New tires. Drag radial sizes.

[marcar1993]

I just finished up an 8.8 to strange s60 swap in my car and only had stock 14s and the mustang wheels that were on the 8.8. I ordered 18x8s and have tires for them already, but they are a ways from getting here. So I picked up a set of 15x8 weld wheels with 4.5"bs and 28x9x15 slicks.

They rub the 1/4 lip.
I do not want to roll my lip, especially with the wheel well trim.
Not to mention I don't like driving on a slick, or a bias ply in back. So what size and brand drag radial would you guys suggest? I want short, like 26" or less for gearing purposes. I had 245/45r17s and don't want to be taller than those. It looks like my options are pretty slim for a wide short radial in 15"

Thanks guys!

 

[fleming442]

Will a 255/50 fit? I know 235/60 is a popular choice, but I think it'll be hard to hook with a stick. Where are you running, DelMar? Best thing to do would be talk to the stick Mustang guys, and see what they say.
As far as drag radials, the M/Ts are the best at the track, but the sidewall is too soft on the street (for me, anyway). I loved my BFGs, but I don't know if they make them anymore and they got hard with age. I currently have Nitto 555Rs (all 275/60-15s), and they're a bit tricky, although I only got 3 runs in. So far, they seem to like about 20lbs of air and a really soft launch; they spun dumping the clutch at 2000.

 

[UNGN]

The problem with shorter tires is they hook worse than taller tires. A 27" tall 255/60 will hook slightly better than a 26" tall 275/50 and things get worse when you go below 26".

Its not just the sidewall height, its the contact patch length + reduced leverage. A 255/60 with the right BS wheel (a 15X7 is fine) should just fit inside the fenderwell and yield the best traction option.

 

[bracketchev1221]

Like was said, 1" height will give you a bigger impact on traction, than 1" in width.

 

[UNGN]

There has been a myth that has been around for probably 50 years that 26" tires are always "quicker" than 28" tires at the drag strip.

This stems from the fact that 26" tires have 7.7% more mechanical advantage than 28" in tall tires... why... that is like going from 3.08 gears to 3.31 gears!

The problem with this logic is that in reality, on any car that has enough torque to spin the rear tires in 1st gear, it really only applies to "slicks" on a fully prepped track. For every other scenario, the tire that "doesn't spin" is quicker than any tire that does.

Drag radials provide way better traction than regular tires, but they still can spin... especially at a "no prep" street night at the drag strip.

For drag radials at a "street night", 28" tall tires are almost always quicker than 26" tall tires, because they are less likely to blow off when more power is applied.

 

[marcar1993]

Ok, so the real question. I have 15x8 with 4.5" bs, I need a little more 1/4 clearance. Would a 15x8 with 5.5 fit or too much? How about a 15x7 with 4.5, that should pull the tire in a full inch, no? but wouldn't the same tire buldge a little more on a narrower wheel?
I like the 28x9x15 mt slicks, and I'd like to be able to keep running them, but right now they rub hard on the wheel well/trim. I'm also looking at a 275/60r15 mt radial, but that too would need some different backspace. Would the 7" wide 4.5bs rim work for that 275? Or is it just too wide?

According to mt's website:
the 28/9/15 is 27.3 tall with a 10.3 section width and 8.8 tread width.
the 275/60r15 is 28.2 tall 11.1 section width and 9.3 tread width on an 8" rim, I'd be putting this on a 7"
or another tire that I probably cant get in time for me leaving would be
the 255/60r15 whish is 27.1 tall 10.1 section width and 8.8 tread width on a 7.5" rim, I'd be putting this on a 7" rim.

Do you think I can make the 275 work on a 7" rim with 4.5 bs? Or is it going to be a nightmare worse than the 28/9/15 on an 8" rim?

 

[fleming442]

The problem is that the sidewall bulges more on the skinnier rim, so you get a "same but different" scenario. There was a thread here recently about a no-prep guy trying to fit 10" rims because it squares up the contact patch/sidewall. That may be the better direction to head....

 

[UNGN]

275/50's or 60's will rub the the frame with anything more than 3.8" BS on a 7" rim.

The difference between GN wheels (3.9" BS) and T-type wheels (3.75" BS) was the difference between frame rub and no frame rub.

 

[olds307 and 403]

I know the 26x10.5-15 MT ET slicks rubbed on the frame on my 88 CSC with factory 15x7 SS2 rims, which have 0 offset.

 

[UNGN]

The perfect offset in back is right around -.25"

Zero is close, zero with a .25" spacer is closer.

The T-type wheels are close to zero offset. the GN wheels are about .2" offset.