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92CelicaHalfTrac
92CelicaHalfTrac SuperDork
8/22/11 12:43 p.m.

I know i'm looking a bit into the future, but i'm curious to learn some things, and get some input on some other things.

1) The car in question will be COMPLETELY untested, no other car out there to really compare it to directly, blah blah blah. Soo... i've gotten input that i should test and get my base-line setup using the same basic type of tires that i'll be running on end result. a) how important is it to run the same size that the car will eventually run during base-line setup? b) how important is it really to just run the SAME tire i'll eventually be running? I'm not real psyched about potentially throwing away a grand or two on tires due to ruination during base-line tuning.

2) Size input. I have to run 15" wheels at a minimum due to brake clearances. (I could maybe do 14", but there's no real benefit to that due to lack of sizes) In my research, i've found why all the fast 15" guys run 275/35-15 Hoosier A6s (despite that the sidewall doesn't seem to be ideal). It's because that's really all there is. Assuming i have three choices in mind, which do i run and why?

Choice A: 275/35-15 front, 225/45-15 rear A6
Choice B: 275/35-15 front, 275/35-15 rear A6
Choice C: 245/45-16 front, 245/45-16 rear A6

Car in question is a FWD macstrut car, will weigh between 2100 and 2200lbs, and make about 200whp for the time being. DOES have a limited slip. If needed, i can find gear ratios for the transmission i'm running. Stock tire size was 185/60-15.

There was a time when i was excited to be running "real" tires, because i thought i'd have more size choices. Not so much, apparently.

I appreciate any input, thoughts, pointing fingers and laughing, etc etc etc.

DILYSI Dave
DILYSI Dave SuperDork
8/22/11 1:13 p.m.

First question - If you're talking about making sure the car is sound, the engine isn't going to blow up, etc., then any tire will be fine. If you're talking suspension tuning, then yeah - doing much of anything on the wrong tire will be of little use. Especially if you end up going staggered, as that throws a lot of the conventional wisdom right out the window.

I'm running 375/35/15 on 15 x 10's on the front and 225/45/15 on 15 x 7 on the rear. I'm planning to try out a 205/50/15 on the rear at some point, but I haven't yet.

I went with narrower rear tires for a few reasons.
1. Don't need a lot of tire. There isn't much weight back there, and it's not putting down power or turning. Much less work than the fronts.
2. The rear tracks tighter than the front. A wide front / narrow rear can take a tighter line than a wide front / wide rear.
3. $$$
4. I can tuck a narrow tire into the bodywork, meaning I can get the car low without cutting the unibody. Cutting the fenders - BFD. Cutting the unibody is a lot of work.

jungle
jungle New Reader
8/22/11 1:19 p.m.

plus the rear tires on a FWD take so darn long to heat up...I have continual issues w/ having the fronts warm enough to stick but the rears are still cold.

92CelicaHalfTrac
92CelicaHalfTrac SuperDork
8/22/11 1:33 p.m.

I'll be making sure the drivetrain is sound on my local "SMS" setup, which is simply some 205/50-15 Star Specs, so this is suspension setup.

So basically, dave, you're saying to just bite the bullet and be ok with sacrificing a set of A6s to get the car set up in that regard.

How long do your A6s last? I can afford probably 2 sets a season, much more than that and i'm eating a lot of Ramen. I would be REAL happy if i only went through 4 275/35s and 2 225/45s through a season.

Do you think the 275/35-15f 225/45-15r setup makes more sense than 245/45-16s all around?

I'll have to do some cutting to fit the 225/45-15 in the rear, but not much. This is mostly due to a STUPID wheelwell shape back there. (It's got a square top. BRILLIANT.)

On the flip side, if i go with the wide/narrow 15s setup, i can just modify a spare set of front fenders so i don't have to roll around all the time with huge overfenders over some 205/50s and look stupid.

92CelicaHalfTrac
92CelicaHalfTrac SuperDork
8/22/11 1:34 p.m.
jungle wrote: plus the rear tires on a FWD take so darn long to heat up...I have continual issues w/ having the fronts warm enough to stick but the rears are still cold.

Also a good point that i admit i didn't think about at all. This is why i ask these things, and why this board rules!

2002maniac
2002maniac HalfDork
8/22/11 2:49 p.m.

245/45/16 seems like it would be way too tall for you.

DILYSI Dave
DILYSI Dave SuperDork
8/22/11 2:54 p.m.

I get a full year out of the rears, and even then they aren't done. But for Nats, I just put new tires on all around out of general principle. I go through 2-3 sets of fronts, but that's hitting a lot of events with a lot of drivers. I've gotten as many as 80 runs, and as few as 35. The 80 run ones, they were WAY heat cycled out by then. The 35 run ones, I had a bad wheel bearing that contributed to some nasty outer shoulder wear. 40 runs is about all I would count on for them being decent National level tires. For local, run them until they cord, once you're no longer dialing in stuff. But for the dialing in phase, yeah - count on going through some tires. It's the only way.

alfadriver
alfadriver SuperDork
8/22/11 2:54 p.m.

In reply to 92CelicaHalfTrac:

Why do you need A6's vs a cheaper alternative for development? Will V710's be a better value (better wear + cheaper)?

Seems as if you are looking more at the chassis, they are close enough that you can get more value out of them.

Actually, do you really need A6's at all?

81cpcamaro
81cpcamaro New Reader
8/22/11 3:16 p.m.

In reply to alfadriver:

Kumho doesn't make tires in the 275/35-15 size. They should as they tend to last a bit longer than the A6.

DILYSI Dave
DILYSI Dave SuperDork
8/22/11 3:23 p.m.
alfadriver wrote: Actually, do you really need A6's at all?

If you want to play at the pointy end of National competition, yes.

alfadriver
alfadriver SuperDork
8/22/11 4:18 p.m.
DILYSI Dave wrote:
alfadriver wrote: Actually, do you really need A6's at all?

If you want to play at the pointy end of National competition, yes.

Which is why I'm asking. I didn't see part of the project goals to go to the solo nationals, let alone be at the front of that.

red5_02
red5_02 Reader
8/22/11 5:44 p.m.

Wide up front, skinny in the back seems to be the trick 'round these parts for SMF. I think you'd be wasting your time if you're tuning for one tire while running on another.

iceracer
iceracer SuperDork
8/22/11 6:02 p.m.

The 275/35x15 is quite a bit shorter than stock. I always ran the same size F&R. and rotated them. Adjusted suspension and tire pressures to compensate.

DILYSI Dave
DILYSI Dave SuperDork
8/22/11 11:33 p.m.

It's very close to the stock diameter of the civic tires.

92CelicaHalfTrac
92CelicaHalfTrac SuperDork
8/23/11 5:43 a.m.
2002maniac wrote: 245/45/16 seems like it would be way too tall for you.

It's actually only about 2.3% taller than stock, while the 275/35-15 is about 3-4% shorter than stock.

92CelicaHalfTrac
92CelicaHalfTrac SuperDork
8/23/11 5:44 a.m.
alfadriver wrote: In reply to 92CelicaHalfTrac: Why do you *need* A6's vs a cheaper alternative for development? Will V710's be a better value (better wear + cheaper)? Seems as if you are looking more at the chassis, they are close enough that you can get more value out of them. Actually, do you really need A6's at all?

Kumho seems to make horseE36 M3 sizes.... I may use a set of those in a "close enough" size to try to get to my base-line, but they don't have the sizes useful to me to run at Nationals anytime soon.

92CelicaHalfTrac
92CelicaHalfTrac SuperDork
8/23/11 5:46 a.m.
alfadriver wrote:
DILYSI Dave wrote:
alfadriver wrote: Actually, do you really need A6's at all?

If you want to play at the pointy end of National competition, yes.

Which is why I'm asking. I didn't see part of the project goals to go to the solo nationals, let alone be at the front of that.

Sorry 'bout that, my fault. This is concerning "ZE Scort," the car that i'm building for National level SMF competition.

And because i'm still learning, i yet again forgot to check what tire sizes were available until way later in the build than i should have.

alfadriver
alfadriver SuperDork
8/23/11 7:08 a.m.

In reply to 92CelicaHalfTrac:

Are you planning to spend a season developing, or plan on being at the pointy end of the results next fall?

What matters here is outlay.

You can spend a ton of money blowing through A6's, which is fine, if you can. Or you can work on it to be pretty close with cheaper alterntatives. Bear in mind, much of what you are developing is not the chassis.

I've run brand new A6's before on my GTV- and without a doubt they were faster. But I didn't actually alter the set up from my Victoracer set up, and it still drove similar- just faster.

All I'm trying to make you think about is cost of development. A6's are, indeed, awesome tires. But they are both expensive, and don't last as long as good alternatives.

If the A6's are in the budget and development plan, by all means, the sizes that dave has suggested will probably be good- although I might suggest even a little more in the front, due to the V6 power.

92CelicaHalfTrac
92CelicaHalfTrac SuperDork
8/23/11 7:14 a.m.
alfadriver wrote: In reply to 92CelicaHalfTrac: Are you planning to spend a season developing, or plan on being at the pointy end of the results next fall? What matters here is outlay. You can spend a ton of money blowing through A6's, which is fine, if you can. Or you can work on it to be pretty close with cheaper alterntatives. Bear in mind, much of what you are developing is not the chassis. I've run brand new A6's before on my GTV- and without a doubt they were faster. But I didn't actually alter the set up from my Victoracer set up, and it still drove similar- just faster. All I'm trying to make you think about is cost of development. A6's are, indeed, awesome tires. But they are both expensive, and don't last as long as good alternatives. If the A6's are in the budget and development plan, by all means, the sizes that dave has suggested will probably be good- although I *might* suggest even a little more in the front, due to the V6 power.

I'm going to Nationals for 2012. My only goal that year is to not be DFL, though. I would be ecstatic with a mid-pack finish, considering it'd be a "new" car, one that nobody has gone down the same path before me with, and i'm a relative autocross newbie, with this being my first trip to Nationals. 2013 would be my serious bid for the pointy end. (Partially because i think i'll find with the 2012 season that i'll be needing to find some power for 2013.)

I'm lucky in where i live, i can literally hit an autocross within 2 hours of me almost every weekend. (3-4 regions very close to me)

I think i'd like to get "pretty close" on a cheaper tire, then "finish" dialing in on A6s. I'll have to take another look at Kumhos and see what i can get i think.

Another problem is that there aren't many SMF cars locally, so even if i show up on all-seasons, i'm probably getting a trophy at the local events. Looks like i'll be doing some traveling to hit some larger events.

I'm pretty new (read: VERY NEW) to this sort of tire... any idea where i should look to try to find something bigger than a 275/35-15? The only other tires that come to mind are the Hankook Z214 and the Kumhos, neither of which come in wider than 225 in 15", but i think they're both available in 245/45-16, and one has 265/45-16.

For what it's worth, i doubt i'll be making any more power than Dave is with the first iteration of the motor that i'm using.

Thanks for the input!

alfadriver
alfadriver SuperDork
8/23/11 7:42 a.m.

In reply to 92CelicaHalfTrac:

Are there any other drives who go to nationals?

Between the past years results and current driving, you should get a good relative feel where you are without real H-H driving.

Oh, and make friends. You want some of those national drivers to help you learn to drive better as well as set the car up.

mtn
mtn SuperDork
8/23/11 7:43 a.m.
92CelicaHalfTrac wrote: I'm lucky in where i live, i can literally hit an autocross within 2 hours of me almost every weekend. (3-4 regions very close to me)

Do you have CCSCC on your list? Champaign County Sports Car Club in Illinois. They put on 23 events a year, and it is incredibly cheap too. Most are in Rantoul. Decent competition too, this year we have 7 or 8 going to nationals. Nobody in SMF though.

92CelicaHalfTrac
92CelicaHalfTrac SuperDork
8/23/11 7:48 a.m.
alfadriver wrote: In reply to 92CelicaHalfTrac: Are there any other drives who go to nationals? Between the past years results and current driving, you should get a good relative feel where you are without real H-H driving. Oh, and make friends. You want some of those national drivers to help you learn to drive better as well as set the car up.

There's a few local guys that go to Nationals, and i think i can use PAX to figure roughly where i am.

I know at least a couple them know me well enough... Of course, knowing them, they'll probably just tell me "STFU GET THAT PILE OF CRAP OUT OF HERE!!!!"

92CelicaHalfTrac
92CelicaHalfTrac SuperDork
8/23/11 7:49 a.m.
mtn wrote:
92CelicaHalfTrac wrote: I'm lucky in where i live, i can literally hit an autocross within 2 hours of me almost every weekend. (3-4 regions very close to me)

Do you have CCSCC on your list? Champaign County Sports Car Club in Illinois. They put on 23 events a year, and it is incredibly cheap too. Most are in Rantoul. Decent competition too, this year we have 7 or 8 going to nationals. Nobody in SMF though.

Not yet... but i'll look into it, thanks!

I've got KY region, Indy Region, Fort Wayne, and Columbus on the list right now.

DILYSI Dave
DILYSI Dave SuperDork
8/23/11 11:22 a.m.

Unfortunately, for national level competition locally, unless you're real lucky it means running against other classes with top shelf drivers in them. I Atlanta, we've got several National Champions at every event, so even though they aren't in my class, I get a good feel for where I stand via the index.

As for an even wider choice, I've considered what it would take to put a 315/18 under my car, but for the time being, I'm going to do everything I can to get the most out of the 275/15.

92CelicaHalfTrac
92CelicaHalfTrac SuperDork
8/23/11 11:50 a.m.
DILYSI Dave wrote: Unfortunately, for national level competition locally, unless you're real lucky it means running against other classes with top shelf drivers in them. I Atlanta, we've got several National Champions at every event, so even though they aren't in my class, I get a good feel for where I stand via the index. As for an even wider choice, I've considered what it would take to put a 315/18 under my car, but for the time being, I'm going to do everything I can to get the most out of the 275/15.

18s?!?!?!?

SCCA Donk class.

I'm still not sure what to do for base-line setup tires. The kumho sizing isn't even close unless i want to buy another set of wheels and run 245/45-16 to set the car up. (I don't.)

How dumb of an idea would it be to use a set of Kumho 225/45-15s to get my base-line, and once that's ok, go ahead and jump to the big A6s? Looks like that would save me a cool $300 or so. (Which... i guess is small peanuts at this point, huh?)

I suppose if the rears are going to last a long time (likely) i could just buy a spare pair of fronts to sacrifice, and just always run A6s.

So at the beginning of the season, buy 6 fronts and 4 rears and see if that'll carry me through.

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