ratt_finkel

So yesterday I hosted a Test and Tune event in conjunction with Evolution Dynamics and AST-USA. We used Mineral Wells as the event site. There is a ton of room there. Unfortunately, it has degraded over time and there is lots of gravel and or sections where nature is trying to reclaim it. However, there are still lots of good usable areas. Including the the large patch where a permanent TnT course is laid out.

We setup the course which has two medium size sweepers connected by a 6 cone slalom on one side and offsets on the other side. Good proportions while being balanced depending on vehicle type.

We had purchased a pile of used BGF's in 285/30/18 that had between 80-90% life left in them. I've had my eyes on these for a while. And I have heard good things about them. After 8 years of running Kumhos and Hoosiers I was ready to try something new.

Had them mounted on my red 10.5" RPF1's and black CE28N's in 9.5" width wheels.



As you can see, they look positively fat on the 10.5's. Hoosiers and Kumho's both look slightly stretched on these rims normally.

Also, I have no problem fitting H's and K's under my mutilated rear fenders. Here are the BFG's installed.



Um, houston, we have a problem LOL

The fronts looked like they would be fine even though they filled up the wheel well quite nicely. But just driving around paddock we noticed the front were rubbing too.



The front tires were rubbing on this metal tab which is part of the fender. BUT, we are not allowed to to modify anything in the wheel well inside of the hub face. And this tab is %75 behind the plane of the hub face.

So not only are these much wider than hooiser or kumhos. They are also significantly taller. The rear could be made to work with 10.5" rims but you would need to clearance (read cut off) significant portions of the rear fender. The problem is in the front. While pointed straight and even during slight steering angle they clear. Significant steering angle, i'd say the last %40 of steering angle WILL result in contact with that metal tab and the side skirt.

I would be highly suspicious of anyone running these in ASP on 10.5" rims in the front. With a different offset they MIGHT work. But it will be very tight. We do plan to try this in the future FYI.

Luckily, the TNT was not ruined. As I did bring the 9.5" width wheels too. So we mounted them up to see how they fit. Again, you can really see how much wider and taller they are on these wheels. We had to play around with numerous spacer congratulations. As they were rubbing everywhere front and rear. Luckily that was an easy fix.




I won't bore everyone with all the changes we made and tweaks we performed. But the car is better in every way possible.

Now on to the tires. This was my 1st time on the BFG R1-S. Mineral Wells is a medium grip asphault. Temps ranged from the mid40's to low 60's during testing.

We ran between 38-40 psi and the tires seemed happy at the ranged. We will play with that more later. Front camber was set at 3.3 negative. Rear was 1.5 negative.

After scrubbing the crud and opr off the tires it was time to see what they could do.

Most of the testing was done with 3 total laps. 1st runs seemed to be about what you would expect from a Kumho V710. Good grip but better towards the end of the run. 2nd runs felt more like a Hooiser that was cold. 3rd run was an entierely different league. These tires have some SERIOUS grip. But they DO like heat.

V710's don't work great in the cold but they are passable and I have seen some fast times fresh out of the gate from them. They handle heat well. And once up to temp don't really get much faster or slower. And are very tough to get greasy.

A6's work great cold but overheat quickly. It's possible to overheat by the end of one run if ambient temps are in the 70-80 degree range.

The BFG's cold seem to produce similar grip levels to the V710. But don't feel as vague. Once they heat up the grip just keeps getting better. It started to get very warm by the end of the day where we had all started the morning bundled up. Were looking for t-shirts, hats and sunscreen at the end of the day.

Even with multiple drivers, passengers and lap after lap. The BGF's never got greasy and just loved the heat. I'm really excited to see how they stand up once we get some hot weather here in Texas.

In closing, I personally felt like the BFG's were better than H's or K's. But since we didn't have matching sets to compare too it's only anecdotal evidence. We will continue to run and test with them. For national events, it will be crucial to get a clean 3rd run, as that is when we found the tires to be fastest. Something to think about if you are considering these tires.

RJones

iTrader: (5)

Nice writeup. I'm thinking about buying a set from that guy on sccaforums for testing and I think you just sold me. I'm in SM and already have those tabs in the front "clearanced" since I run 11" +10s and used to have the taller 295/30s on the car, so I shouldn't run into that issue.

griceiv

iTrader: (2)

I bet it's a mess with your "wrong" offset wheels. With better offset they do fit legally and yes it is VERY tight.

also, i compared them to a hoosier on the same size wheel and they were almost identical diameter.

white_turbo

iTrader: (2)

Thanks for the information.

Do you have a side-by-side comparison with the tires on the 10.5 and 9.5 wheels?

Given its wider spec compared to V710/A6, do you feel any difference in the turn in response on the 9.5 wheels?

psushoe

iTrader: (8)

Since that tab is part of the fender, I read this as it is fair game to modify. Anything that does not come off when you unbolt the fender, however, is not if it is inside the plane of the hub. Guess I'm a little more liberal with that rule, coming from SM where I can change the whole fender

Back to the tires, anyone know how the 315 widths compare between the A6 and R1-S?

psushoe

iTrader: (8)

Also, anyone who runs a full cockpit (two drivers plus ladies driver or two) may not want to stick with BFG. They limit to four tires per event on the payout. For most of us, we'd probably never run into that per event limit... but I know at least one car out there that would fairly consistently.

ratt_finkel

Marshall, I don't think the front wheels are the wrong offset for the front. There is some room, but not much to bring the wheel inboard.

And I just cannot believe they are the same diameter. These look at least 1/4 in taller or more. I have some hoosiers at the shop. I will mount some, measure and take pics. But IF they were the same diameter. Then why all of a sudden would the BFG's start rubbing when I never had any issue with Hoosiers or Kumhos?

I can take pics later this week. I did not have a chance to run on the 10.5 wheels with this test as the rubbing would have caused irreparable damage. I did not notice any significant reduction in steering feel or response considering.

Yeah, like most SCCA rules it is a little vague. But reading that paragraph again, I still don't think it's legal.

griceiv

iTrader: (2)

in the front I'll agree that offset isn't terrible. We definitely rub on the back of the wheel well but we do with the hoosiers too. the alignment is more critical with the wider tires and there is some compromise between running whatever camber/caster/ride height/steering angle you want and the tire fitment. But they do fit.

i think the profile of the tire makes a huge difference. the bfg is very square compared to the others and its the corner of the tire that is the most critical to steering clearance. so while the tires are about the same overall height they are significantly taller at the very edge. Also the narrower a wheel you mount them on the more significant the OD difference is going to be because you're pinching them more resulting in the tread surface bending up. that extra width has to go somewhere once the side wall runs out of flex.

griceiv

iTrader: (2)

the limit doesn't appear to apply to the finale (and i'm guessing it won't to nationals either). Even with a full cockpit taking 4 tires is a challenge. finding the classes with enough competitors isn't easy at local tours/pros, so i'm not sure it's really much of a restriction.

a 4 tire limit at nationals/finale would be a deal breaker though.

ratt_finkel

Marshall brings up a good point. Some additional caster will help to bring the wheel forward. My setup was maxed at around 5.7 degrees? So we didn't have the option of trying that. To be honest, I'm so happy with my setup I am scared to change it LOL! But the real test will be at Lincoln for Springs Nats.

Another good point about the profile. But I would call it section width, which adds to the overall width of the tire. PS, on the narrower wheels we did not experience rubbing in the same place. ( though I agree with your comment on making the tire taller) They were rubbing on the coilovers in the front and LCA in the rear. I used a 20mm spacer in the front and 5mm spacer in the rear to solve the issue.

RJones

iTrader: (5)

You're right, you should be able to solve the rubbing on the tab by adding caster at the LCA, a la something like the Perrin PSRS. Supposedly the wheel is moved forward something like 1/4 - 1/2".

ratt_finkel

Sadly, that piece is not legal for ASP.

griceiv

iTrader: (2)

only because it's made of aluminum, not delrin.

RJones

iTrader: (5)

Sounds like there's a market for it. Marshall, make it happen!

EVOizmm

iTrader: (10)

Nice write-up Jeremy. It sounds like the R1S would be a great TT/TimeAttack tire.

Thanks for sharing.