Performance Drop Off for Heat Cycled Tyres

Hi all,

Just looking at some secondhand tyres and wondering what value they present.

They are A050's. Cost is $600 (AUD).

It's obviously hard to know exactly how much work they have done. The ad says "Did a few test days and a round of racing". Worst case they are 'heat-cycled out'.

Image of tyres:

My question is then how would the performance compare to new tyres. Lets say compare them to V730's. For me these are $1000 fitted (so say $900 for the tyres).

Even if the A050's are heat-cycled out, would the performance be at least equal to the V730's? Will their performance fall off a cliff at some stage?

Cheers

I don't know about these particular tires (they sure are shiny), but I had a set of Azenis completely fall off a cliff when heat cycling. They were absolute trash with lots of tread depth. 

So if "a few" means 3, and "a round of racing" means a race weekend, these tires might have as much as 20 heat cycles on them.  I have no idea how many good cycles you can get out of an A050, but for the Hoosiers I use the max useful number is somewhere in the range of 6-10.  I expect those tires are done, and even if someone gave them to me for free I would question the value of the $100 to mount/balance them.

Also, how old are they and how long have they been stored?  Tires are not like wine, they don't get better with age.  This is especially true for race rubber once they have been used.  Date codes older than a couple years would also consign them to the trash heap, as far as I'm concerned.

Aged race compounds don't just get slower, they also get more knife-edged and harder to drive.

codrus (Forum Supporter) said:

Aged race compounds don't just get slower, they also get more knife-edged and harder to drive.

This is so true.  "Knife-edged" is a good description.  As tires heat cycle out their ability to re-gain traction after they start to slide goes way down, and the transition from starting-to-slip to all-the-way-sliding becomes very narrow.  If you can't catch the spin because the tires are hard that $300 you saved could cost you 20 times that in accident damage.

Track time costs tires; tires are expensive.  Cost of doing business.  Predictable tires are worth it.

In reply to Keith Tanner :

I had the same with AD09's. Plenty of tread left (still easily street legal) and they lost about 1s over a 1:09 track.

R-comps with that many heat cycles won't be competitive with fresh R-comps for sure and their performance will fall off a cliff at some point, it's quite possible these are already off it. When they fall off that cliff they'll not only have less grip than 200TW tires (maybe more like 300TW, they might be as sticky as Firehawk 500s at best) but they'll be much less forgiving. I'd say that if being competitive with 200TW tires is acceptable, look for some used or even new 200TW tires so you can almost forget about heat cycles and have a tire that will have much more consistent performance over its life.

codrus (Forum Supporter) said:

So if "a few" means 3, and "a round of racing" means a race weekend, these tires might have as much as 20 heat cycles on them.  I have no idea how many good cycles you can get out of an A050, but for the Hoosiers I use the max useful number is somewhere in the range of 6-10.  I expect those tires are done, and even if someone gave them to me for free I would question the value of the $100 to mount/balance them.

Also, how old are they and how long have they been stored?  Tires are not like wine, they don't get better with age.  This is especially true for race rubber once they have been used.  Date codes older than a couple years would also consign them to the trash heap, as far as I'm concerned.

Aged race compounds don't just get slower, they also get more knife-edged and harder to drive.

Agree regarding uncertainty of use. I suppose my main question is would they still be an ok tyre or does the performance fall off a cliff.

The ad says they were purchased late last year so (in theory) ok in that regard.

As I think has been covered, the answer to that varies wildly by tire, you basically need an answer specific to the tire. And that tire doesn't seem to exist in north america so it's doubtful that anyone here will have much information for you. Just looking at the photo, I wouldn't be too optimistic; that bluish discoloration is *usually* not a great sign.

DWNSHFT said:

codrus (Forum Supporter) said:

Aged race compounds don't just get slower, they also get more knife-edged and harder to drive.

This is so true.  "Knife-edged" is a good description.  As tires heat cycle out their ability to re-gain traction after they start to slide goes way down, and the transition from starting-to-slip to all-the-way-sliding becomes very narrow.  If you can't catch the spin because the tires are hard that $300 you saved could cost you 20 times that in accident damage.

Track time costs tires; tires are expensive.  Cost of doing business.  Predictable tires are worth it.

Yeah my plan was always to get V730's which I've used before and seem to present good value for money.

Just thought it might be worth looking into used tyre *if* they still provided decent performance once heat cycled out.

Buy the 730s. You know what you're getting, and they're a good tire. 

Floating Doc (Forum Supporter) said:

Buy the 730s. You know what you're getting, and they're a good tire. 

this.

$600 is a lot of money for used tires of unknown provenance. For $200 to help someone solve their storage problem they're worth the hassle, but not for 3/4 the price of new rubber that you can properly heat cycle yourself and you know will be good.

At our 1/4 mile paved oval it is widely accepted that Hoosier race tires gain one tenth (on a 15ish second lap) per race day. So if you keep the same tires all season you go from the front to the back. For this reason some oval groups limit how many new tires a car can run in a season. 

waggat said:

In reply to Keith Tanner :

I had the same with AD09's. Plenty of tread left (still easily street legal) and they lost about 1s over a 1:09 track.

My experience was on an autox car (we didn't have a local track at the time) but the drop-off was closer to 4 seconds in my case. Part of the problem was that the old tires weren't generating enough grip to get the chassis working fully, so I was also dealing with handling problems due to the decreased grip. 

I cooked a set of RE-71s by running them too long on a 105 degree day.  They were still runnable, but lost about 2S running time trials.  With a used tire you don't know what they've been through.

Not much to add here other than to say how tires are stored between cycles is also important, as is the depth of the cycles.

Further, race tire compounds tend to be more susceptible to cycling out than typical Super 200 street tires.

My quickest laps on streets are almost always when the tire has been worn to about 1-2/32nds.  Yes, very edgy and harder to drive -- but always quicker when I can connect all the dots for a lap.  Takes more time to come in but also more consistent thereafter during a session.  A 2/32 A052 is nothing like a full-tread version.