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concerns over tire choice


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im still in the process of picking a tire, boy what a lot to think about! ive narrowed down alot of choices. i am no longer conerned with "n" ratings, though i understand and appreciate peoples concerns for it. i am no longer interested in only OEM approved tires, there are so many other tires out there that are comparably capable. i do have the following concerns though:

-what is more important, retaining the same rpm as stock, the same overall diameter as stock, or just that the overall diameter front and back is within a few percentage points? by this i mean, stock tires have an ~25" diameter, if i go to ~26" all around, will that throw things off?

-i recall reading the owners manual that i shouldnt be running an r-compound tire without some oil system mods, to prevent starvation. would a tire with a wear rating below 200 UTQG be to sticky for the stock oiling system to continue to pump and lube? the MPS PS2 is listed at 220, im looking at a few tires that range from 140 (the hankook ventus rs-3) to 180 (kumho XS). i do autocross (infrequently 2-3 a year) and do open track days (2-3 a year). im a total novice, so im probably harder on my tires than i need to be, even if im not driving quickly. id like something that will be enjoyable on the track, at a reasonable cost that if i had to replace the rears every 1.5 years, i wouldnt be breaking the bank.

-i have an unmodified (suspension wise) 2002 c4s, with 15mm spacers rear/7 mm spacers front. the previous owner of my car installed 245/35/18 MPS PS2's up front, with a 295/30/18 rear. i researched it, and most people suggested the widest tire possible on the fronts. so id like to stick by that. even with the wider tire, im still at ~25" diameter all around. in order to find tires my next set of tires, ive just been searching by size for 245/35/18, and then looking for a rear that i can accomodate. I can get a Kumho XS front in 245 wide, by is it going to be feasible to run the 315 wide rear on the stock 11" wheel with a 15mm spacer rub issues? to wide of a tire for an 11" wheel? tirerack specs suggest the tire can be mounted on anything up to an 11.5" wheel...

-next choice would be kumho MX, but they really dont stack up at all compared to the others on my list.

-any thoughts on the nitto invo's?

-Im really liking the nitto nt-05. this is the tire i want. cheap, sticky, looks to be daily drive-able. i do truely daily drive my car, everywhere, in all conditions. they are a ~26" diameter tire. this refers again to my initial questions about overall diameter. would this work? thanks for the input-

-also, i would like to eventually modify my suspension, not necessarily a massive drop (im not doing the kind that is more aesthetic than functional), but an engineered solution to stiffening it up, reducing body roll, and getting the wheels to stay on the ground... therefore there is again cause for concern with overall diameter.

Thanks for the input and help! :thankyou:

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I replaced the Pirelli P-Zeros on my 2002 C4S with Sumitomo HTR Z III tires this year. I stuck with the OEM sizes. I have about 4,000 miles on them now, and overall I am very pleased. They are hard to beat for the money (roughly $700 for all four installed).

Good luck.

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I have a 2003 C2 with 18 inch rims. 225/40/18 front, 285/30/18 rear. I have had a couple of different tires. I would steer away from the Pirelli Pzero Rosso tires. They wear really fast and take a while to warm up. I only run Michelin's now with PS2's in the front. The ps2 is a great tire but also really expensive. A friend recommended the Michelin Pilot sport AS Plus. I picked up a set and have loved them ever since. They fell much like the Ps2 and offer better traction in colder weather since they are an all season tire. Even if you are running the car in the summer only I still recmmend the PS AS plus tires. I have found no feel difference between these and the PS2's. This is just my opinion of course but they are a great tire. Not to mention they are only half the price of ps2's. Stick with Michelin. I have been buying their tires for years with great success. I have gone out on a limb with other such as Pirelli and was very disappointed with the performance and wear characteristics. If money wasn't an object I would go with the PS2. However.....the PS AS plus tire is still awesome.

im still in the process of picking a tire, boy what a lot to think about! ive narrowed down alot of choices. i am no longer conerned with "n" ratings, though i understand and appreciate peoples concerns for it. i am no longer interested in only OEM approved tires, there are so many other tires out there that are comparably capable. i do have the following concerns though:

-what is more important, retaining the same rpm as stock, the same overall diameter as stock, or just that the overall diameter front and back is within a few percentage points? by this i mean, stock tires have an ~25" diameter, if i go to ~26" all around, will that throw things off?

-i recall reading the owners manual that i shouldnt be running an r-compound tire without some oil system mods, to prevent starvation. would a tire with a wear rating below 200 UTQG be to sticky for the stock oiling system to continue to pump and lube? the MPS PS2 is listed at 220, im looking at a few tires that range from 140 (the hankook ventus rs-3) to 180 (kumho XS). i do autocross (infrequently 2-3 a year) and do open track days (2-3 a year). im a total novice, so im probably harder on my tires than i need to be, even if im not driving quickly. id like something that will be enjoyable on the track, at a reasonable cost that if i had to replace the rears every 1.5 years, i wouldnt be breaking the bank.

-i have an unmodified (suspension wise) 2002 c4s, with 15mm spacers rear/7 mm spacers front. the previous owner of my car installed 245/35/18 MPS PS2's up front, with a 295/30/18 rear. i researched it, and most people suggested the widest tire possible on the fronts. so id like to stick by that. even with the wider tire, im still at ~25" diameter all around. in order to find tires my next set of tires, ive just been searching by size for 245/35/18, and then looking for a rear that i can accomodate. I can get a Kumho XS front in 245 wide, by is it going to be feasible to run the 315 wide rear on the stock 11" wheel with a 15mm spacer rub issues? to wide of a tire for an 11" wheel? tirerack specs suggest the tire can be mounted on anything up to an 11.5" wheel...

-next choice would be kumho MX, but they really dont stack up at all compared to the others on my list.

-any thoughts on the nitto invo's?

-Im really liking the nitto nt-05. this is the tire i want. cheap, sticky, looks to be daily drive-able. i do truely daily drive my car, everywhere, in all conditions. they are a ~26" diameter tire. this refers again to my initial questions about overall diameter. would this work? thanks for the input-

-also, i would like to eventually modify my suspension, not necessarily a massive drop (im not doing the kind that is more aesthetic than functional), but an engineered solution to stiffening it up, reducing body roll, and getting the wheels to stay on the ground... therefore there is again cause for concern with overall diameter.

Thanks for the input and help! :thankyou:

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you get what you pay for, there is no free lunch

absolutely true. but much like wine, cost has nothing to do with quality. there are def. better tires out there than the ps2, and for cheaper (if that was what you were referring t0).

def. not into the pilot AS, im not entertaining all season tires right now. the sumi's crossed my mind, i could beat the snot out of a set every year and pay less than i do for a pair of fronts of michelin ps2's. but in consideration of the tires companies like toyo, nitto, hancook, kumho, etc. have been putting out, im not convinced there isnt a tire out there that will do what im looking for.

again my primary concern isnt the tire, its about sizing. its the technical piece im looking for answers on. will going to a 26" tire be a problem for the awd/abs/ various other sensors that are in play? will a 315 wide fit on an 11" wheel with 15mm spacer? the hard part about that question is that every manufacturer seems to have a different measurement regardless of the number (i.e. 295 wide for michelin is not the same as 295 for kumho...) is a tire with a treadware rating below 200 to sticky for the stock oiling system?

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Just me, but I wouldn't go with a taller tire for autocross. You end up with slightly taller gearing. I know it's not much, but in my autocross days I would never have given up any acceleration out of turns.

Also, you describe yourself as a 'total novice'... if so, and I might get smacked down for saying this, I think I would leave the front/rear width proportions as they are until you have some track time under your belt. The tendency of the car to understeer under certain conditions can give you a margin of safety. And it's very easy to manage in these newer cars with the passive rear-steering property of the rear suspension. Altogether, it's a more manageable and predictable package to learn on, IMHO, before you start riffing on the OE setup. It's a lot harder to outdrive it than you might think.

You'll be a better driver in the long run, my .02.

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im a novice to racing a car, but i have been karting for the past 2 seasons. i have a decent understanding of what im feeling, but the car adds a whole lot more variables in there, what with squishy bushings and electronic nannies (cant beat that tube frame metal on metal connection of a kart)... <_< youre right, im trying to keep it as predictable as possible, but considering im accustomed to street driving the car with this setup (7/15 mm spacers, 245 fr/295 rr) i think id like to stay with it. i immediately noticed the spacers. in fact, i played around with it for two days, all different combos of spacers, 15 fronts, 7 rears, 7 rears, no fronts, 15 rears no fronts. logged it all. 15mm rear, no fronts was my favorite, but for aesthetiques, i put the 7mm fronts in for the street. on a track, id probably take the fronts out. just my opinion thus far. i think a different set of bars and an alignment would offer me alot, but im not ready to start tweaking at that level. i can do it on my kart, but i know my kart inside out and upside down.

i didnt know different treadware ratings differed among mfg, honestly, could they make it more difficult?! its surprises me what i do and dont know about these things...

any thoughts on how sticky i can go before oil starvation becomes a problem?

effects on gearing and acceleration aside, will a 26" tire be to tall for the stock system?

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Car and Driver recently reviewed summer max performance summer tires and they really liked the Hankook Ventus V12 EVO. Here is a link http://www.caranddriver.com/reviews/compar...comparison_test

I need tires soon and I am seriously considering them. In my size they are less than half the price of PS2's.

RE 18" vs 19". I recently bought a 02 C2 Cab that has 19" Carrera 2 wheels with worn 235 35 19 and 295 30 19 Conti's front and rear. The car handles great on the street and the tires are quiet, vibration free, and track straight as an arrow at speed.

As a PCA member I asked the 996 specialist at PCA ,who has encyclopedic knowledge, about tire selection for the 19's on the car. He told me that 19's were not designed for the 996 and that they were all wrong for my car. 996 was designed for a 25" tire/wheel combo. Mine were 25.5" front 26" rear.

He said my speedo and odo would be reading lower than actual. In some cases ABS light could come on, gearing would be taller, aerodynamics would suffer, ride would be stiffer and on and on.

Well, after driving my car for a few months now under a variety of conditions with the right tire inflation pressures I can tell you that I do not have a problem with the ride, it handles as if on rails, and I think my car is quite quick and the gearing seems perfect to me.

Upgrading from 18's to 19's is done all the time usually for cosmetic reasons. I was going to switch back to 18's but decided I have no issues with my current set up, it was cost prohibitive, plus the 19"wheels look awesome.

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I really ilke them Hankook ventus EVO too!

Yes going with 1" taller tires will definately make your speedo read slower,

even though no ABS light comes on it could still ruin those rotors/pads possibly in some cases.

Please explain to me how upgrading to 19" wheel/tire combo could possibly ruin pads and rotors.

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Car and Driver recently reviewed summer max performance summer tires and they really liked the Hankook Ventus V12 EVO. Here is a link http://www.caranddriver.com/reviews/compar...comparison_test

I need tires soon and I am seriously considering them. In my size they are less than half the price of PS2's.

RE 18" vs 19". I recently bought a 02 C2 Cab that has 19" Carrera 2 wheels with worn 235 35 19 and 295 30 19 Conti's front and rear. The car handles great on the street and the tires are quiet, vibration free, and track straight as an arrow at speed.

As a PCA member I asked the 996 specialist at PCA ,who has encyclopedic knowledge, about tire selection for the 19's on the car. He told me that 19's were not designed for the 996 and that they were all wrong for my car. 996 was designed for a 25" tire/wheel combo. Mine were 25.5" front 26" rear.

He said my speedo and odo would be reading lower than actual. In some cases ABS light could come on, gearing would be taller, aerodynamics would suffer, ride would be stiffer and on and on.

Well, after driving my car for a few months now under a variety of conditions with the right tire inflation pressures I can tell you that I do not have a problem with the ride, it handles as if on rails, and I think my car is quite quick and the gearing seems perfect to me.

Upgrading from 18's to 19's is done all the time usually for cosmetic reasons. I was going to switch back to 18's but decided I have no issues with my current set up, it was cost prohibitive, plus the 19"wheels look awesome.

I think your last statement about cosmetics is correct every time, and I'm glad for you that you're enjoying your setup. But the the warnings of your PCA friend are still pretty much on the money: 19s give back a bunch of performance in exchange for looks. They just do. It's a choice anybody is free to make, but they should make it based on good information, like you were able to do.

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i wasnt going to go with a 26" tire on a 19" wheel, i meant going to a 295/35 which in most of the instances im seeing, has an overall diameter of 26". is this a problem? i have no intentions of going to 19's.

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Larger wheel diameters always put more stress on rotors, though I honestly don't think they can't handle the difference. The wheel diameter is the same concept as a longer breaker bar on a socket, or gearing. A large wheel going across the ground at 65mph when the brake is applied exerts more torque to the brake than a smaller wheel. It's the same reason that you will be geared higher with a higher diameter and run lower RPMS, than with a smaller diameter. Notice I'm saying diameter not 18 or 19" wheels...totally different. If the poster wants to put 295/35 tires on 18" rims, instead of 285/30s, it will make the car look more 4WD, raise the center of gravity, and may contact the wheel wells on bad bumps. But he will get better mileage and slower 0-60s, and be able to drive thru snow better. How much of each I can't say, but it's not what it was designed for, so make the change, take the risk. I'd think they'd suck on the track. I honestly have no idea if they fit, as that is very manufacturer dependent, but 1/2" all around doesn't sound too much to me (that's almost the same as normal tire wear, ie a worn 295/35 will be close to a brand new 285/30 in diameter), and they will not trigger ABS, or 4WD limp mode.

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