I'm trying to figure out the best tire for street tire class in auto-x, and I have it narrowed down to Falken Azenis sport, Kuhmo MX, or Goodrich T/A KDs.

I have a stock '98 M3 with 17" 7.5F and 8.5R wheels and I'm having trouble finding tires I want.

The Falkens don't come in a good size for my rear wheels, but the others do. Would a narrower Falken on the rear still be better than a 245 Kuhmo MX? Would the Goodrich's be a good alternative to the Falkens, better than the Kuhmos even?

Falken -- 225/45/17 F&R
Kuhmo -- 225/45/17/F, 245/40/17 R
Goodrich -- 225/45/17/F, 245/40/17 R

I hope to get a few DEs in wit these tires too.
~~I know this always gets asked, but I searched and read, but didn't see anyone using 225 falkens on the rear...maybe there's good reason?
Anyway, thanks for any input!!
--Jonathan

i know i will be useing falken 225s all around on my 325i when my pilot sports wear down. the falkens are great tires for the $$$ and you can get the azenis in 245.

http://www.1010tires.com/tire.asp?tirebrand=Falken&tiremodel=Azenis+Sport

i just did a search and came up with that link to show tire size. although they are 245-45-17 its your call. if you want the correct size for you M3 go with a different brand is my recomendation.

the 225/40/17's are only $117ea at www.tires.com

edit. they are $104 ea from www.victoriatire.com

the link i posted was just a reference for the sizes.

what kind of tires do you guys use for 17x8.5 all aorund?

Originally posted by lhoward
i know i will be useing falken 225s all around on my 325i when my pilot sports wear down. the falkens are great tires for the $$$ and you can get the azenis in 245.

http://www.1010tires.com/tire.asp?tirebrand=Falken&tiremodel=Azenis+Sport

i just did a search and came up with that link to show tire size. although they are 245-45-17 its your call. if you want the correct size for you M3 go with a different brand is my recomendation.

Yeah, thanks. I know they come in 245/45/17s, but I heard that size will rub on a stock M3...

if i remember correctly i had 255-45-17 on my 325i in the back. no rubbing although the fenders were rolled and the car was not lowered.

I have the 225/45/17's all the way around on my 325i (17x8 rims), and they are wonderful. Also have a friend with an E36 M3 who ran them for a while. They were great for Autox, but his car devoured them way too fast (I think he has a rear alignment problem). I also have a set of 245/40/17 MX's laying around waiting to go on next. From what I've heard, the MX's just aren't quite there in terms of grip. However, they seem to deal with heat better. Don't worry about putting the 225's on an 8.5" rim, it's not that much of a stretch.

I wouldn't mix different tires, as it always ends up handling really strange. A vette owner I know in Houston ran Azenis up front and MX's in the rear and quickly gave up on that setup because the two tires kept changing grip levels at different rates as they heated up. He claimed this unbalanced the car.

As for the KD's...they are nice, but way too expensive. Try them if you want, but I don't know anyone who thinks they are worth the money.

-Bret

I run the 205 (dinky!) azenis on my hatchback for auto-x- great tire! They do overheat a bit on longer courses, but it hasn't been too bad yet.
I wouldn't worry about the width- it seems that most people will agree that the azenis are substantially wider than their competitor's equivalent (i.e. my 205's aren't much narrower than a 225 MX).

if you think the Azenis run wide, you should check out the new Hoosier A3S04's. A friend of mine mounted up some brand new 225's this weekend, and when he laid one down next to his 265 street tires (Bridgestone S-03's) they were pretty much the same width! Gotta love race tires :clap:

-Bret

I ran the Azenis 225's on 8" Borbet's last year in street tire class (ST/BSP). I also put about 5K miles on the tires on the street.

With stock suspension and me and my co-driver learning the ropes of autocrossing, I think the tire was the right choice and I would buy them again in a heartbeat. They are competitive but fairly forgiving.

As with most street tires, when they get hot they get "greasy", so driving with 2 drivers usually requires cooling the tires between runs. I found that the rapid change from "good" to "greasy" served as sort of a gentle introduction to the world of r-comps, where I have discovered that tires work up to their limit, then just let go (leading to cone massacres...).

They do wear fast on the road, but they stick like crazy and they look good (imho) and they are relatively cheap.

-Gordon

Gordon-
if I recall correctly, the '97 M3 came with the staggered M Double Spoke II's -- 7.5 front, 8.5 rear (and looking at the pic of your car this looks to be the case). I was considering running all 4 Azenis 225s, even with the staggered wheels like yours.

Did you notice any drawbacks from using the same size tires (225/45/17) on the staggered wheels?

I will be trying Azenis on my M coupe this year 225/245. I hope they will give me much improvement over the stock pilots, for autoxing.

The staggered tire size was the single biggest problem with the car's handling. The pic in my sig was sith the stock wheels and staggered Sumitomo's (235/245 if I recall). Fine for the street but the understeer was horrid at the autocross.

I ran the Azenis on 8" Borbets all the way around.

Now I am back to staggered wheels, not by choice, but by circumstance. But I run 255 V-racers all the way around. The wheel stagger has not been a problem, not even noticable at my limited skill level.

-G

I'm not up on class rules, but why aren't you considering 235/40 tires. I run 235/40 on 17x8 all around. More rubber than 225s... non staggerred setup for reducing the cars tendency to push

Limited tire size availability --

Falken Azenis only available in 225/45/17 and 245/45/17.
Kumho MX avail in 225/45, 235/45 (will possibly rub in front - not sure), and 245/40.
I haven't found anything that will autocross as well as these tires for the price.

For wheels, I have the staggered M Double Spoke II 7.5x17, 8.5x17. I would consider going 8x17 all around, but don't want to go through the hassle of selling these, finding new ones, etc. Perhaps next season or after I go through this set of tires I'll upgrade to lighter wheels and R-compounds.

I ran the Sumitomo 235's on stock rims with no rubbing.

They have the same section width as the Kuhmo's according to the factory specs.

Links:

http://www.kumhousa.com/Products/PtnDetails.asp?mainCatID=1&PtnID=KU-15

http://www.tirerack.com/tires/Spec.jsp?make=Sumitomo&model=HTR+Z+II

-G

Well, I ended up going for the MX's, 225/45F and 245/40 rear. I hope these will understeer less than my current Proxes T-1S, as I think the soft sidewall of the Proxes contributes to the understeer? I'll find out this weekend at the autox.

If not much better I'm going to look into getting some 17x8 wheels all around, but am wondering if changing wheel widths will bump me out of stock class?

Your tire sizes are contributing to your understeer. Not knowing anything else about your suspension setup, just running a 20mm stagger like that will make the car understeer.

I doubt one brand of tire vs another has anything to do with it. You would've been much better off running 235-40's or 245-40's all the way round...

mmm yeah - to answer your question about the section width of the 235 being the same as the Falken...I'm actually concerned about the overall diameter of the tire. A 235/45 (what the Kumho comes in) is at least .5" larger than a 225/45. It's doubt that it will rub, but it definitely is possible for the rear of the front tire to rub the plastic wheelwell liner (or whatever it is called). I want to avoid any cutting, so I would rather stay with the 225/45 front, or 235/40 (not avail in the MX or Azenis)

Originally posted by DocWyte
Your tire sizes are contributing to your understeer. Not knowing anything else about your suspension setup, just running a 20mm stagger like that will make the car understeer.

I doubt one brand of tire vs another has anything to do with it. You would've been much better off running 235-40's or 245-40's all the way round...

I have pretty much stock suspension setup, and as I mentioned, 7.5f and 8.5r wheels. I know the staggered setup contributes to understeer, I just don't know the best way to go about fixing it with stock wheels. (will going to 17 x 8s all around disqualify me for BS?)

Kuhmos don't come in a 235/40, and I doubt I can fit 245/40's all around on a stock setup with no rolling. If rolling wasn't an issue I would've gotten 245/45 Azenis sports.

Someone had mentioned running the same size tire on a staggered rim setup would yield strange handling characteristics, as the front tire would have a wider sidewall section than the rear that would be stretched out on the wider rim, i.e. 225/45 Azenis all around.

With staggared wheelset, there doesn't seem to be any good choices/solutions for autox!! Again, anyone know if going to 17 x 8s all around disqualify me for BS?
--JD

That's BS. The m3 ltw came with 235-40's all the way round on staggered 7.5/8.5 wheels.

I'd run S03's in 235 all the way round, but with a stock suspension you should be able to fit 245's on the front easily. They're a bit big for a 7.5" rim, but will work and will help with the understeer.

With the stock suspension, wheels and tire size, you're going to understeer regardless of tire choice. If you don't want to get different wheels, then I'd get a set of single adjustable koni's and dial them in to get rid of the understeer.

That's what I did last year, I ran the stock suspension with koni's and I was pretty much able to get rid of the understeer with tire pressures and shock settings.

I'm pretty sure that would be illegal for stock classes.
I would probably just go with the 225s all the way around. Sometimes a skinnier tire can actually be benificial in auto-x, where you don't have much time to get some heat into 'em.

I run 205s and do just fine. :D

Originally posted by Fraser
I'm pretty sure that would be illegal for stock classes.
I would probably just go with the 225s all the way around. Sometimes a skinnier tire can actually be benificial in auto-x, where you don't have much time to get some heat into 'em.

I run 205s and do just fine. :D
What would be illegal?

I'd really appreciate anyone who has access to the 225/45-17 Azenis Sports taking a ruler or measuring tape to them to find out the treadwidth.

Koni's are perfectly legal for stock class, the single adjustable inserts anyway (i.e. the basic ones you find on tire rack etc.) Changing the strut body or the springs is illegal, but your typical set of single adjustable Koni's don't change any of that.

Oh, and you don't really want to get alot of heat into Azenis. They tend to overheat pretty quickly. Some tires like heat, some don't. Azenis don't. I'd go measure mine tonight and tell you the width, but my car is in the shop. However, I think it isn't really going to be all that helpful. Just try the Azenis, 225's all the way around, and if you don't like them don't buy 'em again. They are cheap and fast, and I bet you will love 'em.

-Bret

Originally posted by TeamSlowdotOrg
What would be illegal?

I'd really appreciate anyone who has access to the 225/45-17 Azenis Sports taking a ruler or measuring tape to them to find out the treadwidth.

I think he means changing wheel size would be illegal for stock class...

Originally posted by DocWyte
That's BS. The m3 ltw came with 235-40's all the way round on staggered 7.5/8.5 wheels.


It did?

Anyway, I see what you are saying, and maybe if it gets too bad I'll try adjustable shocks, I need new ones pretty soon anyway. As it is, if I place well in my class then I'll just be doing that much better!:clap:

Next year I'm probably going to move up to BSP, and maybe race rubber. In BSP I'll be able to change wheels to whatever I need for the right tires. :eyes1

Originally posted by BlueMaxx9
I'd go measure mine tonight and tell you the width, but my car is in the shop. However, I think it isn't really going to be all that helpful. Just try the Azenis, 225's all the way around, and if you don't like them don't buy 'em again. They are cheap and fast, and I bet you will love 'em.

-Bret I've already used them for street tires on the Civic, they're cheap and fast (the fastest, actually) on an autocross course if you have a water sprayer, or on a light car on a road course in cool weather.

They're no substitute for R-compounds so for my purposes they're just another nice street tire, and I'd rather pay an extra 50 bucks each for the 235/40 S03's (about the same width and twice the usable life on the street).

I'm tabulating this stuff for people who want to know. Looks like they're somewhere in the neighborhood of 9.7" section width and 8.5" tread width but I want more data to average into the measurement.

From the Falken website, the Azenis 225/45/17 section width is 9.1 and tread width is 8.3.
For comparison, see my post in another thread regarding the Azenis compared to the S-03 or MX:
http://forums.bimmerforums.com/forum//showthread.php?s=&threadid=182598&highlight=azenis

I'm thinking that 225/45 all around might be the answer. I'm still fairly new at this, but can the heat buidup really be that big of a deal on a 3000# car over a 1:30 course? And will that difference really be noticeable to a novice?

I would consider R-comps (I'm still trying to figure out SCCA classes -- my limited experience is with BMWCCA), but they are pretty costly compared to the Azenis ($500 mounted) or the MX ($600 mounted).

I just got my 225/45 falkens taken off today because tehy rub on my front fender lining (next to brake duct on e36 m3)...

ordered v700's now....

Last week I had Azenis Sport 225/45/17 mounted on a staggered set of M Double Spoke IIs. I drove on them for a week, then did an autocross today (9 total 90-second runs). My impressions (and comparison to staggered Potenza S-03s):

Street: Azenis Sport actually seemed like a smoother ride in many respects. Less tramlining. But firmer ride -- feel the bumps more-- due to stiffer sidewall. Didn't notice any difference in noise levels, but they are still new.

Autocross: Did not notice any major adverse problems with the smaller rear tires. But then again, I couldn't say definitively that using the same tire at all four corners helped the handling, either. The Z-3 and M Coupe are fairly tail-happy already, so I think I would have been OK with the 245/45 rear. Autocross performance was as good or better than the S-03s (I'm using my times, compared with the the top finishers who were at both events). It rained at the last autocross, and the S-03s were awesome. Still havent' tested the Azenis in the wet. No problems with overheating or getting "greasy".

Just thought I'd pass on what I learned...