Optimal Wheel size for HPDEs? Specifics inside

[Wh33lhop]

V700 is an r-compound tire and will run wide. My 205 R888s were pretty square on my 8s too.

(don't mind the crap the tire picked up)


For comparison's sake here is a 205 XS on an 8 (in front)

[GrandRoyaL]

i am running kosei´s 15x8 with 205 50 15 kumho v70a medium compound (or v700 in the usa i guess) (but on the m3 e30)
it fits perfectly and do not stretch, i would say it is better as the tire walls seem to be really straight with the rim. if you know what i mean.

the tire grips and grips... did one track day in the wet with them just broken in, i was surprised it was that good. (but not on standing water of course). in the dry even better.

[kts]

You guys are overlooking a big part here... and that is that you can easily slap a 205 on an 8 (I've done it), but you can't really run a 225 on a 7. It's ten bucks more for a 15x8 C1 than a 15x7 C1. So you are actually limiting your options by going 15x7, unless you plan on racing in a class that prohibits them. Moreover a 205 will actually be FASTER on a 15x8 as it will put down more contact patch on a mild stretch. No, I am not a stancefag, but the tire will behave better when it is slightly stretched than when it's square.

If it were me, right now, I'd get the 15x8s and 225/45 Rivals. They won't slow you down unless maybe you are on a really high speed track.. which probably isn't a good idea with an E30 anyway. And you will downright giggle at the amount of grip you will get. If for whatever reason you want a 205 later, just get a set and put it on.

+1

My car came with my 15x7 Team Dynamics but if I ever pick up another set of 15" wheels I'll get the 15x8 TRMs so I have options for 205 or 225s. For $10/wheel more it makes sense to get the 15x8s.

[FLG]

Set of D-Force rims would prob be perfect. Cheap and light...last time they were on sale at UUC for like 365 for a set, guten also had them for about the same price.

[unevolved]

I'd definitely agree with the 205/50/15 as the tire size to choose, you've got lots of cheap, good choices in that size all across the spectrum.

There are some valid points in the 15x8 vs. 15x7 argument, though. I run 15x7s, but 15x8s may not be a bad call.

[phenryiv1]

Liking the info so far. Thanks!

[jlevie]

This may seem like a stupid question, but can a stock M20B25 produce enough power to justify a 225? My WRX could not really overpower a good 245 on the track, but I have never tracked a RWD car so I don't quite know the dynamics.

The engine power is only one aspect. Braking and cornering are usually more important and the larger contact patch of a wider tire wins.

[djjerme]

To "win" your run group, totally go 15". When they switch to open passing you may be able to stomp the hell out of some vette's..

[Wh33lhop]

This may seem like a stupid question, but can a stock M20B25 produce enough power to justify a 225? My WRX could not really overpower a good 245 on the track, but I have never tracked a RWD car so I don't quite know the dynamics.

The cost difference between a 15x8 & 225 setup and a 15x7 & 205 setup is not much, so I don't want that cost to be the deciding factor.

I just don't want the extra inch of tread (resistance), added weight, and other factors that I can't identify to be a waste or a detriment.

So far, strongly leaning toward a 15x7 with a 205/50 or a 15x8 with a 225/45.

Perhaps because with a 15" wheel there are more 205 options than 225. And if he's not dead set on spending the cash on just choosing a single tire for the next number of years, why not go 7" and have all the options available?

I'm running 15x7 Team Dynamic wheels (not flashy, light and cheap, look good) with Dunlop ZII 205/50. This setup is perfect for my light HPDE needs. Wheels are light and didn't break the bank. Tire options are great (I was torn between 4 great tires this year) and when looking at 15" wheels the tire options are far cheaper than their 16" and 17" brothers.

You guys are overlooking a big part here... and that is that you can easily slap a 205 on an 8 (I've done it), but you can't really run a 225 on a 7. It's ten bucks more for a 15x8 C1 than a 15x7 C1. So you are actually limiting your options by going 15x7, unless you plan on racing in a class that prohibits them. Moreover a 205 will actually be FASTER on a 15x8 as it will put down more contact patch on a mild stretch. No, I am not a stancefag, but the tire will behave better when it is slightly stretched than when it's square.

If it were me, right now, I'd get the 15x8s and 225/45 Rivals. They won't slow you down unless maybe you are on a really high speed track.. which probably isn't a good idea with an E30 anyway. And you will downright giggle at the amount of grip you will get. If for whatever reason you want a 205 later, just get a set and put it on.

[Earendil]

205 on a 15x7 is "enough", but why not go with 15x8 and 225s.. just a bit more. $440 for 15x8 C1s and it's like $500 for a set of Rivals or RS3s.

Perhaps because with a 15" wheel there are more 205 options than 225. And if he's not dead set on spending the cash on just choosing a single tire for the next number of years, why not go 7" and have all the options available?

I'm running 15x7 Team Dynamic wheels (not flashy, light and cheap, look good) with Dunlop ZII 205/50. This setup is perfect for my light HPDE needs. Wheels are light and didn't break the bank. Tire options are great (I was torn between 4 great tires this year) and when looking at 15" wheels the tire options are far cheaper than their 16" and 17" brothers.

[phenryiv1]

This may seem like a stupid question, but can a stock M20B25 produce enough power to justify a 225? My WRX could not really overpower a good 245 on the track, but I have never tracked a RWD car so I don't quite know the dynamics.

The cost difference between a 15x8 & 225 setup and a 15x7 & 205 setup is not much, so I don't want that cost to be the deciding factor.

I just don't want the extra inch of tread (resistance), added weight, and other factors that I can't identify to be a waste or a detriment.

So far, strongly leaning toward a 15x7 with a 205/50 or a 15x8 with a 225/45.

[Wh33lhop]

205 on a 15x7 is "enough", but why not go with 15x8 and 225s.. just a bit more. $440 for 15x8 C1s and it's like $500 for a set of Rivals or RS3s.

[nrubenstein]

Realistically, 205/50-15 on a 15x7 is adequate. And more to the point, it's one of the cheapest out there. Could you try to cram in more tire? Sure. 275/35-15 on a 10+" wheel might be optimal. But it won't be cheap or easy.

[z31maniac]

There is also the new BFG Rival coming out in 225/45/15, it and the 205/50 are a bit short compared to the factory OD" on the car, but it's alright.

I might suggest a set of camber plates.

I'm running the Carbotech XP10 front and XP8 rear on my Miata, great great pads.

[Danny]

Whatever is cheap and a decent summer tire. I would to 205-50-15 due to cost.