Got me Yokohama A048's - Care and feeding?

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[randedge]

In another thread, I was asking about tires.
Now I have A048's in 225/45 16 M compound (the softer of two that are available to us).

Anyway, who has run this and what pressures do you run?
Car is Front Engined AWD.

Racing weight is 1320kg (with driver) or 2904lbs

830 over front axles or 1826 lbs
490 over rears  or 1078 lbs

Wow... that's a bit front heavy eh?

[Spec Volcanic]

My racecar is 2700 w/ driver and something like 64%/36%
I think the tires are the M comp as well (but there are 205/50/15)

I run about 36 hot, starting(cold) 31-32 front and 33ish rear depending on day.

[Spec Volcanic]

My racecar is 2700 w/ driver and something like 64%/36%
I think the tires are the M comp as well (but there are 205/50/15)

I run about 36 hot, starting(cold) 31-32 front and 33ish rear depending on day.

That was for the road course... for solo more like 36 cold

[Talonman]

830 over front axles or 1826 lbs
490 over rears  or 1078 lbs

Wow... that's a bit front heavy eh?

Hmmm wonder why my DSM won't handle?

[randedge]

Turn in is more dull than what I'm used to, having been trained in the MR2.  But I feel the car oversteers a LOT in higher speeds.  On the few times we had a 3rd gear event (last year in the Roadcourse) the car has always tried to swap ends on turn 3. But the awd and long wheelbase makes it infinitely more catchable than the MR2.  To fix turn in, I see more caster and track in my future.

[randedge]

Bruce M. drove on R888's from Edmonton to Red Deer.

Mine is wearing alright that I'm wondering of doing just that for at least an event or two.  What about it?  Doable?  Or would I heat cycle it to death? 

[rx7racerca]

Bruce M. drove on R888's from Edmonton to Red Deer.

Mine is wearing alright that I'm wondering of doing just that for at least an event or two.  What about it?  Doable?  Or would I heat cycle it to death? 

I wouldn't worry about it, but that's me.  Doesn't the Elise/Exige come with the A048 as it's street tire?
It's not the same tire, but FWIW, I drove the better part of three summers on a set of RA-1s - I mean 300+ autocross runs, back when the big lot at the Westerner and Race City road course were our main venues, and better than 12,000 city and highway kms. And I left the car stored in my unheated garage over 2 winters with the car parked on them.  They did not appreciably loose grip until just before I corded them.  I'm guessing the A048-M is a lot closer to the RA-1/R888 than 710s or A6s. By contrast, the old set of 710s I ran at the last couple of events did not age well - grip was predictable and they were responsive, but the ultimate grip level was not there.  But that set had all seen 100+ autocross runs, which is a lot for 710s; 3 were 3 years old, and one was 4 (and had spent a couple of winters in the garage). And perhaps not coincidentally, the 4 year old one corded on my fun runs - lol.

IIRC, Reijo once mentioned a top competitor down in San Diego - Andy Hollis is who comes to mind - drove 50+ miles on the freeway on 710s to get to events. Highway driving apparently doesn't really heat cycle the tires a whole lot.

[Murray Peterson]

A few people this weekend mentioned that highway driving would heat up front tires quite badly if they were driving a FWD car with lot's of front end weight.

OTOH, I drove around on my A6's this weekend, and even a 10 mile drive didn't heat them up at all.

[randedge]

INteresting. My car does have an insane amount of front weight bias.  The S2000 and RX7 are 50/50 or close.  Bruce M's Porsche, though rear heavy, has a lot of stagger - the heavier end, has a lot more rubber.

[DBM]

Yokohama rubber seems to heat cycle out much worse than toyo rubber. Toyo's seem to keep their stick longer.

As for wear, I think that as long as your alignment is conservative, you shouldn't add much wear to them. In 2004, I drove my MR2 from red deer to edmonton on A032R-S (same compound as A048-M iirc) and didn't notice any wear. However, when I bought those tires new, I performed the initial heat cycle to them by driving on the highway for 40 minutes. They got surprisingly hot and surprisingly soft!
I would only consider a highway trip 1 heat cycle, same as 1 autocross run, so I don't think it would have a huge effect on the tires life.

[Spec Volcanic]

My racecar is 2700 w/ driver and something like 64%/36%
I think the tires are the M comp as well (but there are 205/50/15)

I run about 36 hot, starting(cold) 31-32 front and 33ish rear depending on day.

I'm now using 33PSI hot a the track

[randedge]

In keeping with my habit of long story arcs, I'm revisiting this topic again.
(note that all pressures are cold)
Initially, I was running 38f-35r.  Worked ok initially as a compromise to not having much front camber.  I knew that I should drop the fronts more, but I was eating up the outer edge.  When I finally got around to getting camber up front, I ran 35f and 30 to 31 rear.  Worked superb!

I never did drive on them on the way to the events.  Perhaps next season, during the start, I might since they still have decent amount of tread left.  54 runs or so maybe?

[randedge]

Here I go again with long story arcs.


The middle of these tires are getting eaten up!  Now, could it be because I'm running it in 7" wide rim when 8" would be more ideal?   Should I drop the pressures?  As mentioned, I now run them cold 35f-31r (Psi)

The sidewalls seem stiff enough and I have adequate camber up front.  With the centers being worn down, I feel like I should drop further to 32f-28r... but that seems low

[Audi200tq]

You'd need a pyrometer to confirm, but if the middles are wearing that's a good indication of too much pressure.  Having said that, your tire width-to-rim width ratio and your camber curves will require certain pressures keep from rolling over.  If any of those two aren't in the idea range, you may be required to overinflate, and the centre-wear may be unavoidable.

[randedge]

http://cscc.speedracer.ca/forums/index.php/topic,9194.0.html

Conclusion:

100+ runs.
Could probably squeeze another 20 runs, but they're a bit unpredictable now, what with the groove of death and all: The middle has now worn to nothing but with the sides still possessing visible tread.

70 of those runs there was no discernible falling off. Not even after the winter since these tires were stored properly.  Afterwards, they fall off quite rapidly. 

Final Verdict:

Better than R888's, which I am now running and regret very much.
V710 didnt' come in my size, otherwise I would have run those next.

Lesson:

Run a good R tire, or just run good streets - no point in mediocre R tires nowadays what with the revolution in street tire technology.