Is anyone running the BFG R1's? I have 275/35/18's and was wondering what tire pressures people are using.
Last edited:
BFG R1 tire pressures
- Thread starter steve121
- Start date
I just got a set to replace my corded RA1s, and will try them out at Summit Point in 2 weeks.
A friend who ran them late last year in a '97 Cobra vert with suspension mods said I should start around 29F/27R. A bit different from my old Avon Tech Rs and the Toyos, but all tires are different. :shrug:
A friend who ran them late last year in a '97 Cobra vert with suspension mods said I should start around 29F/27R. A bit different from my old Avon Tech Rs and the Toyos, but all tires are different. :shrug:
I'll be at Lime Rock Park tomorrow. I found some information from BF Goodrich
http://www.bfgoodrichtires.com/assets/pdf/R1_Guide_online_2.26.07.pdf
http://www.bfgoodrichtires.com/assets/pdf/R1_Guide_online_2.26.07.pdf
Good find, Steve. :thumbsup:
These pressures sound more in line with what I was expecting.
Let us know how you like them. I heard good things when they first came out.
These pressures sound more in line with what I was expecting.
Let us know how you like them. I heard good things when they first came out.
36 F 34 R is a good place to start cold and work up to 40-42 hot.
I start at 36/34 and then check again as soon as I come off track. If they are 40-42 great, leave them and let them cool.
If over 42, I let them cool and then drop another couple of psi when they cool. I DON'T let any air out till they cool back down.
I've found if you get into the 45 psi region, tires start going away and get greasy. 35-36 psi hot and they seem to wallow.
I've done that for years when you could actually talk to a BFG engineer at divisional and national SCCA autocrosses.
Heard the same thing from Kumho and the guys at Hoosier at SEDIV roadraces, although they say the new R6 can run a couple of psi less but still in the 40 psi hot range.
29 psi cold and you will never get the rears up to temp, unless you are just spinning tires on every corner. Not good.
BTW we used to start with 10 PSI on Hoosier and Goodyear slicks with the formula ford.
I start at 36/34 and then check again as soon as I come off track. If they are 40-42 great, leave them and let them cool.
If over 42, I let them cool and then drop another couple of psi when they cool. I DON'T let any air out till they cool back down.
I've found if you get into the 45 psi region, tires start going away and get greasy. 35-36 psi hot and they seem to wallow.
I've done that for years when you could actually talk to a BFG engineer at divisional and national SCCA autocrosses.
Heard the same thing from Kumho and the guys at Hoosier at SEDIV roadraces, although they say the new R6 can run a couple of psi less but still in the 40 psi hot range.
29 psi cold and you will never get the rears up to temp, unless you are just spinning tires on every corner. Not good.
BTW we used to start with 10 PSI on Hoosier and Goodyear slicks with the formula ford.
Last edited:
I started out with 37F 35R which made the car tough to control in the turns. It took almost the full first session before enough pressure built to stabilize the handling. The last couple of laps the car was handling as expected. I checked pressure once I was back to the paddock, 42F 41R. The next session came before the tires were completely cold and I went out with 41F 40R. The car seems good right from the first lap and a check of the pressure at the end of the session revealed 42F 40R. It seems like the tires like a higher starting pressure than I expected.
Obviously, you aren't going fast enough.;-)
Seriously, our races are 30-45 minutes and the Hoosier come on pretty quickly- a lap or so. I count on about 4-5 psi increase during the course of a race.
When I ran BFG's back in the '80's- early '90's they acted similarly.
Seriously, our races are 30-45 minutes and the Hoosier come on pretty quickly- a lap or so. I count on about 4-5 psi increase during the course of a race.
When I ran BFG's back in the '80's- early '90's they acted similarly.
What's interesting is the pdf you found, Steve, lists the pressure recommendations. For a car over 3100 pounds (anyone here like that? Go ahead, raise your hands, don't be shy.), they recommend cold of 29-34, and hot of 37-43.
So it looks like you're in the hot range, but they didn't gain as much as one might expect.
Add 500 pounds to your car, and try again. :thumbsup:
So it looks like you're in the hot range, but they didn't gain as much as one might expect.
Add 500 pounds to your car, and try again. :thumbsup:
We have run BFG R1's with factory advice in the last year. We baseline 30front 28rear cold temps. At Road Atlanta weekend before last we adjusted for the track starting at 29 LF 31RF 27 rears.
Our temps across the tire were consistant and performance on the line.
If your are starting at or near 40psi cold and not seeing any increase in pressures, you are either going slow or going in a straight line a lot.
Our temps across the tire were consistant and performance on the line.
If your are starting at or near 40psi cold and not seeing any increase in pressures, you are either going slow or going in a straight line a lot.
I'm raising my hand WAY UP seeing I'm at 3600 + with me in the car and a full tank of fuel! The chart is showing 37-43+ hot for a 3100 lb car so if I end up with 41-44 hot for a 3600 lb car that must be in the acceptable range. The tires are wearing evenly across and they are rolling over to the side indicators.
Rob
What are you ending up with hot?
Looks like you did OK down there with NASA event.
Are you going to do ARRC again this year? Looks like I'm going to miss SIC, so I may come down for it. Butch sez there will be a ton of GTA cars......wait, GTA..make that SEVERAL tons of GTA cars.
Steve
Interesting you aren't getting more heat and pressue build up.
How many laps and how long are your sessions?
:idea:SAaaaaay!
You aren't using nitrogen, are you?
Dave
What are you ending up with hot?
Looks like you did OK down there with NASA event.
Are you going to do ARRC again this year? Looks like I'm going to miss SIC, so I may come down for it. Butch sez there will be a ton of GTA cars......wait, GTA..make that SEVERAL tons of GTA cars.
Steve
Interesting you aren't getting more heat and pressue build up.
How many laps and how long are your sessions?
:idea:SAaaaaay!
You aren't using nitrogen, are you?
Dave
Mmmmmmmm......nitrogen. 
Rob, a couple questions if I may. While I've been at this a bit, I still have huge, cavernous black holes of knowledge to fill in.
First, why 29LF and 31RF when RA is predominately a clockwise track? Are you honing in on a turn or series of turns with that?
And second, (and Steve, I hope this fits in with the info you're looking for so I'm not technically hijacking), the general consensus seems to be for our type of car (heavy, RWD) running around 2 pounds more in the front than the rear. I've sometimes gone out with equal pressures front and rear, and the car has been very balanced. Now I understand that every track/car/driver combo can have different requirements. But what is the prevailing thinking behind the 2 pound increase in the front over the rear?
Sorry, I often ramble when I'm trying to get something out of my brain. :bash:
Rob, a couple questions if I may. While I've been at this a bit, I still have huge, cavernous black holes of knowledge to fill in.
First, why 29LF and 31RF when RA is predominately a clockwise track? Are you honing in on a turn or series of turns with that?
And second, (and Steve, I hope this fits in with the info you're looking for so I'm not technically hijacking), the general consensus seems to be for our type of car (heavy, RWD) running around 2 pounds more in the front than the rear. I've sometimes gone out with equal pressures front and rear, and the car has been very balanced. Now I understand that every track/car/driver combo can have different requirements. But what is the prevailing thinking behind the 2 pound increase in the front over the rear?
Sorry, I often ramble when I'm trying to get something out of my brain. :bash:
Cold pressures were 37F 35R (275/35/18's), I ended up with about 43-44F 41-42R after the first session for about a 6 psi gain. The tires never had a chance to cool down between the next sessions.
Sounds about right then. You are about 400 lbs heavier than I have to be.
Greg
For the very reason you mentioned. Since Road Atlanta is mostly right corners, several pretty fast... 1 and 12 come to mind, the outside left is going to have more load, soo...........
As far as going out on equal pressures. I've done that too.
More of a fine tuning thing.
If optimal grip is going to be around 41 psi and 190*, you can tune out a bit of understeer with optimal pressure in the fronts and maybe just close in the rears. See-The-Face-of-God grip in the front and pretty-darn-good in the rear.
Maybe a slightly longer footprint in rear helps acceleration, too. Dunno, just sounds good. ;^)
Remember, not as much load on the rears, what 65%-45% and under braking, even less.
Greg
For the very reason you mentioned. Since Road Atlanta is mostly right corners, several pretty fast... 1 and 12 come to mind, the outside left is going to have more load, soo...........
As far as going out on equal pressures. I've done that too.
More of a fine tuning thing.
If optimal grip is going to be around 41 psi and 190*, you can tune out a bit of understeer with optimal pressure in the fronts and maybe just close in the rears. See-The-Face-of-God grip in the front and pretty-darn-good in the rear.
Maybe a slightly longer footprint in rear helps acceleration, too. Dunno, just sounds good. ;^)
Remember, not as much load on the rears, what 65%-45% and under braking, even less.
Last edited:
Same thing I've found. Again, I would have probably dropped a couple of psi before I went back out, even while still warm. :beer:
That's what I was thinking. But in my train of thought, since that would cause the LF to get worked harder, it would need a pound or two more to keep from getting overheated, assuming the front pressures are already dialed in. If I can use circle track as an example (I know its apples to oranges), don't they run a bit higher on the outside?
So is what you're saying that the LF would rise say 6~7 lb, and the RF rise say 5~6, so you get a balance accross the front? Am I answering my own question?
David: Our hot pressures were 38-39.
Yes, we are running the ARRC enduro again. We will have two cars entered for that. The Cobra R and my '08/'09 magazine project, a '99 Cobra Bondurant car.
I may run one of the cars in the ITO sprint race just to get some practice for the enduro. There will be 500-600hp cars running in the sprint in ITO and no point in racing them.
I think we will run the October VIR SARRC in AS for the first time. Try and get a base line on that question. 3680 is ridiculous. Tom Ellis is going to run the ARRC enduro with us and he told me today that the weight penalty is prohibitive.
Cassidy: The reason for the 31psi in the right front and 29psi in the LF at Road Atlanta is to balance the tire pressures when they heat up. RA has several high speed right handers that had our left front 2 to 4psi higher than the right front. That caused us to have an evil loose in condition that was VERY uncomfortable at Road Atlanta. Without that the right front pressures are two to four psi higher than the left front and the car gets real nervous under hard braking.
We have found that the tires grip better when cool and the better grip at that time washes a good deal of the unsteadyness til the pressures build up to even. Then when the tires are hot and not gripping so well, the pressures are even and the car handles much better.
As for going out with even pressures, my car tends to be a tick loose. I've found that raising the rear tire pressures is a sure fire way to tighten a car up. However, my preference after finding the new pressures working, is to then change the rear shock settings to mimick the increased tire pressures and then reduce the pressures back to soften the rear tires for forward bite.
Yes, we are running the ARRC enduro again. We will have two cars entered for that. The Cobra R and my '08/'09 magazine project, a '99 Cobra Bondurant car.
I may run one of the cars in the ITO sprint race just to get some practice for the enduro. There will be 500-600hp cars running in the sprint in ITO and no point in racing them.
I think we will run the October VIR SARRC in AS for the first time. Try and get a base line on that question. 3680 is ridiculous. Tom Ellis is going to run the ARRC enduro with us and he told me today that the weight penalty is prohibitive.
Cassidy: The reason for the 31psi in the right front and 29psi in the LF at Road Atlanta is to balance the tire pressures when they heat up. RA has several high speed right handers that had our left front 2 to 4psi higher than the right front. That caused us to have an evil loose in condition that was VERY uncomfortable at Road Atlanta. Without that the right front pressures are two to four psi higher than the left front and the car gets real nervous under hard braking.
We have found that the tires grip better when cool and the better grip at that time washes a good deal of the unsteadyness til the pressures build up to even. Then when the tires are hot and not gripping so well, the pressures are even and the car handles much better.
As for going out with even pressures, my car tends to be a tick loose. I've found that raising the rear tire pressures is a sure fire way to tighten a car up. However, my preference after finding the new pressures working, is to then change the rear shock settings to mimick the increased tire pressures and then reduce the pressures back to soften the rear tires for forward bite.
Last edited:
There you have it.
Rob
I've been following you on ASedan.net
A/Sedan could get crowded with all these new cars.
3680 is pretty porky.
There will be 500-600hp cars running in the sprint in ITO and no point in racing them.
Ya think? :beer:
I saw a few of them at Road Atlanta SARRC.
Rob
I've been following you on ASedan.net
A/Sedan could get crowded with all these new cars.
3680 is pretty porky.
There will be 500-600hp cars running in the sprint in ITO and no point in racing them.
Ya think? :beer:
I saw a few of them at Road Atlanta SARRC.
I know you go to Asedan.net. Seems I am about the only guy revolting against the weight penalty. Yet everybody in AS that I know in the southeast including Tom Ellis and Bob Eubanks tell me that weight is unsafe.
Bottom line is that the powers that be want infuse new entries in the class, but only if they will show up and lose.
Bottom line is that the powers that be want infuse new entries in the class, but only if they will show up and lose.
A work in progress, for sure.
Rodney Sneed at Hoosier told me the "new" Hoosier liked a couple of psi less, so 38-39 hot sounds right for them, too.
I'm an Econoracer, so I've been using a bunch of R5's I bought cheap.
Just bought a set of R6 at Road Atlanta last month, and then blew a gasket before I got to try them.
You going to Birhmingham?
Rodney Sneed at Hoosier told me the "new" Hoosier liked a couple of psi less, so 38-39 hot sounds right for them, too.
I'm an Econoracer, so I've been using a bunch of R5's I bought cheap.
Just bought a set of R6 at Road Atlanta last month, and then blew a gasket before I got to try them.
You going to Birhmingham?
Users who are viewing this thread
