Scrubbin hard on the outside fronts of my Miata. How much camber is too much?

I've got a problem I'm trying to solve on my track Miata, where I'm scrubbing the fronts pretty hard on sweepers where I can't use the brakes to help upset the balance and help turn-in.   I know that this is being exasperated by the crappy R1Rs that I have on right now, but I was unable to find a set of Rs-4s or Re-71rs on this half of the country when I corded my Rs-4s last month.

The car is a Miata with a FatCat Motorsports tuned Bilstein package and the 9livesracing medium downforce kit.  It does get driven on the street but only to the track and back.

I've recently had an alignment and corner-balance done, which helped tremendously when I had the Rs-4s (before cording).  That put me at -3.4 degrees.  I was thinking about grabbing these Extended Ball Joints, and go 3 more degrees.

Is 6.4 degrees too much? Should I get these and then redo alignment, and if so, to what?  Will installing these change the toe at all (my guess is no)?

The extended ball joints move the range of adjustment. You can bolt them on and then back your camber off to 4.0 degrees (for example).

Toe will change when you install them, but that's easy to fix.

You might also consider a little more roll stiffness or a handling balance that doesn't depend on your unsettling the car, at least for tracks that won't let you do it.

I guess it makes sense that they change the toe, eh? :)

I think my next two events are on courses that don't require so much straight mechanical grip as they're better cambered, so maybe I'll just try increasing roll bar stiffness and see how that goes.  I don't think I'll have a chance to do an alignment before then.

WonkoTheSane (Forum Supporter) said:

I guess it makes sense that they change the toe, eh? :)

I think my next two events are on courses that don't require so much straight mechanical grip as they're better cambered, so maybe I'll just try increasing roll bar stiffness and see how that goes.  I don't think I'll have a chance to do an alignment before then.

What are the temps across the tire?  That can tell you were your camber and pressures should be.

wvumtnbkr said:

WonkoTheSane (Forum Supporter) said:

I guess it makes sense that they change the toe, eh? :)

I think my next two events are on courses that don't require so much straight mechanical grip as they're better cambered, so maybe I'll just try increasing roll bar stiffness and see how that goes.  I don't think I'll have a chance to do an alignment before then.

What are the temps across the tire?  That can tell you were your camber and pressures should be.

Unfortunately, I don't have them.. I only have a cheapy infrared pyrometer, but even then, the batteries were dead yesterday.  You know how it goes :)

It sounds like your tire pressures might be too low also. What pressures are you running, cold and hot?

To answer your original question though.   Yeah, -6+ degrees of camber is too much. That's stance boi territory.

  Your -3.4 sounds perfect.

I should mention that I've always been happy in the 2.5-3° and this was dialed in by a very good spec Miata shop.

I've just been really struggling since I got these R1Rs.

I found they were happiest yesterday at about 38 psi front, hot. I had the rears at 36.  For reference, I started the day around 34-35 hot, which is where I liked the RS-4s & 71rs.

At no point in the day did the tires get overly hot to the touch, and the rear was noticably cooler than the front, like you could rest your hand on them indefinitely.

I was about 1.5 seconds a lap slower than last time I was there (on RS-4s).

In reply to WonkoTheSane (Forum Supporter) :

FWIW I run -4.1* front & -3.2* rear on my STS Miata & it seems to work well for me (with the rest of the suspension setup). I've never had it on track though. 

R1Rs don't like being overheated. 

I was going to ask you for more detailed suspension info, but then I read your most recent post and the right answer is that you shouldn't be making major setup changes based on crappy tires that you don't intend to run long term. If you're happy with the setup with the RS4s/RE71Rs, then it sounds like there's an obvious solution that's probably not any more expensive than throwing parts and alignments at the car trying to bandaid the problem.

Any thing over  3 neg is too much.

work on roll stiffness

too much camber an you lose contact patch

dps214 said:

I was going to ask you for more detailed suspension info, but then I read your most recent post and the right answer is that you shouldn't be making major setup changes based on crappy tires that you don't intend to run long term. If you're happy with the setup with the RS4s/RE71Rs, then it sounds like there's an obvious solution that's probably not any more expensive than throwing parts and alignments at the car trying to bandaid the problem.

Yeah, but I'd like to get more than 10 hours out of the crappy tires since I probably won't be able to replace them (due to supply) until next spring.  So if a $125 purchase would prevent me from spending $650 on another set of crappy tires and being stuck with them for months, that's a win to me :)

So from the end of the screen, where it's easiest to make technical suggestions, do you guys suggest increasing front, rear, or both? 

For reference, the rear feels really good and planted now and I can dial in exactly the response I want (when I can get the front to play...).

I have racing beat adjustable bars with FM end links, so it's easy to adjust, I'm just normally instructing, so I don't have a lot of time to play during the day, so it would be good to get it (hopefully) set up before hand.

Thanks!

WonkoTheSane (Forum Supporter) said:

dps214 said:

I was going to ask you for more detailed suspension info, but then I read your most recent post and the right answer is that you shouldn't be making major setup changes based on crappy tires that you don't intend to run long term. If you're happy with the setup with the RS4s/RE71Rs, then it sounds like there's an obvious solution that's probably not any more expensive than throwing parts and alignments at the car trying to bandaid the problem.

Yeah, but I'd like to get more than 10 hours out of the crappy tires since I probably won't be able to replace them (due to supply) until next spring.  So if a $125 purchase would prevent me from spending $650 on another set of crappy tires and being stuck with them for months, that's a win to me :)

What size are you running that's completely unavailable for another 6 months?

Assuming  steady state / steady throttle understeer I would start by adjusting the front bar. 

Don't buy parts to fix a crappy set of tires, if the camber was fine with the other tires just make the available adjustments to get it the best it can be for now. 

If you like the balance as it is now I'd think you'd want to increase both ends by roughly the same amount to reduce the roll and keep the same balance.

dps214 said:

What size are you running that's completely unavailable for another 6 months?

The same as everyone else with a miata apparently, 195/50r15.

Tom1200 said:

Assuming  steady state / steady throttle understeer I would start by adjusting the front bar. 

Don't buy parts to fix a crappy set of tires, if the camber was fine with the other tires just make the available adjustments to get it the best it can be for now. 

Copy that.  I appreciate you guys talking me off the ledge.

I'll start by tightening up the front, the rear is fast enough to do in the paddock, so I'll leave that for after the first session.

WonkoTheSane (Forum Supporter) said:

dps214 said:

What size are you running that's completely unavailable for another 6 months?

The same as everyone else with a miata apparently, 195/50r15.

Is that a rules restriction or something? Why not run 205/50/15, the size that everyone else with a miata actually runs and is readily available in like 5 different flavors (brands) for maybe even cheaper than the 195s would be?

You're sure you haven't had your alignment slip at all? I would mark the bolts. 

dps214 said:

The same as everyone else with a miata apparently, 195/50r15.

Is that a rules restriction or something? Why not run 205/50/15, the size that everyone else with a miata actually runs and is readily available in like 5 different flavors (brands) for maybe even cheaper than the 195s would be?

Huh... My car came with 195s and I've been just keeping with that size. I thought I remembered reading that was the size of spec miata, but I see that you're right.  Hah!  I've been under-tired for a few years!  Thanks!

accordionfolder said:

You're sure you haven't had your alignment slip at all? I would mark the bolts. 

I'll have to check, but all of my bolts are marked.  I don't believe that was the case, it was pretty even scubbing in either direction.

If you stiffen the front and leave the rear alone, I think you're going to make the problem worse unless you're running out of front travel. That's going to move your steady state balance more towards understeer. I'd go the other way, either soften the front or stiffen the rear.

Could it also be a matter of turning in too fast and overwhelming the tires? Those R1Rs might need a more gentle hand than your RS4s did.

Keith Tanner said:

If you stiffen the front and leave the rear alone, I think you're going to make the problem worse unless you're running out of front travel. That's going to move your steady state balance more towards understeer. I'd go the other way, either soften the front or stiffen the rear.

Could it also be a matter of turning in too fast and overwhelming the tires? Those R1Rs might need a more gentle hand than your RS4s did.

This, by "scrubbing on turn in" do you just mean understeer when you load up the car? It sounds like you're compensating for understeer on the other corners with trail braking, but can't on these "sweepers"? Adjustable rear bar 1 position firmer, would be where I go if it's easy to do and you're trying to use up the tires. But remember to move it the other way if the other tires are happier on turn in and you don't want to get TOO tail happy. 

Left foot braking might help turn in, but it's better in my novice mind to fix the balance then compensate with more trail braking.