Is the BFG R1S a Hoosier R7 or A7 Alternative
 

Many years ago, when the Hoosiers were allowed in the Stock autocross classes, this thread discussed them: Hoosier A6 vs BFG R1-S on a BS s2000 CR https://www.s2ki.com/forums/s2000-ra...00-cr-1019431/

Last summer, this review was posted on TireRack:
There are sporadic posts on a variety of forums. They seem to indicate grip similar to the Hoosiers (unclear if R7 or A7 at times) but that they maintain their grip longer in a session and for more heat cycles without excessive wear. Price maybe 5% lower than the Hoosier. I believe they are the spec tire for the MX-5 Global Cup. This is the BFG page for the tires: https://www.bfgoodrichracing.com/roa...force-r1-r1-s/

They come in a wide variety of S2000 compatible sizes from 245/40-17, 255/40-17, 275/35-17, 265/35-18, 285/30-18, and 315/30-18.

Are they a viable or preferable tire for NASA TT, BSP autocross, or track day events?

The R1S is comparable to the A7 and the R1 is comparable to the R7.

I can't speak much on the R1S since it is banned in ST/TT5 but I've been doing a lot of research on the R1. It has similar grip to the R7 but last considerably longer. They are lasting at least twice as long as the R7 on cars in our weight range. Most people used Hoosiers for the generous contingency but now BFG is matching Hoosier contingency for TT so I think many of people will switch over. We will be testing the 245 R1 to the 225 and 245 R7. o

I am interested to hear feedback on the grip levels of the R1S VS A7'S. I run the A7's currently.

How is the sizing of the 245 R1 compared to the Hoo-Hoo's?

I preferred the A7 over the R1S. Slightly better overall lap times but more than that the A7 has better feedback - more predictable slide-characteristic.

In the earlier S2ki BFG R1S thread, posters said the sidewalls were less stiff exasperating the lower feedback. They posited that it should work better with wider rims. On another forum comparing the R1S to the R7 a poster wrote "The Hoosier has a much more forgiving arc once you get past their happy point in slip.. When the BFG starts to slide, it's more noticeable. however, every time you do this to a Hoosier, you remove about 10 laps of rubber from it. You lose almost none on the BFG."

What size tire and rim did you use?

Another thing to note is the BFG sidewalls are extremely stiff.

Interesting...but this review said just the opposite: "Our immediate reaction after driving on the tires for the first time (on the practice course at the TX National Tour) was that the BFG felt VERY different than the Hoosier. It was very apparent that the sidewalls on the BFG were not as stiff as those on the Hoosier. The car moves around a LOT more on the BFG, but it is not the tires that are sliding... it is the tires bending under the transitional load of the car! That took some significant getting used to...". https://www.s2ki.com/forums/s2000-ra.../#post22507357

They concluded that they worked best in classes that allowed wide rims and would work better in lower-profile series. They were using 40-series tires on 17" rims rather than 30-series. In another forum years ago a poster had spoken with a BFG engineer who said the R1/R1S have squared shoulders and don't respond well to being 'overtired' on the rims.

245/40-17 on a 17x8 wheel (per the SCCA STU rules). Only used in a road racing context.

I don't know about sidewall stiffness, but the Hoosiers are significantly lighter than any other tire of comparable grip.

Two questions:

1) How long a race were the A7 and R1S used for? I would have thought a 30-minute w2w race was long for an A7.

2) The 8" rim would probably have been narrow for the R1S. Several reports are they like a wide rim because of construction and tread. 8" is the smallest specified for that tire and I imagine 9"-9.5" would have worked better. I wonder if the 225/45 would have worked better on that rim. I think Samed has tried both with the Hoosier R7s.