tire size

[denny]

ok i'm almost ready to buy my tires for my 81 malibu. i just want to be sure i don't run into problems with tire fitment. right now i have the stock housing (7.5)and have read where the max tire size is 255x60x15 which i want to install. this is the rear. i was going to buy 245's just to make sure i have some wiggle room in case of problems. i have 8 inch wide vision rallys,with 4 1/2 back space. i would be ok with 245's but would really like to get 255's if there is no problems. i'm just about ready to install my QP 9 inch ford which is made for my g-body so it is the same width as the stocker in there now. i'll run the new tire and rim setup for a while before i make the swap. the rear disc brake set up says it will be .125 wider. i don't think that will be a problem just being a 1/8 wider on each side. i'll run my koni coilovers and have mocked them up and it looks good to go. just want to be sure the 255's will be ok without any rubbing problems. what do you think? thanks
,

 

[superbon54]

I had 255/60-15 mounted to 15x8 with 4.5” backspace and the had almost a finger width of clearance on the inside. Each car varies slightly so depending on how the welders/assemblers did and how centered the rear is under the chassis, your setup should work fine.

 

[denny]

I had 255/60-15 mounted to 15x8 with 4.5” backspace and the had almost a finger width of clearance on the inside. Each car varies slightly so depending on how the welders/assemblers did and how centered the rear is under the chassis, your setup should work fine.

thanks for the reply. that helps a lot.

 

[lilbowtie]

You can figure it out mathematically. You have aprox 5.5 in. from the drum to the frame. With 4.5 BS you have about an inch left. The cross section of the tire you want to use is 9.5 inchs so the tire is going to be 3/4 inch wider than the 8 in rim on both sides. There is a little room on that number since BS is measured from the lip and not the bead seat of the rim.

 

[Doug Chahoy]

I’ve got the QP 9 with LS disc’s and Vision wheels 17X8 4.5 BS and 245/45X17 tires. Good clearance all around

 

[denny]

You can figure it out mathematically. You have aprox 5.5 in. from the drum to the frame. With 4.5 BS you have about an inch left. The cross section of the tire you want to use is 9.5 inchs so the tire is going to be 3/4 inch wider than the 8 in rim on both sides. There is a little room on that number since BS is measured from the lip and not the bead seat of the rim.

ok thanks

 

[denny]

I’ve got the QP 9 with LS disc’s and Vision wheels 17X8 4.5 BS and 245/45X17 tires. Good clearance all around

thanks Doug

 

[403Olds]

I've got a 7.5", but using aluminum drums, with 255/60/15 and 15X8 w/ 4.5" BS Welds, it's centered real well, with a finger width on both inside and outside.

 

[scoti]

15x8; 4.25"BS, 255/60's, & at least 3" of drop. I did have to trim the lip slightly on the drivers side because as mentioned "each car varies slightly so depending on how the welders/assemblers did and how centered the rear is under the chassis". Fronts are different/smaller size.

Previous cars/El Caminos done w/similar rear set-ups didn't require trimming.

 

[denny]

I've got a 7.5", but using aluminum drums, with 255/60/15 and 15X8 w/ 4.5" BS Welds, it's centered real well, with a finger width on both inside and outside.

thank you for the reply Olds. looks like it's gonna be 255's for me.