correct size tyres for 73 RSR front/ rear?
 

anyone know the correct tyre sizes for a 1973 RSR?
front and rear? i have heard that getting the rear tyres is a problem.........

Front
230/600 on 9x15

Rear
260/600 on 11x15

bill, what would the 600 part match to in todays sizes? 60 profile perhaps?

285/40 x 15 is a road tyre size, but it went out of production many years ago

Adomakin,
230/600 means 230 mm wide, and 600mm in diameter
260/600 means 260 mm wide and 600 mm in diameter
This racing nomenclature is helpful when setting gearing for a particular track.

There are no exact modern equivalents, the #s work out to be pretty close to 225/35x17 and 255/30x17. But there are no tires available in those sizes.

235/40x17 and 265/35x17 are the closest modern street tire equivalents. At least in the specified tread width and overall diameter.

Hoosier do some DOT tyres that are very close to the original sizes, but they are not legal in the UK.

i can get my hands on either 255/60/15, 275/60/15 or 265/50/15 tyres from new, how do they compare?

Check out the rolling circumferences here

a 230/600 is ~9"widex23.6"tall

a 260/600 is ~10.25"wide x23.6" tall

the tire you specified are all way too tall
255/60 is ~ 10 x 27"
275/60 is ~ 11 x 28"
265/50 is ~ 10.9 x 25.5"

Any of them are very poor choices

how about a 265/40/15? i think i can get them new?

If you can find some(I can't) 265/40x15 are ~10.4"wide x 23.4"tall. They would be a good size for the rear.

thanks very much people. bill, ill let you know if i can get them 265/40's if you are interested

285/40 - 15 ... 23.98" for front on 9 x 15 Fuchs

345/35 - 15 ... 24.53" for rear on 11 x 15 Fuchs

are a good match for the street on an RSR clone ...

The 345's are still available, and occasionally I hear about attempts by Pantera folks worldwide for a group buy of special-run batch of 285's.

I am certainly not interested in those tires but I am curious as to what manufacturer makes them.

The only 345/35x15 that I know of is the PZero at 13.9" x 25.9" an 11" rim is at the minimum end of the recommended range and as Warren pointed out there is no available mathing front.

I have a brand new pair of Yokohama AV1 345/35 ZR 15 for sale.

I'm running 255/45-15 front 345/35-15 rear.
Never heard of a 265/40-15.
Yokohama no longer produces any of those sizes (255, 285, 345) in 15 inch.
23.6" is a short tire. You may want to consider the gearing you have when choosing tire sizes. An inch in tire hieght makes a noticeable difference in the final gear ratio. Going to a 17" rim with ultra low profile tires will also help out the handling.

will a 345/35/15 fit under a 73 rsr arch? if it does then im all for it!

Depends on the wheel.
Should work fine using the right width and offset.

I'm running 315's with a one-inch spacer. If you plan accordingly, it shouldn't be a problem at all.

Keep in mind, though, there's a point of diminishing returns, in terms of drag, where the width isn't getting you anything, if you don't have a whole lot of extra power to push it -- at least when it comes to lap times.

Rarly doesn't have that problem, of course. ;)