BFG Drag Radials and Road Courses

[JeffYoung]

So I'm slowly building my 72 into a track worthy vehicle.  Firm Feel 3 box, 1.18 bars, tubular uppers, road race leafs, etc.  I've got the stock Rallies on it now, but looking to switch over to wider wheels and grippier tyres.

A buddy of mne has a 72 Torino and he has the BFG drag radial on it.  In looking at sizes, and I want to stay 15" diamater, BFG goes as big as 325 in the back.  Can you get those to fit without moving the leafs?  Backspacing needed?

I think 275 up front 325 in the back would be great if workable.

Note I"m an SCCA road racer (Improved Touring S), regional champ as a matter of fact, and I have some basic idea of what I'm doing.  Next question is will the drag radials work for just an "average" lapping day? Or do they heat too quickly?

[Patronus]

Not too sure on the 3rd gens, someone from that crowd might help you more. But Im under the impression neutral backspacing is best with the fatties. 15x10 = 5" b.s. There's also a few more choices for the drag radials, Nitto and Goodyear too..

[HPP]

While drag radials are billed as a street tire, they are still a soft sidewall construction for drag racing and that is enough to keep me from trying them on a road course or autocross effort.

A better tire may be the M/T S/R line. Dedicated street tire developed in the last decade for serious street performance applications. Since it was desigend for the larger diameter wheels but is also available in 15" and comes in an H speed rating, it is the most modern 15" street performance tire available outside of dedicated racing tires.

Another option would be the Maxxis MA-S1 Marauder line of tires. http://www.maxxis.com/AutomobileLight-Truck/Light-Truck-SUV/MA-S1-Marauder.aspx

[RallyeMike]

Don't know much about the soft drag radial, but I would have the same concern about sidewall stiffness on a drag radial.

Frankly, I think if you really want to use a decent tire for road course action, you have to go larger than 15" to get any selection at all. At 16" you can at least get several makes of the 255/50/16 which is pretty wide, the size fills the wheel wells (26" tall), and soft compound/stiff sidewalls are available. At least that's what I ended up running....

Steel 16" rims are readily available cheap, but they are heavy.

[myk]

Ok, on the note of wheel sizes, what is a good size for road racing?  I've been trying to decide what size would be optimal for handling.  With all due respect to the Pro-Touring crowd I'm not so sure that those relatively giant wheels, 18" and larger actually help handling performance? 

[thedodgeboys]

Look for a tread wear rating of 200 or less depending on what the ruls are for the event you plan to run. Most have a tire rule of some sort unless your going for exabishion or an open track day just for fun.

The larger wheels are a 2 fold process one benefit to larger wheels is the ability to stuff larger diameter disks on your car for greater stopping and less brake fade. I supose less sidewall would help in the handling department I have seen some tall tires really lean or roll to the point of busting the bead in a hard corner. (Less roll better track times higher cornering speeds)

Lastly it's about what's available from the tire makers themselves. With all the new cars going to 18-20s it's gets hard to find good rubber in a 15 or 16 most of the track tires are in the 17-19 range thanks to the popularity of the oem car builders.


Anybody try to buy 14's latly?

[HPP]

Ok, on the note of wheel sizes, what is a good size for road racing?  I've been trying to decide what size would be optimal for handling.  With all due respect to the Pro-Touring crowd I'm not so sure that those relatively giant wheels, 18" and larger actually help handling performance? 

If your actually racing, the sanctioning body will have a spec tire you have to use. Not much negotiation around that.

If your doing track days for fun, then its all up to you. I've seen constant debates about merits and drawbacks of the ever increasing wheel sizes of today. If you are turning road course laps, even in fun, you still need to make sure you have enough brakes for the sessions you run, and that will drive your wheel sizes more than anything else.

Regardless of all that, the approach I'd recommend is if you go big, go to a size offered by the OEMs on readily available vehicles. The reason for this is that as the size availabilities change over the years, they will always produce at least some tires in the sizes originally offered by the OEMs. So if you go 17" diameter, find a way to fit 275 front and 335 rear. These were original sizes on Vettes and Vipers and will continue to be available long after other size ranges dry up. Same if you step up to 18" or 19" or whatever. These custom boutique sizes that are popular now will eventually go away, but the OEM sizes will remain.

If you want to stick with 15" tires, then the biggest brakes you can possibly get in there is the 12.19 kit offered by Wilwood. This offers additional braking leverage over stock stuff. Another option would be some oval track based 11.75 units that are 1.25 thick. While bigger and heavier, they are a better heat sink than a 1" rotor and that will help reduce fade. Pad selection is important so don't plan on sticking parts store replacement pads in there if you actually running road courses. 15" tires in H speed rating can be found, The S/Rs and Maxxis mentioned by me above are both H rated. There are still some V and Z rated 15" tires out there, but they are spendy, typically $300-500 a tire, offered by Goodyear, Hoosier, Avon, American Racer, Towel City, and Dunlop. Most of these are actually d.o.t. style race tires or repop racer tires, so the aren't true street tires per say.

[Ghoste]

Don't know much about the soft drag radial, but I would have the same concern about sidewall stiffness on a drag radial.

That's what I would tend to think as well, there is a reason the tire mfg's offer different products for different forms of motorsport. 

[RallyeMike]

Regardless of all that, the approach I'd recommend is if you go big, go to a size offered by the OEMs on readily available vehicles.

This is a great point, and exactly a good reason to select the 255/50/16 size. 255/50/16 were OEM size on the earlier Vettes, so they are readily available and there is still good selection of tires with low UTOG ratings.

Here is a sample:

http://www.tirerack.com/tires/TireSearchResults.jsp?customSizeSearch=&width=255%2F&ratio=50&diameter=16

Combine that with the price of what you can buy 16" steel wheels for, and you have cheapskate racing performance at it's optimum.

[Budnicks]

I was going to suggest the BFGoodrich G-Force or Comp T/A's  but RallyeMike beat me to it...