Can anyone tell me how can a 235 wide tire be wider than a 245 tire? I had 235/60 15 Cooper cobras and change them to 245/45 17 BF Goodridge Scorchers. The BFG are much thinner which really pissss me off. I've measure them many different ways but still the 245 come up short. I've check other cars with similiar size tire and all are wider. My BMW 740 has 235/50 18 up front and they are over an inch wider. Maybe BFG made a mistake,, maybe they don't know the metic system or I just got taken???????

See my car here www.tonymey.de

 

245 is a norrow tire for a 17" rim, GM from the factory runs 275/40-17 on the fourthgens, same thing with the 91-92 firehawk's. Also what are the width on the 17" rim?

 

well, every tire is diffrent, not really sure how a 245/45 tire can not be as wide as a 235/60 the math just doesn't work out

 

My rim size are 17x8,,,, and you are right,, the math does not come out right..... believe me,, no matter how I measure them they are not as wide as my 235.... as I mention before I have my BMW with 235 up front and they are much wider, my old 235-60 are wider,, I just thought maybe I got a bad set Maybe I should wright BF Goodridge and ask them...

 

This is not a very good picture but is all I have for now... check out my site for more www.tonymey.de

 

not a good pic, but my back tires (255/50/16) look just as fat in person if not fatter than a 275/40/17. From this pic, you really cant tell.

 

how far will 40's stick out

 

Tires are measured at their widest width. The tire maybe wider, but the tread width may be smaller.

 

The first number is the width. "40's" would be the profile (or a really narrow tire). A 40 series tire would have a profile that is 40% of the width.

 

but the aspect ration is smaller on the 17's then the 15's so the percentage of that width that is tread width should be BIGGER on teh 17's.

it should be...

tire #1 235/60 235 is the bead to bead with, the aspect ration is 60%, so percent of the 235mm is used up by the sidewalls.

tire #2 245/45 so 245mm bead ot bead width, the aspect ratio is 45%, the math i learned says that 245 / .45 is always bigger than 235 / .60.

 

I've just re-measured my tires here is what I got...
BF Goodridge 245/45-17 thread width 21 cm complete tire width 23.5 cm

Cooper Cobras 235/60-15 tread width 21 cm,, tire width 23 cm

my ZZ1 Avons 235/50-18 tread width 23 cm,, tire width 25 cm.


This is measured in the metic system...

I just thought that since I had 235s that if I went up to 245 I'll have a wider tire,, that is not the case,,,,at least with these BFGoodridges....

Buyer beware and check because the numbers don't add up....

 

The 1st # (235/245)refers to the widest part of the tire,Which is measured at the center of the sidewall where it bulges out the most.The 2nd #(60/50) refers the the height of the sidewall in MMs as a percentage of the 1st #.so a tire w/a 235(width) has a sidewall height that is 60% of 235(or 141mm)a 245 has a sidewall that is 122.5mm tall.A 235/60 will have a taller sidewall causing it to bulge out more making it look wider perhaps than a 245/50.the 245 is still wider,but only by 10mm & thats at the widest part of the sidewall not the tread necessarily.i have the formula for this somwhere.Maybe ill post it if i can find it.

 

Remember every company makes different widths even though they still might have the same size on the sidewall.

Also the Scorcher's are tuner tires. Sport Compacts can fit very wide tires in their wheel wells. I realize that the size should be the size but they could be engineered differently.

 

He's right, actual tire sizes vary from manufacture(SP?). Each one is different. Oh, and when did GM put 17 inch wheels on 3rd gens? Did I miss something?

 

GM didn't but SLP did on the 91-92 Firehawk's - Messed up earlier i meant fourthgen's not thirdgen's *edit*