Philosophical endurance tire question.

Chump, so limited to 180tw. My musings are this: Buy several sets of Rival/Z11/R1R 200tw tires, run quickly, spend more money on more expensive tires and more of them, OR, Find a DZ102/Yoko Sdrive/etc 400 tw tire and sqirm around, but burn up fewer, cheaper tires that are a second/5 seconds/10 seconds per lap slower, hoping to not chunk them to pieces and end up using just as many tires over 24 hours.

New pavement, but 2 long, long hairpin corners. Rain is certainly possible, but probably not likely. 98 Integra.

Opinions?

Are you trying to win? Or at least be near the front? Whenever there is a rule #1 in racing it always involves tires, and there's a reason for that. For what it's worth, the non Star Spec Z2's had spectacular wear on One Lap for the cars that were on them. Driven insanely hard with minimal wear.

if money is no consideration, how many seconds slower are the longer lasting tires, and how long does it take you to change all 4?

Say 5 minutes to change all 4? 300 seconds.

a 12 hour event on 2:00 minute laps means 360 laps. So if the more durable tires last all day and the less only half the day, then you better be no less than about .8 second per lap slower on the more durable tires.

EDIT - if the longer lasting tires last all weekend (and they probably would) but the faster tires last all day, then you would need to be less than .4 seconds slower per lap on the longer lasting tires for it to be worth it.

5 minutes to change 4 tires? Are there special rules in Chump as to how you can work on the car? I think we could do a set of tires in under 90 seconds on the Thunderhill endurance team with no special tools, just a practiced team. Of course you've got your pit in/out, but if you combine it with refueling it's not a big chunk of time.

The basic question has an assumption in it that seems reasonable, but in practice has been found to be untrue: 400 treadwear tires will last longer than 200 treadwear in an endurance race environment. Many lemons teams have tried this, and found that the 300-400TW tires just over heat and then chunk and feather and wear away quite quickly, often within one race, unless you drive so slowly that you are almost in the way, especially at a chump race. The lower TW tires are better able to deal with the heat, and because of it tend to last much longer. We have been running Rivals for the past 2 years, and star specs before that, and our Civic gets 3-4 complete races with testing day out of a set, and even the boat (actual 16' boat on an S10, 3000lbs) gets 2-3 races out of a set.

Thinking that higher TW tires will last longer or save money is false economy, and also lots less fun when you have much less grip than everyone on track with you. With an integra that is setup well with enough camber and not being super overdriven, you should see similar results as our civic

Keith Tanner wrote: 5 minutes to change 4 tires?

Yeah, I just guessed at how long it would take most 'chumps' with a big buffer put on to make sure the calculation was fair. If I said 90 seconds the 400TW tires would have to be within .25 seconds per lap of the 200TW tires to be worth it. and that's assuming one 'on-the-clock' tire change.

If your 200TW tires can last all day and you can change in-between races then there is no consideration other than money. (and the above mentioned experience of not assuming 400TW tires will actually outlast 200TW tires on track).

I'm not sure about the rules currently, but early on when I ran with them, stops involving fuel meant a mandatory 5-min fuel stop to ensure proper safety.

Also driver's are limited to 2-hour stints, most cars can usually only go 1-1/2 to 1-3/4 hours on a tank of fuel. So figure you're going to have a minimum of 6 stops in a 12-hour race, that's 30 minutes of stops (not counting the time spent coming in and out of the pits).

turboswede wrote: I'm not sure about the rules currently, but early on when I ran with them, stops involving fuel meant a mandatory 5-min fuel stop to ensure proper safety. Also driver's are limited to 2-hour stints, most cars can usually only go 1-1/2 to 1-3/4 hours on a tank of fuel. So figure you're going to have a minimum of 6 stops in a 12-hour race, that's 30 minutes of stops (not counting the time spent coming in and out of the pits).

This is all pretty accurate. We are hoping for closer to 1 hour 50 on fuel, but that remains to be seen. The tire changes probably wouldn't add too much to the overall time, unless we change all 4. I've run this track in my IT car on Rivals, and other than needing to turn the rr brake right off to avoid turning that tire into an octagon, (much, much trail braking) a set is good for 6-7 hours at full song. The Neon is much fatter and less...Honda-ey, I guess, in the suspension and is very, very hard on fronts. I'm thinking 8 Rivals would likely do the 24, based on 3 sets on the front, and maybe a f/r swap halfway through.

Concerned about Rival performance in the rain if it shows, too.

No mid race break, either. Straight 24 hours.

I think I agree with the harder tires chunking, too.

Thanks for the math, rcutclif. I've been randomly doing mental arithmetic for a couple of days. Without practice, its pretty hard to come up with a lap time difference. Certain assumptions can be made, though, and I think the math doesn't support the idea.

Except a DZ102 is worth $83 each from my distributor. Rivals or similar will be twice that by the time we get them here.

A really good set of summer tires cost eight hundred dollars. But an affordable set of tires, which were sort of OK for a session or two and then chunked like hell when the cardboard gave out, cost about three hundred dollars. Those were the kind of tires MCarp always bought, and drove on until the tread was so thin that he could tell what turn he was in on a foggy night by the feel of the curbing.

But the thing was that good tires lasted for hours and hours. A team who could afford eight hundred dollars had a set of tires that'd still be turning fast laps in ten sessions' time, while the poor team who could only afford cheap tires would have spent a thousand dollars on tires in the same time and would still be slow.

This was the Captain Samuel Vimes 'Tires' theory of motorsports unfairness.

/hat tip to Terry Pratchett

Keith Tanner wrote: 5 minutes to change 4 tires? Are there special rules in Chump as to how you can work on the car? I think we could do a set of tires in under 90 seconds on the Thunderhill endurance team with no special tools, just a practiced team. Of course you've got your pit in/out, but if you combine it with refueling it's not a big chunk of time.

I've only done one Chump race … all I can remember is that there is a min time for a pit stop … and you MUST be out of the car for re-fueling, can't touch car while re-fueling … so tire change would come after fueling was complete

and if LeMons, then the only thing that can be done on pit road is change driver and re-fuel … so to change tires, you'd have to go your paddock … and re-fueling is allowed on pit road only … means 2 stops, because to return to pit road for fueling, you'd have to return to the track, and come around again and re-enter pit road

Run the Rivals (not the rival S). If you can't get them (currently nationally backordered), run the Dunlop Z2 Star Specs.

These tires will last at least 36 hours track time if you have good setup and choose the right tire pressures.

Last year our 944 ran Daytona 14hr, Sebring 14hr, and Homestead 24hr, and we still have tread.

Also, we ran the rivals in some pretty wet stuff and they did great, the whole thing about rivals being bad in the wet is hearsay.

Also, in Chump, you can change drivers when you fuel, but that's it, no other work while the cap is off.

Don't sweat this, just get the good tires, if you don't, you will regret it.

At Thunderhill, you can only do a driver change while refueling, and could only change one tire in the hot pits. If you wanted to do a full tire change, you had to go into the paddock. But what track doesn't let you get from the hot pits to the paddock without going on to the racing surface? What if the car comes in for fuel and you discover a major problem like a busted subframe (done it)? Surely you're not expected to send the car out for a lap like that to get to the paddock.

The big loss of time is the in and out laps, and if you combine a tire change with a fuel stop then you only pay that penalty once. Come in, fuel, whip around to the paddock, crew descends upon the car and swaps tires, car heads back out. I don't have my notes here for actual time elapsed, but a tire change added less than two minutes to a fuel stop iirc.

It should be noted that we were the only team practicing tire changes in the dark before the race. Everyone had a role, even to the point of the gun men having spare lug nuts stuck to their arms in case they drop one. It's easier to save time in the pits than to gain it on the track.

I don't have direct experience with trying to make 400tw tires last on the track, so I can't comment there.

I don't wanna throw more data in here and cause confusion but I'll try and help.

My Dz101s have lasted about 2 years. That includes daily driving, 4 hpde events, about 18 autocross events and spirited street driving on the weekends.

They have been about 3-4 seconds off of the fastest STF car here consistently on a 40-50 second course. And that's a Mazda 3 on Rivals that are wider (I'm running 205 versus his 225 widths I think). The 101s feathered a bit at hpde days but never chunked with 30-ish minute sessions. My car is also under prepped compare to his car and less capable platform in general too I think. If I added coilovers and better tires I'd still be a second or so off.

I'd have to check on what my total mileage was over the life of the tires, I can't remember at the moment.

Speedjw wrote: Also, we ran the rivals in some pretty wet stuff and they did great, the whole thing about rivals being bad in the wet is here say.

not hearsay … what the reports come from is standing water … wet track … they're no worse than others … standing water is their Achilles heel

Okay, I have done a good bit of tire testing for chump.

R1r are fast but wear out in 7 hours on track.

Rs3 are not the fastest but close. They wear like iron. Probably last 24 hours with no rotating.

Rivals are awesome but pretty picky about setup. Tire pressures and camber need to be pretty good. They are very quick in the rain BUT they feel very slick.

Azenis are good and wear well but are not as quick.

Z2 ss are okay but aren't the quickest and don't wear as well as rs3 but about the same as rival.

Test whatever tires you choose with a pyrometer to see how happy the tires are. We found 3 deg camber and 34 psi hot was ideal for most tires.

Make sure you get a good heat cycle in on any tire you get before racing them. All of these tired will be grippier over the long haul and last way longer.

For the record we are 3x lemons winners and 3x chump winners.

My choice of tires is rivals in 225 45 15 in a 2400# rwd car.

wbjones wrote:

Speedjw wrote: Also, we ran the rivals in some pretty wet stuff and they did great, the whole thing about rivals being bad in the wet is hearsay.

not hearsay … what the reports come from is standing water … wet track … they're no worse than others … standing water is their Achilles heel

Fair enough, but when it gets really wet (standing water on track) you should avoid the water. And, if standing water extends all the way across the track, its been my experience that both Lemons and Chump will red flag the race.

That said, I can't say enough good things about the Rivals...

For reference, we have run the following on our 944 since 2010:

1st set: BF Goodrich G-Force Sport (225/45R15), ok tire, lasted forever, poor grip.

2nd set: Dunlop Direzza Z1 Star Spec (205/50R15), loved these tires lasted well, excellent wet traction, just wish they had them in a 225/45

3rd set: Dunlop Direzza's again, still great

4th set: Falken Azenis (205/50R15), supposed to be same compound at the Dunlops... definitely weren't only ran these 1 race.

5th set: BF Goodrich Rival (225/45R15), great grip, even better wear. We run in florida, so almost every race we run has a mix of dry and wet, and we have no complaints in either. Like I said, these tires lasted us a year

6th set: Hankook Ventus R-S3 version 2 (225/45R15), BF's are backordered, and didn't want to step down to the smaller 205/50, so we will be running these at Daytona this weekend. Lets see how they work...

P.s. the higher treadwear tires do not like endurance racing. They have softer sidewalls and more squirm. They end up hotter than lower treadwear tires.

Oh and another thing...

You can change drivers while fueling in chump.

If you fuel, minimum of 5 min stops.

You can work on the car anytime in pit lane as long as the gas cap is on.

On our million pound coronet the the 225 15" rivals last multiple races. Not sure how you're going to blow though a set faster unless you're doing it on purpose.

If you want to be cheaper, these here GT Radial UHP1s I bought for my daily driver continue to surprise the living berkeley out of me. They're like like previous generation of fast ST tires grippy and havent shown appreciable wear after a couple thousand street miles. The 205 17's were only like $256/set shipped from discount tire and they're as wide as the 225 RE01Rs they replaced.

If you have to stop the car for a minimum of 5 minutes every time you fuel, seems to me that tire changes wouldn't affect pit stop duration at all.

again (for Chump) that would work fine (assuming all their races allow 4 tire change on pit lane) … but if you venture over to LeMons … that's a no go (no time limit on pitstop) but ZERO work on the car allowed on pit lane … can't even check tire pressures