Toyo R888 Wear

#61

I came across this post on specmiata.com and thought it might be helpful.

[quote]I received information from Toyo on some of the differences of the RA1 and the R888. The tire is not a bolt on and away you go replacement.

From Toyo Tire USA
The Toyo Proxes R888 is a totally redesigned product. The construction is completely different than the RA1. Therefore it may require a setup change. The Proxes R888 is a more refined product that requires less slip angles and less camber than the Proxes RA1. If the R888 is driven with the same setup, tire pressures and driving style it may go slower.
The Proxes R888 will not respond well if driven at the same slip angles as the RA1. For example if you slide your car around and build up to much heat the tire will wear prematurely.

Toyo Tire USA

With that being said consider this. High negative camber will give you more bite in the turns but has less contact patch straight ahead, so you have less braking force. With less negative camber braking points can be deeper. All of the instructors I’ve talked to say “smooth is fast.” Sliding scrubs off speed and overheats the tires. High tire temps should not exceed 200 degrees. The new tread design of the Proxes R888 is less succeptable to tread squirm so shaving is less of an issue. But shaved tires are lighter so they have less rotating mass. The Proxes R888 has tread grooves full depth, so a 3/32 tire will still have some water channeling.
When I get more information I’ll be sure to pass it on.
Joe
TheTireShoppe[/quote]

There were some follow-up questions about what value Joe considers to be “high negative camber,” but no answers yet.

Joe is recommending a narrower operating temperature range than Toyo states on its website (max 200 deg., not 220).

Time to change my driving style a bit from the slide-it-around RA1…

Steve D.

PS - I wonder if my sliding the R888s contributed to the fact that I had to start with much lower temps to avoid going over 40 hot. I wonder if I am building more heat than would be typical with less sliding… Which in turn greases the tires, causing more sliding…

#62

Crosslinking to other forums with info:
There’s a thread on corner-carvers about the r888 at http://forums.corner-carvers.com/showthread.php?t=39126
It links to a subie forum with some toyo tire engineering data and a zipfile. This is the text that came with the zipfile:

zipfile link: http://spda-online.ca/modules/newbb/dl_attachment.php?attachid=1221822651&post_id=32700

#63

Interesting. This might explain why I am losing time on 888’s.
My driving style tends to be kind of high slip-angle :slight_smile:

I’m still not convinced its as good as the RA1 :frowning:

#64
  • Owning a pyrometer is the best way to tell how a tire is performing.

I’m getting one.

#65

I will share more data later when I have time, but I did some pyrometer checks back to back with RA-1’s. Temps were similar for R888 an RA-1.

The R888 does not like to slide. You could slide the RA-1 all day. Slide the R888 and it will go off. Also at least for us the R888 seems to get faster as it wears down. The time gap between RA-1 and R888 is getting smaller.

Also I started at 35 psi cold and got to 41 to 43 psi hot. Edge wear was ok.

#66

MikeD wrote:

[quote]* Owning a pyrometer is the best way to tell how a tire is performing.

I’m getting one.[/quote]

Bingo !!

As Steve D. and Michael S. have stated, you have to learn what the car is doing. There are so many factors involved, i.e., car setup, driving style, track surface, ambient temp, etc, that one will have to discover what works best for them…in most cases anything over 40psi and 220 degrees is not going to work

I always ask, what are your hot pressures and what are your pyrometer readings ?..uh ??? I don’t know, is the common answer way too many times. Test test test…practice practice practice…keep notes on all these things for every track…it will speed up your lap times as well as your car prep…then you can spend more time concentrating on the “art of racing”…all this will equal more fun and maybe less money spent looking for that “fast answer”, when all the time it was sitting behind the wheel…:slight_smile:

#67

944spec#94 wrote:

[quote]
Also at least for us the R888 seems to get faster as it wears down.[/quote]

Same here, thats why you get them shaved :wink:

944spec#94 wrote:

[quote]
Also I started at 35 psi cold and got to 41 to 43 psi hot. Edge wear was ok.[/quote]

I still think your pressures are too high.

#68

They could be too high still.

I have been working the pressures down, but only had 3 sessions over 2 days to do that. I never got them to lower than 35 cold. I will probaby shoot for 40 hot next time. This would be 2 psi more than where I run my RA-1’s.

#69

I was given a pyrometer from a friend a while back and I am glad I didnt buy it because it proved to be a waste. Here are a few of the many challenges:

You have to get the temps seconds after ten tenths driving (the tires cool very quickly- faster than pressures im told). If you think you are going to drive into the pits, get out of your car, pull out the pyrometer, and then take temps, forget it.
I found that between the time you take the outside LF temp and the inside RR temp, the temps can drop so much that you wont have a reliable reading for the RR.
Also, as explained to me by an ex-WCTC crew chief, the inside of the tire will heat up much more on momentum cars like ours because they simply spend so much more time on the straights. This means that the temperatures will not accurately represent how hard the tire is working across the surface, so you can not use your readings to help change your alignment setup.

IMO stick to pressures, but this is just my difficult experience- if you want to try it, go for it!

#70

944 spec Toyo R888 Review Heat Cycles 3-6.

I ran 3 more heat cycles on my R888 this past weekend. Temps were 90F and 85F for each day. I ran the pressures lower starting at 34 to 35 psi cold. Hot pressures were 41 to 43 psi. I also took tire temps, but a red flag during the first practice session meant temps were of limited value since I was sitting on track for 4 minutes before I came on.

Over all the tire feels softer at these hot pressures. They rolled over the side wall bit more, but never over the edge of rain groove in the tire. Based on data on construction I believe this is acceptable. Next track day I will experiment with still lower pressures and target 40 hot.

Speeds seem to improve and the gap between the RA-1 and R888 is smaller. By the 6th heat cycle I consider this not only 0.3 to 0.5 seconds. The R888 do require a different driving style as they do not take well to sliding. If you slide the R888 they will lose grip and lap time will increase.

I was able to take tire temps on Sunday back to back with the RA-1 and the temps were very similar and in many cases with in 5 degrees. The profiles across the surface were reasonable as well.

Here are some photographs of the tires after 5 and then 6 heat cycles. The tires were rotated in X pattern meaning LF when to RR as compared to the first 3 heat cycles. This means all 4 tires ran backwards this weekend. This was my pattern of use with RA-1s to even up the wear on each tire to maximize overall life.

Jim Foxx has record 14 heat cycles on a set of R888 and they still have tread depth and still have good grip.

Heat cycle data (Note PIR is most left hand and has a left hand oval just before the PIT in. This will bias tire temps and to a lesser degree pressures.

Heat Cycle 4 (Temps & pressures taken after redflag on track)
Pressure = 34 cold all 4 tires
LF = 42 Hot, Temps (O, M, I) 129,143,165
LR = 42 Hot, Temps (O, M, I) 132,158,163
RF= 43 Hot, Temps (O, M, I) 131, 154, 158
RR =44 Hot, Temps (O, M, I) 178, 176,162

Heat Cycle 5 (Pressures take in Paddock after session no temps)
Pressure = 35 cold on all 4 tires
LF = 41 Hot, Temps (O, M, I)
LR = 41 Hot, Temps (O, M, I)
RF= 41 Hot, Temps (O, M, I)
RR =43 Hot, Temps (O, M, I)

Photos After Heat Cycles 4 and 5
Left Front

http://members.rennlist.org/m758/HC5-LF.jpg

Left Rear

http://members.rennlist.org/m758/HC5-LR.jpg

Right Front

http://members.rennlist.org/m758/HC5-RF.jpg

Right Rear

http://members.rennlist.org/m758/HC5-RR.jpg

Heat Cycle 6 (Temps & pressures in paddock after “hot” cool down lap)
Pressure = 35 cold all 4 tires
LF = 43 Hot, Temps (O, M, I) 128,139,161
LR = 43 Hot, Temps (O, M, I) 129,153,164
RF= 43.5 Hot, Temps (O, M, I) 150, 163, 166
RR =43.5 Hot, Temps (O, M, I) 173, 179,171

RA-1 Temp data (Temps & pressures in paddock after “hot” cool down lap)
Pressure = 31.5 cold all 4 tires
LF = 39 Hot, Temps (O, M, I) 122,144,162
LR = 39 Hot, Temps (O, M, I) 137,169,156
RF= 40 Hot, Temps (O, M, I) 147, 161, 165
RR =40 Hot, Temps (O, M, I) 170, 177,171

Photos After Heat Cycles 6
Left Front

http://members.rennlist.org/m758/HC6-LF.jpg

Left Rear

http://members.rennlist.org/m758/HC6-LR.jpg

Right Front

http://members.rennlist.org/m758/HC6-RF.jpg

Right Rear

http://members.rennlist.org/m758/HC6-RR.jpg

#71

Thanks for the update.
I still think your pressures are too high. And keep in mind that if you are running unshaved tires, they will heat up much more and get greasy more easily.

#72

allenr wrote:

How much you want for it?:stuck_out_tongue:

You are spot-on. Some tracks work well for getting temps and pressures (Mid-Ohio) and some are horrible (Road Atlanta). At the end of the long straight, the tires have cooled significantly.

Doesn’t your dad travel to races with you? Put him to work taking temps!:wink:

That being said, temps are still valuable info. If you come in after a ‘not so hot’ cool-down lap and the temps are 180, you can bet that your tires are above their happy zone during your flying laps.

I’m not sure I follow his logic. If you have zero toe, the tires aren’t going to generate that much heat on the straight. That heat may not indicate that the tire is “working” hard in the corners, but if the goal is to have the tire temp even across the surface, the temp gained on the straight enters the equation.

Steve D.

#73

The way I understand it, taking a single tire temp sample or averaging your 3 readings from a tire will show you how close you are to the optimum temp for a tire. This is good but there’s only so much you can learn from that.

The more advanced reason for taking temps across the surface is to figure out how much camber you need. To go fastest in a turn, you want the biggest possible contact patch. To get the largest contact patch, you want the tire to be flat in mid corner. If the tire is flat (ideal camber), you will theoreticaly have even temps on the inside, middle, and outside. Too high temp on the outside= not enough camber, too high on the inside= too much camber. I have heard of guys in se30 putting much less camber on the right side tires to give them more grip in left turns (most turns are left turns). This is the sort of thing you would want to use a pyrometer for.

When a tire with neg. camber is on the straightaway, the inside is generating a lot more heat on than the outside while the outside is cooling. Obviously this will happen with any car. But there is a point where the cars are just so slow and thus spend so much time on the straights that the inside will heat up so much and the outside will cool so much that the temp readings are compromised. You can not figure out how much of your temp is a result of being on the straightaway and how much is a result of your alignment.

So what I’m saying is if you keep it real simple, you’ll be fine. If you try to get deeper into it, you will have headaches- trust me.

ps- my dad is a great sponsor but a not so great mechanic :wink:

#74

allenr wrote:

[quote]The way I understand it, taking a single tire temp sample or averaging your 3 readings from a tire will show you how close you are to the optimum temp for a tire. This is good but there’s only so much you can learn from that.

The more advanced reason for taking temps across the surface is to figure out how much camber you need. To go fastest in a turn, you want the biggest possible contact patch. To get the largest contact patch, you want the tire to be flat in mid corner. If the tire is flat (ideal camber), you will theoreticaly have even temps on the inside, middle, and outside. Too high temp on the outside= not enough camber, too high on the inside= too much camber. I have heard of guys in se30 putting much less camber on the right side tires to give them more grip in left turns (most turns are left turns). This is the sort of thing you would want to use a pyrometer for.

When a tire with neg. camber is on the straightaway, the inside is generating a lot more heat on than the outside while the outside is cooling. Obviously this will happen with any car. But there is a point where the cars are just so slow and thus spend so much time on the straights that the inside will heat up so much and the outside will cool so much that the temp readings are compromised. You can not figure out how much of your temp is a result of being on the straightaway and how much is a result of your alignment.

So what I’m saying is if you keep it real simple, you’ll be fine. If you try to get deeper into it, you will have headaches- trust me.

ps- my dad is a great sponsor but a not so great mechanic ;)[/quote]

I will be spending 8 hours on track in early december taking tire temperatures and making small adjustments. I’m curious to see if it makes a difference.

#75

Is that chin at VIR? I’ll hopefully be there instructing…

#76

allenr wrote:

[quote]Thanks for the update.
I still think your pressures are too high. And keep in mind that if you are running unshaved tires, they will heat up much more and get greasy more easily.[/quote]

I tend to think so as well.

I start RA-1 at 31.5 to 32 to get 38 hot. This has worked well, but even better is to bleed them down to 38 hot after the session and let them be for the next one. However I never had the chance to really do this on the R888 due to when I was running the tires. So I started 35 or 34 hot shooting for 42 and never ended up quite right. Seems like I will need to start lower next time as I am shooting for 40 hot. 38 hot may be work a try too, but I need to inch my way there because I don’t want to damage the edge of the tire. For our cars 36 or 38 hot may do that. Hard to say 100%.

Still I have learned alot about these tires and the biggest take away is they need a much smoother style. The days of “drifting” the car around a corner are done for.

#77

allenr wrote:

Is that chin at VIR? I’ll hopefully be there instructing…[/quote]

Yea I will probably only take my car and possibly the M3. I don’t think we will take my dads car.

#78

Joe, how much camber do you have?

#79

Ranger wrote:

-3.5 front and -2.5 rear. Also remember that the track I took tire temps has about 1/3 of the track as a slightly banked oval. This has an influence on tire temps. The camber setting I have been using were optimized for RA-1 on this track. Based on the temps I don’t plan on changing camber yet. It may change, but only have I adjust my driving style and tire presures in a more optimal range.

#80

allenr wrote:

[quote] I have heard of guys in se30 putting much less camber on the right side tires to give them more grip in left turns (most turns are left turns).

[/quote]

Most turns are Left? You running Ovals? Any track I can think of, mopst turns are right.

Don