The commercial stuff seems extremely overpriced, so my plan is to get one of these:
https://www.amazon.com/PerfectPrime-K-Type-Sensor-Probes-HeadProbe/dp/B07PY3KSRN
and one of these:
https://www.amazon.com/Proster-Thermocouple-Thermometer-Dual-Channel-Thermocouples/dp/B071V7T6TZ/ref=pd_lpo_sbs_328_t_1?_encoding=UTF8&psc=1&refRID=X55CQ73XFYDTEDJ4E7PE
And save myself $100. IR thermometers only measure the temperature of the tire surface - the temperature at the belts is really more representative. Since the tread temperature gets quite a bit of convective cooling, they will have cooled off a lot by the time you get pulled into the pits, jump out of the car, measure temps, etc. Most manufacturers will post a target temperature when measured this way (180-210F usually)
morello159 said:
The commercial stuff seems extremely overpriced, so my plan is to get one of these:
https://www.amazon.com/PerfectPrime-K-Type-Sensor-Probes-HeadProbe/dp/B07PY3KSRN
and one of these:
https://www.amazon.com/Proster-Thermocouple-Thermometer-Dual-Channel-Thermocouples/dp/B071V7T6TZ/ref=pd_lpo_sbs_328_t_1?_encoding=UTF8&psc=1&refRID=X55CQ73XFYDTEDJ4E7PE
And save myself $100. IR thermometers only measure the temperature of the tire surface - the temperature at the belts is really more representative. Since the tread temperature gets quite a bit of convective cooling, they will have cooled off a lot by the time you get pulled into the pits, jump out of the car, measure temps, etc. Most manufacturers will post a target temperature when measured this way (180-210F usually)
I'm going to copy your plan. I may even get this 4-channel probe so that eventually I can build a rig to take temperatures across 4 spots on the tread at once:
https://www.amazon.com/Thermocouple-Thermometer-RISEPRO-Channel-200-1372%C2%B0C/dp/B07D9JF5SD/
captainawesome said:
I also wonder how much a stretched tire effects the wear? These are 235 40 18 on a 9.5" wide rim, with the next ones will be jumping one size up to a 245 40 18.
That's pretty skinny. I'm running a 275/35-18 on a 9" wheel. If you want a grunch more grip, throw as much tire on it as you can.
In reply to morello159 :
That is how I arrived at my final set up. Helps wit pressures too.
In reply to captainawesome :
It's relative as long as you are consistent.
In reply to Toyman01 :
It is a bit skinny, mainly because my biggest issue is clearance. I bought the car with a set of 235/40/18's, and they rub at full lock on the inner fender liner up front. I'm taking a chance the 245 isn't much worse at this point.
My future track set will just be 17x9 as that's the common size for most track or autocross wheels for the 86. Also tire cost is way more manageable at a 245 40 17. From what I gather, going up to a 265 and up won't really gain any time without the power to roll them around on the FRS. I'm at ~200hp to the rear wheels on a good day, so I need one of them underhood whistles to justify that sort of rubber.
As a counterpoint, I run a 225 on my 15x9" Miata wheel. Someone (may have been GRM actually?) did a 205 vs 225 on 15x7, 15x8 and 15x9 roundup a while back and found that the 225 on a 15x9 was fastest and most consistent.
Also, we messed with making a multi-point tire probe, but it was difficult to place on the tire accurately and also push the probes in. It didn't end up saving any time, and you'd have to build in some kind of adjustability if you ever wanted to use it on a different tire size.
captainawesome said:
In reply to Toyman01 :
It is a bit skinny, mainly because my biggest issue is clearance. I bought the car with a set of 235/40/18's, and they rub at full lock on the inner fender liner up front. I'm taking a chance the 245 isn't much worse at this point.
My future track set will just be 17x9 as that's the common size for most track or autocross wheels for the 86. Also tire cost is way more manageable at a 245 40 17. From what I gather, going up to a 265 and up won't really gain any time without the power to roll them around on the FRS. I'm at ~200hp to the rear wheels on a good day, so I need one of them underhood whistles to justify that sort of rubber.
235/40/18 and the 245/40/18 are too tall for the 86 and your offset is likely wrong.
An 18x9.5 ET 38 (the size/offset Enkei specifically designed for the twins) with 255/35/18s will fit easily with no rub, lock, or anything on the twins. No need to roll fenders or anything. This is the setup I ran on my BRZ with Star Specs.
As for 245 vs 265.......depends on your track.
In reply to z31maniac :
These are et40 so in the ballpark. As far as I understand these were a custom offset for the 86, but there's potential I'm wrong about that. I'm not rubbing anywhere unless it's at full lock, so the only time I have the issue is at tight autocross courses or parking lot shenanigans. I had zero issues at Hallett. I don't know how you got lucky with no rubbing, but I'm not the only one who has had this issue. Maybe that 2mm is just enough?
They are taller, but they are also $75+ cheaper per tire than the 255 35 and the gearing is nice for autocross. Personally I like the look, but understand it's not ideal. The plan from the beginning has been to get a set of 17x9s for autocross and track. The 18's will be my purty dancing around town shoes. As for 245 35, there isn't any tires in that range that are 200tw but the 265 is a thing. The 265 is basically the same diameter as the 235 40 but 3 pounds heavier. I guess that's not as relevant though, as the 245 supposedly weighs the same as the 265.
Did you ever run your BRZ at Hallett? Curious what times you were running if so. I have only been once on the clockwise direction and managed a 1:37.45 with these tires. I think there is a second or two left on the table too.
No, never got to run the BRZ at Hallett.
Years ago before it was repaved, 2013, I was running 1:36s in a 1.6 Miata with years old R888s.
Toyman01 said:
captainawesome said:
I also wonder how much a stretched tire effects the wear? These are 235 40 18 on a 9.5" wide rim, with the next ones will be jumping one size up to a 245 40 18.
That's pretty skinny. I'm running a 275/35-18 on a 9" wheel. If you want a grunch more grip, throw as much tire on it as you can.
From my testing in champcar and lemons races, a 245 on a 10 is about perfect. The wider tire than rim situation makes the car lose feel and creates more squirm.
Longacre has a refurbished catalog that often has temp probes for sale for around 100$.
wvumtnbkr said:
Toyman01 said:
captainawesome said:
I also wonder how much a stretched tire effects the wear? These are 235 40 18 on a 9.5" wide rim, with the next ones will be jumping one size up to a 245 40 18.
That's pretty skinny. I'm running a 275/35-18 on a 9" wheel. If you want a grunch more grip, throw as much tire on it as you can.
From my testing in champcar and lemons races, a 245 on a 10 is about perfect. The wider tire than rim situation makes the car lose feel and creates more squirm.
Longacre has a refurbished catalog that often has temp probes for sale for around 100$.
This, 275 on a 9" wheel is way narrow. As mentioned, the Miata guys learned years ago to put R-Comps and 200TW tires on wide wheels.
My own track rat had 205 R888s on 8" wheels. Some guys run 205/50/15 Hoosiers on 9" wheels in the Miata world.
In reply to wvumtnbkr :
I've read a general rule of thumb is to keep the rim width equal to tread width, but also have read from a ton of Miata guys that a slight stretch will yield better feedback/control which probably accounts for better times. I think it may depend on the tire and car setup, but without testing I couldn't verify or deny either suggestion. I'm hoping with the amount of seat time I've had in my car currently with the 235 that I'll be able to judge the 245 performance difference. It's not a large jump though so may not mean squat, but at least I'll know if the extra cost is worth it.
Also, I found a Joe's Racing one on ebay for $72.65 shipped with a digital tire tread gauge thrown in with it. Hoping it's here before Saturday.
In reply to captainawesome :
How hard are you attacking the curbs at Hallett? When you go counter-clockwise "the normal direction" your butt (literally where you sit) needs to be on top of the curb in 1. And going that direction, I don't agree with the "instructor line " for 4-5. And you really have to "send it" over 7-8 into "The Bitch" always more grip there than you think.
For clockwise, I feel, the most important areas are how late you wait to get on the brakes going into "The Bitch", how well you get out of 2, and how well you attack 1 for the long run uphill.
In reply to z31maniac :
Not that aggressive. Since it was my first time out, the first session I rode with an instructor while he drove my car. The second session I had a different instructor ride with me. My 5th session was with another instructor riding with me. All in all my fastest laps were when I was solo. I could focus better on what felt right and begin to work my line a bit. I should be in a different group this next trip out, so hopefully spend less time waiting for a point by.
I was able to get "the bitch" entry pretty decent quite a few times. Even though it is a blind entry, the braking zone is still a good indicator for placement, but I still have room for improvement. Turn 2 I was pretty consistent on entry/exit but always getting wadded up with traffic just right before I could get back on the throttle killing momentum. I felt like each lap I continually underestimated how much speed I could carry through 1 up the hill. Turn 10 I was best off with a double apex only to be stuck with traffic again back into the bitch.
In reply to captainawesome :
Sounds like you're already getting to know the track well! I was lucky to have a serious professional driver as my instructor one day I was there (Kristin Traeger)..........I picked up a ton of speed very quickly once she showed me what my car could do on the brakes and in the corners.
That blind entry to 9 going clockwise is definitely a pucker factor the first few times you do it. I'll have to see if I can find the pictures, there was one lap where I totally boned it with an instructor in the car with me. Dropped the right rear off the curb, kept my foot in it, my instructor just said, "Good job, you didn't lose it. Keep going." And the photographer happened to get a nice 3-4 shot sequence of me boning the corner, dropping the wheel off, and back on track.
In reply to captainawesome :
Going the "normal" direction going into "the bitch" is actually where I wrecked on my sport bike years ago. Went wide in 7, caught the curbing at 8, couldn't get it shut down and turned into 9 before going off track.
In reply to z31maniac :
I'm trying to. We are running clockwise on my next outing again so at least I can see how much I remember. Going to strap some gopros and a 360 camera to get some footage to go over afterward. Maybe some veterans can pick apart some of my laps to help reel in some more time. Next year I'm hoping to get out there at least once every couple months.
Hopefully the bike wreck wasn't too serious. I've always wanted to put a bike on track, but never got around to it.
In reply to captainawesome :
Definitely watch Emilio's lap around Hallett (other direction from what you'll be doing, but my own lap times say his line into 4-5 is the better approach if you have the grip).
Unfortunately, the bike wreck was kind of serious. I was unconscious long enough they stopped that particular session, so of course my buddies were giving me a hard time about ruining their track time, post-concussion syndrome and still a bit of an awkward walk 12+ years later. Touched every piece of plastic on the bike, broken subframe, clip-on destroyed the tank, etc.
But I'm still walking and talking, so perfectly OK with that.
I'm currently running 225-45/17 Firestones Indy 500s on 7 inch wheels. The Tires get rotated and removed after every event. So far so good. If you don't mind doing that after every event, should last a very long time.
