same.

And while you may be right that there are no issues with a slightly squared-off tire in the front, I think the reasoning is that the more worn the tread, the more likely the tire is to suffer a puncture, and we'd rather have the lowest risk tire in the front, where the handling issues are more serious.

It's not a huge deal, but when I'm descending at 45 mph I want my best tire on the front. _


I gave this some more thought on my commute to the office this morning. :idea: It left me with the staunch belief that you do not get maximum mileage with the front-to-back method. You end up pitching your rear tire prematurely - say, at 1,500 miles - whereas if you rotated at about 1,000 miles, you likely could get closer to 2,500 miles out of each.

My tire of choice is the high-performance Michelin PR2 or 3. Probably more prone to puncture than a stiff-walled, kevlar belted, high mileage tire. But the handling in wet or dry give me far more every-moment safety than the slim chance of flatting around a turn.

Ultimately, my color coordination habit dies hard.


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## Kerry Irons (Feb 25, 2002)

*Thinking clearly*



fast ferd said:


> I gave this some more thought on my commute to the office this morning. It left me with the staunch belief that you do not get maximum mileage with the front-to-back method. You end up pitching your rear tire prematurely - say, at 1,500 miles - whereas if you rotated at about 1,000 miles, you likely could get closer to 2,500 miles out of each.


Too bad you're not thinking clearly, or maybe just really bad at simple arithmetic. Tire wear is the scrubbing of rubber from the tire due to power dissipation, and there is very little wear on a front tire. The rubber is being abraded on the rear only, and when you are doing heavy braking on the front (very few miles as a percentage of the total). So, since tires only really wear on the rear, it's the miles you put on the tire when it's on the rear, and that doesn't change just because you rotate tires around. If you wear out a rear tire every 2000 miles of riding, and you start with two new tires, then after 10,000 miles, you will have worn out 5 tires and you will have one on the front, ready to move to the back. You can't and don't change this simple math by moving a tire to the front where it won't experience wear.


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## fast ferd (Jan 30, 2009)

Kerry Irons said:


> Too bad you're not thinking clearly, or maybe just really bad at simple arithmetic. Tire wear is the scrubbing of rubber from the tire due to power dissipation, and there is very little wear on a front tire. The rubber is being abraded on the rear only, and when you are doing heavy braking on the front (very few miles as a percentage of the total). So, since tires only really wear on the rear, it's the miles you put on the tire when it's on the rear, and that doesn't change just because you rotate tires around. If you wear out a rear tire every 2000 miles of riding, and you start with two new tires, then after 10,000 miles, you will have worn out 5 tires and you will have one on the front, ready to move to the back. You can't and don't change this simple math by moving a tire to the front where it won't experience wear.


Too bad you're bad at logic. And took the liberty to change the numbers used in my example. It does sound like you enjoy riding that rear tire down to the cords.  

Okay, fair enough, let's use your figures. But my method. Rather than let that tire wear to the cords at 2,000, move it to the front at 1,000. Again, using your description of wear, that front going to the back should show scarcely any wear, so it will run another 2,000 miles on the rear. Viola! We just got 3,000 miles out of our set of two tires! With your method, we lost 1,000 miles of wear on that prematurely tossed rear tire.

And, for the record, I'm an accountant. By your reckoning, not a very good one, tho.


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## Anderssen (Jul 28, 2009)

fast ferd said:


> Too bad you're bad at logic. And took the liberty to change the numbers used in my example. It does sound like you enjoy riding that rear tire down to the cords.
> 
> Okay, fair enough, let's use your figures. But my method. Rather than let that tire wear to the cords at 2,000, move it to the front at 1,000. Again, using your description of wear, that front going to the back should show scarcely any wear, so it will run another 2,000 miles on the rear. Viola! We just got 3,000 miles out of our set of two tires! With your method, we lost 1,000 miles of wear on that prematurely tossed rear tire.
> 
> And, for the record, I'm an accountant. By your reckoning, not a very good one, tho.


No, I'd say not a terribly good one 

The front to back rotation gets 2,000 miles on the rear out of every single tire, given the assumptions you've both made so far. It isn't possible for any other rotation scheme to beat that, because no tire is discarded until it is completely worn to being unusable. He replaces 1 tire every 2,000 miles, you're suggesting getting 3,000 miles then replacing 2 tires (you could stretch it to 4,000 by using a completely worn tire on the front). I'm sure an accountant sees the problem in stating that 3,000/2 > 2,000...

You can change the numbers to whatever you want, have tires wear at whatever relative rates you want between front and rear, it doesn't matter. The idea of front to back rotation and discarding a rear tire only when completely worn is optimal in getting mileage out of your tires.


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## fast ferd (Jan 30, 2009)

Anderssen said:


> No, I'd say not a terribly good one
> 
> The front to back rotation gets 2,000 miles on the rear out of every single tire, given the assumptions you've both made so far. It isn't possible for any other rotation scheme to beat that, because no tire is discarded until it is completely worn to being unusable. He replaces 1 tire every 2,000 miles, you're suggesting getting 3,000 miles then replacing 2 tires (you could stretch it to 4,000 by using a completely worn tire on the front). I'm sure an accountant sees the problem in stating that 3,000/2 > 2,000...
> 
> You can change the numbers to whatever you want, have tires wear at whatever relative rates you want between front and rear, it doesn't matter. The idea of front to back rotation and discarding a rear tire only when completely worn is optimal in getting mileage out of your tires.


Alright, I see it a little better, but not due to your explanation.  Moving the front to the rear after 2,000 miles presumes accumulating another 2,000 miles of riding on the rear, if I'm not mistaken. This means that when the 2nd tire gets the heave-ho, they show a combined 6,000 miles of usage. Thus, (2 x 3k) = (2k + 4k).

I guess that's possible, although I still find my rotation optimal. It keeps the fashion police at bay. Moreover, us accountants are major skeptics, as you can surely tell.


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## tihsepa (Nov 27, 2008)

Blah blah blah. I am not riding any bike but mine. I have had a front blow and well........ it blows. I cant do math either. I am not a accountant, politician, architect, CPA, CPL, LMA, LAMO, or whatever. What I do know is that if your front tire blows, flats, folds or combusts it is way worse than the rear. I am putting the good rubber up front. I dont have piles of money for tires either but who cares, they are cheeper than the right side of my face I had to replace once. Now look at me.


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## JCavilia (Sep 12, 2005)

*Good advice*



> I am putting the good rubber up front.


in so many areas of life.


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## Kerry Irons (Feb 25, 2002)

*Cpa?*



fast ferd said:


> Alright, I see it a little better, but not due to your explanation.  Moving the front to the rear after 2,000 miles presumes accumulating another 2,000 miles of riding on the rear, if I'm not mistaken. This means that when the 2nd tire gets the heave-ho, they show a combined 6,000 miles of usage. Thus, (2 x 3k) = (2k + 4k).
> 
> I guess that's possible, although I still find my rotation optimal. It keeps the fashion police at bay. Moreover, us accountants are major skeptics, as you can surely tell.


On an ongoing basis, you get 4000 miles out of each tire, 2K on the front followed by 2K on the back. Due to the front tire aging (sunlight, ozone) it will get a little less mileage on the rear than a new tire, but that will depend on how long it takes to accumulate the mileage. The assumption is always that you continue this practice and don't put new tires on the rear (why would you?). If it somehow makes you happy to assume 1500 miles on the rear, then you get 3K miles out of each tire. Whatever. How hard is that to understand?

Remind me not to have you do my taxes


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## tihsepa (Nov 27, 2008)

Kerry Irons said:


> Remind me not to have you do my taxes


Why? Cant you confuse the IRS enough that they will just give you money?


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## ZoSoSwiM (Mar 7, 2008)

I have over 3000 miles on my GP4000's... Besides a few nicks and such both tires are in great shape. No flats either. I am starting to see a slight flattening on the top of the tire but they're still solid.

Sound like you're running too low a pressure maybe.. Or you lock your rear wheel up when braking.


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## PMC (Jan 29, 2004)

Ride it until it dies which would mean it is damaged or you start getting multiple flats on it. Then buy one new one and put it on the front, move the old front to the rear and you're good to go.
Mileage differs depending on lots of stuff including rider weight, road surfaces and even riding style. I wouldn't worry to much if it doesn't look new after a thousand miles, I actually think that is normal. You probably have plenty left in it.

I always found Conti tires to show wear sooner than other tires I used although it could be because Conti actually puts tread in the center. 

Good luck and the Gators are great tires IMO so give them a chance.


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## Blue CheeseHead (Jul 14, 2008)

fast ferd said:


> I gave this some more thought on my commute to the office this morning. :idea: It left me with the staunch belief that you do not get maximum mileage with the front-to-back method. You end up pitching your rear tire prematurely - say, at 1,500 miles - whereas if you rotated at about 1,000 miles, you likely could get closer to 2,500 miles out of each.


Okay, we will make this real simple and remove all the numbers so there will be no confusion:

One does not prematurely toss a rear tire because one does not replace it mearly on a mileage schedule, but rather does it due to physical wear. Presuming you are using the same tires, rubber will wear off the rear tire at the same rate regardless if the tires are rotated. 

Given I am more comfortable running the rear tire more thread bear than the front, If I followed your rotation method with the goal of changing both equally worn tires at some point, I would indeed toss the rear tire "prematurely". That is because the rear tire would still have suitable rubber for the rear, but not enough to continue to use in the front.


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