Targa Miata
MIATA BUILD
May 15, 2007 - As part of a discussion on tools to carry on the Targa Newfoundland message board, it was recommended that we carry a spare tire.
I hadn't been planning on it because, well, that's an extra 30 lbs or so that I didn't want in the car. But it might be a very useful 30 lbs.
The first step, of course, is to see if we actually can carry a spare. Uhoh.
entry 176 - tags: tires
May 15, 2007 - The tire in the previous picture was a 225/45-15, the tire size I'm favoring for the race.
This is a 205/55-14, identical in size to my second-choice 205/50-15. In a number of competitions, I've walked away swearing I'd never want for rubber. But the smaller size is 3 lbs lighter (rotating unsprung mass, the worst place for it) and, as you can see, it fits in the trunk. The larger rubber will fit in the trunk if I make some small alterations to the sheetmetal though.
Some advise against running too much tire in the Targa for more resistance to hydroplaning and more grip on gravel, but even a 225 is a smaller tire than a lot of cars will run. I want the sheer mechanical grip of the larger tire. According to Toyo's measurements, the 205 has a tread width of 8.4" when mounted on a 6.5" wheel. The 225 has a width of 9" on a 7.5" wheel. We'll have 7" wheels, but how much of that extra width comes from the extra wheel width? So many questions.
entry 177 - tags: tires
May 16, 2007 - More tire thoughts.
I spent some time on the phone with Joe Woodward, a fellow racer who just finished the One Lap. His day job sees him at the Tire Rack and he used to run Spec Miata, so he's very well suited to answer questions.
He noted that in direct comparisons between the 225/45-15 and 205/50-15 RA-1s, the smaller tires were actually faster on a Spec Miata. This could have been due to lower rolling resistance, as Specs are relatively low-powered cars. But he reports that the car is easier to rotate with the smaller rubber. This could also be a power-related artifact of course. Still, between the lighter weight and these reports, perhaps I should rethink my 225 obsession.
Other tire suggestions were the Yokohama A048 and the Michelin Pilot Cup. They're both considerably more expensive than the RA-1, but it's worth investigating.
entry 178 - tags: tires
May 23, 2007 - Okay, the wedding is out of the way.
Some good discussion on the Targa forum has reinforced my decision to run the Toyo RA-1 or possibly the upcoming R888. We'll see about the latter, availability may be a problem as it's a brand new tire for North America.
Over the course of the wedding weekend (essentially a 4-day BBQ with a short ceremony stuck in the middle), Eric got a chance to see the Targa Miata for the first time. Good news, he fits in the co-driver's seat and I was able to sort out the location for the footrest.
Time to get back to work.
entry 179 - tags: tires, ergonomics
May 26, 2007 - I got an email from Ander Tenno about tire selection.
He's tried both the R888 and the RA-1 on his car in the past, and here's what he has to say:
The short summary is this: the RA-1 gives up very little grip in optimal circumstances (~20-25 C sunny weather with heat in the tires) to the R888 while being significantly better in the wet and when the tires are cold. If the RA-1 was still available in Europe, Id be still using those.
It certainly sounds as if the RA-1 would be the better choice for the Targa! Thanks so much for the feedback, Ander!
entry 182 - tags: tires
June 16, 2007 - So, after a final wander around the car, Brandon and I bolted on some wheels.
Okay, in the rear we fixed the alignment of the brake lines, then we bolted on some wheels and lowered the car to the ground.
It's funny. I work around Miatas all day. There's another one in the garage parked by the Targa car. But as we dropped the white Miata down on to the ground, it looked smaller. Much more compact than its usual stance of being nearly 2' in the air, that's for sure.
The suspension currently consists of "whatever I could find sitting around", and I suspect the rear springs came out of a late 1996-97 car while I know the fronts are from a 1990. There's a bit of rake going on. It doesn't matter, the car rolls and suspends. Its best angle is from the rear quarter, where the white roll cage is most obvious.
The wheels are a +30mm offset with 225/45-15 tires. I'll be running +20 offset with 205/50-15 tires, so the outer edges of the tires are in the correct place with this setup. The car looks good. Very white.
entry 213 - tags: tires
July 1, 2007 - I spent the weekend working on another Miata.
Janel's little supercharged Miata is now turbocharged. The operation was a great success.
But that doesn't mean the Targa Miata was completely neglected. The new tires (Toyo RA-1 in a 205/50-15 size) came in so I had them mounted up. The wheels are some white SSR Competitions. Hang on, they never came in white! Ah, but they did in Japan. These date back from a previous race effort that was sponsored by SSR Japan. They're a custom 15x7 with a +20 offset, and are perfect for this application. The fact that they have a little tricolor stripe that happens to match the Martini colors is simply icing on the cake!
entry 228 - tags: tires, other cars, Martini
July 1, 2007 - Wheel weigh in time.
The white wheel is the race setup. The graphite one is a Kazera KZ-M with a 225/45-15 RA-1. The weight difference? Just over 5 lbs! The white SSR package showed up between 28 and 29 lbs on the scale, the KZ-M was a solid 34. Not bad, but that extra 5 lbs is significant.
entry 231 - tags: weight loss, tires
November 4, 2007 - An unfortunate finish to the day.
Bill took the Targa car out to see how it was working, and I borrowed his Westfield. The little car was working beautifully and I was quicker in it than I had been in the Miata. With 700 lbs less weight and only a bit less power, that's not a big surprise. Bill wasn't lagging too much, though, and some slower traffic bunched us up. Shortly after getting free, we entered turn 5, the best turn on the track. It's like a baby version of Eau Rouge, as one driver pointed out - an uphill corner with a nice compression at the bottom and a blind exit. Very entertaining and nicely quick. I came out of the series of bends and noticed Bill was gone from my mirrors - and there was a big cloud of dust on the inside of 5 with a Miata shape inside. The car had stopped just short of a flag station and tire wall.
Back in the pits, we saw the typical damage for an off-track excursion around here - one tire pulled off the wheel and another with grass jammed in the bead. There were some scuff marks and scratches on the nose as well.
We pulled the wheels off and headed for the local Discount Tire. I was still wearing my driving suit, and when I got out of the truck a little kid asked "are you a racing car driver?". Not really, but I'm trying!
The staff at Discount were really helpful, getting right to work despite the fact that it was the middle of a busy Saturday. They pulled off the tires, vacuumed them out (to our great amusement) and reseated them in about 4 minutes. Then we were called in to have a look at the balancing machine. One wheel was wobbling badly. There are custom-made SSRs and can't be replaced, nuts. It's a good thing that I have access to a total of 8-12 of them.
Oh well, we figured we'd see how it felt. After all this, the tire shop didn't even charge us! Note to self, always wear Nomex to a tire store. Thank you Discount.
Back at the track, the tires went on and I headed to the track for some gentle exploratory laps. Heading down pit lane, I noticed that my steering wheel was off center. That was it, I headed for the trailer. Between a potentially shaky wheel with some damage and unknown suspension problems, it was not time to go push hard.
Nothing was obviously bent under the car although it appears one of the caster adjustment cams might have slipped. I didn't get the chance to mark the suspension settings before loading on to the trailer, unfortunately, and this simple change may account for the steering wheel offset. I'll check that out shortly. The paint damage is all on the lower half of the front bumper and should be easy to fix.
A sad finish to the day, but nothing that can't be repaired fairly easily and nobody was hurt. We never did figure out exactly what happened to cause the off, from looking at tire marks I think the car simply ran out of grip, possibly brought on by a slight crest in the track there. This is why we test on the track instead of the road, though!
entry 336 - tags: testing, other cars, tires, crash
July 25, 2008 - A big yummy stack of Toyos arrived today.
Yup, those are the race tires. I'll mount them up and scrub them in, then stash them away to await the trip to Newfoundland. Right now, I'm trying to pace the wear on the current tires. There are three track days and an autocross between now and the race, and I want them to wear out on the last lap of the last track day. I'd hate to pull off a set of tires that still have life in them. Right now, they're in great shape.
entry 500 - tags: tires
September 22, 2008 - The Toyos worked out well.
The RA-1, of course, is a very friendly tire that doesn't surprise the driver at the limit. I drove well within those limits over the week, with a couple of exceptions where I took advantage of every bit of grip available to me.
In the wet, the car was great. It's almost a shame we didn't have more wet stages, as it turned out that we were very competitive under those conditions. I don't have much wet weather racing experience (and all of that came over the course of the Targa!) so I was quite reassured at how well the car worked there.
The R888 tires might have been stickier and I certainly saw them on a number of cars. Tire wear wasn't an issue for us at all, so they'd be a good option. I'd want to know how they work in deep water first though.
entry 608 - tags: post-race, tires
October 15, 2008 - These tires have all seen three days on the Targa plus an autocross.
They look good enough for another year! I have race tires everywhere in the garage now - the six Targa ones plus the four I used for testing.
entry 636 - tags: tires
January 14, 2009 - There was an announcement of a tire rule change for the Targa in 2009.
R compounds - such as my Toyo RA1s - are no longer allowed. In fact, the tires must have a wear rating of at least 200, which gets rid of a range of popular sticky street tires such as the Falken Azenis and the Bridgestone RE01R. There's an exception for cars built before 1950 and those with stock 10" tires. The number of tires available to be used for the event has also jumped from 6 to 8, although with the harder required rubber that's not a big deal.
This means I'd probably end up running on a Hankook Ventus R-S2, although I haven't done a big search for other options. It would also make it much harder to meet the target times, which is probably the goal. Is it an improvement? Well, it's certainly a change.
entry 646 - tags: tires, regulations, 2009
September 5, 2010 - Whoops.
I figured out what was wrong with the car yesterday. Yesterday morning I'd set the tire pressures and found them a bit low. At one point during the day, I tried pulling a bit of pressure out just to see how it worked. It seemed to get a bit better but I was still chasing the handling.
Just to confirm, I went back to my notes to see what the hot pressures should be - and I'd mistakenly set the cold pressures about right for the hot pressures! Even better, it was cool that morning and the day got pretty darn hot - up to the mid-90s. So that explains what was going on. On the first, relatively cool session I was probably pretty much dead on until the tires started to take temperature. And my second lap was the fastest. On later ones, as the track got hotter and I started taking more aggressive warmup laps to get heat in the tires, they were getting badly over-inflated.
I've dropped the pressures down to my usual track starting point now. We'll see how well it does at the track this weekend. I suspect much better! Boy, is my face red.
entry 762 - tags: tires, handling
June 17, 2011 - The tires are here!
Long-time readers may remember the decision process for the tires in 2008. I finally went with a 205/50-15 Toyo RA1, and I'm happy with that.
But the rules have changed. Specifically, all tires must have a minimum treadwear rating of 140. That means no more nice sticky R compound tires. This leaves me with what I call the "Azenis class" of tire, the gummy street tires designed for autocross. We are allowed to run 8 tires this time instead of 6. Given the ability of this car to spin the wheels, that may not be a bad thing.
The tire size was fairly easy this time around. With my new power/weight ratio, I want as much tire as I can get. And in the stock tire diameter, that means a 225/45-15. In that size, I have the choice of two tires: The Hankook R-S3 and the Toyo R1R. I'd love to be able to run the Dunlop Star Spec, but it's simply not available in the size.
Asking around, it appears the Toyo is a better tire in the wet and possibly overall. So, 225/45-15 Toyo R1Rs it is! I like to call them "pirate tires". Arrrr!

There actually were a couple of other options out there. The Toyo T1R comes in a 245/35-16, but that's not the right tire for the job. The R1R comes in a 245/35-17 that could work, but it needs a 17x8 wheel at minimum and preferably something wider - which isn't really available. So we're going with the light and tested setup we have.
entry 863 - tags: tires
July 11, 2011 - Yup, that one's done.
That's not just cord you can see, but steel belt. In three places.
entry 870 - tags: tires
July 13, 2011 - Check out the race wheels!
It's a pretty cool looking car with the crazy Toyo R1-R tread pattern and the white wheels. The ride height is set fairly tall as well, to give me room to deal with the roads. Right now, it's at 13.5" front and 14" rear. Current spring rates are 550 front and 450 rear. That's a fairly high rear spring rate, but this car has always needed more rear spring than usual for some reason. It could be the way it gets used! Normally, I'd use a 375 or so to match those fronts. There's a V8 customer car at FM with that exact setup and it's a sweetheart.
On the road, the suspension feels pretty good. The car hasn't been aligned since the ride height increase and a changed lower control arm, so I've not gone far. But it does seem to have the right suppleness I need. One thing I've learned about the AFCOs since the 2008 race is that they love stiff springs. It's almost as if they ride better with the heavy springs than they do with the light ones as you move into the higher damping settings. I'm looking forward to running this car at speed.
I've also moved it to my home garage for a while. I find it easier to work on the car at home instead of staying late at work. That's the theory, anyhow. I've got a good list of jobs to do on the car. Little stuff, but it still needs to be done and it all adds up.
Driving the Targa Miata and the LS1-powered MGB back to back also illustrates that I need to spend more time tuning the Miata's engine. It doesn't feel anywhere near as strong as that MG does, despite a similar weight on the two cars.
entry 874 - tags: suspension, wheels, tires
July 25, 2011 - Lots of little work on the car.
This oil light, for example. It's bigger and brighter than the old one, which didn't survive the disassembly process. The Revlight has been recalibrated for the new engine's redline. There's a power jack mounted in the car now so I can easily plug in things like laptops and phone chargers should the need arise. I'm working my way through a long list of things to do.
I did find out that my tire pressures were too high on the weekend. It turns out the R1R really doesn't need much pressure, and a number of people suggested dropping them to around 27 psi cold or so. I had them at 31 based on some feedback from an autocrossing friend, but his narrower tires may have been a factor. Regardless, I'll be back at the track doing some pressure testing in the next little while.
entry 883 - tags: tires, instruments, ergonomics
July 29, 2011 - I've been reading up on the Toyo R1R tire a bit.
Apparently the reason they were so greasy last week was that I had the pressure too high. They like surprisingly low pressures. I started at 31 cold last week, but next time I'll drop it down to 27 and work from there. It's a bit of a challenge trying to anticipate how much the tire pressures will rise over the course of a stage versus a 5 minute track test, but it'll give me somewhere to start.
It's interesting looking at the different wear on the front and rear tires (middle and right positions in the photo). The front is showing some scalloping while the rears just look overheated. This particular set is being abused heavily so I can determine how these tires work and last.
entry 891 - tags: tires
August 3, 2011 - Nancy in full livery.
Most of the sponsor stickers are on the back half of the car, where we can get more contrast and visibility with the solid black rear instead of trying to fit in the mixed white and purple. We will have to load the car up with an undisclosed number of event stickers as well, so we're leaving room. The one sticker on the front half of the car is the Heifer International logo. They're not a sponsor of the car, but Flyin' Miata is a sponsor of theirs.
Check out the new black C3M wheels wrapped in new Dunlop Star Spec tires in a 245/45-17. Thanks to Tire Rack for donating the wheels and Dunlop for supplying tires. Why a 245 when we've been running a 255 in the past? Because Grassroots Motorsports found that size to be measurably quicker in their testing on a car very much like ours.
Both cars will spend the next two days pounding around the track, showing off their abilities to Flyin' Miata fans. It'll also serve as a good shakedown for them. Neither car is completely in Targa spec yet, but they're close.
entry 900 - tags: Nancy, tires, wheels, sponsors
August 20, 2011 - Race rubber!
The painted 6UL wheels are an awesome, blinding white. Whiter than the powdercoat was, which is kinda nice. They've now been mounted with the actual tires that will be used in the race, a set of six Toyo R1Rs in 225/45-15.
A rehash of the tire rules that led to this choice: I am allowed a maximum of six tires for the race, and they have to have a minimum of 140 treadwear. This means I can't run a tire such as the Toyo RA1 that did so well for me last time. So the Toyo R1R is it.
entry 917 - tags: tires, wheels
January 21, 2012 - Time to get the car ready for a different sort of use.
It's going to be seeing the track a fair bit in the next year, and that means a different setup than the rally one.
The R1Rs were good for the Targa, but they get overwhelmed on the track. So I went back to my old favorites, the RA1 in the same 225/45-15 size. Honestly, I would have put on some Nitto NT-01s if they were available, but they are not. Still, the RA1 is a good choice because they're just so consistent and long lived. I'll be running this set of tires for some time.
The springs will get changed, probably to the 750/450 set I ran for a while previously. It's a fair bit of spring, but the AFCOs make them work and it'll keep the car planted on track. It'll tame the rear end a bit, as I don't want quite such a mobile tail as I had during the rally. I'll drop the ride height as well. I'm thinking of dialing in a bit more front camber than I had before. We'll see.
I'll be at the Miatas at Mazda Raceway Laguna Seca event again at the end of March, so that will be the first "big track" event for the car with a healthy engine. I might see if I can sneak over to High Plains Raceway for a test day before then, but that's a challenge with Colorado winter weather. Still, it's time to get the car out of the garage and tearing up the pavement again!
entry 1012 - tags: testing, tires, track, suspension
August 7, 2012 - Summer Camp track time!
The Summer Camp is where the car made its first tentative laps of the track and is usually the last test before the Targa. Not this year, of course. But it's always a bit of a milestone.
This year, there were three back-to-back days and I was to be giving rides all day, every day. That's at least 150 laps if all went according to plan. Because of the upcoming movie premiere, I had reverted the car to full Targa spec, right down to the tires and the tall ride height.
Okay, that wasn't a great plan. The weather was hot, the usual 95F sunshine we get in Grand Junction in August. After two laps, the rear tires simply turned to slime followed quickly by the fronts. Even if I tried to drive very conservatively, I'd only get two and a half laps before the rear started to behave like it was on castors. It actually wasn't that much fun to drive. The car was also having trouble staying cool. Every car was, actually - even a stock Z06 and the other V8 Miatas.
Then, just as I came in to the difficult braking zone, I heard a clunk and the steering wheel shifted. I'd had the car aligned the week before and hadn't put a wrench on every single bolt, and one of them had moved. Just like last year! Luckily, I had marked the cams so it was a simple matter of putting the bolt back in to position and torquing it hard. All the others were nice and tight. I let the car cool for a bit too, it was getting pretty warm under there to do suspension work.
For the next day, I put my undercar ducting on, swapped in the RA1 tires and dropped the car by 5 turns on the spring perches. Much better. The car was fun again, and reasonably quick even though I wasn't going for fast times. Average lap times were in the low 1:04 to high 1:03 times, which is as fast as anyone was going. The improved front airflow seemed to have solved the cooling problem too, as the car was happier all day while all the others continued to wilt in the heat.
On Friday, I went out for my first session and the car felt great. We came in to the pits and I popped off the steering wheel and laid it on top of the instrument cluster, as normal. It slipped off, so I lifted it a bit higher and put it back on - and when I did so, the padded rim of the wheel bumped against the windshield. It wasn't that hard, so I was shocked when I looked up and saw the big star in the glass. It wasn't safe to drive like that so my day was over. What a goofy problem!
A local glass company had the windshield in stock, so I scooted over there and had it installed. I was back at the track a few hours later, but decided not to push my luck as the adhesive was still curing. It's the third time I've had a new windshield put in this car, and I have yet to actually break it in a traditional manner. In sympathy, Nancy decided to take a rock later in the day and also cracked the glass.
So that was the end of the Summer Camp track time. Greasy tires, hot engine, broken glass and slipped alignment cams. But also some nice clean, quick runs and I tried a couple of things that may come in handy later. So it was not a complete waste. But it sure was frustrating.
entry 1050 - tags: testing, tires, suspension, glass
December 15, 2014 - It's time for some traction.
Maxxis has just introduced a new size of their RC-1 track tire: a nice fat 245/45-15. It's been a long time coming. The tire is aimed at the track day crowd, promising a long life and good traction. I'll be mounting them on a set of Jongbloed 15x10 wheels.
I'll have to do some work to make them fit under the fenders, that's for sure. But I'm looking forward to the first track day in the spring!
entry 1131 - tags: tires, maxxis
January 21, 2015 - The tire fitment on the rear is a bigger problem.
I don't think I can pull that fender enough to clear the tire. Almost all of the extra width of the big 245/40-15 ends up on the outside. So it's time to look at some real body modifications.
entry 1134 - tags: tires, maxxis