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-   -   Is this normal tire wear? (225 rs3, xidas) (https://www.miataturbo.net/race-prep-75/normal-tire-wear-225-rs3-xidas-97754/)

less 08-12-2018 03:07 PM

Is this normal tire wear? (225 rs3, xidas)
 
Did my first track day yesterday at thunderhill, and checked my tires (225 RS3s) afterwards to find this. 3 of them look fine, but the front right looks way more ripped apart than the others. Granted the track was ccw so more left turns than right.

Alignment was set to 949 dual duty when I first put the tires on. Tires have ~13,000 mi on them, and are just over 2 years old. Before this I’ve done a few autocrosses on these tires

Unfortunately I did not check pressures or temps beforehand or during..

Is the wear on the front right normal? Here’s a pic:

https://cimg2.ibsrv.net/gimg/www.mia...21e30a2fe.jpeg

Here’s the other 3 tires:
https://cimg4.ibsrv.net/gimg/www.mia...544d81ce1.jpeg
https://cimg5.ibsrv.net/gimg/www.mia...ce55629be.jpeg
https://cimg7.ibsrv.net/gimg/www.mia...9b8f2b706.jpeg

thumpetto007 08-12-2018 04:55 PM

I think this is impossible to answer. You have driven a long time on that alignment, it could have changed from potholes, curbing, loosening of bolts, bushing fatigue...

You dont have tire pressure readings.

you dont have pyrometer readings.

Plus a bunch more variables i'm too stupid to think of. Get a pyrometer, check alignment, tire pressures, then you can know if your tire wear is appropriate.

less 08-12-2018 05:23 PM

Thanks for the response, I’ll make a point to check pressures and temps next time. Sounds like it may be worth getting it re-aligned as well..

You guys think this tire is safe to drive on the street until I get new ones (which I’ll try to do soon)?

I’m considering just getting new fronts (RS4s) and leaving the rears as is, unless this is a stupid idea? I assume the worn tires have less grip than new ones and I’d prefer somewhat less grip on the track while I’m still learning, hence only replacing the fronts due to the extensive wear on the one tire

Wingman703 08-12-2018 07:28 PM

If your learning you really shouldn't be on a 200tw tire anyway... find some crappy all seasons to learn on so your not destroying "nice" tires like seen above. Move to stickier tires once you have a handle on things.

Blkbrd69 08-12-2018 07:59 PM

Tire pressures first and always.

Check toe.

mx5-kiwi 08-12-2018 09:39 PM

I would reiterate what the others have said...

Persoanlly I think your crazy not doing presures, close but under making sure you have fresh, high temp brake fluid.

They are that critical IMO to,

A/ a good time (as in fun)

B/ a good time as in lap time.

C/ to a certain degree, safety.

less 08-12-2018 10:21 PM


Originally Posted by Wingman703 (Post 1496143)
If your learning you really shouldn't be on a 200tw tire anyway... find some crappy all seasons to learn on so your not destroying "nice" tires like seen above. Move to stickier tires once you have a handle on things.

Yeah, unfortunately I learned this more recently and I don't even have the stock wheels to throw some all seasons on anymore. Doesn't seem to be many crappy choices in the 225/45/15 size to fit my wheels. I did get to do some autocrosses a couple years ago with the stock wheels and balding all seasons which helped me learn some car control, but no track days..



Originally Posted by Blkbrd69 (Post 1496147)
Tire pressures first and always.

Check toe.


Originally Posted by mx5-kiwi (Post 1496159)
I would reiterate what the others have said...

Persoanlly I think your crazy not doing presures, close but under making sure you have fresh, high temp brake fluid.

They are that critical IMO to,

A/ a good time (as in fun)

B/ a good time as in lap time.

C/ to a certain degree, safety.

Noted, I'll be checking pressures next time. I'll also work on getting a compressor to bring, and will search to see what psi people recommend running



I also realized after looking at the tires again that what I was thinking was some sort of delamination is actually just the difference between my actual tires and the rubber that I picked up on the track, so they aren't quite as torn up as I initially thought (though they are clearly quite worn)

On that note - do you guys usually peel off the rubber from the track to remove it from your tires after a track day (particularly if it is a dual duty car)? I imagine it would just throw off the wheel balance to leave it on (among other things maybe)

Thanks for all the info

moocow 08-13-2018 12:59 AM


Originally Posted by less (Post 1496168)
On that note - do you guys usually peel off the rubber from the track to remove it from your tires after a track day (particularly if it is a dual duty car)? I imagine it would just throw off the wheel balance to leave it on (among other things maybe)

Just drive them, they'll clean off any buildup after a bit. I will clean out the rubber on the inside of the wheel once I get home and clean the brake dust off the car.

Your Drunkle 08-13-2018 09:47 AM


Originally Posted by less (Post 1496168)
Noted, I'll be checking pressures next time. I'll also work on getting a compressor to bring, and will search to see what psi people recommend running

I use a harbor freight tank with like 100 psi in it. I have never had to refill at the track or autocross it but if you do I'm sure someone at a track day will be ok with helping you out. Save the money.

As for pressure, you will need to find out for yourself. I'm no expert but this is what seems to work for me at the HPDEs I've done. I would start around 32 psi hot (I check as soon as I get back to the pit). From there you will want a tire marker (or any paint marker) to mark the edges of your tires and adjust until you are wearing the tire to the very tip of the triangle on the side. It will look more or less like this:
https://f30.bimmerpost.com/forums/at...1&d=1507059477

engineered2win 08-13-2018 09:33 PM


Originally Posted by Your Drunkle (Post 1496238)
I use a harbor freight tank with like 100 psi in it. I have never had to refill at the track or autocross it but if you do I'm sure someone at a track day will be ok with helping you out. Save the money.

As for pressure, you will need to find out for yourself. I'm no expert but this is what seems to work for me at the HPDEs I've done. I would start around 32 psi hot (I check as soon as I get back to the pit). From there you will want a tire marker (or any paint marker) to mark the edges of your tires and adjust until you are wearing the tire to the very tip of the triangle on the side. It will look more or less like this:
https://f30.bimmerpost.com/forums/attachment.php?attachmentid=1699677&stc=1&d=150705 9477

The triangles on the sidewall denote the location of the tread wear indicators. They have nothing to do with the useable tread limit of the tire.
You need to monitor tire carcass temperatures and hot pressure.
Adjusting tire pressure to increase/decrease contact patch is pointless. Things like alignment and spring rate/damping have much more affect on how the tire's contact patch is utilized.

Your Drunkle 08-14-2018 03:26 PM


Originally Posted by engineered2win (Post 1496374)
The triangles on the sidewall denote the location of the tread wear indicators. They have nothing to do with the useable tread limit of the tire.
You need to monitor tire carcass temperatures and hot pressure.
Adjusting tire pressure to increase/decrease contact patch is pointless. Things like alignment and spring rate/damping have much more affect on how the tire's contact patch is utilized.

My advise is just based on what some more experienced guys have told me and what seems to work. What would you recommend doing for someone who is new and not turning consistent lap times regardless of set-up? Monitoring hot pressures won't help if you don't have something to shoot for and wont be able to tell based on lap-times what is and isn't working. Most novices will not have a pyrometer. Would watching carcass temperature with a laser temp gauge (like the cheap ones from Lowes) do any good? And again, what are you looking for?

mx5-kiwi 08-14-2018 03:41 PM

You dont have to go that crazy and cart around a compressor. A tyre pressure gauge and a foot or MTB pump will work fine.

Initially you want to ask around when at the track to find out what other more experienced people are running as their hot pressures for the same or similar tyre.

You pretty much just letting a couple of psi out OR pumping a couple of PSI in to achieve these hot guide pressures (air compressor is overkill for such fine tuning). As you get more experience you will come to understand and see by simply looking at the tyre, what is a good range for you, your driving style and the tyre.

Down here we find 30-32 hot is about right, I notice some of you guys run a bit higher but our tyres tend to ship in softer compounds than yours. For us a starting point of 24-26 cold is often in the ballpark.

Infrarred gun isn't ideal BUT it can give you a rough idea of whats happeing and more imprtantly get you in the habit of actually taking note of whats happening for when you do buy a pyrometer. Amazon sell the longacre and Joes Racing products pretty reasonably, thats where i got mine from after a few years with IF gun.


I've started using an Orange branded TPS system (also from Amazon) for a pretty accurate PSI reading and puncture alarm while racing.


cwatson 08-17-2018 05:14 PM

  • Assuming your pressures and alignment were reasonable (which isn't clear): no, that is not normal tire wire. However, a lot of it looks like other people's rubber (OPR)..are you sure it's from your tires?
  • edit- I reread and noticed you recognized a lot of it is OPR - leave it on at the track but doesn't hurt to take off the easy bits before leaving the track - the imbalance is more of an issue than any change in grip.
  • Overheating usually results in small chunking of the treads followed by delamination, where the softer tread block material separates from the harder base layer.
  • A good tire gauge, small pump/tank, and pyrometer cost about as much as one tire
  • Last we tested on our Champcar (GWR E30), we settled on 35 psi hot with 245 RS4s (R15x10, 2550#, full aero, 160whp) and run about 20°F gradient across the tread width, with the insides measuring hotter. Run less gradient across the tire to improve wear at the expense of grip. The tire will wear the inside slightly more when tuned for the quickest lap time.
  • Ensure toe is correct (I'd guess near zero in a near stock power Miata on a road course, but refer to 949/TSE...) before looking at temperatures. Excessive toe with some camber will heat the inside of the tire.
  • Your pressures are in the ballpark when inside-middle-outside temps form a straight line (that is, M-I = O-M) or the middle is slightly above line formed by the inside and outside of the tire. If the middle temperature is lower, raise pressure. If the middle temp is higher, lower pressure.
  • Once your temperatures and pressures are in the ballpark (say, +10,+5,+0°F I/M/O), play with them one axle at a time and focus on balance changes to judge improvements in grip from the tire tuning change. Complete lap time for a new driver in a track day environment isn't a reliable metric.
  • Once you know your targets - easiest to start high and bleed off - this usually works okay because you want the highest cold pressure on the street and the track/driver heat up over the course of the day. Refill at the end of the day.
-Chris

https://www.facebook.com/GuarinoWatsonRacing/

dc2696 08-17-2018 10:22 PM


Originally Posted by less (Post 1496120)
Is the wear on the front right normal? Here’s a pic:

Front Right looks like you have a lot of hard lefts, or not enough camber, and the rubber is piling up on a section of tire that isn't getting worked hard enough to get pulled off again.

Next event make you not only check your pressures but write them down or keep a log (Track conditions; hot AF/cloudy, morning or afternoon session, # of heat cycles on the tires) it might be excessive but you'll learn how to dial in tires a bit quicker this way.

Something else to consider is flipping tires as well as rotating them to get the most use out of a set.

As for peeling the rubber off, I usually do a few scrubs on the cooldown lap to try and knock off anything loose, other than that stay out of the marble build up.

flier129 08-18-2018 11:08 AM

Those RS3s look great for 13k+ miles on them.


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