Need Help Identifying wheels/tires

[DGRacing56]

Hey everyone,
New user here. I was thinking of buying a backdraft cobra and wanted to replace the wheels and tires with the set seen in this photo but need some help identifying the wheel and tire sizes. I assume 15".
Legendary HB45's? I couldn't find a deep well size for the rears in this pic. Looks like maybe 11"?

[mrmustang]

Originally Posted by DGRacing56

Hey everyone,
New user here. I was thinking of buying a backdraft cobra and wanted to replace the wheels and tires with the set seen in this photo but need some help identifying the wheel and tire sizes. I assume 15".
Legendary HB45's? I couldn't find a deep well size for the rears in this pic. Looks like maybe 11"?

Each manufacturer has their own back spacing, offsets, and adapters for their specific suspension set up. So, for specifically the Backdraft setup, see the attached URL: https://vintagewheelsus.com/index.ph...ex&cPath=59_66

Trigo also makes a nice set of knock off wheels, but you'll need to call them for their specific Backdraft setup:
https://www.trigowheels.com/Wheels.html


Bill S.

[eschaider]

Notwithstanding the Billboard lettering in that picture, those are not Billboards. They used glued-on lettering to recreate the image of billboards. The giveaway is the tread pattern.

The rear tire sizes frequently used on these cars are;

295 x 50 x R15 rear — 26.6 inch diameter
295 x 55 x R15 rear — 28.0 inch diameter
295 x 65 x R15 rear — 30.3 inch diameter
325 x 50 x R15 rear — 27.8 inch diameter

Different manufacturers will bounce back and forth between the 50, the 55, and the 65 series rear tires. Some will offer multiple series for the same tire. Mickey offers the 65 series version of the tire only in their drag radial offerings.

The car will look more aesthetically pleasing/correct if you use a front tire of approximately the same diameter but a narrower width. Your candidates, in terms of size, look like this;

275 x 60 x R15 — 28.1 inch diameter (M/T & Cooper Cobra)
275 x 65 x R15 — 29.1 inch diameter (pretty much unobtanium these days)
265 x 75 x R15 — 30.6 inch diameter (General and Firestone, good size match for 295 x 55 rears)

The Cooper Cobra tires and the M/T 275 x 60 x R15 are essentially the same tires. Mickey is owned and manufactured by Cooper these days.

The no excuses, anywhere, any time, go to tires are Avons. The Cobra Avon sizes are;

245 x 60 x VR15 — 26.7 inch diameter fronts
295 x 50 x VR15 — 26.9 inch diameter rears.

The Avons will cost you about $2,000, which is the high watermark for pricing on this list. They are also the highwater mark for traction (other than Drag Radials used in a straight line). In the FWIW bucket, Avon has been purchased by Goodyear.

Be cautious in your tire choices. These cars are extremely traction limited. The quickest way to get dead is to pick the wrong tires. Good tires / the right tires will be soft and wear out quickly. The wrong tires will be hard and last a long time or until you crash, which will be sooner rather than later. You want something with a UTOQ wear index of 100 or 200.

You can run harder tires, and a lot of people do. When you do, you are betting on the old Russian Roulette admonition that says, "Every trigger pull does not necessarily find a primer ..."


PostScript:

Some 235 x 75 and 245 x 75 tires will appear to have the "right" diameters. More often than not, they will be for SUVs or light trucks. Notwithstanding their "right-sizing," diameter-wise, these tires are wrong for our cars because their construction is engineered for a much heavier vehicle and a different type of use. They will put you into unintended skids, slides, and crashes.

Another thing I overlooked mentioning is that you want to keep in mind the tire load rating. I'll pick on the 295 tires because they are painfully obvious. A 295 tire inflated to its recommended 35 psi has a load-carrying capacity of 2061 lbs per tire. A 2500 lb Cobra only has 625 lbs on each tire with good balance and a 50/50 weight distribution. Many of us have 48% on the front and 52% on the back. A tire with a 2000 lb (or more) load-carrying capacity will never put a full footprint on the ground. Sooo, now you could have a poor traction rubber compound and a smaller than intended footprint if the tire were inflated to manufacturer specs — just a couple more worry beads to rub together.

[Tom Wells]

DG,

Don't forget brake disk diameter. Above a certain OD, 17" wheels are required. 15" wheels may not fit. Just another thing to check...

Tom

[eschaider]

Good point, Tom!

From my own SPF brake research, I have discovered they do not use rotors larger than 12 inches in diameter with the 15-inch wheels on their cars. While I suspect you might be able to fit a bit more rotor in a 15-inch rim, I am not persuaded it is worth the effort. A step up to a larger diameter rim is the shorter, smarter braking solution — and that opens up a whole new vista in tires ...

[DGRacing56]

Thanks for the info everyone. I will digest it and see what I can find.