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Ranger wrote:
Toyo offically states
2-4 psi more air and less camber. However given our cars (944 spec) rolling the edge (something we never did on RA-1) I can’t see how less static camber would help that. 
I will say it is tough to get data on these since so much of it seems to inconflict. Toyo says on thing. Speed world challenge guys someting different. Porsche guys something else, you guys something diffeent still and data from our drivers on track something differnet still.
Anything to consider is that I think these tires run just a tad wider than the ra1 (not positive) so maybe a 225 on a 7" rim is making the problem worse. I have not seen any unusual outside shoulder wear so far. I really have only data from Mid Ohio so the jury is still out on the tires. But I’ve been running around 37 hot and the wear has been even and the grip pretty consitent through out a race. I ran them slightly higher at Putnam the first time out and they seemed to overheat quickly so I dropped the pressures. I don’t take temps. Shaved has definitely been faster than unshaved. Also I’m not sure if this makes a difference but I’ve been heat cycling my tires before using, which I never did with the RA1 as based on the initial reviews it seemed longevity was a problem. I got good life out of my first set admittely at a track fairly easy on tires. I still need more data from different tracks in different weather but so far they have been fine. Although I wouldn’t complain if we went back to the RA1.
944spec#94 wrote:
[quote] However given our cars (944 spec) rolling the edge (something we never did on RA-1) I can’t see how less static camber would help that.
[/quote]
I don’t disagree.
But are you sure the tire is really “rolling the edge”?
I don’t know if it is possible, but might the outer edge be wearing simply because the stiffer sidewall is pushing down harder on that edge than with a soft-wall RA1 under the same loads?
Is this “rolling the edge” happening on fronts AND rears?
Also, in comparing RA1 and R888 don’t forget that stickier is not necessarily faster in a momentum class. This year and last year at MidO the front SM guys were digging through the crappy-old-20-heat-cycle-RA1 piles looking for Sunday tires. The grippier tires were simply bogging the cars down in the turns.
Steve D.
PS - I absolutely love the R888. Mostly because it is the only legal tire.:silly:
Steve D wrote:
Here is photo of the front and rears after 3 heat cycles all at elevated hot pressures (46-47 psi)
I don’t have good shot of the RA-1, but I would never wear down the wear indicator triangle. On the RA-1 I would run right to the tip, but never over it. On these I have seen 5-6 sets run at RA-1 type pressures where the trianges are worn off. Two more sets corded right at this edge and looking at the tire it looked very much like they had worn down both tread rubber and sidewall rubber and joint between these two is where the cords came up. At this point the tire still feel sticky and had rubber everywhere else. One of these drivers I have raced with for 6 years and we both have gone through many sets fo RA-1 without issue so I don’t believe he had a :“Set-up issue” which caused that cording.
Now it is good information to know if you guys don’t have this issue. I do find it very strange that we would have a problem like this and you guys do not. Our cars are about the same weight, same hp and run similar lap times. We even run tires that are almost the same size. Now this would lead me to believe that the R888 on an E30 would workd similar to those on a 944. The fact they don’t is very telling. Now what to do with that data? I am not sure yet.
Mine also cord on the outside edge- almmost on the sidewall. My RA1s used to cord on the outside but not this far over.
I was wondering if b/c it is a wider tire as simon says maybe it is rubbing the fender under full load. I dont know if this would be enough to cord it and it probably wouldnt be the same for 944s and e30s so this is probably not whats happening- just a thought.
allenr wrote:
Where is the cord in relation to the wear triangle? Would the tire still stick and be usable if they did not show cord?
The only way we used to see cord on our RA-'s was flat spotting or other abuse. They would always lose grip long before they showed cord anywherel. For us our fenders are well clear of the tires so no issue about fender rubbing.
Honestly I’ve never noticed the “wear triangle” before- I always run them to the cords to get the most for the buck.
I dont think they are as strong when they are worn this low but honestly I haven’t noticed a major difference in grip level- definately very usable.
I generally only get one weekend or maybe two out of a set so I could be wearing them down to the cord before I put too many heat cycles on them.
allenr wrote:
[quote]Honestly I’ve never noticed the “wear triangle” before- I always run them to the cords to get the most for the buck.
I dont think they are as strong when they are worn this low but honestly I haven’t noticed a major difference in grip level- definately very usable.
I generally only get one weekend or maybe two out of a set so I could be wearing them down to the cord before I put too many heat cycles on them.[/quote]
I think that the wear triangle is more a matter of shoulder roll then amount of wear.
944spec#94 wrote:
I might be mistaken, but I thought the tread wear indicator triangle is simply a DOT requirement. I wouldn’t interpret it as a measurement device designed by Toyo that would be meaningful - or consistent between RA1 and R888 tires.
I think the propensity to cord the outside edge is related to the stiffer sidewall in the R888.
Drop the pressures to get better grip. Halfway through the expected life flip the tires on the rims and rotate them to the other side. If you can add camber (and tire temps tell you you should), that will help even out the wear.
I’d be ecstatic to have a tire that runs out of grip and rubber at exactly the same time. Looks like the RA1 runs out of grip before rubber. And the R888 runs out of rubber before grip (at least on a 944 spec).
Steve D.
Steve D wrote:
[quote]
I might be mistaken, but I thought the tread wear indicator triangle is simply a DOT requirement. I wouldn’t interpret it as a measurement device designed by Toyo that would be meaningful - or consistent between RA1 and R888 tires.
Steve D.[/quote]
I am using the location of the triangle on the sidewall as an indication of where we are running the edge of the tire.
Really and tire you want to run on tread surface and not the side wall. Sidewalls are not designed to be driven on that is clear. So where does the sidewall start and tread rubber stop? That is how I am using the triangle. On nearly all tires the triangle is printed on the sidewall. The top tip is at the edge. On the RA-1 the tire would be worn down to the tip, but we never scuffed the triangle off. We started to when running R888 at RA-1 pressures or below. So at first it was considered no big deal. That triangle is just stupid DOT mark anyway? Well that was until we corded tires on the edge. Looking at the corded tire it was clear that it had been running over the edge of the sidewall and burned through that rubber. Our Toyo tire guy told use this was because we were running over the sidewall and that keeping the wear mark above the triangle and we would not cord the edge. Looking back at all the RA-1s we noticed we ran to the tip, but never over. Also if you run your hand over the tire you can feel the edge drop away at the tip if the triangle.
So our feeling is wear away the triangle and the tire will cord at this point. It will cord long before the rubber cycles out or the main tread surface is worn down. This wearing out too soon. Now you could “flip the tire” when you saw cord, but have you structurally damage the tire to the point were at speed it could destry itself? Pretty stupid to run a potential damaged tire and have it fail and put your car in the wall.
So that is the concern.
BTW… Everyones life span on RA-1’s was different depending on how hard they pushed. I was getting 26-30 heat cycles from RA-1’s before they cycled out. I would need to be getting 20-24 at a minimum from R888 to consider its life acceptable. I am not sure how many heat cycles in “one weekend”, but if that means 6 I am very afraid. :ohmy: That kind of wear makes our tire bill skyrocket. So far even the corded R888 seem to have gotten more than that, but exactly how many is a big question. I have about 10-15 944 spec guys here in Az recording how many heat cycles we get from the R888 in a effort to see what their usable life really is.
944spec#94 wrote:
[quote]I am using the location of the triangle on the sidewall as an indication of where we are running the edge of the tire.
snip
Now you could “flip the tire” when you saw cord, but have you structurally damage the tire to the point were at speed it could destry itself?[/quote]
I defer to the Toyo guys, but I would think that big rib on the edge of the tire would be a good indication of the sidewall/tread dividing line.
Let me be clear on the “flipping”. You should do that WAAAAAYYYYY before you see cord. I said halfway through the expected wear.
Steve D.
I’ll echo what SteveD just said. I don’t think the triangles should be relied on like that. The “lip” is really the edge of the tread. If you really compare the RA1 and R888 shoulders, you’ll see very different designs. The tall tread block on the RA1 is much different than the rolled edge of the R888. Lots of us wore off this outside block on the RA1.
Keep running the high pressures if you want, but I think you need to heed the advice of using a pyrometer to find your ideal pressures/settings. As mentioned in some of the quotes above, the setup of the car will need to be different with this tire, so the fact that what you have done for years worked doesn’t mean it will be fine now.
Toyo’s website says to aim for high 30s/low 40s hot.
mskeen wrote:
[quote]
Keep running the high pressures if you want, but I think you need to heed the advice of using a pyrometer to find your ideal pressures/settings. As mentioned in some of the quotes above, the setup of the car will need to be different with this tire, so the fact that what you have done for years worked doesn’t mean it will be fine now.
Toyo’s website says to aim for high 30s/low 40s hot.[/quote]
Has someone in SpecE30 done some R888 testing with a pyrometer? If so, can we share what was discovered about air pressure and camber?
Ranger wrote:
Most people are running about a degree less of camber as compared to what they were running with the RA1’s.
Ranger wrote:
Ranger -
I wish I had more to offer, but we only used the pyrometer for the first couple days before the rains came at MidOhio. We were really just trying to adjust pressures to get even temps across the tire.
The temp readings gave us another data point indicating massive wheelspin (really hot inside edge of right rear tire) before we softened up the rear bar. But we were making some pretty big air and bar adjustments, so I am not sure the pyrometer was any more help than the buttometer.
Here’s what Toyo suggests:
“General Proxes R888 setup guidelines:
Operating Temperature: 140°F to 220°F, optimum around 200°F
Hot Inflation Pressures: High 30s to Low 40s (psi)
Camber: -2.5° to -5.0°
Caster: As much positive as possible”
Interesting that some people are suggesting less camber than the RA1. Toyo suggests the same range for both tires. Since adding caster tends to add negative camber to the outside tire and add positive camber to the inside tire, it seems like the recommendation is to get as much camber as would typically be possible on production-based cars like ours.
With max camber front & rear, I was seeing temps at MidO of 160-195, but never got them very consistent across the tires. I don’t run many tracks that are as good as MidO for tire temps though. Road Atlanta is horrible since you have the long back straight cooling the tires off. Roebling and CMP are probably the best shot I will have for data in the coming months.
Steve D.
I looked at my used tires in the garage and most of them had the triangle completely worn off.
Steve D wrote:
[quote]Ranger wrote:
Ranger -
I wish I had more to offer, but we only used the pyrometer for the first couple days before the rains came at MidOhio. We were really just trying to adjust pressures to get even temps across the tire.
The temp readings gave us another data point indicating massive wheelspin (really hot inside edge of right rear tire) before we softened up the rear bar. But we were making some pretty big air and bar adjustments, so I am not sure the pyrometer was any more help than the buttometer.
Here’s what Toyo suggests:
“General Proxes R888 setup guidelines:
Operating Temperature: 140°F to 220°F, optimum around 200°F
Hot Inflation Pressures: High 30s to Low 40s (psi)
Camber: -2.5° to -5.0°
Caster: As much positive as possible”
Interesting that some people are suggesting less camber than the RA1. Toyo suggests the same range for both tires. Since adding caster tends to add negative camber to the outside tire and add positive camber to the inside tire, it seems like the recommendation is to get as much camber as would typically be possible on production-based cars like ours.
With max camber front & rear, I was seeing temps at MidO of 160-195, but never got them very consistent across the tires. I don’t run many tracks that are as good as MidO for tire temps though. Road Atlanta is horrible since you have the long back straight cooling the tires off. Roebling and CMP are probably the best shot I will have for data in the coming months.
Steve D.[/quote]
Thanks for the info Steve. I’d not bothered with a pyrometer because I’d assumed that I was on the low end of what I needed for camber and there was nothing I could do about it. I do a lot of track days with RA1’s, but only bring out the R888’s for racing. I’ll see if I can’t take the R888’s and a pyrometer with me to CMP this weekend.
Ranger wrote:
Ranger -
I still think the pyrometer helps. Even if the lack of camber doesn’t allow you to get even temps across the tire, the operating range is pretty wide, so you can still get all temps within that happy range.
I plan on taking the pyrometer to Little Talladega next weekend. If we have solved my stalling problem, I should have some more R888 data to share.
I have not yet achieved rules-max camber on the front either. I have been thinking about tinkering with an adjustable strut tower brace that would draw the towers together a bit. I understand that the other option some have used is to bend the struts, but that is clearly illegal whereas my solution is kind of a gray area. 
Steve D.
I have a race coming up this weekend and will see if I can get tire temps. Both on R888 and my trusy RA-1’s.
I will share here as well as with my 944 spec guys.