Autocross tires

['03 Sonic Blue]

A little off topic, but hoping someone here has the info I need.

My wife's MazdaSpeed Miata's (that she lets me drive sometimes) Kumho Ecsta V700 tires are about toast. They are used for AX only and worked fairly well. I would get them again but sadly, they are no longer available in the required 205/40-17 size. If fact race rubber of any kind is hard to come by in that size.

It turns out that the Nitto NT-01 is available.

For those of you who have used the NT-01 for AX or anywhere else:
Does anyone here have experience to compare the cold (as in 45 second AX run) traction of the Kumho Ecsta V700, the NT-01 and maybe the Hoosier R6?

The Toyo RA-1 is another possibility.

Any help here would be appreciated.

Thanks, Mike

 

[Primaris]

That is a rough size. For autocross I would only consider the Hoosier, since the others are track tires. But, that's me. Won't a 225/45-17 fit?

 

['03 Sonic Blue]

That is a rough size. For autocross I would only consider the Hoosier, since the others are track tires. But, that's me. Won't a 225/45-17 fit?

I wish.

I have a set of 225/45-17 Hoosier A6 that do not fit. They rubbed in several places during a 10 minute test drive on the street on the front and one place in the rear. I think I would have required body repair and had at least one destroyed tire if I had tried to AX them.

The R6 is also considered a track tire. I was told by Tire Rack that it would have significantly less grip under AX conditions than the Kumhos I've been running.

I feel like I've been hung out to dry by the tire manufacurers.

--Mike

 

[SoftBatch]

[QUOTE='03 Sonic Blue]I wish.

I have a set of 225/45-17 Hoosier A6 that do not fit. They rubbed in several places during a 10 minute test drive on the street on the front and one place in the rear. I think I would have required body repair and had at least one destroyed tire if I had tried to AX them.

The R6 is also considered a track tire. I was told by Tire Rack that it would have significantly less grip under AX conditions than the Kumhos I've been running.

I feel like I've been hung out to dry by the tire manufacurers.

--Mike[/QUOTE]

Get Kumho V710s or Hoosier A6s anything else will not be competitive in comparison to thoes tires. If the 225s don't fit then go a width down.

 

[WPGFORDGUY]

Get Kumho V710s or Hoosier A6s anything else will not be competitive in comparison to thoes tires. If the 225s don't fit then go a width down.

X2

I know a few pply had problems with a5's ( not me or anyone I know) but hooiser is blowing out vairious overstock sizes and my buddy selling his as well...

http://www.wpg-autox.org/forums/showthread.php?t=9768

or

https://www.hoosiertire.com/discontinuedtires.htm

710's are still the best imo and so far have lasted longer than the a6's... ( for us anyway) and almost as fast.

I still love V700 Victoracers ( the old mules) I have a set for "regular days" and my Hoosiers for regionals etc.

 

[Primaris]

[QUOTE='03 Sonic Blue]I wish.

I have a set of 225/45-17 Hoosier A6 that do not fit. They rubbed in several places during a 10 minute test drive on the street on the front and one place in the rear. I think I would have required body repair and had at least one destroyed tire if I had tried to AX them.

The R6 is also considered a track tire. I was told by Tire Rack that it would have significantly less grip under AX conditions than the Kumhos I've been running.

I feel like I've been hung out to dry by the tire manufacurers.

--Mike[/QUOTE]

Yea track tires are not going to be competitive with an autocross tire.

Well one thing to note is Hoosiers are way wide for what they list on the side of the tire. So maybe another brands 225's will fit? I don't know if they do it but call the tire rack and see if you can get real world measurement on the width of the tires. For example the Hoosier A6 225/45-17 is listed as 8.8" tread width while the Avon Tech R-A is listed as 8.3". I don't know if these are real measurements though or just factory provided info.

What class are you running the car in?

 

['03 Sonic Blue]

Yea track tires are not going to be competitive with an autocross tire.

Well one thing to note is Hoosiers are way wide for what they list on the side of the tire. So maybe another brands 225's will fit? I don't know if they do it but call the tire rack and see if you can get real world measurement on the width of the tires. For example the Hoosier A6 225/45-17 is listed as 8.8" tread width while the Avon Tech R-A is listed as 8.3". I don't know if these are real measurements though or just factory provided info.

What class are you running the car in?

The car is running in C Stock. I could change wheel size and get any tire I wanted, but it would end up in BSP and would not be competitive there. I understand that it might stand a chance in SM2, but only after extensive mods.

For those suggesting Victoracers, V710s and A6s, I'd love to, but they are not available in a size that will fit the car and remain in stock class.

I've run Victoracers and V710s on the Mustang and they work great. If you can find them in a 205/40-17 or 215/40-17 I'll buy them.

I think I'm going to end up with Kumho Ecsta MX or Falken Azenis RT615 and hope for cold temperatures for the rest of the season. That will keep the rest of the competition on race rubber pushing through the corners.

--Mike

 

[Primaris]

Don't know if this Miata is the same as yours:
https://www.hoosiertire.com/rrtire.htm

Tire info from GRM:
http://www.grassrootsmotorsports.com/images/samples/august_100_115_tiretest.pdf

Good luck with that size.

 

['03 Sonic Blue]

Don't know if this Miata is the same as yours:
https://www.hoosiertire.com/rrtire.htm

Tire info from GRM:
http://www.grassrootsmotorsports.com/images/samples/august_100_115_tiretest.pdf

Good luck with that size.

Thanks for the info.

The 99 Miata Sport came with 15 inch wheels. The availability of race tires in that diameter is much better than for the narrow 17 inch wheel of the 04 Mazdaspeed Miata and for stock class, you can't change wheel size. I don't know if they built enough of them to entice the tire companies to offer some AX tires in a suitable size in the future. Maybe if the Mazdaspeed Miata can kick some butt at Nationals this year is CS they'll recognize it as a market to go after.

I'm going to call Hoosier to see if they know whether the new 225/40-17 will clear the sheet metal on the Miata. Based on thier specs, it should have over 3/8 inch more clearance at the edge of the tread face than the 225/45-17.

I really hate the idea of going back to a street tire on this car. Especially when the guys I'm competing against for Regional Solo points are running V710s and A6s:cuss:

--Mike

 

[BlackBolt9]

[QUOTE='03 Sonic Blue]Thanks for the info.

The 99 Miata Sport came with 15 inch wheels. The availability of race tires in that diameter is much better than for the narrow 17 inch wheel of the 04 Mazdaspeed Miata and for stock class, you can't change wheel size. I don't know if they built enough of them to entice the tire companies to offer some AX tires in a suitable size in the future. Maybe if the Mazdaspeed Miata can kick some butt at Nationals this year is CS they'll recognize it as a market to go after.

I'm going to call Hoosier to see if they know whether the new 225/40-17 will clear the sheet metal on the Miata. Based on thier specs, it should have over 3/8 inch more clearance at the edge of the tread face than the 225/45-17.

I really hate the idea of going back to a street tire on this car. Especially when the guys I'm competing against for Regional Solo points are running V710s and A6s:cuss:

--Mike[/QUOTE]

225/45-17 is about 24.97" Diameter
225/40-17 is about 24.09" Diameter

So with almost an 1" less overall that should give you about 0.5" more clearance on the diameter, lower the car (center of gravity) 0.5" and lower the gearing too for more acceleration although you will run higher RPM's to get the same speed.

Granted I don't know how noticable that would be but according to the engineering principles it works out that way LOL.

 

['03 Sonic Blue]

225/45-17 is about 24.97" Diameter
225/40-17 is about 24.09" Diameter

So with almost an 1" less overall that should give you about 0.5" more clearance on the diameter, lower the car (center of gravity) 0.5" and lower the gearing too for more acceleration although you will run higher RPM's to get the same speed.

Granted I don't know how noticable that would be but according to the engineering principles it works out that way LOL.

The Mazdaspeed would benefit from taller gears. The factory wheel size, (diameter of 23.5), results in top end speeds of 29 in 1st gear, 49 in second gear. Based on Hoosier's published diameters for those tires: 24.5 and 23.9 respectively. The 225/40 would raise 1st gear to 30 and second to 50. The 225/45 brings it to 31 in first and 51 in second.

Overriding all other issues is tire clearance.

--Mike

 

[BlackBolt9]

Oh I see, good luck with finding the tallest that will fit then:thumbsup:

 

[WPGFORDGUY]

Ra1's Or Azenis?

Hmm I'm Stuck Now Too

 

['03 Sonic Blue]

Ra1's Or Azenis?

Hmm I'm Stuck Now Too

Well, I finally managed to get time to call Hoosier today. (I hate places in the Eastern time zone that close at or before 5:00 pm.)

The gentleman named Jeff there said the 225/40-17 size for the A6 and R6they introduced in July of this year was specifically made to address the Mazdaspeed Miata stock wheel size issue. epper: He took my order and said if there was any problem, let them know. I really hope I don't have to call him back.

Problem solved. (I hope)

--Mike

 

[Primaris]

:banana: Good deal, and it lets me use that goofy "smiley" to boot.

 

[WPGFORDGUY]

great news!