Q&A With a Tire Engineer: R-Comp Race Tires vs. 200-Treadwear Extreme Street Tires

I have a question to the question: What other tire questions does the group have? Experts are standing by.

Thanks. 

Very interesting and entertaining Q&A. We've been running Maxxis VR-1s on our 94 Accord Champcar for the last two years and the Q&A segment about heat got the gears moving in my noggin about issues we've run into with the VR-1 in a hot setting. Sebring in September for a 14 hour race, I can't think of a more brutal venue for a tire when you factor in all variables such as heat, track surfaces, speeds, and so on. Once the track got hot in mid-day we started losing corner exit grip on the VR-1s, they would bite in great on entry; but, as the car apexed it would start to plow. At night when things started to cool off they went back to the same driving characteristics we had in the early hours of the race and eventually to a class victory. As mentioned, the heat also caused much more wear on the tires than our previous race in a much cooler setting. 

I wonder, would shaving the VR-1 tires help? 

How similar is the actual compound between the street and r-comp?   On a street tire is the better wet grip 100% due to the tread design or does differences in the compound help too?

What would be the coldest storage temperature you would want to allow for the 200 treadware and the R Comp tires?

Good question and keep them coming. Spoiler alert: There's a part 2 in the works. 

In reply to David S. Wallens :

In our experience, yes. We were one of the race team asked to participate in early testing durin the development of the VR1 and RC1. Heat cycling is just heat x time. The longer the tread is exposed to heat, the harder it gets. The deeper the tread, the more it deforms, which generates more heat. The extra rubber mass also holds more heat. So a shorter tread has the double benefit of generating less heat and shedding whatever thermal load much faster than a full tread. Wehave shaved VR1's and RC1's for various events. Quicker than full tread and they actually last nearly as long. Proble is few shops still shave tires, fewer still know how to do it right and it ain't free. 

In reply to Patientzero :

Surprisingly, we have seen some of the latest 200tw EHP (extreme high performance) tires have lower durometer and faster wear rates than some older 100tw race tires. The softest wet specific race tires like a Hoosier H2O are actually designed to generate casing heat in the rain. They are fast in the rain even when cold but surreal once they heat up. Normal to come off track on full rainy day on H2O's and they're steaming, too hot to leave your hand on. The lack of sipe(tread grooves) and casing design are major factors in performance. EHP's ride like crap and are noisy. That's not tread design, that's casing design. The best current EHP's (A052, RE71R are far more sophisticated than the 100tw race tires of 15 years ago, like the NT01 for example.

I liked this line "Yes, tread wear seems to be an issue that tire companies haven’t been able to overcome."

Jeez, I wonder why that is? lol

Anyways, very interesting and I'm looking forward to part 2 (also looking forward to eventually upgrading from 200 TW to R).

Im curious about the distribution of how tires shed heat. As in, how much goes into the rim, how much goes across the contact patch, how much goes to outside air, etc. This is just pure curiosity. 

Up here in the North, we have track days and races early in the season with track temps right around freezing. Even worse, we have sessions only 15 minutes long and sometimes raining / snow. What type of tire would give you the fastest lap times for cold, wet, short race sessions?

adam525i (Forum Supporter) said:

I liked this line "Yes, tread wear seems to be an issue that tire companies haven’t been able to overcome."

Jeez, I wonder why that is? lol

Anyways, very interesting and I'm looking forward to part 2 (also looking forward to eventually upgrading from 200 TW to R).

Think of it this way. Kleenex tissue companies haven't figured out a way to continually reuse Kleenex either. 
Actually there is a way to get long wearing tires.  Use harder treads. Race with TW600. 

In reply to frenchyd :

Or go slower. 

I have joked with friends in the tire biz: Why can't you make a tire that's really fast and also long-wearing? Oh, and I only want to pay $75 for it. 

carpeforza said:

Up here in the North, we have track days and races early in the season with track temps right around freezing. Even worse, we have sessions only 15 minutes long and sometimes raining / snow. What type of tire would give you the fastest lap times for cold, wet, short race sessions?

I wonder how the continental extreme contact or michelin p4s would hold up for those cold sessions, and as the day goes on swap to the 200tw stuff later on?

In reply to aw614 :

FWIW, you do often see those tires in One Lap. 

Patientzero said:

How similar is the actual compound between the street and r-comp?   On a street tire is the better wet grip 100% due to the tread design or does differences in the compound help too?

Compound and tread pattern both have a role. A "slick" tire with a good wet compound would be fine in damp/wet conditions with no pooling or running water, as hydroplaning would not be a consideration. The rubber compounds trade off fillers between carbon black and silica to tune dry/wet performance. Of course, it's waaaaayyyyy more complicated than that, with all the other performance considerations.

Emilio700 said:

In reply to Patientzero :

Surprisingly, we have seen some of the latest 200tw EHP (extreme high performance) tires have lower durometer and faster wear rates than some older 100tw race tires. The softest wet specific race tires like a Hoosier H2O are actually designed to generate casing heat in the rain. They are fast in the rain even when cold but surreal once they heat up. Normal to come off track on full rainy day on H2O's and they're steaming, too hot to leave your hand on. The lack of sipe(tread grooves) and casing design are major factors in performance. EHP's ride like crap and are noisy. That's not tread design, that's casing design. The best current EHP's (A052, RE71R are far more sophisticated than the 100tw race tires of 15 years ago, like the NT01 for example.

You left out RS-3/4. At least for a FWD race car. We could get 40+ hours of racing out of a set and never felt performance peel back over the life. 

I won't  even bother looking at the list of available sizes, as I'm almost certain they're not catering to vehicles with smaller wheel diameters. 

How would these work on a dirt oval that is restricted to DOT tires?

Coupefan said:

I won't  even bother looking at the list of available sizes, as I'm almost certain they're not catering to vehicles with smaller wheel diameters. 

There are plenty of good tires still being made for 15" wheels.

David S. Wallens said:

I have a question to the question: What other tire questions does the group have? Experts are standing by.

Thanks. 

I would LOVE to get deep into tire tech.  I would love to know what goes INTO a tire and what those quantities produce in terms of qualities.... like higher plutonium content increases sticktion, increased dilithium crystals helps keep it more stable in wider temps, more dicktonium prevents UV damage, etc.

I know a little about tread patterns and how certain blocks do better in mud, snow, dry, quiet, rain, etc, but I've always had to trust the manufacturer that when they say 300TW and "all season high performance" that they will fall into a certain category... and I'm usually disappointed by at least one advertised parameter.

I want to know all there is to know.

David S. Wallens said:

I have joked with friends in the tire biz: Why can't you make a tire that's really fast and also long-wearing? Oh, and I only want to pay $75 for it. 

I totally understand that and this kinda points up my previous post.  Take for instance brake pads or clutch material.  The different materials that go into them all have pros and cons, but the mingling of possible combinations of those materials can make them more than the sum of their parts.

- brake fade/temp
- longevity
- noise
- dust
- brake torque

Of those qualities, manufacturers have been able to mix and match ingredients so that it isn't a direct trade-off.  You can have brake pads that excel at both dust and fade (ceramic), or pads that provide good brake torque and longevity (semi-metallic) etc. I'm wondering how those ingredient-mingling properties work for tires.... or if I'm just making assumptions that aren't really valid.  I don't expect to be able to formulate a magic tire for $75, but I feel like tires are advertised like a parts store advertises brake pads:  You get the value line, the silver line, or the gold line without really knowing what is in the box.  At least with brakes, you can open the box and see what you're getting.  I feel like tire manufacturers just write up marketing blurbs about how "this tire has exceptional performance for your family sedan in most categories, and is also good at everything else, and they have a 360 TW.  Good luck guessing how they'll actually suit your driving style."

David S. Wallens said:

I have joked with friends in the tire biz: Why can't you make a tire that's really fast and also long-wearing? Oh, and I only want to pay $75 for it. 

Quintessential GRM. :)

"Yes, why isn't Ford building a track-ready, four-door wagon, with 500hp, manual gearbox, and RWD for $18,990?"

Curtis73 (Forum Supporter) said:

Good luck guessing how they'll actually suit your driving style."

For one thing, "driving style" doesn't really become a factor until you're talking about competition tires. Beyond that, a big part of the problem is it varies depending on what vehicle the tires are going on, what kind of driving you're doing with them, etc.

Follow-up question. 

At what point will we see the 200tw super tires out today be able to hold up to 4 or 5 track weekends a year? Give me RC1 or NT01 grip levels that can handle 32 sessions while driving to/from the track please (potentially driiving to events in the rain). 

Also, was NT01 the target for your RC1 offering? Where do you see success in dethroning the ultimate HPDE tire and where do you see room left to improve? What causes a tire to better handle braking zones and why does one tire prefer to have higher angles of slip versus another in the same treadwear segment?

THANKS SO MUCH for building a tire in the 275/35/17 profile, it is awesome having an HPDE tire in this shape!

In reply to David S. Wallens :

I'm interested in the differences between high end R-comps (like Hoosier R7s) compared to true slicks (like Hoosier C3000s). Also, R-comps vs. asphalt circle-track slicks. 

In reply to Olemiss540 :

Hankook RS4 does this now.  We get 3 whole lemons weekends out of a set, that's 50 hours of track time.  

Sonic said:

In reply to Olemiss540 :

Hankook RS4 does this now.  We get 3 whole lemons weekends out of a set, that's 50 hours of track time.  

I have about four track hours on my current set of RS4s and a few thousand street miles and they look like they're barely scuffed in.

dps214 said:

Curtis73 (Forum Supporter) said:

Good luck guessing how they'll actually suit your driving style."

For one thing, "driving style" doesn't really become a factor until you're talking about competition tires. Beyond that, a big part of the problem is it varies depending on what vehicle the tires are going on, what kind of driving you're doing with them, etc.

If that were true, there would be no test-and-review articles about tires.  companies like Tire Rack will pick a category and buy a set in every category, put them on the same vehicle with the same drivers and get vastly different results.  I have a 4x4 compact pickup.  The tires I chose for mine will satisfy me in PA, but not do so well for someone in Nebraska on the farm.  So yes, driving style has everything to do with it.

This is my whole point.  We either trust what manufacturers claim, or try to read between the lines of a review that may or may not exist.

Anyone remember the original BFG Comp TA R1 tires?  Not sure what the wear index on them was but those of us who ran them on the track sure did shave them first as they lasted far better and didn't build up enough heat to chunk.

The follow-up piece is coming together.

Thanks again for all of the interst in the topic. We could talk about tires all day. 

dps214 said:

Curtis73 (Forum Supporter) said:

Good luck guessing how they'll actually suit your driving style."

For one thing, "driving style" doesn't really become a factor until you're talking about competition tires. Beyond that, a big part of the problem is it varies depending on what vehicle the tires are going on, what kind of driving you're doing with them, etc.

Also the average non-competition driver has almost no self-awareness regarding their driving style and even plenty of competition drivers. Makes it tough to write ad copy.

In reply to GCrites80s :

I do think people realize when they're not happy with their tires--too noisy, too harsh a ride, etc. But you're right, most people don't realize what goes into a tire and want it all. And at a fair price. 

I should add that competition drivers do have access to data analysis these days to help them immensely with their self-awareness.

In reply to David S. Wallens :

definition of a heat cycle?  eg, if I drive to autocross in the morning,  but don't run until the afternoon,  how many 200tw "heat cycles" is that day?  1, 2, 5? 

2nd, if I spray water on tires between runs, will I heat cycle my tires out sooner?

I'd say everything's a heat cycle, even when your garage drops 10 degrees overnight. But more extreme heat cycles do more for aging out. Overnight temp changes are still 365 heat cycles of some degree each year.

David S. Wallens said:

I have joked with friends in the tire biz: Why can't you make a tire that's really fast and also long-wearing? Oh, and I only want to pay $75 for it. 

Honestly I'd be fine with fast wearing and sticky but cheap.  It's paying Hoosier money for something with such a crazy short service life that grates on the nerves.

Also would like to see comparisons between A7's and true slicks.  What is the end all be all fastest tire and all that.

GCrites80s said:

I should add that competition drivers do have access to data analysis these days to help them immensely with their self-awareness.

Based on racing tire temps, I'd say close to zero.  Highway driving just doesn't build heat like racing and neither does autocross.  Autocross is a cold tire sport. The runs aren't long enough to build up heat and change tire behavior.  I'd consider a 15-30 min lapping session a full heat cycle.  
 

I don't think anything sticks harder than an A7. There's no way tires built for a race series can need to take on water once a lap.