Stock Miata autocross alignment specs?

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

DickRasmussen wrote:

Mike,

I won't go into alignment since you know the theories at least as well as I do and I have no Miata experience.

Tramlining may be mostly a function of the tires and lack of toe in.

Dick

Tramiling deserves its own separate thread. One data point -- on this car it tramlined like *mad* with worn-to-the-bars SO3s and hardly at all with new Azenis. So I agree on the tire comment. I don't know yet what the front toe is currently -- need to measure it before I decide on final alignment specs.

Every other competition car I've had aligned I went with zero front toe, seems to make the most sense to me.

Eric Peterson · **Joined:** Mon Sep 01, 2003 10:24 am **Posts:** 494

Mike,

I've only got a few minutes, so here's a quick stab at it....

On Tim's 10 AE w/ stock Bilsteins we ran zero toe front and rear. Tim liked a really loose car and he even ran the 1 1/8 inch bar on the soft setting. We maxed front camber and we're lucky (as with all 1999 Miatas) to get -1.25 degrees up front. I think rear was about -1.7. The car was really fast.

We drove that car all over the country on Kumho Victos while pulling a trailer and, as expected, had no trouble with tire wear w/ zero toe.

On the silver car we run a little toe out up front, a little toe-in at the rear, -1.25 up front (max), between -1.5 and -1.7 with the front bar at full stiff. Part of that is due to the shocks and the way Telehowski liked to drive the car. It's set up to be pushy and require a fair amount of trail braking.

If you are running the Bilsteins try running the bar on full stiff with the above camber settings, and zero toe - that should get you close. Then, adjust the toe as needed depending how the car handles at a couple of different sites. I wouldn't worry about tire wear with reasonable toe in/out at either end.

That 10AE is a fast car, you'll do very well with it.

Good luck,
Eric

Patrice Bousquet · **Posted:** Tue Dec 12, 2006 8:51 am

Here what I got on mine that is my daily driver and once in a while used in autocross.
Front:
Camber: -1.0 deg
Caster: 5 deg
Toe: -0.1 deg

Rear:
Camber: -1.5
Toe: 0.12 deg

I'm up to 8000 Miles now on a set of Azenis RT615 the wear is even across the tread. I usually rotated them at every
oil change ( 3000 M. ) they should be good for another 4000 M. They all have the same wear at the moment.
The car drive fine with no ill effect, at least to my taste.

Patrice

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

So for everyone that runs with rear toe-in -- what's the rationale behind that?

AdamBreakey · **Posted:** Tue Dec 12, 2006 10:49 am

MikeWhitney wrote:

So for everyone that runs with rear toe-in -- what's the rationale behind that?

it helps keep the rear end where it is supposed to be when adding power (in a corner). Of course, in a miata it isn't quite as large of a problem as it is in the z06. I pull much of the rear toe out of the z06 on grippy surfaces and add more on slippery surfaces. Adjusting the rear toe in grid is not a big deal at all.

adamb

Aaron Buckley · **Posted:** Tue Dec 12, 2006 11:00 am

MikeWhitney wrote:

So for everyone that runs with rear toe-in -- what's the rationale behind that?

As loose as you liked your previous cars, I would run zero toe. Bryan and I run zero toe in the rear of the RX-8 and it works pretty well on all surfaces. I tend to like the car a little more loose than he does though, so we add 5-7# of air to the rear on my runs. - AB

Patrice Bousquet · **Posted:** Tue Dec 12, 2006 11:06 am

Like he said " it helps keep the rear end where it is supposed to be "

On the Porsche, rear toe out is a NO-NO, except if you like to do some 360.

Patrice

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

Aaron Buckley wrote:

MikeWhitney wrote:

So for everyone that runs with rear toe-in -- what's the rationale behind that?

As loose as you liked your previous cars, I would run zero toe. Bryan and I run zero toe in the rear of the RX-8 and it works pretty well on all surfaces. I tend to like the car a little more loose than he does though, so we add 5-7# of air to the rear on my runs. - AB

So I think I shoot for a Frederickson/Aro Spec alignment. 1.2F 1.7R Zero toe all around. Sounds like fun

I think I'll put the car up and set the front camber+caster to max on the adjusters, and try to get the rear camber set before taking it to Mark. That way we can just mess with fine-tuning the toe on the rack, which is the hardest to do at home.

Thanks everyone!

DickRasmussen · **Posted:** Tue Dec 12, 2006 1:27 pm

Graham Jagger wrote:

[
That's interesting Dick. On the Z06 I'm running the FS WO for my street tires. 30lbs on all 4 corners. I have -1.5, with 0 toe front and -1.0 with 1/8 total toe-in on the rear. I get little to no tramline issues with it. Now if I put the GY F1 Supercars back on then it shows up. But I believe your Mustang is heavier and the balance is more to the front. I'm at 52/48 or 51/49 front/rear.

Graham,

My Mustang's front end weight is probably higher plus the wheels are only 8 inch wide with small 245X45/17 tires. Probably takes more air pressure to get the tires into their appropriate profile. Also, you have a sports car. I have a small truck with a really small load area. :lol:

In regard to rear toe, even a typical formula car usually doesn't "like" or "need" rear toe out.

The main advantage of front toe out (or minimum toe in) is to increase the steering angle of the inside front tire. The less ackermann, the more toe out. On my formula car I think any increase in straight line scrub (as if there is significant straight line time in an autocross :wink:

) just tends to heat the tires which is a good thing for my car.

Dick

Chuck Frank · **Posted:** Wed Dec 13, 2006 3:45 pm

Our alignment is very similar to everyone elses, we run a 1/16" toe out in the front. Been driving on Azeni 615s for > 1 year without any street driving issues. The Celica's alignment settings are far more radical and still no street driving issues except a little more inside edge wear, so we run a harder compound Kumho all season on the street.

Eric Peterson · **Joined:** Mon Sep 01, 2003 10:24 am **Posts:** 494

Mike, it looks like we posted at about the same time when I shared my thoughts on the alignment a few nights ago. I just noticed that you are running the stock bar. With that being the case, I recommend putting in a small amount of toe-in at the rear (like an 1/8th inch total). The car will still have great turn-in and you'll be able to get on the throttle *really* early with the stock bar, but it will also be looser in transition & corner entry. The added toe-in will help settle the rear and make it more progressive/easier to catch when the rear steps out.

FWIW, we've never changed the alignment on the silver Miata when switching between stock Bilsteins when sending the Konis off for repair and the car has worked very well in all cases. The stock Bilsteins are really good shocks. Even if you're going to just be playing with the car I'd strongly suggest considering putting on the Racing Beat 1 1/8 inch bar up front - it will be a big help.

Good luck,
Eric

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

Eric Peterson wrote:

Mike, it looks like we posted at about the same time when I shared my thoughts on the alignment a few nights ago. I just noticed that you are running the stock bar. With that being the case, I recommend putting in a small amount of toe-in at the rear (like an 1/8th inch total). The car will still have great turn-in and you'll be able to get on the throttle *really* early with the stock bar, but it will also be looser in transition & corner entry. The added toe-in will help settle the rear and make it more progressive/easier to catch when the rear steps out.

FWIW, we've never changed the alignment on the silver Miata when switching between stock Bilsteins when sending the Konis off for repair and the car has worked very well in all cases. The stock Bilsteins are really good shocks. Even if you're going to just be playing with the car I'd strongly suggest considering putting on the Racing Beat 1 1/8 inch bar up front - it will be a big help.

Good luck,
Eric

Thanks Eric. When you say the RB front bar will be "a big help", how do you think it helps?

As others have commented, I really like a loose car. That's why I have always been hesitant to add front roll stiffness. I enjoy loosness on corner entry, transitions, and corner exit

Maybe it's not the fastest setup but at this point I think it's the fastest way *I* drive

DickRasmussen · **Posted:** Thu Dec 14, 2006 1:22 pm

Mike,

You will have to try it to be sure but my experience is that a stiffer front bar on an already loose car just means you can drive harder without spinning, etc. and put the power down better. i.e. you don't lose the good stuff and you do lose some bad stuff. The main thing is that if it doesn't gain corner exit push and you can still rotate it as needed to turn in you have not lost anything. Plus, now that you've learned the corner entry techniques discussed last summer in order to minimize the BMW's PUSH you may find that even a "tendency" for the Miata to push is easily dealt with.

Dick (who learned about the benefits of a big bar in 1977 . . . just in time to use it to good advantage for the 1977 Nationals :lol:

)

Donnie Barnes · **Posted:** Thu Dec 14, 2006 3:04 pm

IMHO, a Miata can be fast with zero rear toe, but only so fast. If you put a little toe in the rear (toe *in* in the rear, I mean) and then learn to trail brake it enough to still get it to rotate, YOU WILL GO EVEN FASTER on the clock. It isn't natural, doesn't feel as ragged-edge-fun, but it's faster on the clock. Why? You carry speed longer, brake the same amount, and can still carry speed in corners. With a zero toe setup I think you have to brake to "terminal" speed for the corner earlier and thus you are at terminal corner speed longer instead of previous straightaway speed. You're effectively able to safely brake later without hurting corner capability.

I got in the right zone a couple times in that Miata with that setup and did well. I can't say that it was as "fun" to do, though it was "fun" to come in second at the Pro Finale with a tough class. It was "fun" to be FTS and FTPax (and miss FTRaw only because McGeorge was there in the now-mine Spyder) at a Laurinburg event with a 72 second course. But your definition of "fun" may certainly vary.

That's my opinion based on driving the silver car and based on things Steve said, but more importantly based on the things Steve *did* in that car. When you get it working right it *looks* fun as shit, but doesn't really feel like it actually looks from inside the car. Inside the car you're still working around stock class deficiencies.

--Donnie

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

Donnie Barnes wrote:

IMHO, a Miata can be fast with zero rear toe, but only so fast. If you put a little toe in the rear (toe *in* in the rear, I mean) and then learn to trail brake it enough to still get it to rotate, YOU WILL GO EVEN FASTER on the clock. It isn't natural, doesn't feel as ragged-edge-fun, but it's faster on the clock. Why? You carry speed longer, brake the same amount, and can still carry speed in corners. With a zero toe setup I think you have to brake to "terminal" speed for the corner earlier and thus you are at terminal corner speed longer instead of previous straightaway speed. You're effectively able to safely brake later without hurting corner capability.

--Donnie

Excellent explanation, thanks for that. Has me thinking about the tradeoffs now...

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Stock Miata autocross alignment specs?

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