Tire shaving

[Nikolas]

I have a set of Bridgestone Potenza RE050A on my Subaru. They still have more than 60% thread left on them and they have about 40k miles on them. From the date code, they are manufactured about 3 years ago.

The problem is that with the local weather conditions (heat, sun) the thread has dried a bit and they don't handle as well as they used to. Would shaving a mm or so from the thread help with bringing some of the fresher rubber in the surface? Would that create any unsafe condition?

PS Am I too cheap?

 

[Quattro Pete]

I doubt shaving them will help at this point. But you could always just go to an empty parking lot and peel out some donuts... turn off traction control and do it on a wet sufrace if you have difficulty getting the AWD to spin the tires.

 

[CapriRacer]

First shaving the tires isn't going to get you anywhere, the rubber will be nearly the same below the surface.

I tend to think of rubber as a plate of spaghetti. The noodles are the rubber molecules (except in the tire, they are actually cross linked) and the sauce and chunks of sausage, green pepper, tomatoes, etc., are all different things that are mixed into the matrix. (Who would have thought that talking about tires would make a person hungry??) As the rubber is flexed, these mixed in things are free to migrate, so stuff like oil, waxes - stuff that makes the tire "soft" - evaporates on the surface and gets replaced by what is still imbedded in the rubber matrix. When you get to the point where the rubber properties have changed, this migration has pretty much used up whatever it was that affected that property within the matrix, and not just on the surface.

So if the idea is just to bring back a bit of the grip, you might try using tire traction treatment such as Formula V. Just be aware that you have to take the tires off the car, and it will be at least 24 hours before you can put the car back in service.

But if your goal is get a bit more life out of them - I'm going to suggest that if the rubber has dried out on the surface, the rubber has dried out around the belts - and that means the tire has lost some of its durability - and it would be safer to replace them than to try to "rejuvenate" them. An indicator of where you are in the duarbility part of this is the cracking. If the cracking is superficial, then the tire is probably OK (notice I said probably), but if the cracks are plentiful and or deep - and especially if the cracks are on the tread surface - the part that contacts the road - then it's time to replace the tires.

What do I mean by "Probably OK"? I have seen tires that show very little cracking that have failed - and the common denominator has been age - many of these have been spares as installed at the vehicle assembly plant and becae part of the second set of tires. Cracking is a combination of material properties and flexing. So a tire that hasn't flexed very much, isn't likely to show cracks as readily as a tire that has.

 

[Volvohead]

Handling is not as good anymore? Could be the tires are just worn past their sweet spot of optimum performance. For every tire, it's different, but for some it's shorter than others. Some Bridgestones can be prone to this; especially those with the dual compound design. You're also driving a max performance summer tire; those tend to burn up their effective tread much faster than other designs. I know of some R owners who burned through the OEM Pirelli P-Zeros in under 20k.

Unless the manufacture date of these tires is six or eight years ago, you shouldn't have weathering related degradation of the tire. Certainly, a three year old tire is still within the design life. Manufacturers include in their compounds agents that provide UV/weathering protection as exposed; it's the "brownish" sidewall tint that a tire develops over time.

 

[alreadygone]

Put on new, keep old and list on Craig's list or local bargain shopper sales paper.

Bob

 

[Nikolas]

It seems that the general consensus is that the tires should be tossed. They are still decent on good roads, but they scared me a couple times on worn/polished roads. They are not as progressive as they used to be and traction is lost more abruptly.

I was talking to a tire dealer the other day and he said that all those performance summer tires are very hard compounds. That explains why I cant wear them out, assuming the guy is right.

I am considering something milder for my next tires, probably with lower speed rating. I mean, the tire is rated for 300 km/h and i am not living in Germany and driving a Mercedes AMG for that to be relevant. I'll probably have to change over to 16" wheels, but that's not a problem, I can find steel wheels cheap. Will a lower speed index/milder tire wear out faster so that it doesn't dry before it's worn? Or I will just lose in the handling department and gain nothing in the end?

 

[Volvohead]

What size tires are you running?

 

[Nikolas]

They are 215/45/17 with similar diameter to 205/55/16.

 

[Tornado Red]

Originally Posted By: Nikolas
It seems that the general consensus is that the tires should be tossed. They are still decent on good roads, but they scared me a couple times on worn/polished roads. They are not as progressive as they used to be and traction is lost more abruptly.

I was talking to a tire dealer the other day and he said that all those performance summer tires are very hard compounds. That explains why I cant wear them out, assuming the guy is right.

I agree with the idea of getting new tires and selling the old ones on craigslist. My old Bridgestones still had a lot of tread and probably would have given 15k miles of adequate service to someone else who couldn't afford a new set.

 

[Volvohead]

Originally Posted By: Nikolas
They are 215/45/17 with similar diameter to 205/55/16.


Too bad. I have a full set of 235/40-18 95Y rated Pirelli P-Zero Rossos sitting in my basement with all of 100 miles on them. Could have sold them to you for cheap, as I'll never use them (I run UHP A/S tires).

 

[bluemax1]

BTW, just so folks know for future reference, NO tire shop will shave tires that have been driven on. Doesn't matter if you had them mounted and drove them out of the shop and then turned around 2 miles later and decided to come back to get them shaved.

Once tires have been driven on, sand, grit and dirt get embedded in the tires. This will rapidly blunt the blades on the tire shaver so the shops will refuse to do it.

And Nikolas, I'm not sure exactly what the 'tire dealer' meant but if he was talking about the top of the line extreme/maximum performance summer tires, they tend to be made of softer compounds than regular tires. As a general rule, the grippier the tire, the softer the compound and the faster they wear. The higher the rated treadwear, the harder the compound tends to be.

Take Yokohama tires for instance. Their top of the line pure street tire, the Advnn Neova AD07 has a Shore A durometer of ~70 and a treadwear rating of 180. The Yokohama ES100 measure about 73 durometer and have a treadwear rating of 280. Yokohama's A048 DOT-R tires measure about 65 durometer and have a treadwear rating of 60.

As mentioned, if the tires aren't seriously cracked, you can try using a chemical tire rubber softener to increase the grip, but it's still better to get new tires. 3 years and 40,000 miles is plenty on a single set (but this is coming from someone who tracks their car and gets maybe 7-10k miles from a set at the most).


Max

 

[Nikolas]

Volvohead, thanks for the offer!

I don't want to get rid of serviceable tires, on the other hand I don't want to end up like some people that run 8 year old tires just because they have enough thread left

The thread is not severely cracked, only upon close inspection you see little cracks, maybe a hair's width. And it is more on the outside part of the fronts, the part that ends up wearing fastest on this car.

At this point, does it make sense rotating them front to back? They haven't been rotated at all so far. The back ones are in much better shape. The only problem I can think of is the rule that says to put the good tires in the front. Maybe also the fact that they have taken a wear pattern that I will be reversing by rotating them at this point. Would rotating make thinks worse?

 

[Tornado Red]

Originally Posted By: Nikolas
At this point, does it make sense rotating them front to back? They haven't been rotated at all so far. The back ones are in much better shape. The only problem I can think of is the rule that says to put the good tires in the front.

The rule is to have your best tires in the back. There are some tire shops that will only install in the back, if you're only buying two.

But unless the difference between front and back is too great, then rotating might help. If the difference is huge, then replace the front pair.