Advice on track tires/rims . . .

[rcl4668]

I have a 2008 convertible with autoform rollbar and 6-point harnesses that I use/will use for about 4-8 driving schools and 6-8 autocrosses per season (early Spring to late fall here in Oregon/Washington).

I currently have a set of lightweight Sidewinders rims with the stock Michelin Pilot Sport PS2 tires on the car:

I am considering ordering another set of Sidewinders from Jon B at Partsrack for driving school/autocross use only (this rim has the dual advantage of being an OEM, manufacturer-approved rim while being one of the lightest rims out there for the Viper short of magnesium/carbon fiber rims). I am at best an intermediate/novice driving school student and am completely new to autocross with this being my first year doing some SCCA Solo 2 events.

My options for tires it seems are as follows:

1) Sidewinders with the same Michelin Pilot Sport Cups tires as the ACR in the ACR sizes (345/30/19 rear 295/30/18 front). Advantage: more grip in the dry with a dedicated DOT-approved R compound competition tire, less understeer because of slightly wider front tire width. Disadvantage: I have heard that these are not that great in the wet and here in the NW a wet track day in the fall is a real possibility (I drive to and from the track and don't want to trailer alternate rim/tire sets);

2) Sidewinders with the Hoosier A6 or R6: I don't really have any firsthand info about these tires although I imagine they would have even slightly higher dry grip than the Sport Cups. I would also guess that they would be even worse in the wet given their semi-slick design; and

3) Sidewinders with another set of Michelin Pilot Sport PS2 tires in stock sizes. Disadvantage: No increase in performance although I must say these tires have been doing great during driving schools (they feel a little greasy in autocross but that may due to high torque/tire pressure setup). Advantage: Best wet weather performance, I can use the rim tire combo as temporary "spares" if I ever get a flat on my street tires.

What say you all? Thanks.

/Rich

 

[mjorgensen Woodhouse]

Truthfully the PS Cups and the Hoosier's are NOT really road tires. They will wear and "harden" rapidly on the street and then will suffer in overall grip. They will also "pepper" your car with road debris because they pick up everything!

The Hoosier's would be the tire for the autocross but you would want the A6 not so much the R6. This would be another compromise from road course to Solo.

Then the PS2's would be great all around for all the other reasons, wear, wet, streetable (less puncture prone) and you won't have to re learn the car at the events because it drives the same all the time. This will help improve YOU rather than all the cars effort.

IMHO of course.

 

[rcl4668]

Truthfully the PS Cups and the Hoosier's are NOT really road tires. They will wear and "harden" rapidly on the street and then will suffer in overall grip. They will also "pepper" your car with road debris because they pick up everything!

The Hoosier's would be the tire for the autocross but you would want the A6 not so much the R6. This would be another compromise from road course to Solo.

Then the PS2's would be great all around for all the other reasons, wear, wet, streetable (less puncture prone) and you won't have to re learn the car at the events because it drives the same all the time. This will help improve YOU rather than all the cars effort.

IMHO of course.

Mark --

I actually had the Viper cleabra'ed in case I started using DOT-R compound tires but you have given sage advice as always. I actually called Luke at Tirerack and he had the same advice about just buying another set of PS2s, especially given my geographic location.

/Rich

 

[mjorgensen Woodhouse]

That Luke hes a character huh? Good guy and I know the choice will suit you fine. Have fun and if you run into Scotty White out there tell him hi from me.

 

[viperfuntime]

I had PS2's and loved em. I am thinking about switching on the new car to different tires as well so your question is timely. All I can say is the runcraps are just that. I am staying with the 18/19 set up so I will stand back and wait to hear what people say.

 

[Viper X]

rcl4668,

There are a bunch of threads on tires. You may want to check the archives and the tire section of this forum. In short, if you intend to do only autocross, want to do this for fun only and drive your car too and from, the PS2's are likely your best choice.

There are better choices if you want to run faster. 18 inch rear tires and wheels will be lighter, lower the center of gravity of your car, lower the overall gear ratio and improve handling. Motons would be a good add along with an e-brake relocation kit. JonB is a great source of info on this.

A couple of tires that come to mind are Kumho Ecsta V-700s. Much stickier, fully treaded, dot approved and do fine in the rain. This would be my first choice in your situation.

The new Toyo R888's are similar to the Kumhos though not quite as sticky but would also be a good choice.

The A-6 is a very sticky tire with short tread life and would be dangerous in the wet.

Good luck,

Dan

 

[mjorgensen Woodhouse]

I have different opinions on the V700. I'm currently 1 of just a handful of KUMHO contract drivers and have thousands of race miles on them. The V700 is a heavy tire and any grip improvement will be negated by the weight IMO. It is also a race tire that will chunk when over heated at full tread depth (plus overheating will kill it's grip capabilities) so it will only work well if shaved. The full depth tire is only effective in the rain where the tread can stay cool.

The V710 is basically a slick but can even work in damp conditions because of the compound and radial grooves with no shaving required. Also the best thing about the KUMHO tires are that they are very well suited for the track and autocrossing without compromise. The best benefit for Viper drivers though in my opinion is that they possess the BEST break away characteristics of any of the choices so it is much easier to feel the limits without risking a end swapping episode.

The Toyo although a great tire is not the same. It was developed for use in a series and has good wear capabilities along with working as an intermediate rain tire. It should also be shaved for optimum grip though. I have run this tire as take offs from the WCGT team on my daily driver and they do offer great wear and grip on the street right to the cords if you want.

rcl4668,

There are a bunch of threads on tires. You may want to check the archives and the tire section of this forum. In short, if you intend to do only autocross, want to do this for fun only and drive your car too and from, the PS2's are likely your best choice.

There are better choices if you want to run faster. 18 inch rear tires and wheels will be lighter, lower the center of gravity of your car, lower the overall gear ratio and improve handling. Motons would be a good add along with an e-brake relocation kit. JonB is a great source of info on this.

A couple of tires that come to mind are Kumho Ecsta V-700s. Much stickier, fully treaded, dot approved and do fine in the rain. This would be my first choice in your situation.

The new Toyo R888's are similar to the Kumhos though not quite as sticky but would also be a good choice.

The A-6 is a very sticky tire with short tread life and would be dangerous in the wet.

Good luck,

Dan

 

[GR8_ASP]

I have different opinions on the V700. I'm currently 1 of just a handful of KUMHO contract drivers and have thousands of race miles on them. The V700 is a heavy tire and any grip improvement will be negated by the weight IMO. It is also a race tire that will chunk when over heated at full tread depth (plus overheating will kill it's grip capabilities) so it will only work well if shaved. The full depth tire is only effective in the rain where the tread can stay cool.

The V710 is basically a slick but can even work in damp conditions because of the compound and radial grooves with no shaving required. Also the best thing about the KUMHO tires are that they are very well suited for the track and autocrossing without compromise. The best benefit for Viper drivers though in my opinion is that they possess the BEST break away characteristics of any of the choices so it is much easier to feel the limits without risking a end swapping episode.

The Toyo although a great tire is not the same. It was developed for use in a series and has good wear capabilities along with working as an intermediate rain tire. It should also be shaved for optimum grip though. I have run this tire as take offs from the WCGT team on my daily driver and they do offer great wear and grip on the street right to the cords if you want.

I also have run the V700. Not sure that they are that heavy. Maybe when compared to Hoosiers but not in comparison to Sport Cups. I run different sizes for Kumhos (305/335 vs 295/345) but the total weight for all 4 is 8 lbs more than Cups and 22 lbs less than stock. Be ready for extreme tire wear, especially in the autocross on high friction surfaces. Get shaved if you plan on tracking them, they indeed do chunk as Mark indicated.

 

[rcl4668]

Unfortunately, for SOLO and other reasons i need to stay with the same rim sizes/dimensions as stock, so it's 18 x 10 front and 19 x 13 for me. Unfortunately, it doesn't look like the Kumhos or the Toyo R triple 8 are available in the right sizes.

/Rich

 

[Viper X]

Mark,

I've chunked a few Kumhos too including shaved ones, as I got faster. I didn't have any issues chunking any tires as a novice though (which is what rcl4558 says he is). Never got close to chunking any tire in an Auto Cross - courses are way too tight, short and slow out here.

"The V700 is a heavy tire and any grip improvement will be negated by the weight IMO."

You have to be kidding on the weight / grip issue. Check the weights on a 19-inch Viper rim and PS2 vs a 18-inch Kumho on an SSR. The PS2 is 3 pounds heavier than the V-700 not including the rim! Stock 19-inch rims can be 5 to 10 lbs heavier than the SSRs, per wheel. The V-700 has a tread wear rating of 50 (this is almost slick sticky) while the PS2 has a tread wear rating of 220. This isn't close. The Kumho offers a signifcant grip advantage over the PS2 or the PS Cup.

When I first started tracking my Vipers I melted many Pilots, Cups and then proceeded to melt PS2's. Any tire will loose grip if overheated. The Kumhos take the heat much better than either of these tires and the Toyos are even better.

We do agree on a few things, the Kumho Ecsta V700 is extremely predictable compared to other tires in this tread wear rating. It is vastly superior, IMHO, to the PS Cup and it's lighter than the 19-inch Cup too (besides being less costly).

I also agree that either of these tires should be shaved and heat cycled for maximum tread life on the track with an aggressive driver.

It does sound like this discussion is for naught though as Rich is planning to run 19-inch rears. Not many choices there ..... yet.

Good luck,

Dan

 

[mjorgensen Woodhouse]

Yes as I said, IMHO the V700 is not worth running if the choices are it OR the V710 that I was comparing it to (I was talking tire weight only). It is heavier, not as grippy, and will chunk if you are running low enough pressures to do well in any autocross.

And by the way the tire wear ratings when you are talking race tires are NOT really that important, or relevant.

For what he is asking I think he will be fine with the PS2's at the level he considers himself to be at now.

Mark,

I've chunked a few Kumhos too including shaved ones, as I got faster. I didn't have any issues chunking any tires as a novice though (which is what rcl4558 says he is). Never got close to chunking any tire in an Auto Cross - courses are way too tight, short and slow out here.

"The V700 is a heavy tire and any grip improvement will be negated by the weight IMO."

You have to be kidding on the weight / grip issue. Check the weights on a 19-inch Viper rim and PS2 vs a 18-inch Kumho on an SSR. The PS2 is 3 pounds heavier than the V-700 not including the rim! Stock 19-inch rims can be 5 to 10 lbs heavier than the SSRs, per wheel. The V-700 has a tread wear rating of 50 (this is almost slick sticky) while the PS2 has a tread wear rating of 220. This isn't close. The Kumho offers a signifcant grip advantage over the PS2 or the PS Cup.

When I first started tracking my Vipers I melted many Pilots, Cups and then proceeded to melt PS2's. Any tire will loose grip if overheated. The Kumhos take the heat much better than either of these tires and the Toyos are even better.

We do agree on a few things, the Kumho Ecsta V700 is extremely predictable compared to other tires in this tread wear rating. It is vastly superior, IMHO, to the PS Cup and it's lighter than the 19-inch Cup too (besides being less costly).

I also agree that either of these tires should be shaved and heat cycled for maximum tread life on the track with an aggressive driver.

It does sound like this discussion is for naught though as Rich is planning to run 19-inch rears. Not many choices there ..... yet.

Good luck,

Dan

 

[Boxer12]

Why get another set of the same thing? Just run em PS2's till they wear out and get another set put on!

 

[rocman]

Truthfully the PS Cups and the Hoosier's are NOT really road tires. They will wear and "harden" rapidly on the street and then will suffer in overall grip. They will also "pepper" your car with road debris because they pick up everything!

Hey, the cups were fine for my 2400 mile trip home.

I already have a couple nice chips on my passenger door from debris on the track. They really do pick up a lot of crap on the track.

 

[mjorgensen Woodhouse]

I'm sure they were it was only 1 heat cycle!

Hey, the cups were fine for my 2400 mile trip home.

I already have a couple nice chips on my passenger door from debris on the track. They really do pick up a lot of crap on the track.

 

[j-rho]

Unfortunately, for SOLO and other reasons i need to stay with the same rim sizes/dimensions as stock, so it's 18 x 10 front and 19 x 13 for me. Unfortunately, it doesn't look like the Kumhos or the Toyo R triple 8 are available in the right sizes.

/Rich

Rich, don't you have headers on your car? If that's the case, you won't be eligible to run in Solo2 "Super Stock" class, and will be bumped to "A Street Prepared" class, where any size wheel/tire is allowed. That being the case, if it were me, I'd get something wider for the front than 18x10; I'd do 18x12, but even an 18x11" will better support the 295 tire, and give you the chance to run a 305 or 315 with near-optimal wheel support, as supposed to pinching them onto 10's.

As noted by others, getting some 18" rear wheels opens up additional tire options (Kumho among them) that are a bit less expensive. If I were to prep my car for Street Prepared right now, I'd get 18x12" wheels up front, and 18x14" for the rear, from CCW.

That said, I would recommend getting the Michelin sport cups. They'll teach you about heating up a tire and to feel the difference in grip through temp changes. They won't chunk in any of these endeavors. They'll be faster than PS2s, and make the car more fun to drive, especially at autocross. They aren't the best for the rain, but they're better than a 710/A6 slick-style tire, and you'll still be able to get to/from events (just have to go a bit slower). Trying to race this car in the rain is going to **** no matter which tire you're on (in fact, I wouldn't recommend taking the car out on the track in the rain at all, regardless of tire) so you might as well get one that is a bit more fun in the dry.

Hope you enjoy whichever choice you make!

Mark, I don't think Scotty makes it out to dodge cones so much any more, not since I bought his car anyway..

 

[rcl4668]

Rich, don't you have headers on your car? If that's the case, you won't be eligible to run in Solo2 "Super Stock" class, and will be bumped to "A Street Prepared" class, where any size wheel/tire is allowed. That being the case, if it were me, I'd get something wider for the front than 18x10; I'd do 18x12, but even an 18x11" will better support the 295 tire, and give you the chance to run a 305 or 315 with near-optimal wheel support, as supposed to pinching them onto 10's.

As noted by others, getting some 18" rear wheels opens up additional tire options (Kumho among them) that are a bit less expensive. If I were to prep my car for Street Prepared right now, I'd get 18x12" wheels up front, and 18x14" for the rear, from CCW.

That said, I would recommend getting the Michelin sport cups. They'll teach you about heating up a tire and to feel the difference in grip through temp changes. They won't chunk in any of these endeavors. They'll be faster than PS2s, and make the car more fun to drive, especially at autocross. They aren't the best for the rain, but they're better than a 710/A6 slick-style tire, and you'll still be able to get to/from events (just have to go a bit slower). Trying to race this car in the rain is going to **** no matter which tire you're on (in fact, I wouldn't recommend taking the car out on the track in the rain at all, regardless of tire) so you might as well get one that is a bit more fun in the dry.

Hope you enjoy whichever choice you make!

Mark, I don't think Scotty makes it out to dodge cones so much any more, not since I bought his car anyway..

Thanks for weighing in on this post; I attended one of the Oregon SCCA Solo driving schools back in April and I thought my instructor told me that as long as I had "exhaust-only" mods I would still fit into the stock class. So headers would bump me into ASP?

Thus far this season this has been a nonissue for me as I have been treating all the Solo events as a driving school to improve my car control skills and have even run some events outside my class to get more runs in because I told the SCCA staff that I was not running for points.

At this point I am still waffling between the Sport Cups and the PS2s. The other useful posts regarding the Kumhos and other dedicated race tires suggest that they are a little more than what I need now in terms of both driving to and from the track, proper care and feeding of the tire (proper heat cycling, shaving etc) and limited life span. On the one hand, I have had many people I respect tell me that I wil learn more about car control on a good street tire like the PS2 whereas others have suggested that the Sport Cups are a good "intermediate" step between the PS2s and the full-on race rubber like the Hoosiers and the Kumhos.

/Rich

 

[j-rho]

Only cat-back exhaust allowed in Stock, nothing between the air filters and cats can be changed.

If you plan on one day competing in timed events on R-compound tires, the PSC's are your first step in that direction. They have most of the characteristics of R-tires (heat sensitivity, heat cycles, rock-flinginess) but not to the extreme, and without the water-hazardousness and puncture susceptibility, of something like a Hoosier A6. If you're just there to learn and have fun, then it doesn't really matter which of the tires you're on. I'd guess the PSCs and PS2s have similar lifespans under the duress of track and auto-x.

I personally find the car a lot more fun to drive on stickier tires. You can use more throttle more of the time, and the extra grip starts to really work the great chassis in the corners. Even stock, a well-driven Viper on R-tires is a very very fast car; on its stock tires, it is not as fast as much lesser cars on R tires.

 

[rcl4668]

Only cat-back exhaust allowed in Stock, nothing between the air filters and cats can be changed.

If you plan on one day competing in timed events on R-compound tires, the PSC's are your first step in that direction. They have most of the characteristics of R-tires (heat sensitivity, heat cycles, rock-flinginess) but not to the extreme, and without the water-hazardousness and puncture susceptibility, of something like a Hoosier A6. If you're just there to learn and have fun, then it doesn't really matter which of the tires you're on. I'd guess the PSCs and PS2s have similar lifespans under the duress of track and auto-x.

I personally find the car a lot more fun to drive on stickier tires. You can use more throttle more of the time, and the extra grip starts to really work the great chassis in the corners. Even stock, a well-driven Viper on R-tires is a very very fast car; on its stock tires, it is not as fast as much lesser cars on R tires.

Thanks. I am leaning more towards the Sport Cups at this point. After all, Dodge saw fit to use them as OEM on the ACR. Presumably, Chrysler engineers (as well as their legal department) anticipated that the ACR would be driven by many owners as a street car as opposed to a track-only car. If things get wet on a given track day or autocross, I can throw my PS2s on the car and use them as my "wet" tires.

Thanks again everyone for the great feedback.

/Rich

 

[mjorgensen Woodhouse]

Another thing to ask and I do not know the answer just the possibility. Are the Sport Cup tires on the list of tires approved or not? I can't remember seeing them on any cars before. I may be wrong so just asking.

Thanks. I am leaning more towards the Sport Cups at this point. After all, Dodge saw fit to use them as OEM on the ACR. Presumably, Chrysler engineers (as well as their legal department) anticipated that the ACR would be driven by many owners as a street car as opposed to a track-only car. If things get wet on a given track day or autocross, I can throw my PS2s on the car and use them as my "wet" tires.

Thanks again everyone for the great feedback.

/Rich

 

[rcl4668]

Another thing to ask and I do not know the answer just the possibility. Are the Sport Cup tires on the list of tires approved or not? I can't remember seeing them on any cars before. I may be wrong so just asking.

Mark --

Do you mean approved for SCCA Solo or something else?

/Rich

 

[j-rho]

You can run any tire you want in SCCA Solo, as long as it's not corded or otherwise "unsafe". If the tire is DOT approved you can run in Super Stock, A Street Prepared, or Street Modified 2, depending on modification level. If you are running non-DOT race slicks, you have to run in a Prepared or Modified class (XP and EM I think, not sure though). You could also run DOT tires in the Prep/Mod classes, though good P or M cars are usually very very fast tiny bantamweight high-strung purpose-built autocross machines.

 

[mjorgensen Woodhouse]

Yes was wondering about the Solo rules?

Mark --

Do you mean approved for SCCA Solo or something else?

/Rich

 

[Dave Moore]

Rich,
I have been spending money on extra rims and tires for the track as well, and have decided that non of the decisions I have made have been the perfect solution. I will share some of the short falls.
First I bought a set of the light weight ACR wheels, stock size. The mistake here was not getting the 18" rears. I highly recomend you do that. In the long run they will offer you many more and less expensive tire options. It is easier to get "saved" at thetrack as well. I had a tire go down at the track once and because I could get the 18's on my car a buddy was able to loan me rims and tires to get home.

Are you driving or trailering the car? Running sport cups in the dry is fine, but a scary in the rain. I live in NJ and drove to Mid-Ohio for a Viper Days weekend on sport cups. It started to rain 45 mins into my 6.5 hour trip and rained hard most of the way out. Very scary and unpredictable. Turned out to be a beautiful weekend and the sport cups were great on the track, but I won't drive to the track for a multiday event on sport cups again.

I don't have a bunch of experience with many different tires but the sport cups take a bit to warm up and are not the best choice for auto X. And comparitivly speaking are much more expensive than many of the other solutions.

Good luck with your decision, but most of all have fun. The easyist thing to do is run the street tires for awhile. And let the decision evolve as you add experience.

 

[rcl4668]

Rich,
I have been spending money on extra rims and tires for the track as well, and have decided that non of the decisions I have made have been the perfect solution. I will share some of the short falls.
First I bought a set of the light weight ACR wheels, stock size. The mistake here was not getting the 18" rears. I highly recomend you do that. In the long run they will offer you many more and less expensive tire options. It is easier to get "saved" at thetrack as well. I had a tire go down at the track once and because I could get the 18's on my car a buddy was able to loan me rims and tires to get home.

Are you driving or trailering the car? Running sport cups in the dry is fine, but a scary in the rain. I live in NJ and drove to Mid-Ohio for a Viper Days weekend on sport cups. It started to rain 45 mins into my 6.5 hour trip and rained hard most of the way out. Very scary and unpredictable. Turned out to be a beautiful weekend and the sport cups were great on the track, but I won't drive to the track for a multiday event on sport cups again.

I don't have a bunch of experience with many different tires but the sport cups take a bit to warm up and are not the best choice for auto X. And comparitivly speaking are much more expensive than many of the other solutions.

Good luck with your decision, but most of all have fun. The easyist thing to do is run the street tires for awhile. And let the decision evolve as you add experience.

Dave --

Thanks for sharing your insights. At this point, I have two more driving schools at my local track and maybe two more SCCA autocrosses and then that's it till next spring. So there is a lot of wisdom in becoming more familiar with the 08, finishing out the year on the PS2s, and then using the winter to further research the rim/tire issue.

On that note, I have had more than one person recently offer to sell me their 18'' BBS rims. These are the same rims used on the competition coupe. Does anyone know what these rims weigh? I assume that because they are OEM on the competition coupes they are "battle tested" and can withstand frequent track use. Are there any negatives (other than needing to buy an e-brake relocation kit) to using these rims? Can the tire pressure monitoring feature be retained with these rims; in other words, can I buy an extra set of TPMS sensors and mount them on these rims?

/Rich

 

[Kai SRT10]

I think that Michelin stopped making the Pilot Sport Cup in 18 inch rear sizes.

 

[B767DRIVER]

Dave --

Thanks for sharing your insights. At this point, I have two more driving schools at my local track and maybe two more SCCA autocrosses and then that's it till next spring. So there is a lot of wisdom in becoming more familiar with the 08, finishing out the year on the PS2s, and then using the winter to further research the rim/tire issue.

On that note, I have had more than one person recently offer to sell me their 18'' BBS rims. These are the same rims used on the competition coupe. Does anyone know what these rims weigh? I assume that because they are OEM on the competition coupes they are "battle tested" and can withstand frequent track use. Are there any negatives (other than needing to buy an e-brake relocation kit) to using these rims? Can the tire pressure monitoring feature be retained with these rims; in other words, can I buy an extra set of TPMS sensors and mount them on these rims?

/Rich

I believe the rear BBS wheels will be 18 x 12's. Whichever wheel you go with I would suggest a 3-piece wheel. If you bend it you can replace the shell and not have to replace the whole wheel. A three piece wheel may weigh a couple pounds more than the lightest 1-piece but well worth the weight savings. Most drivers will not be able to discern the difference in a couple of pounds.