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PostPosted: Mon Apr 15, 2019 12:34 pm 
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So CVAR has updated their rules to include a "group 8" which is stuff a little bit newer than the pre-1972 rules they've previously run with. I have been invited and encouraged to bring the RX7 out, but I understand I need "treaded" tires. some have suggested the Toyo R888R, but the widest I can get it in a 15" is a 225/45/15, and it's slightly taller than the Hoosier slicks I've been running..

Wondering if any of youz guys can maybe point me to a tire legal for vintage and still fits the "EP large tire".. Hoosier Bias was 23 x 9.5-15, and the radial was 245/580/15, approx 9.x tread width and 23" overall diameter.

The Toyo R888R in 225/45/15, but I'm concerned about having this tire last a full race. I realize any DOT / vintage tire is going to have performance limitations due to heat buildup, so I'm hoping to fit the widest rubber I can and still maintain a 23" diameter and 15x7" rim.

as I'm just doing this for fun, I don't intend to change setup away from current EP build, just go play with the vintage boys since they have cool cars as well..

Any suggestions on a tire other than the Toyo R888R?
Thanks

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PostPosted: Mon Apr 15, 2019 1:02 pm 
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Location: Belmont, CA
The Hoosier R7 in a 225/45ZR15 has a 22.8" overall diameter From the chart @ TireRack on the Hoosier R7 specs

https://www.tirerack.com/tires/tires.js ... reModel=R7

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PostPosted: Mon Apr 15, 2019 1:11 pm 
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See if Hoosier has a "Speedster" tire in your size. Love them!! Been good to me.

Tim,

Most vintage clubs will not let you run a R7 or A7.


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PostPosted: Mon Apr 15, 2019 4:42 pm 
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Matt, does that vintage group have a min treadwear value you can use?

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PostPosted: Mon Apr 15, 2019 5:20 pm 
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Matt93SE wrote:
So CVAR has updated their rules to include a "group 8" which is stuff a little bit newer than the pre-1972 rules they've previously run with. I have been invited and encouraged to bring the RX7 out, but I understand I need "treaded" tires. some have suggested the Toyo R888R, but the widest I can get it in a 15" is a 225/45/15, and it's slightly taller than the Hoosier slicks I've been running..

Wondering if any of youz guys can maybe point me to a tire legal for vintage and still fits the "EP large tire".. Hoosier Bias was 23 x 9.5-15, and the radial was 245/580/15, approx 9.x tread width and 23" overall diameter.

The Toyo R888R in 225/45/15, but I'm concerned about having this tire last a full race. I realize any DOT / vintage tire is going to have performance limitations due to heat buildup, so I'm hoping to fit the widest rubber I can and still maintain a 23" diameter and 15x7" rim.

as I'm just doing this for fun, I don't intend to change setup away from current EP build, just go play with the vintage boys since they have cool cars as well..

Any suggestions on a tire other than the Toyo R888R?
Thanks


225-45-15 R888R is 23" dia, 245-580-15 is 22.8", not a big change.

Did you look at the specs for the 225-50-15 R888R or RA1 (which is 23.9") by mistake?

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PostPosted: Mon Apr 15, 2019 6:30 pm 
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R7s are a no go with CVAR. They must be treaded.

I just started racing again this year with CVAR after a long hiatus. It looks like most people who are running Hoosiers are using the TDRs.

I went with the R888Rs on my “new” Midget. I’m not going very fast yet so can’t really give you much direct feedback yet, but the basic gist that I’m hearing is that the Hoosiers are probably a little faster, but the Toyos last a full season or more without much drop off until you get down near the cords. Sorry, but secondhand info is all I’ve got.

Races are short, only about 20 minutes, so you’re probably not going to run out of tires before the race is over.

Come on out to MSRH on Cinco de Mayo weekend and check it out. I’m in the green/yellow #572 FP Midget.


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PostPosted: Mon Apr 15, 2019 7:09 pm 
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Jason@SportsCar wrote:
225-45-15 R888R is 23" dia, 245-580-15 is 22.8", not a big change.

Did you look at the specs for the 225-50-15 R888R or RA1 (which is 23.9") by mistake?


toyo's website didn't have an overall diameter, just revs/mile. I backtracked that to a 23.3" diameter, just a touch larger than the Hoosier. I'm not worried about the gearing change, moreso the potential tire rub I ran into with the last set of tires I tried, wound up being a $1000 mistake. (I think they were indeed 225/50/15)

Tim,
the group doesn't have a specific tire rule- simply 'call the group representative and ask them'. my recollection of the conversation was "it needs to have tread" and "we know it when we see it"

so unfortunately I'm going on intent and innuendo regarding an exact tire spec.

I figure the R888R is an easy try, and they're not THAT expensive. they'll last multiple events and if they really suck, there's always a Miata locally needing cheap tires.

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PostPosted: Mon Apr 15, 2019 7:11 pm 
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hpmowog wrote:
R7s are a no go with CVAR. They must be treaded.

I just started racing again this year with CVAR after a long hiatus. It looks like most people who are running Hoosiers are using the TDRs.

I went with the R888Rs on my “new” Midget. I’m not going very fast yet so can’t really give you much direct feedback yet, but the basic gist that I’m hearing is that the Hoosiers are probably a little faster, but the Toyos last a full season or more without much drop off until you get down near the cords. Sorry, but secondhand info is all I’ve got.

Races are short, only about 20 minutes, so you’re probably not going to run out of tires before the race is over.

Come on out to MSRH on Cinco de Mayo weekend and check it out. I’m in the green/yellow #572 FP Midget.

Thanks!
that's what I'm trying to get ready for. the car has been parked for months due to work and life commitments, but I'm trying to make the may MSRH race. Russ really is hoping for a good showing for the new group 8 cars since many people have worked for a long time to get it to happen. I just need to get the car ready- new belts, tires, who knows what other maintenance is required since it's been sitting for so long..

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PostPosted: Mon Apr 15, 2019 7:52 pm 
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Great! You’ve got about a week to register before the late fees start kicking in.

So, with a rotary, are you going to be in G8-4?


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PostPosted: Mon Apr 15, 2019 8:34 pm 
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I have run the Toyo 225-45-15 R888R on my IT7 (ITA spec 1st Gen RX7.) for the past 3 years. Its a great tire for that or Spec Miata. I have run them on my 2nd Gen with 185 RWHP and it burns them off the car. Really hard to get the power down. They are 2-3 seconds slower than Spec Miata tires on the same car and slicks are about 1 second faster than that.

For sure get them shaved or they will not be as fast and will not feel as good. I have never worn out the tread on a set. They just get slower and will still have OK tread left on my car at least. They need 1 gradual progressive heat cycle and then to be cooled off completely ( a couple of hours) and then they are good for 20 heat cycles.

Street TD's are great but Bias Ply.

Vintage rules are funny. They say they want the tires to not generate too much grip so that spindles etc do not break . And then they allow almost any internal engine part. So go figure. The difference in them working great on my IT7 and not on my 2nd Gen is Power.

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