Toyo Proxes RA-1, 25.6 lbs, $ 188

Kumho MX, 27.0 lbs, $ 206

Azenis, 26.9 lbs, $ 218

The Proxes are the lightest and cheapest, so I'm leaning that way. If you know of any other Max, Extreme or Brutal rated tires, that deserve consideration, please advise. All other obscure brands and all comments are welcome.

Kumho MX - street tire suitable for everyday use
RT-615 - very soft street tire, more of a street legal autocross tire
RA-1 - hard R-compound

I know some Porsche owners use the RA-1 as a street tire on a weekend car but I'm not convinced this is a good idea.  I think it is too susceptible to hardening from too many heat cycles.

I drove the Azenis Sport (RT-215), the precursor to the 615, on the street some and I liked it but I also AX'd it and only had the tires for 1 year.

The Azenis 215 had very stiff side walls and the 615 seems to also.  I currently have 2 sets of 615's in 245/40R18 and 245/40R17.  I have a set of RA-1's in 255/40R17.  But I dont drive any of them daily on the street.

I suppose I'd characterize the RA-1's as somewhat stiffer then the average performance tire and I'd say the MX is just as stiff as the average performance tire.

Jeron
BMW / PCA / Apex HPDE Instructor
97 M3/4 Byzanz/Magma; 2001 330i Silver/Gray; 97 R1100RT; 91 F-150 5.8l

So in comparison to the Azenis neither of the 2 tires are as stiff as the Azenis? In descending stiffness order they are Azenis, RA-1 and MX? Is that correct?

Comparing the RA-1 to the Azenis. Is it 80% or 90% of the Azenis's stiffness or what percentage?

Would the Azenis and the RA-1 build up enough heat, in normal street use, to heat cycle the tire? Or is there a threshold temperature that the core rubber has to reach to qualify as a heat cycle?

Road course, track and street, superior turn-in, maybe some drag as in boulevard queen.

I'm just giving you my impressions of the tires I don't have any empirical data to support it, but yes that is the order I would give.  I don't think I could express the relative stiffness meaningfully much less as a percentage.

Tire get pretty warm on the street, enough to get pressures up 5psi.  I've had a tires that I filled cold jump 4psi just from sitting in the sun for an hour.  In addition, the soft compounds seem to harden more rapidly from the elements and time.

I think the RT-615 will be a better street tire than the RA-1, but neither one will last long though.  I hope you understand what you are getting into with the 615 and the RA-1.

Overall what I'm trying to say is those 3 tires run the gamut from street, to streetable track, to track only and they shouldn't make it into the same "final three" list.

Jeron
BMW / PCA / Apex HPDE Instructor
97 M3/4 Byzanz/Magma; 2001 330i Silver/Gray; 97 R1100RT; 91 F-150 5.8l

There are at least 3 street/racing tires available with a stiff sidewall. They are the Falken RT-615, the Hankook Z212 and the new Toyo Proxes R888. If you know of any others in this category please add them.

Has anyone experienced or heard about the new R888 in regards to sidewall stiffness or anything else?

And the final question, can anyone rate the sidewall stiffness of these 3 with the stiffest being the best?

There is a thread in LSC General about them but it wont answer your question.

Jeron
BMW / PCA / Apex HPDE Instructor
97 M3/4 Byzanz/Magma; 2001 330i Silver/Gray; 97 R1100RT; 91 F-150 5.8l