I have a set of 275/60-15 drag radials on the back of my car. The BFG spec sheet says they should have a diameter of 28 inches. Whether loaded or unloaded, they actually have a diameter of roughly 27 inches.

I also have a set of 255/60s and 235/60s - they are right at the spec values of 27 and 26 inches.

So what gives with the 275/60s? Does someone out there have the same tires or radial TA 275/60s and can check the diameter?

Ed

when you apply the formula, a 275/60R15 is 28 inches. Each tire manufacturer does have diffrent tolerences.

[This message has been edited by CJ (edited 01-25-2002).]

I have no problem with them calling the drag radial a 275/60-15 and allow them some freedom in what the dimensions really are, but one would think they would get the diameter correct in their own spec sheet.

Ed

i have the exact same on my rear and they measure 27 as well...but 28 is what the spec sheet says..

Rim width will affect overall diameter. A wider rim will shorten diameter by pulling the side wall out and down. So you can get a different actual installed diameter than whats advertised. If you compare a 275/60 15 mounted on an eight inch wide rim to the same tire mounted on a nine or ten inch wide rim youll get different diameters with each. Also are the tires inflated to the tire manifactures specs. If there at 15 or 20 psi they will sit lower than at the max psi that the tire can run at.

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70 Camaro 307cid(350soon) /350th ex. dark purple (dark blue soon) in. black
74 Trans Am 400cid/th400 ex. red in. red power windows

[This message has been edited by Joekool1234567 (edited 01-27-2002).]

My tires are on an eight inch rim, are properly inflated and have the same diameter
loaded or unloaded - short by an inch relative to the spec that is.

Anybody have the TA (as in non-drag radial) 275/60 that can give a measurement of it?

Ed

Ed,

My old L-60/14's on a 9" rim were like a modern 298/53-14, so go figure(???) pdq67