Your opinions on my wheel/tire set-ups.

Matthew Huizing wrote: The OP said, "The car would not be auto crossing or competition racing." Sounds like even Star Specs are not really what he wants. Some less extreme performance summer tires--like Super Sports, DW, HTRZIII, etc. Tire Rack suggests 205/45R17 as an optional for his car which is a size that several of the Max Performance tires come in.

I missed that part, but I agree... a Star Spec might not be the best tire for his needs. Nor would the 15" R-S3 for that matter since it's about 2" shorter than the 225/50-16 size he also mentioned, although maybe it would depending on what the gearing in a Celica is like.

92CelicaHalfTrac wrote: How many choices do you actually have out there in a tire that will work for you on a 16x8? It's pretty few, and that number has been doing nothing but go down in the last 5 years.

Actually 16's seem to be much like 15's such that while there is a significantly reduced selection of sizes available from the various manufacturers, there are a few specific sizes that are extremely well supported in the even the stickiest of street compounds. For 15's if you want a 195-205 width tire that has a 22.5-23.5 inch diameter, there is plenty of selection that does not appear to be going away anytime soon based on its continued popularity in the aftermarket and autox performance world...People have been proclaiming the death of 15's for since 16's rose to popularity, and yet these specific sizes are still a requisite for the manufacturers. Same appears to be holding true for 16's if you want a 205-225 width tire that has a 24.7-25.0 inch diameter, which just so happens to be the tire that the OP is asking about. Outside of that though, yes you will probably be best served by moving to 17's for performance street tires.

A 245/50-15 is very close to the 235/40-17 in section and diameter. TR motorsports 15x8 wheels are on closeout in a fe w bolt patterns and offsets. Light and strong too.

I picked up a set of 12 for under 800 shipped two weeks ago.

What's available in a 245/50R15 other than Hoosier R6s?

245/45R16 has also been hard to find outside of R-Compounds, though Bridgestone just came out with a Potenza RE-11 in that size, but they are $214 each. I bought my 225/45R16s from a national level SCCA Solo Celica GTS driver. They needed more than class limit width rims--probably more width than 225/50R16s. There are also a few 215/45R16s.

The last GRM tire article demonstrated that there is a small handling benefit from a larger rim diameter by itself.

I still feel like i haven't reached any conclusion..

Well, then let me piggyback on this:

I also have a celica, and i run 16x8s. What sort of autocross/summer tire rubber is out there that's worth a damn? 225 is the absolute minimum section width i will run, and the car had 205/55-15s stock.

I've been looking for 2 years for replacement tires, and it sounds like for the last two years, i've been overlooking a bunch of choices i didn't know existed? All i've really found is RA1s and R1Rs.

I've been agonizing over selling my RP01 Special Editions because the selection blows so badly.

92CelicaHalfTrac wrote: I also have a celica, and i run 16x8s. What sort of autocross/summer tire rubber is out there that's worth a damn? 225 is the absolute minimum section width i will run, and the car had 205/55-15s stock.

That kind of depends on what your specific needs and limitations are. It looks like the 92 Celica came stock with 23.5-24.0 inch tires. Realistically, in order to run either 16's or 17's that are 225+ width, you've got to be willing and able to run 24.5-25.0 inch tires. Like I said, as long as you're willing to go down to a 225 width, you're in the clear with 16's still. Just about every one of the top ST autox tires are offered in 225/50-16 which is just under 25 inches. That includes the RE-11, Z1 SS, RS-3, R1R, XS, AD08, and RT-615K. Not sure what other autox/summer tires you could possibly want? Depending what exactly your current 245 street tires are, I wouldn't be surprised if they're slower than any one of these compounds in 225. If you absolutely feel the need to run tires wider than 225 in these compounds, then yes you'll probably still want to move to 17 inch wheels.

The Toyos R1Rs are available in 225/45R16 as are BFGoodrich g-Force T/A KDW 2 (23.9" diameter). The Kumho XS and Falken RT-615K are available in 215/45R16 (23.6" diameter). Neither of those are very good street tires.

Many of the new Max Performance tires are coming out only in 17" and larger wheels sizes, or only offering a skinny 16" size or two (e.g., 205/55R16).

Driven5 wrote:

92CelicaHalfTrac wrote: I also have a celica, and i run 16x8s. What sort of autocross/summer tire rubber is out there that's worth a damn? 225 is the absolute minimum section width i will run, and the car had 205/55-15s stock.

That kind of depends on what your specific needs and limitations are. It looks like the 92 Celica came stock with 23.5-24.0 inch tires. Realistically, in order to run either 16's or 17's that are 225+ width, you've got to be willing and able to run 24.5-25.0 inch tires. Like I said, as long as you're willing to go down to a 225 width, you're in the clear with 16's still. Just about every one of the top ST autox tires are offered in 225/50-16 which is just under 25 inches. That includes the RE-11, Z1 SS, RS-3, R1R, XS, AD08, and RT-615K. Not sure what other autox/summer tires you could possibly want? Depending what exactly your current 245 street tires are, I wouldn't be surprised if they're slower than any one of these compounds in 225. If you absolutely feel the need to run tires wider than 225 in these compounds, then yes you'll probably still want to move to 17 inch wheels.

Right now it's got RS2s on it... i'm a bit miffed since i spent a lot of time tracking down the factory widebody fenders. I can FIT every bit of a 285 section width under this car.

I'm pretty 17s are going to have to happen.

Huge amounts of room. This picture is with the 245/45-16s. (And they ran wide.)

Matthew Huizing wrote: The Toyos R1Rs are available in 225/45R16 as are BFGoodrich g-Force T/A KDW 2 (23.9" diameter). The Kumho XS and Falken RT-615K are available in 215/45R16 (23.6" diameter). Neither of those are very good street tires. Many of the new Max Performance tires are coming out only in 17" and larger wheels sizes, or only offering a skinny 16" size or two (e.g., 205/55R16).

Why aren't the XS and RT615K good street tires? I've been running tires in that class as my street tires for years....

92CelicaHalfTrac wrote: Why aren't the XS and RT615K good street tires? I've been running tires in that class as my street tires for years....

The XSes require a lot of heat to stick, so they are actually less grippy on the street than most of the lesser tires. I certainly love mine as secondary dedicated autocross tires, but I've also been spinning quite often using them. From all other accounts, I would never recommend them for street use. They seem like a very good choice for dedicated dry track tires.

The RT-615Ks might be okay on the street, though if they are the same compound, the Star Specs have a more wet friendly tread pattern. I daily drove the older RT-615s--Kumho SPTs were a big improvement over those on the street.

My main point is great dry autocross or track tires are seldom great street tires. The Star Specs are a great compromise, but they are still compromised. There are better tires for street only use. Many of those also work better at the track in the rain.

I really can't see much point in wider tires for street use either. The 245/40R17s felt horrible on the Saturn on the street. They were great on the autocross course. The 215/45R17 HTRZIIIs feel great on the 325i, but I've only had 205/50R16 SPTs and 205/60R15 crap to compare them too.

Eden, when your question gets straightened, I'd like to threadjack. Same topic, different car.

Matthew Huizing wrote:

92CelicaHalfTrac wrote: Why aren't the XS and RT615K good street tires? I've been running tires in that class as my street tires for years....

The XSes require a lot of heat to stick, so they are actually less grippy on the street than most of the lesser tires. I certainly love mine as secondary dedicated autocross tires, but I've also been spinning quite often using them. From all other accounts, I would never recommend them for street use. They seem like a very good choice for dedicated dry track tires. The RT-615Ks might be okay on the street, though if they are the same compound, the Star Specs have a more wet friendly tread pattern. I daily drove the older RT-615s--Kumho SPTs were a big improvement over those on the street. My main point is great dry autocross or track tires are seldom great street tires. The Star Specs are a great compromise, but they are still compromised. There are better tires for street only use. Many of those also work better at the track in the rain. I really can't see much point in wider tires for street use either. The 245/40R17s felt horrible on the Saturn on the street. They were great on the autocross course. The 215/45R17 HTRZIIIs feel great on the 325i, but I've only had 205/50R16 SPTs and 205/60R15 crap to compare them too.

Dual purpose car, 2.2 stroker 3sgte.

I am sure the 245/45R16 RE-11s are the best current 16" street/autocross tire. Expecially since Kumho discontinued their 265/45R16 XS. The RE-11s are much better street tires than those Kumhos anyway. I have a set of 205/50R15 RE-11s on the Saturn right now, though I haven't actually driven on them yet. The 225/50R16s are good, and there are a lot of options in that size--I'd recommend the Star Specs. Those are just going to be slower than some of Max Performance tires in wet conditions.

The 225/45R16 R1Rs should work well cold and/or wet, normally the draw back of R1Rs is tread life. Most of the sizes wear pretty quickly down to a harder base compound. My first autocross/street tires were 205/50R16 Toyo T1-Ss that seemed to suffer from that problem. I absolutely hated those--slid off the road one rainy morning driving to an event.

Have at it, John.

'64 Triumph TR4, for autocross in GPrep. Max wheel size 15x7. Pattern is 4x 4.5 (114). Car is FR, about 100hp, live axle in back, double wishbones up front. Minimum weight 2138lb.

In terms of wheels, should I be looking for 13s or 14s as wide as I can find, or go with the 15x7's? 14's seem to be a bit of a pain to find tires for, though maybe I'm just looking in the wrong places. Tires for 15's are doable. '62-'64 Novas ran 13x6 wheels in the right pattern, tires are available for wheels that size, but with taller sidewalls.

I'd rather not run tires with treadwear below 140 or so, just to keep my seasonal budget down.

Any input? Not looking for THE answer necessarily, but advice would be great.

JohnInKansas wrote: Light Car 100 hp >=140 TW Tires 15x7 max wheels

Best possible setup for that given your restrictions is 195/50-15 R1Rs, shaved.

The UTQG treadwear numbers don't correspond to how long tires will last during competition. My last set of 30 Treadwear V710s lasted 4 seasons. I put considerable wear on my new 300 treadwear Sumitomos in just a couple of runs. Shaving treaded tires actually helps them last longer when autocrossing. Used tires can work well as long as they are not heat cycled to death or one of those dual-compound designs.

I wouldn't be surprised if on a small light car like your Triumph you could get long life out of a R-Compound like the Toyo RA1s (205/60R13) or R888s.

Of the fastest street tires only the Star Spec and RT-615K come in 14" size(s). The top national STS and STC autocross cars which weigh a little less than your Triumph run 195/50R15 Toyo R1Rs on 15x7.5 rims. That particular size works well right to the cords. If you can fit 15x9s: 225/45R15 R1R>R-S3.

The set of RE-11s and the set of XSes I was given both came with very uneven wear patterns. I am very happy with how the latter are wearing now. XSes and R-S3s seem like good choices for resisting autocross wear.

JohnInKansas wrote: '64 Triumph TR4, for autocross in GPrep. Max wheel size 15x7. Pattern is 4x 4.5 (114). Car is FR, about 100hp, live axle in back, double wishbones up front. Minimum weight 2138lb.

Is this a summer street and autox toy that happens to fall into GP, or is this a dedicated GP racer? If it sees dual duty, are you opposed to having two separate sets of tires (street and race) or do you want just one set of compromised "all in one" tires?

It will see dual duty, but probably not too much street use, as I imagine it'll be a bit harsh. Not at all opposed to two sets of tires, I was pretty much planning on it.

John, the main issue I see with any on the 15" tires mentioned is overall height. The oe 15" tire on a TR4 is fairly tall.

Personally, I'd look into the Hoosier vintage race tire, which is designed for cars like yours. While meant more for road racing, I'd imagine they'd be comparable to ST tires for autox duty.

These on these maybe?

Don't know much about Hoosier "vintage" compounds, but those appear to be a discontinued size with a 24 inch diameter. So when you wear them out, you'll be searching again. They do offer the same basic tire (tread pattern, compound, width, and diameter) as a 205/50-15, or a narrower but same diameter 185/65-15, still listed as in production on their site. But aside from the price, I would consider looking more at modern type tires.

It appears that the TR4 originally used a tire in the 25-25.5 diameter range. Depending on your gearing and ride height, a smaller diameter tire may or may not be desired. I think probably the best way to find a tire size is to determine the maximum and minimum desired overall diameter, as well as the maximum and minimum desired width. Additionally how this actually fits on the car will require determining a maximum and minimum offset...Which of course will vary somewhat, depending on whether your at the max or min diameter and max or min width. Once you have overall sizes picked out, you can then track down the closest to ideal sizes for various wheel diameters from the manufacturers to select the one that will work best for you. Non-streetable race tires will probably be most popular in 13 and 15 inch wheel diameters for your situation, although I honestly couldn't say for certain. Street tires I would lean towards 15's normally, but even then I don't think that there is much availability if you're looking for close to the original overall diameter in a modern street tire. Unfortunately I don't think that's something that anybody without similar first hand experience with a modified TR4 will be able to specifically help you with in great detail.