FARTBREF wrote:
[quote]
I vote for Azenis for next year…
Al[/quote]
not a bad idea. Khumho has excellent contingencies as well.
Toyo R888 Wear
andrew240z
#23
allenr wrote:
all nasa spec tire classes have to use toyos.[/quote]
Does it say we have to run the R888? 
Proxes 4 = $80.00 each…
155MPH
#24
MikeD wrote:
[quote]Someone explain this to me. This is about 10 heat cycles.
[/quote]
Looks like the pressures are too high.
drumbeater
#25
What’s the correct pressure to use a baseline? I know different tracks require slightly different pressures.
John
MikeD
#26
155MPH wrote:
[quote]MikeD wrote:
[quote]Someone explain this to me. This is about 10 heat cycles.
[/quote]
Looks like the pressures are too high.[/quote]
That was my first thought but these never got over 40.
allenr
#28
IMO 40 is too high esp. if you get that reading after you come into the pits. I aim for ~38 in the hot pits.
Elephant4
#29
FARTBREF wrote:
[quote]Simon, when were yours produced?
Al[/quote]
How do I check the production date on the tire?
csrow
#30
Elephant4 wrote:
On the sidewall of the tire, there should be a date stamp in the form of 4 digit (usually with in an elliptical). First two digits represent the week of the production and the last two digits is the year.
MikeD
#31
allenr wrote:
IMO 40 is too high esp. if you get that reading after you come into the pits. I aim for ~38 in the hot pits.[/quote]
At mid ohio I was running them much lower hot and they seemed to be better. I don’t think it’s a secret but these tires seem better at lower pressures. Has anyone run them below ~35psi hot? I’m not expecting to get an answer to that but I thought I would try B)
944spec94
#32
Guys,
I run a 944 spec car in Arizona. Our series also used RA-1 as the spec tire and is now on the R888. I am dropping by in an attempt to gain more information about how to run these tires. We have had guys run pressure similar or RA-1s but cored the outside edge of the tire. We have been told that keeping the tire from running over the wear indicator triange will prevent this cording. To get there we seem to run crazy high pressures. 46 psi hot in my estimation. Here is some information I put together for the 944 spec guys on my firt 3 heat cycles with the R888.
I have another race Oct-4,5 and will share more observations and photos after than event.
Basic chassis data
Tire size = 225/50 R15 at all 4 corners.
Car weight = 2625 with driver
Car power = 132 whp (maybe less)
Camber front = -3.5 both sides
Camber Rear = -2.5 both sides
Spring rates 350lbs front, 30 t-bars rear. (335lbs effective rate)
No changes from running the RA-1s
I ran my R888 for the first time this past weekend. Track was PIR and my home track and highs were 100F. This is normal for September. I also ran RA-1 this weekend to compare the times and feel. PIR is most a left turn course and tends to put extra wear/heat into the right side tires.
Firstly I ran the R888 starting at 38 psi cold (left) and 39 psi cold (right) on Saturday morning. These came to 46 psi hot on the left and 48 psi hot on the right. I pulled these off the car let them sit for 24 hours until Sunday when I ran them again. Photos are show after one heat cycle. Notice I am just close to running over the triangle on the side wall. The tire felt ok, but a bit slick. A slick feel is somewhat normal for the first session in September at PIR. Lap times were well off the pace, but again this normal for this session. I put on 14 heat cycle RA-1’s running at 38-39 psi hot and picked up one second. Some of this due to track and driver warm up. The RA-1s’ felt stickier.
Set of 4 (shown from rear in position run on the car)(link below picture is full size image)
http://members.rennlist.org/m758/HC1-Set-46-48psi.jpg
http://members.rennlist.org/m758/HC1-LF-46psi.jpg
http://members.rennlist.org/m758/HC1-RF-48psi.jpg
http://members.rennlist.org/m758/HC1-RR-48psi.jpg
http://members.rennlist.org/m758/HC1-LR-46psi.jpg
Sunday I ran the R888 for two more sessions. I had bleed them to 46 psi hot on Saturday and left them at this pressure for Sunday. Starting pressures were 38 and 37 psi hot (L & R). Ending pressures from the first session were 47 psi hot all the way around. The tires were run again about 90 minutes later. Estimates for speed were about ¾ to 1 seconds slower than RA-1s at this time. This is for a 1.5 mile 1:15 type lap.
Photos are shown. (link below picture is full size image)
http://members.rennlist.org/m758/HC3-LF.jpg
http://members.rennlist.org/m758/HC3-LF2.jpg
http://members.rennlist.org/m758/HC3-RF.jpg
http://members.rennlist.org/m758/HC3-RF2.jpg
http://members.rennlist.org/m758/HC3-LR.jpg
http://members.rennlist.org/m758/HC3-LR2.jpg
http://members.rennlist.org/m758/HC3-RR.jpg
http://members.rennlist.org/m758/HC3-RR2.jpg
Overall wear was ok. I believe that we cannot run the tires at hot pressures lower than 46 psi hot. Doing so will cause the tire to roll over the triangle and wear down the sidewall/tread rubber edge and will cord in a short period of time as we have seen on at least two other 944 spec cars. Grip so far seems less than RA-1’s in their prime. These tires were run full tread and there is not evidence of tread squirm similar to full tread RA-1s. It is hoped that the grip improves similar to a shaved RA-1 once 5-6 heat cycles are completed.
allenr
#33
Your pressures are dangerously high. You could see huge improvements in laptimes and handling if you dropped them. The “slick” feeling you describe is too high pressures.
What makes a tire wear the best is not necessarily what makes it perform the best. You cant use tire wear alone as an indication of how the tire is performing. If you are able, get a pro to drive your car for some feedback.
Also- suck it up and go with shaved. We used to run full treads to save $ but trust me its not worth it.
You say lots of 944s are doing this? That could explain some things…
MikeD
#34
944spec#94 wrote:
[quote]Guys,
I run a 944 spec car in Arizona. Our series also used RA-1 as the spec tire and is now on the R888. I am dropping by in an attempt to gain more information about how to run these tires. We have had guys run pressure similar or RA-1s but cored the outside edge of the tire. We have been told that keeping the tire from running over the wear indicator triange will prevent this cording. To get there we seem to run crazy high pressures. 46 psi hot in my estimation. Here is some information I put together for the 944 spec guys on my firt 3 heat cycles with the R888.
I have another race Oct-4,5 and will share more observations and photos after than event.
Basic chassis data
Tire size = 225/50 R15 at all 4 corners.
Car weight = 2625 with driver
Car power = 132 whp (maybe less)
Camber front = -3.5 both sides
Camber Rear = -2.5 both sides
Spring rates 350lbs front, 30 t-bars rear. (335lbs effective rate)
No changes from running the RA-1s
I ran my R888 for the first time this past weekend. Track was PIR and my home track and highs were 100F. This is normal for September. I also ran RA-1 this weekend to compare the times and feel. PIR is most a left turn course and tends to put extra wear/heat into the right side tires.
Firstly I ran the R888 starting at 38 psi cold (left) and 39 psi cold (right) on Saturday morning. These came to 46 psi hot on the left and 48 psi hot on the right. I pulled these off the car let them sit for 24 hours until Sunday when I ran them again. Photos are show after one heat cycle. Notice I am just close to running over the triangle on the side wall. The tire felt ok, but a bit slick. A slick feel is somewhat normal for the first session in September at PIR. Lap times were well off the pace, but again this normal for this session. I put on 14 heat cycle RA-1’s running at 38-39 psi hot and picked up one second. Some of this due to track and driver warm up. The RA-1s’ felt stickier.
Set of 4 (shown from rear in position run on the car)(link below picture is full size image)
http://members.rennlist.org/m758/HC1-Set-46-48psi.jpg
http://members.rennlist.org/m758/HC1-LF-46psi.jpg
http://members.rennlist.org/m758/HC1-RF-48psi.jpg
http://members.rennlist.org/m758/HC1-RR-48psi.jpg
http://members.rennlist.org/m758/HC1-LR-46psi.jpg
Sunday I ran the R888 for two more sessions. I had bleed them to 46 psi hot on Saturday and left them at this pressure for Sunday. Starting pressures were 38 and 37 psi hot (L & R). Ending pressures from the first session were 47 psi hot all the way around. The tires were run again about 90 minutes later. Estimates for speed were about ¾ to 1 seconds slower than RA-1s at this time. This is for a 1.5 mile 1:15 type lap.
Photos are shown. (link below picture is full size image)
http://members.rennlist.org/m758/HC3-LF.jpg
http://members.rennlist.org/m758/HC3-LF2.jpg
http://members.rennlist.org/m758/HC3-RF.jpg
http://members.rennlist.org/m758/HC3-RF2.jpg
http://members.rennlist.org/m758/HC3-LR.jpg
http://members.rennlist.org/m758/HC3-LR2.jpg
http://members.rennlist.org/m758/HC3-RR.jpg
http://members.rennlist.org/m758/HC3-RR2.jpg
Overall wear was ok. I believe that we cannot run the tires at hot pressures lower than 46 psi hot. Doing so will cause the tire to roll over the triangle and wear down the sidewall/tread rubber edge and will cord in a short period of time as we have seen on at least two other 944 spec cars. Grip so far seems less than RA-1’s in their prime. These tires were run full tread and there is not evidence of tread squirm similar to full tread RA-1s. It is hoped that the grip improves similar to a shaved RA-1 once 5-6 heat cycles are completed.[/quote]
Thanks for the write up!
FARTBREF
#35
Thanks for the Data, your pressures seem to be in the opposite direction from where we have been moving but it is interesting that the RA1’s with 14 cycles were faster… I wonder what Toyo has to say about pressures…
Al
944spec94
#36
Here some information I found poking around Spec Miata web forums. Much was centered around a test SCCA did for Spec Miata
[quote]In the end, my only concern is that ALL of the drivers at the test gave the R888 the worst feedback of the three as far as driveability etc. Most said the turn in was great due to stiffer sidewalls but the compound wasn’t as good as the sidewall construction and mid corner grip and predictability were not as good as the RA1 or the Hoosier. Is the R888 the right choice? I don’t know… I think the cars will be harder to drive fast. In a class widely populated by relatively un experienced drivers… I don’t think a tire that is hard to drive on is the best choice, but when you throw in all the other factors, it may have been the best decision. The sky isn’t falling, we will have to get used to a new tire, but at the end of the day, we should all be fine with the R888.
Jim
Jim Drago
East Street Auto Salvage
jdrago1@aol.com
2006-2007 Mid-West Division
Champion
EAST STREET RACING
[/quote]
[quote]Based on my experience so far with the R888 on an SM, it is a much more consistent tire than the RA1 - i.e. the laptimes are the same whether it’s a new 4/32 shaved tire or a nearly worn out tire. It’s fastest about in the middle of that lifespan, and it is only slightly faster at that point. Overall, I’d say it’s consistency is similar to that of the Hoosier.
What we do not know yet (haven’t had a chance to test yet,) is whether or not it’s considerably faster at 2/32 shave. I certainly hope it’s not.
-Jason Saini :: Fort Worth, TX
-Team MER :: 2006 MX-5 Cup Runner Up
-2007 MX-5 Cup Champion!
[/quote]
[quote]From the Aim Tire Website…
There are a multitude of questions being asked about the difference between the RA-1 and the new R-888.
Our company was the very first company to sell the RA-1 back in 1992. In fact we were the company that originally tested a prototype RA-1 that allowed TOYO the feedback necessary to commit the RA-1 to the USA market. Thus, we have a bit of experience with the RA-1 tire!
The greatest difference between the RA-1 and the R-888 is the tires construction. The R-888 is of an all new design both in tread and construction.
The most obvious difference being the tread pattern and molded tread depth. The R-888 grooves are molded to 6/32nds of an inch. Whereas the RA-1 grooves are staggard with the inner grooves at 8/32nds of an inch and the outer most grooves at 6/32nds. Additionally the R-888 has less and larger tread blocks to promote a quicker steering response and better mid-corner grip.
It should be noted that shaving a R-888 due to the wider grooves will not ceate a ‘slick tire’ as in the case of shaving a RA-1 to below 4/32nds. The R-888 when shaved even as low as 2/32nds will not be a virtual slick tire but will continue to have wide rain grooves.
The wider grooves on the R-888 does enhance the wet weather performance of the tire and has proven superior in the wet than the RA-1.
To maximize the performance of the R-888 over the RA-1, especially on Front wheel drive RACE cars and Spec Miata’s camber, tire pressure and driving technique must be modified.
The R-888 with the stiffer sidewall and softer undertread construction requires significantly less initial camber settings and higher pressure.
By design the R-888 promotes higher levels of grip under braking and at mid-corner.
So, if you simply switch out a RA-1 for a R-888 don’t expect your FWD car to rotate in at mid-corner without taking all of the camber out of the rear suspension settings. Furthermore, less camber in the front will aid turn-in. And an increase in starting and operating pressure of the R-888 over the RA-1, will aid in overall traction and increase tire life.[/quote]
[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]
Steve_D
#37
944spec#94 wrote:
Take this for what it’s worth - I have one weekend on R888s.
I agree with the suggestion to go to lower pressures. I found that pressures in the mid-high 30’s at MidOhio worked well. If I got to 40 or above the car suffered from lack of overall grip.
With the rain, we really didn’t get as much tire temp data as I would have liked, but that will teach you a ton. With the cost of new skins, a tire pyrometer is a bargain.
I second the suggestion to shave. It’s been my experience that shave tires last even longer than unshaved (counter-intuitive, eh?) because they shed heat better and stay in their happy temperature zone. That keeps me from sliding the car as much, so they wear better.
You cited your static camber settings. One thing you didn’t cover in your write-up is dynamic camber. Do you have stiffer-than-stock bushings? If not, you may not have as much effective camber in a turn.
Another possible cause of the “roll-over” problems you are having is the extra 20mm in tread width. We run 205s on 7" rims. 225s may be happier on a 7.5" or 8" rim. I didn’t see any roll-over in my tire wear.
Steve D.
MikeD
#38
Well I think if you read the Miata write-up the general consensus is that the R888’s are crap. IMO they lack mid corner grip and have terrible breakaway characteristics as compared to the RA1’s. In the high speed corners I really haven’t noticed that much difference.
We might as well be running Falken Azenis RT-615’s. They are probably faster and will last longer.
The best part is they are alot cheeper.
$76 a piece.
Ranger
#39
It’s fascinating that some folks are recommending more, not less, air in the R888’s. And I wonder if anyone has tested them with reduced camber.
944spec94
#40
Steve D wrote:
[quote]
You cited your static camber settings. One thing you didn’t cover in your write-up is dynamic camber. Do you have stiffer-than-stock bushings? If not, you may not have as much effective camber in a turn.
Another possible cause of the “roll-over” problems you are having is the extra 20mm in tread width. We run 205s on 7" rims. 225s may be happier on a 7.5" or 8" rim. I didn’t see any roll-over in my tire wear.
Steve D.[/quote]
Steve,
I have hard time thinking the sidewall roll over is due to camber. I have run 6-7 sets of RA-1 over the past few years using the same -3.5 and at times -3.0 camber. All were done with same spring rates and stiffer bushings. I could get the outside of the RA-1 to wear more using less camber, but I never rolled over the edge. The rollingover the edge seems to be unique to the R888. It may also be unique to the 225/50 R15 size. It makes no sense as to why, but it seems hat 235/50 on 15x7 don’t rollover. 225/45 may not either, but that is just conjecture.
I am the Arizona series director for 944 spec and also involved with the National leadership of the class. As such many in the 944 spec group are looking to me to ensure we have deicent tire to race on. Being spec lap times are less important than life and consistancy.
BTW… I apperciate any and all feedback as I am committed to working to give this tire a real shot. If the issuse can be solved with change in size then so be it, but a change like that is just another level of compexity and it introduces all sorts of other complications.