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Solo_S14

Comments on NA Alignment Setup / Tire Wear?

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Interested in your guys feedback on my current setup.  91 NA on Bilstein’s and unknown rate eBay springs / sleeves:

CAE9702B-1690-4332-9663-8CAFD20AA04E.thumb.jpeg.961a6a275e05a514b6d550c27189c777.jpeg

 

I’ll preface by saying I bought the car in April “as-is”, and just ran it as I found it, with the exception of stuff I needed to do to keep it running (Clutch, Lifter service, Brake fluid / caliper service, cooling system stuff, electrical gremlins, leaks, etc in addition to string alignments every other weekend).

Oh yeah, and the regular Miata stuff like a round of wheel bearings, tie rod ends, some ball joints etc.

Asking for feedback since I’ve basically been running “all the camber” at zero toe, and I appear to still wear the outer shoulder faster (much faster in some cases) than the inners.

Note: I think the guy had an extended lower ball joint on the front left, I’ve replaced the FR for play, haven’t addressed FL yet.

(You can ignore the measurements in the 1st pic - just note Camber and ride height - then toe (as close to zero as I cared to get it) translated in the 2nd pic:

I assumed that with me in the car, the ride heights would level out a little bit, I actually don’t know what they are with driver seated.

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I’ll start with the “bad” - 205 RE71R’s on 15x7’s running about 34psi Hot.

- 1st weekend (new) I noticed the majority of the wear on the outer shoulders.  So I flipped them on the wheels (side to side) and swapped front to back (i.e. the “good tread” was now back on the outside, and in the rear).  Pics (Rears, Fronts):

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So after the tire rotation, I ran them a 2nd weekend.  Looks like the transits are continuing to punish the inner shoulders, but overall track use seems to continue to wear the outer shoulders more quickly:

Pics (All, Rear, Front):

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Not going to run these again, although history would say that outer shoulders are taking the beating, the insides are now a bit too sketchy.

For reference, I ran Star Specs in the same size, at the same pressures and alignment setup, for about (9x days) + ~1,800 transit miles, and they are less worn.  (~12-13 track hours).

RE71R’s about (4x) days + ~700 transit miles. (~5-6 track hours).

Star Specs: (Also rotated / swapped them once or twice):

0BCDEE64-A18C-4EEE-B33B-0775BCC476CB.thumb.jpeg.96ef8d6497235b61573d49d45322898b.jpeg

 

So is it pressures?  I say I’ve ran everything at about 34psi Hot (~28psi cold), but some sessions that was 36-38psi initially, and I was taking pressure out as the day warmed up.  They’re sitting at 28psi now.

I was dropping pressures so that they wouldn’t get “greasy” after ~2-4 laps pushing.  Initially at higher pressures, I was doing “cool down” laps once or twice a session.

I generally “over-drive” the tire a little, I like to have the car move around a little (probably see that from 1st weekend’s rear tires) / straddle either side of “the edge” once the car is set in a corner.  I’m also an amateur, so that’s all subjective.  Is the wear all in driving “style”?

I’m running 1:57 in both directions at MSR-H, or about 1:59-2:00 with an instructor riding along.  I had a (Miata guy) instructor drive the car for a session, and he ran 2:00 with me right seat, then dropped me and went out alone, but hit traffic and couldn’t get a clean lap to compare.

I’m “easy” on the brakes into the corners, but I think corner speeds are ok.  The instructor mentioned above was later on the brakes than I was, but I’m taking that approach to get the car set up into the corner at the “level” I’m currently driving.  Corner speeds seem to still be ok?

For Reference (for driving style / inputs, corner speed references, etc.) - runs I think we’re all in “yellow” PCA / Drivers Edge etc.

MSR-H CW (1st weekend in the car):

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MSR-H CCW:

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User inputs, also MSR-H CW (on Star Specs):

 

 

For reference - MSR-C 1.7 CW after a little rain - had removed a rear subframe brace to zero toe, and the car was more “under-steer’y“ than I like:

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For reference - MSR-H 3.1 CCW 2nd weekend in the car:

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So is it me?

Alignment?  Pressures?

Wheel width?

 

Cheers,

- Jonathan 

 

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You need more camber.  Run extended balljoints on each side, check your ride heights, and get as much front camber as you can, and remove a little from the back. 

 

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I agree with the front.  But standing up the rears would make the rear pic below worse. The rears already seem to wear quicker than the fronts.

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If I stood them up in the rear, and increased pressures to compensate - I would run into a pressure / temperature issue again.  I was dropping pressures to get more than 2-3 “hot laps” before having to back off for a lap or two, to let temps/pressures come back down.

Are the RE71R’s known for softish sidewalls?  In that pic they’re rolling shoulders at ~3.3deg camber and ~34psi hot CW at Houston.

The end product of the Star Specs seem to have “better wear”....but if they wear slower in general, then they were able to benefit from more frequent rotation.  They also seemed to take the heat better, and could run in that 34psi range without seeming to get hot/slippery and get worse degradation.

I would like to “learn something” from the RE’s rather than just go to a different tire that wears slower (and laps like 1.5 secs slower).  

What you say probably brings the fronts a lot closer to where I need to be.  For the rears, is the answer just “lean on them less”.  Seems like the answer I don’t want to hear 😂

Do you think that decreasing rake (lowering rear) would help any?  In that pic you posted he has 0” rake in his “race alignment”, then comments 0.25” is ideal.  I’m at (AVG) 0.1875”.  Lowering it would probably give less oversteer - which I wouldn’t want.  But I guess if it helps with grip/sliding, then I could adjust to induce the rotation a little more and take advantage of what should be “more grip” taking out the rake.

Any thoughts?

 

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Side-note:

I took a look at the RE laps (April) vs the Star Spec laps (May).  The min speeds are a lot closer than I thought.  

RE’s are about 1.5mph faster through Sugar and Spice, which shows all the way through the Launch.  Other than that, corners are all pretty close - RE laps are actually faster on the straights (Ambient Temps?), and the Star Specs benefit from a better line through Carousel - Star Specs have 3mph better min speed through there.

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Grabbed another lap from the same pair of sessions.  Here, Sugar and Spice, Bus Stop, and Diamonds Edge are all pretty well equal between the April RE and May SS sessions.  SS’s pick up a lot of time through the exit of carousel onto the front straight, so the RE laps are shaving the time (over a second, considering the loss at the end) on the straights again (more power at lower ambient)?

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Anyway, I guess this all just shows that the tires are a lot more comparable than I seem to have thought.  The RE’s definitely “feel” better on track, so maybe on the same day / conditions they would inspire the confidence to be a little faster.  That said, the Star Specs wear a whole lot better, and you can’t argue with that bang for the buck.

.....so back to that setup question 😂

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34 is higher than most run re71r's.  You usually see targets in the 28-30 range.  I'm guessing too narrow of a wheel (they should be on 8s) isn't helping the cause here.  An 8" wheel should help add some sidewall tension and lead to better lap times and likely better wear as well.  I don't have outer wear issues on my re71r's on my NA. 

Edit, chasing tire wear and alignment settings with spring rates that are likely VERY wrong for the car is kind of a moot point.  A few hundred bucks for some proper springs and bumpstops will go a long way.  

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That’s a good point.  While the car is currently in the air, I might try to take them off and find a redneck way of measuring rate.  I guess I also don’t know much about the damper setup, am I correct in saying guys shoot for 500/300ish as a starting point?

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1 hour ago, Solo_S14 said:

That’s a good point.  While the car is currently in the air, I might try to take them off and find a redneck way of measuring rate.  I guess I also don’t know much about the damper setup, am I correct in saying guys shoot for 500/300ish as a starting point?

Track surface condition dependent, you may be able to get away with spec miata rates (700/350-400) on those dampers.  It all depends.  REs have enough grip that 500# won't cut it in the front.  The more I think about the issue with the rear tires, I'm wondering if you're hitting full compression and essentially forcing the tire to be the only "give" in the setup.  Think auto-x stock suspension with hoosiers lol. 

I run 700/450 on my NA, 205 RE71rs.  Revalved bilsteins and extended rear top hats.  It takes a lot of spring to run low ride heights and very sticky tires on a miata.  I'd be faster on 800/500 but haven't made the jump yet. 

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13 minutes ago, tyhackman15 said:

 The more I think about the issue with the rear tires, I'm wondering if you're hitting full compression and essentially forcing the tire to be the only "give" in the setup.  Think auto-x stock suspension with hoosiers lol. 

 

I was thinking the same thing. That or just extremely low pressures for a few sessions causing the carcass to roll over and die.

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3 minutes ago, Hollywood said:

< Also insert recommendation for RS4s as your next tire here >

I have a feeling I’ll get to try some cooked RS4’s on a better wheel setup in the near future 🙃.  Can’t find them in 205’s

Also just signed up for a Lemons 24hr drive at Houston for November.  Running an NA on 225 RS-4’s as well.  Hope to get some seat time in that thing shortly.

....Also, just picked up these (mix of Toyo RR’s and SM7’s) in 205’s to mess with:

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.....still need to do something with my stash of 18’s that won’t get used on the Evo now as well (think I have a problem)....and to think, I cleaned house at the end of last year before moving down from Canada!

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29 minutes ago, tyhackman15 said:

Track surface condition dependent, you may be able to get away with spec miata rates (700/350-400) on those dampers.  It all depends.  REs have enough grip that 500# won't cut it in the front.  The more I think about the issue with the rear tires, I'm wondering if you're hitting full compression and essentially forcing the tire to be the only "give" in the setup.  Think auto-x stock suspension with hoosiers lol. 

I run 700/450 on my NA, 205 RE71rs.  Revalved bilsteins and extended rear top hats.  It takes a lot of spring to run low ride heights and very sticky tires on a miata.  I'd be faster on 800/500 but haven't made the jump yet. 

Without knowing much about the dampers or springs on this car, kind of thinking a better approach would be to sell these things and buy a SM setup to try those.

Is it true that with Penske’s out this year, there are decent deals to be had on SM setups?

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47 minutes ago, Solo_S14 said:

Without knowing much about the dampers or springs on this car, kind of thinking a better approach would be to sell these things and buy a SM setup to try those.

Is it true that with Penske’s out this year, there are decent deals to be had on SM setups?

What's your goal with the car? Keep it a cheap track toy? You can get SM setups for a decent price, but they're not actually that great in the big picture.  If you don't mind investing some $$ get XIDAs and be done.  Otherwise expect to spend around $400-600 for a used SM setup.  You'll notice they were all "rebuilt last season" lol. 

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Yeah, goal was originally to pick up a cheap track car and get seat time this year - before doing some endurance stuff in the fall (on course so far).

So far the car is what I want at the moment - street legal to drive to and from, cheap to run, reliable.  Could be something I keep to mix track days with some of the endurance stuff.

I won’t be building or modifying this chassis in any real way - don’t really want an “expensive” track day car (think k-swap NB or similar), not really interested in the truck and trailer approach right now (think SM, or Chump, etc.).  So I guess it fits the bill for now.  But if I were to spend any $$ on it, I’d probably go to a cleaner NB, pick a motor swap, and go that route.

So yeah, embrace the crappiness for now 😋

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Stay away from the old Bilstein SM kits regardless of the price. I'd even go so far as saying no to them even it was free. It was hot garbage then but we all had to deal with it because it was spec, no reason to use it now unless you want to learn how to drive garbage and unlearn it all the moment you change off them. If you want simple & non-adjustable with a big market and rebuilds from the factory, the Penske shocks are wonderful (and if you're looking to mirror / gauge to SMs)

 

.....but like he said, Xidas and done if you're looking for dual purpose. They're the end-all for miatas.

 

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4 hours ago, tyhackman15 said:

... I'm wondering if you're hitting full compression and essentially forcing the tire to be the only "give" in the setup. 

Having driven behind this car on track at speed, it is indeed full on compressssseeeddd on the outside and to the rear. Jon, it's like your miata is trying to "high five" the Apex 🙂 I just thought it was that excited.

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Lol, probably explains why it’s sucks up the bumps so well without upsetting the car then too.

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On 7/22/2019 at 12:36 PM, Solo_S14 said:

That’s a good point.  While the car is currently in the air, I might try to take them off and find a redneck way of measuring rate.  I guess I also don’t know much about the damper setup, am I correct in saying guys shoot for 500/300ish as a starting point?

Well.....this is why I shouldn’t have beer and free time.  Looks like a ~375# in the front?

As you can imagine, tough to keep everything centered....I figure the averaging around the spring over the 5 measurements is close enough to know whether it’s a 200ish rate, or a 400ish rate...

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On 7/22/2019 at 5:23 PM, Hollywood said:

Stay away from the old Bilstein SM kits regardless of the price. I'd even go so far as saying no to them even it was free. It was hot garbage then but we all had to deal with it because it was spec, no reason to use it now unless you want to learn how to drive garbage and unlearn it all the moment you change off them.

 

(Hollywood, I think I have “Hot Garbage”....stay tuned 😂):

The rear was considerably worse in terms of deformation (“bending” rather than compressing) with my dodgy press and bathroom scale setup.  You can tell by the spread of values.

So something like a 375/275 F/R setup on “Spec Miata” HD’s? (F4-B46-1488-H1) stickered Fronts / (3202B46 1489H0) stamped rears.  If the rears had a sticker, I assume it would be the (F4-B46-1489-H0).

So will this hot garbage accept a ~375# in the rear and a ~500# up front??

 

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These springs were also 5.5” and 5.25” free length.  I think I’ve seen anywhere from 6-8” recommended.  Are these too short to even re-use the front 5.5” spring on the rear?

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I might harvest my Evo KW V3 springs to mess around next weekend.  Pretty sure the front springs on those are printed 80-200 (80 N/mm = ~450#), (200mm length = ~7.875”).  Run those up front.

Then take the 5.5” ~375# spring from the front of the Miata and run it in the rear to see how it behaves with the higher rates.

If it feels decent, I guess I can look into properly sized ~7” springs.  I’m not sure what the travel / block height looks like on the 5.5” springs.  Maybe they get like 3” of travel, vs ~4” of travel that a proper ~7” spring would get before blocking.  I could always run the KW helper spring to just space the block height out another ~1” but I guess that doesn’t gain me anything.  If the rates feel decent, I can step up to a proper length spring and gain the extra rate before riding the bump stops around.

Curious to see how the dampers like it, I know SM rates are really low, but I’ve also “read the forums” where guys claim that the Bilsteins were always overdamped, and guys claiming that they run pretty high rates instead of relying on the bump stops, and they feel fine.  Guess there’s only one way to feel them out...

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You'll get closer, but you still don't have enough spring for the amount of grip.  700-800# is what you need in the front if you're looking for the best performance and proper tire wear.  But again, 500/375 will be better than what you have now (which is presumably whatever rate your bumpstops are, since you're cornering on them lol).  Run a higher ride height to help keep some roll resistance and get as much travel as you can.  Think like 5.5" pinch weld height. 

 

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problem with the Bilsteins is they are UNDERdamped.  They're a performance street shock designed for spring rates way under what SM is using.

so to reduce body roll and keep the cars from bouncing off the top of the shock, SM used stiff springs and beefy bumpstops.  

also with the single tube damper as it is, heat buildup and performance degradation over a session was noticeable.  the shocks got softer as the race wore on and heat built up...

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Lets see see if this thing fits.  I think it’s going to be pushing it on length.  Thinking lowest height setting + it will raise ride height a little.....if I can squeeze it on there.

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Just to keep everything documented in one place, I’ll note that the front Evo springs were “80-170” not “80-200” as I thought.

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Time to put this other hot garbage back on the Evo.  They’ve seen some Canadian winter...

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