Which 205/50/15 semi slicks?

[rascal]

If you put the same pressure in as you want to run at the track then saves you time when you get to the track.

I used to put in 26 cold in my R888s and then bleed off to 31-32 hot as needed after first practice session, so I'd put in 26 prior to leaving home.
You then wont need to touch them till after first practice when you can bleed some air out as needed.

[Trackphotos]

You're going to put a lot more wear on the outside edges when you're on track. So ideally, you want to overinflate them on the road so that the majority of the wear is done on the centre patch, and not the corners. I run 35psi on the road and bleed them down when I get to the track. It's probably not even necessary, as the amount of wear you're going to do on the way to and from the track is going to be two tenths of bugger all compared to a good day on the track. I'd still prefer to minimise shoulder wear wherever possible though, since track use is definitely going to concentrate the wear there.

[davekmoore]

Ok, so some feedback on tyre choices:

Now have two sets of wheel/tyres - one for the road, one for the track.

Went with R888s in 205/50 on 15x8 wheels. No mods needed to guards, helped by a little negative camber front and rear. Dunno whether it was getting the benefit of a passenger ride with Brendan or the tyres or a mixture but managed to go 6 seconds quicker at Winton.

No surprises that the R888s on 8s are way grippier than road tyres on 7s on the track. It's like learning to drive a different car. Just like road tyres, they let you know when they're getting overheated and/or near the limit of their grip. They just do so at a higher limit of grip, and on about lap 5 instead of lap 2 or 3. The sweeper at Winton used to be 110 on road tyres. 122 on R888s. No doubt I could/should go faster if I didn't look at the speedo and/or was braver and/or kinder on the tyres under acceleration, but the latter is just a downside of a turbo car.

The R888s allow later braking. It would be later still with proper pads which didn't fade half way through the bigger braking zones.

They were $950 for the set. All accounts suggest they'll cope with plenty of abuse. Other R specs may be a couple of seconds quicker for twice the money but that's not the game I'm playing.

The downsides of the R888s, as I was warned, are the noise and harshness on the road. Just about ok to drive to and from a track but you definitely need a second set of road wheels and tyres if it's a DD.

[chrons_rotary]

The downsides of the R888s, as I was warned, are the noise and harshness on the road. Just about ok to drive to and from a track but you definitely need a second set of road wheels and tyres if it's a DD.

I completely agree, noise even at 100km/h is pretty bad, to the point where you think something may be rubbing.
For the money, they are a good start for getting into R spec tyres when doing track days.

[davekmoore]

Thanks for all the advice on this.

After a couple of track days I can now say these are, as you'd expect, way grippier and predictable on the track and several seconds quicker so far at WInton and Sandown. More feedback from them as well. I'm sure there's more speed to come once I feel more confident of finding what happens at the limit of the grip.

There's now a big brake kit on the car so the separate road wheels now need spacers to clear the calipers. So I'm beginning to think the hassle of swapping wheels and spacers may be more of a pain than just living with using the R888s all the time on the road. I haven't bothered swapping them yet since Sandown a couple of weeks ago and they can be lived with if the coilovers are turned fully soft and pressures dropped to 26.

Now, I know the 888s will not be good for tread wear if used all the time, but just how quickly am I likely to wear them out?

[davekmoore]

Just checked the wear ratings online. They're 100, which is three times worse than the road tyres. I generally get 50-60,000kms from 300 rated road tyres, so if these'll do say 10-15,000kms including some super sprints I'll be fully happy. That's less than 10c per km.

If only I could get similar comparative wear rates out of my front brakes. E.g; Heavy FWD diesel wagon (alright, I admit it's a Skoda Superb) at nearly 100,000kms still with 25% wear left on front pads. MX5 does a set of front pads per sprint day and ruins at least one rotor. That's nearly $2 per km, plus a bit of rear pad wear.

While I'm at it, the car does around 35L per 100kms on the track which is about 50c per km.

Oil and filter change every two events.

Etc, etc.

All adds up doesn't it, bit I'm still NOT going to add up all of it.

[rascal]

Dave,

Do you run any ducting to your brakes? If not then maybe time to consider it.. Can make a massive difference to temps, which in turn affects longevity.

Also what pads do you run? To help with the longevity you might need run more race oriented pads and swap them out for the road. A pain I know, but otherwise I don't think you will solve your pad eating issues.

Fwiw, I run hawk blues and they last me an entire season (10 events) on the fronts and two seasons on the rears. And the last set of (cheap plain rda) front rotors lasted 4 years.
I Realize your speed into braking zones is a little higher than mine, (maybe 10% ish) but still doesn't explain the 10fold wear patterns,which would suggest you are using the pads outside of their heat range.

[davekmoore]

Thanks rascal. Yup, Trackspeed ducting going on the brakes next, along with Wilwood E pads at the front and Porterfield R4s on the back.

[wade]

Just checked the wear ratings online. They're 100, which is three times worse than the road tyres. I generally get 50-60,000kms from 300 rated road tyres, so if these'll do say 10-15,000kms including some super sprints I'll be fully happy. That's less than 10c per km.

If only I could get similar comparative wear rates out of my front brakes. E.g; Heavy FWD diesel wagon (alright, I admit it's a Skoda Superb) at nearly 100,000kms still with 25% wear left on front pads. MX5 does a set of front pads per sprint day and ruins at least one rotor. That's nearly $2 per km, plus a bit of rear pad wear.

While I'm at it, the car does around 35L per 100kms on the track which is about 50c per km.

Oil and filter change every two events.

Etc, etc.

All adds up doesn't it, bit I'm still NOT going to add up all of it.

Wow that's crazy re brakes......

Maybe look at different pads?

I run Padgid yellows on a heavier car and they have lasted 10 supersprint sand three track days and don't even look worn....they are expensive (bout 400 for the front) but seem to be worth it in stopping power and longevity....... Heaps better than the DS2500's I use to run.

[Magpie]

Use the same cold pressure as you would on the track. If I drive to the track I put the tyres back to 26 f and 27 r just before I leave home.

[davekmoore]

Update:

Still happy with the R888s on the track. Other cars have more grip on 9s and with wider and grippier tyres including slicks and some also have more grip from aero downforce. My car still looks relatively standard though and still gets dríven not just to the track but also daily.

By the way, Toyo say 30psi cold for the road and 32psi max hot on the track.

The more the R888s wear the noisier and harsher they seem to get on the road. They're even crashy on the freeway now. A second set of wheels and tyres for the road is in the offing.

The brakes now have race pads in for track days and back to road pads the day after. All from the same manufacturer so relatively simple to bed them in after each swap. There's also ducting, which is always blocked off for the road and for the first session on the track.

[Trackphotos]

The brakes now have race pads in for track days and back to road pads the day after. All from the same manufacturer so relatively simple to bed them in after each swap. There's also ducting, which is always blocked off for the road and for the first session on the track.

Hope your slider pins are properly greased and have no leaks, rust patches anywhere in the caliper housing/piston. Otherwise you're going to end up with rotors that pulse regardless of which pads you put on. Unless both your pad sets wear perfecvtly evenly, you're going to end up with sticky spots on the rotor faces, and you will feel it in a big way, both on the track and the street.

[davekmoore]

Wilwoods. Don't seem to be any issues so far, except last time I put the road pads back in I didn't quite bed them in enough. Still stopped perfectly, just a little noisy. Put the race pads in again tonight and the recommended 20 stops from 40kmph seem to have nicely cleaned up the rotors. These (E spec) track pads are great on the road including the first cold stop, but Wilwood say they significantly increase rotor wear if in a DD, otherwise I'd just leave them in.

[Magpie]

This link was posted by NitroDann http://www.miataturbo.net/general-miata-chat-9/anyone-have-any-brake-questions-81577/

Wilwoods do not get very good feedback as a TRACK setup.

Have a set of rotors matched to pads and change them out as a set. It is OK to bed in with a harsher pad as this will wear off the old pad material. However a softer pad won't wear off the harder material.

I leave my W5's in but my car is not really a DD.

My bed is 10 stops at 70/80% from 80 to 40, 10 stops from 120 to 80 and 10 from 120 to 20. There is a little cool down between applications and the brake ducts are blocked.

[davekmoore]

It has 6 pot Dynapros with spec 37 rotors, titanium pad shims, Wilwood brake fluid and lines, ducting etc. The Dynapro is supposedly a stiffer caliper than the Dynalite with a larger pad area and staggered pistons. I do have two pairs of rotors but am too lazy to swap them with the pads. It's possible I won't be traveling as far to work soon so I'll probs leave the track pads and rotors on all the time and swap the road pads and rotors on only when going on a long trip.