SCCA STX E30 Build/Introduction

[race2win]

I was running on Kumho Ecsta XS's. Switching to Hankooks this year, but will still run the same size. The Hankooks are better and cheaper. win-win.

The 255/40-17 XS is 25" tall & has a 10.2" section width, that is well over an inch wider & taller than what I run now, I HAVE to see how you stuffed that much tire under an STX legal non-M E30 fender....

I was also looking at the xxr's however not sure about the weight. 19lbs isnt terrible, but its not great either.

19.8 lbs is VERY heavy, even for a 17. After you factor in the extra weight of the tires, my car would gain around 30 lbs over all compared to my current 15x8 set-up...& I don't have the lightest 15x8s out there. I believe 5-10 lbs difference is just noise...30 lbs however will show up on the watch.

I see benefits to a 17" package as I have mentioned before, I hope to do some testing this summer to see if they are indeed faster. However, going with heavy wheels such as the XXRs may provide false information, if I am going to do it I would rather spend extra on the Arc8s so that I am within that "noise" to get an accurate comparison.

Depending on the results of that testing & budget permitting, if/when I go to Lincoln this year I would like to bring 3 sets of tires/wheels...

1. My current 15x8 225/45-15 RS3 set-up - great gearing out of corners, light, best warm/hot weather tire, should be the best in tight stuff & transitions.
2. Light 17x8s with 235/40-17 Dunlop Star Specs - great all around tire, will work well in colder temps and/or damp, slight width gain over 15s, & will provide a gearing bump for those longer courses.
3. Either Continental ExtremeContact DWs or Michelin's new Pilot Super Sport for standing water/wet sitiations, as both will provide better wet grip than the Dunlops, & especially the Hankooks. These would also double as street tires for the car to drive to & from events, & general weekend use. I just wish they made something smaller than a 17 in the new Michelin...

For now though, locally, I'm sticking with my 15" package...unless it rains, then I may enter my GTI ;-)

[110stx]

Perhaps... but, is it worth double the money for 20 lbs of un sprung weight to you? Especially in an attempt to try something new and on a wheel that is .25" skinnier? Another question is, what offset are these enkeis? I'm betting they are higher offset and will require spacers, thus you're adding more weight to fit them.

My $0.02 Try it with cheap wheels first, if it shows merit, then you can consider cheaper more expensive options down the road.


Doug, I'd love to help you setup your car to fit something like what is being discussed here. I'd travel to KC for a weekend just for that purpose.

Well, the ultimate answer to your question has got to be, Yes, 20 lbs of unsprung weight would be worth the extra bucks. Of course, money is the only thing standing between me and going this route. :-)

At this point, I don't see changing from the 15s this season ... I am anticipating a slight increase in rear spring rate, say to 685 lb-in.

I would love to work on the car with you. You know that. In a freakin' HEARTBEAT, bro'.

However, I would rather bring the car to you and see how it works at LAP, as that's better than tuning it for MCC.

dh

[team9]

can you elaborate on what tire brand/model you're running 255/40's in please?.

I was running on Kumho Ecsta XS's. Switching to Hankooks this year, but will still run the same size. The Hankooks are better and cheaper. win-win.

[GotCone?]

The 527's can fit a 255 on the rear with a little bit of fender rolling. Those wheels weigh in at 19.8 lbs which is pretty darn good for a 17" considering. The best part is the offset. +25

can you elaborate on what tire brand/model you're running 255/40's in please?

19 lbs is heavy when your car is already underpowered relative to its competition.

Make that "my" car ... :-)

Perhaps... but, is it worth double the money for 20 lbs of un sprung weight to you? Especially in an attempt to try something new and on a wheel that is .25" skinnier? Another question is, what offset are these enkeis? I'm betting they are higher offset and will require spacers, thus you're adding more weight to fit them.

My $0.02 Try it with cheap wheels first, if it shows merit, then you can consider cheaper more expensive options down the road.


Doug, I'd love to help you setup your car to fit something like what is being discussed here. I'd travel to KC for a weekend just for that purpose.

[Chris916]

I was also looking at the xxr's however not sure about the weight. 19lbs isnt terrible, but its not great either. Would love to be able to run 245/40-17 conti scrubs :D

[110stx]

19 lbs is heavy when your car is already underpowered relative to its competition.

Make that "my" car ... :-)

[team9]

You should have a decent sampling of Street touring competitors in your area. See if you can't get some worn down scrubs or something from someone. 235/40-17 or 245/40-17.

XXR has some new wheels that should be a good fit. They are cheap, so it's minimal outlay to give it a try and should be easy wheels to resell later.

------------------------------------
XXR 530

17x8.25", 4x100, +25mm
$115 each = $460 set
------------------------------------
XXR 527

17x8.25", 4x100, +25mm
$115 each = $460 set
------------------------------------

They look like great options to try. Otherwise Rota has a 17x8.5 D2, but it's a lot more $$ for an experiment.

I think it can be made to work and will really help the E30 on a national level.

I'd love to help someone in a region near mine give it a try and get the setup dialed in *cough* Doug H.*cough*

Thanks - Jon

The 527's can fit a 255 on the rear with a little bit of fender rolling. Those wheels weigh in at 19.8 lbs which is pretty darn good for a 17" considering. The best part is the offset. +25

[110stx]

Here, Jon, let me get you a tissue for that *cough* :-)

How much do these freakin' wheels weigh anyhoo?

Enkei RPF1s 17X8 (the light ones) are about $230 apiece at about 15 lbs.

Yeah, I'm doin' some window shopping. A guy can dream BIG right?

[InuFaye]

The XXR 530 should fit an e30 easily.

[GotCone?]

You should have a decent sampling of Street touring competitors in your area. See if you can't get some worn down scrubs or something from someone. 235/40-17 or 245/40-17.

XXR has some new wheels that should be a good fit. They are cheap, so it's minimal outlay to give it a try and should be easy wheels to resell later.

------------------------------------
XXR 530

17x8.25", 4x100, +25mm
$115 each = $460 set
------------------------------------
XXR 527

17x8.25", 4x100, +25mm
$115 each = $460 set
------------------------------------

They look like great options to try. Otherwise Rota has a 17x8.5 D2, but it's a lot more $$ for an experiment.

I think it can be made to work and will really help the E30 on a national level.

I'd love to help someone in a region near mine give it a try and get the setup dialed in *cough* Doug H.*cough*

Thanks - Jon

[race2win]

Wow, that's a tall tire! Those are listed at 24.9", which is a half inch taller than the 235/40-17, but the 17s are a half inch wider so the right camber & ride height settings will be important. I wish there was a better 16" option than 225/50...225/40 would be ideal, or maybe a 245/40-16 :)

I'm confident the 17s will fit, the negatives are higher unsprung weight & running a potentially higher ride height for them to clear...two things that can potentially slow a car down through tight transitions. I'm still on the fence whether it would be a benefit or not...

[GotCone?]

FWIW... I ran 225/50-16x8 +20mm w/o rolling and there was zero rubbing issues.



The car was pretty flat






Would require more camber and or other tweaks to fit wider, but the height isn't an issue if you set things up right.

[CrazyB]

Great to see more Bay area e30s running, I am in DSP but caught a few of your runs last year the car looked great out there :)

[e30bulldog]

I hear you on that I wish they would make some wider street tires for a 15" wheel. I did use the toyo R1r for about a half a season, I didn't have much trouble overheating them until I had a co-driver on a hot Mississippi summer day.

[race2win]

Do STX rules allow it? I am in SM, so STX rules are foreign to me lol

You can run up to 265 width tires on up to 9" wide wheels in STX on 2wd cars. The limiting factor on an E30 is the small fenders, STX rules only allow rolling of the inner fender lip, but no change to outer contour is allowed. That being said, 265s on 17x9s won't fit, 235-245 on 8's or maybe 8.5's will be the limit I think.

speaking of 17's toyo is making a 245/35/17.... that is really short and I would love to see someone run it on an e30.

Yes, this tire could be a solid choice in the right situation, but it's wide so I'm not sure it can squeeze in there. At 23.8" diameter, it's only .8 taller than the 225/45-15 RS3s I run now...which would be perfect gearing-wise. But like GotCone? mentions, they would most likely over-heat very quickly in all but the coldest conditions on an E30. Assuming they would fit, they would be a great wet tire though.

The set-up I plan to try is 235/40-17 Dunlop Star Specs on 17x8s. That tire is about .7" wider than my RS3s & should fit, I'm just not sure about the height as they are 24.4" which is almost an inch & a half taller. It will definitely extend 2nd gear...to 62 MPH, which will be about 4 MPH faster than the 15" RS3s. The other benefit to the Dunlops is that they are better in cold & wet conditions, without giving up too much in dry and/or hot conditions. RS3s are hands-down the best tire when it's warm, but they NEED heat to work well & are virtually useless in conditions below 50* and/or wet.

The biggest negative I see to running a 17" wheel/tire package is weight...at minimum it will add 5-6 lbs of un-sprung weight to each corner, I'm just not sure the slight gain in width is worth the weight penalty. So, I still see myself on the 225/45-15 RS3s in most situations.

Now, if they ever come out with a 245/45-15...