scottherbert

Since it's sort of 'off-season' for SCCA autocrossing right now, I'm experimenting with a wider wheel for my DSP Cobalt. I've been running 18x8.5 American Racing 'Rogue' rims with my Hoosiers and using custom-made wheel adapters to make the rims fit (to get enough clearance between the rim and the Brembos). They work pretty well, but at 8.5" wide, the rims aren't really wide enough to do justice to 285 Hoosiers (or even my 255s).

I bought an American Racing Torque Thrust M wheel in 18x10 in a 5x114.3 bolt pattern -- mostly because they come with a 45mm positive offset -- and mounted my 285 Hoosier on the rim. BIG difference in tread-on-the-ground -- looks like more than an inch. When I compare my Hoosiers against other DSP cars that run 10" wide rims, it really looks like I'm running a much smaller tire. I'm sliding around on course when the other guys are sticking.

I'm having a custom made wheel adapter made (25mm thick, hub-centric on both sides, 5x110 to the hub and 5x114.3 for the wheel - 12x1.5 studs) and as soon as it gets here, I'm mounting the new wheel/tire combination to see how everything fits. If I've calculated right, I'll end up with a 20mm positive offset (better than the 15mm positive I've been running with the 8.5" rims using a 20mm adapter) and I should have about 5-10mm clearance, maybe more, between the wheel/tire and the struts.

When I've gotten it mounted on the car, I'll check front and read turning clearance. If it all works, I'll report.

I'm also figuring out a way to (within the SCCA rules) set the rear to 1.5-1.55 degrees of negative camber -- it won't be easy with the 2009 rear setup, the caliper mounting plate is welded to the axle. I can 'shim' the hub, but I'll have to figure out a way to shim the brake caliper mounts too to make it work. Again, if I can figure out a way, I'll report. Even D stock Cobalts could do the rear camber 'legally'.

Scott

alredline04

Have you looked into Team Dynamics wheels? They aren't the lightest, but they are a great value imo for a custom wheel. I was fortunate to win my 17x8's in a drawing. They made them to order in my bolt pattern, hub centric bore and offset. They fit the brembo's no problem and have a very generous back spacing. I am using a 35mm offset for coilover clearance.

Just give yourself some lead time. They take about 12-15 weeks to get. Made in England and shipped via boat.

I know the distributor for NA so let me know if you need any answers.

Team Illuminata

Dart_SI

iTrader: (1)

those look pretty nice. if i knew some more about wheel fitment, id add some stuff, but unfortunently im not a wheel guru

alredline04

I made a cardboard template

jboogie

iTrader: (3)

I emailed team illuminata and they can get us 17x9s! And there doesn't seem to be an up charge for the custom drilling. Alredline, thanks so much for bringing this to my attention. You sir are the man. Looks like my STX build just got easier.

And keep up the good work Scott. You are truly a pioneer in the development of these cars. I can't wait to be rolling on some 265s!

alredline04

On their site they have printouts to make templates. Use the template and trim down the offsets until you get to the one that fits best. I was looking into 17x9's and was thinking the 25mm offset would be the one, but never got around to checking. I did use this method on my 17x8's and they fit perfect with a few mm clearance to the strut at -2.25 camber.

The hub centric bore dimension is 65.14mm +/- .04. You may need that, but they should already have it.

scottherbert

I've investigated many 'custom' wheel manufacturers over the past couple years -- prices ranging from several hundreds/wheel up to more any $1000/wheel -- simply stated, too expensive for me.

Stepping up to a custom 18 x 10 also ups the dollars -- again, the cost of a 15 or 16 or 17" custom rim is much less than 18x10 (based on exchanging emails and phone call with a number of custom manufacturers).

The 285 Hoosiers cost $320/tire (times 4) and you'll need about 2 sets/year if you want to go to the Nationals have a change at success -- it adds up pretty quickly...

I've been running 18x8.5s with Hoosiers, and it's just not a wide enough wheel to put all the tire on the ground.

I paid about $150 each for the AMR Torque Thrust M in 18x10 (with a 45mm offset). I can get wheel adapters custom made for less than $80 ea -- any width I want. So for ~230 per corner, I can adjust the bolt pattern, offset, and clearances anywhere I need them to be. And AMR makes these rims with multiple offsets -- get the idea? -- between different rim offsets and wheel adapters, I can get the clearances 'perfect'. When I get everything together, I'll measure the results -- from there I can make changes if necessary.

BTW, I mounted one of my 285s on the new 10" rim and compared it against a 285 on my 8.5" rim -- visibly more rubber on the ground.

I'm not sure excatly how much clearance I'll have between the 10" wide rim/tire combination and the inside of the wheel wells -- I've already dealt with this problem with the 8.5s and my 285 Hoosiers. I think I'll be OK, but if not, I'll modify the wheel wells (again) to get needed minimun clearance. I don't care if they rub against the rubber wheel well liners, I can wear holes in those and replace them easily, it's rubbing against steel that's my concern.

I realize that I'm kind of out on the extreme end of things here, but running in DSP against the other DSP people at a national-level calls for extreme measures. If you haven't looked closely at the national DSP competitors, you should, they are doing some really extreme things.

BTW, any idea how many Cobalts are competing in DSP nationally?

Scott

jboogie

iTrader: (3)

I was thinking I could get away with 30mm offset? STX isn't as flexable as DSP on fenderwell mods and at about 3/4 turn the wheel looks like it may hit with to little offset. But, haven't done the template thing yet.

I wonder if John Heinricy would show up at nationals?

RooTBeeR

iTrader: (4)

subd for rimz

alredline04

As for how many Cobalts running DSP nationally. Not sure. None in the Great Lakes division. My co-driver/ car owner originally planned on running his new '10 in DSP, but after driving it the car feels really competitive in DS. We don't even have an alignment or anything done to the car yet and it is blowing away the local DS fields.

scottherbert

I've raced in National Tour Events in TX, NM, CA, CO, and WA in 2009 & 2010, and went ot the Nationals in 2009, and have yet to see another Cobalt in DSP. Up in WA, the comment made by the SCCA announcer was that a Cobalt in DSP was unusual.

Just curious. I'd be interested in hearing other peoples' experiences - share notes, so-to-speak.

How about someone in SM (or SMF)? Should be similar experiences.

Thanks, Scott

tom.g

iTrader: (4)

I hate to poke in here and ask such a noob question but this is probably where I will get the best answer from guys that have SS/TC's and autocross albeit much more competitively than me.

I have an 09 SS/TC with some basic bolt ons and I have learned that the car is plenty quick and it's really time to focus on handling (at this point just pedders springs, OTTP rear sway bar and better rear pads). I only have one season of auto-x under my belt but I am now addicted. I have the stock rims wrapped in some winters and then I have some Enkei 18x8's (I know they are heavy ) wrapped in the stock conti's (worn down now) and I am trying to really get the perfect tire for next season and I need some advice. First of all size wise I think that the best size would be a 235/40/18 I don't want them to rub and I know that once lowered wider tires tend to rub or should I go to a 245/35/18? As for the tire I'm looking for a tire that I can get 10k miles of street driving on plus 20-25 autocross events (trying to buy a tire that will last for 2 seasons), which one is best? I've heard great things about the Direzza Star Specs but those are hard to find now (I think they are discontinued) and also have heard good things about Kumho Ecsta XS's any sugestions? As for suspension I was thinking of going to some OTTP CAB's sometime down the road, anything else worth upgrading?

jboogie

iTrader: (3)

Catless DP is gonna hurt you bad classing wise. I've got Kumho XS and on a nice 90+ degree track day I am totally in love. The BEST tire for that, period. On a 55 degree night, like last night at an autox I would do better on frickin all-seasons! I'm gonna go with the star specs next year (hopefully in the 265 variety ) I think they will be a better tire overall. They are a TireRack excusive now. And as far as sizing if what you choose doesn't have a 245/35 (like the Dunlop) Personally, I would go stock size for less sidewall and shorter overall. If it wern't for the extra cash I would love to try the re11s.

And do't worry about modding for autox. Go run another season and see where you wanna be class wise and go from there.

But, everyones got their own opinions about tires.

JT-KGY

I've tried both Kumho XS and Hankook RS3s... the RS3s grip way more than the XS.

Grave

iTrader: (7)

I run in SMF and there are only a couple cars in my area (MS3, SRT4, couple others). I was in mostly local events, only a couple SCCA. Next year, I'd like to get in some bigger events. I'm in the central Illinois area, not sure what division that would be in.

jboogie

iTrader: (3)

I tried to order some of those mid summer and there was a crazy wait time. I heard they like heat as well just not as bad as the XS.

To many choices out there now! lol I miss the days when you just ordered another set of Azenis and din't have to think about it.

tom.g

iTrader: (4)

Yah I know but the Catless DP + Tune is what these cars really need, it does wonders for them.

Where I live (Alberta, Canada) we don't get that many 90+ degree days lol out of the 6 times I've raced so far this year I think only one of them was close to 90°F so what your saying is the Kumho XS may not be the best tire for me? I may have to look into the Star Specs then, so these tires are not discontinued?

As for size If I can't get a 245/35/18 (which I'm not sure if it will fit on a lowered SS/TC) why not a 235/40/18 I know they are a bit taller than stock size but not by much. I have an 8" wide rim now (0.5" wider than stock) so I really want to run a slightly wider tire to get the best use out of the wheel.

I havent heard anything about RS3's how are they on the street, how do they wear?

scottherbert

My new custom-made wheel adapter arrived yesterady afternoon. I'll put everything on this weekend and see about clearances. With luck, I'll have figured everything right and I'll have no problems running 10" wide rims.

I use Hankook R2Ss for my STX winter-time play (last year's tires - cheap at Tire Rack) -- 245s on 17" wheels (the wheels barely clear the Brembos). My 'winter' suspention setup is Eibach Pro Kit springs and an OTTP Hardcore bar. I've beaten some DSP cars running on slicks with the winter setup and 245 Hankooks. It isn't nearly as fast as the DSP coilovers and Koni suspension and tire setup, and I'm not really competitive against the serious national STX competitors, but it makes a great winter autocross tire setup and it forces me to drive better.

Scott

Dirty25RS

Whats your local AutoX track like?

track length (time, distance)?

number of turns?

surface?

I'm a little surpised you can heat up the 285s quick enough given the cobalt's mass.
I was planning on running that width on my BSP STi, which i think is a little heavier than a cobalt.

scottherbert

First! IT FITS LIKE A CHAMP!!! About 1/4" clearance between the most inner part of the tire and the strut -- it rubs against the lining rubber a bit, but the 285s have always done that even with the 8.5" wide rims -- I've got 20mm of positive offset (better then the 15 I had before) --and I'm not rubbing against any metal (a little up front - a strup about 3" long, but I dented it in and it's no longer a problem).

Track lengths are SCCA norm -- but regionally about 1 mile to 1.25 miles -- +or- a bit. About 55-70 seconds in DSP trim. We mostly use Pikes Peak Raceway and Dick's Sporting Good Park parking lots -- very large, very flat, very wide open.

Surface is mature asphault (although we used to use a concrete parking lot at Denver International Airport -- about 1/2 mi X 1/2 mi and very sticky. The airport lot was as big as the Nationals, Pikes Peak Raceway has hosted SCCA regionals, and we hosted an SCCA National Tour Event in Aspen last year (airport, concrete).

The local Porche and Corvette clubs also run on the road-race course at Pikes Peak (shorter than the parking lot courses) and run at Mile High dragstrip course area.

Turns are based on SCCA rules -- 'unprepared' (stock) cars shouldn't exceed the state speed limit of 75 mph top speed, no turns should allow more than 45 mph top speed. You can look on the rmsolo.org website for the Rocky Mountain SCCA data and I think there are some examples of track layouts. Probably, on average - including slaloms, at least 15-20/course to keep it to less than 75.

How to heat Hoosiers:

#1, I use a co-driver to help heat the tires -- just like about everybody else -- he drives first (#65) and I drive 2nd (#165) so I get to run near the end of the runs to watch the competition.

#2, I can easily light the front tires up at start.

#3, After about 2 runs, I'm usually spraying the tires with cold water to keep them cool -- Hoosier A6s like to be between about 110 and 120 degrees temp.

#4, The tires come home melted...

Scott

Grave

iTrader: (7)

Pictures of the 285 hoosiers please. I bought some 245/35 v710's that I thought would be wide for a cobalt.

scottherbert

V710s require a slightly wider wheel than Hoosiers - and they wear a bit better - but in absolute terms, Hoosers are slightly stickier that Kumhos. If you're on stock sized, stock offset rims, 245 is about as big as you can go without problems.

I'll get some pics. Note that I've had to take a hammer to the back edge of the wheel well to get the big tires to fit - and I've spent a lot of time trying different options. I ran 285s on American Racking Rogue wheels at 8.5" wide for a couple years - but I figured I wouldn't have a change to compete successfullly at the Nationals without moving up to 10" rims.

Some local guys placed 5th, 10th and 11th at the Nationals in 2009 when I placed 28th (my first year - my goal for that year was to not place last -- I wasn't last, but at 28th out of 31 I was darned close to last). I've come up to running 1.5 seconds slower than the 10th place BMW and within 2 seconds of the 5th place VW R32. So I need an edge -- we all run 285s, but they're on 10" rims... They've both made comments about rim width for me to go faster -- putting more tire on the ground.

I've just move up to a custom bent 3" ID catback, I'm going to shim the rear camber out to 1.55 degrees of negative, and I'm going to run the 10" rims -- it should help.

Scott

Grave

iTrader: (7)

Is that going to be on a 17'' wheel?

scottherbert

No. My 285/30 & 255/35 Hoosiers are mounted on 18" wheels. My 285s are the most worn (probably 30 runs on the set), my 255s have a total of six runs on them, so I'll use both this summer to see which works best.

There was a good article from SCCA a couple years ago that said if you aren't running at least 285s in DSP, you're wasting your time... But that was before the 255s were built by Hoosier. Sometimes, a smaller (narrower or shorter) slick is faster. The 255s are supposed to be 0.6" narrower than the 285s with rubber-on-the-ground and they're about 0.5" shorter than the 285s.

Because I had some 'left-over' 17" wheels from my old Saturn Ion Redlines, and they fit my 09 cobalt SS (barely), I use them for my 'STX' tires (17 x 7.5) in 245 (these rims will eventually be for Hoosier rain tires 'if' I'm fast enough with 10" rims) and I have another set of 17s (7" wide) that I'll soon be putting studded snow tires on for this winter.

I'll eventually dismount the 255/35 Hoosiers from my 18x8.5 rims and use those rims to mount some 265s to be more serious in STX (off-season).

So to summarize - and I didn't get this all at once but over a period of years - I have five sets of rims: the stock SS 18x7.5" rims, a set of 18x10" American Racing Torque Thrust M rims (anthracite) using custom C&C'd 25mm wheel adapters, a set of 18x8.5" American Racing Rogue rims (black) using custom C&C'd 20mm wheel adapters, a set of 17x7.5" rims, and a set of 17x7" rims.

More info than you wanted to know, eh?

If you want to know where I got the wheels, were I got the wheel adapters custom made, and what the specs are for the wheel adapters, let me know. I can also tell you how to 'adjust' the wheel wells so everything fits. I can also tell you that if you don't use something like OTTPs LCA delrin, your tires won't work -- because the rubber mounts can allow the LCA to shift and thereby bring the tires into hard contact with the back edge steel of the wheel wells.

Scott

Grave

iTrader: (7)

Thanks for the info. I already have the tires, so I'll probably stick with the stock width (maybe up to 8-8.5'') for whatever wheels I get. LCAB's are on my list this winter along with a few other things. I'll be interested to see how beneficial adding rear camber could be.

At my first autocross I rubbed a couple holes through the liner and hit some metal as well. I raised my car about an inch and haven't rubbed yet. I might need to make some more adjustments with the 245s though, we'll see.

I spun out today for the first time, it was pretty fun haha. I also got beat by a turbo civic that I had never seen before.