Whats the widest tire for 17 x 8 bs 4 1/4

[buening 63]

Okay, so 245/17 on an 8" rim is about max then without mods. Would an aftermarket upper control arm give more clearance for a rim with 4.75" backspacing? I don't want that "pizza cutter" look on the front.

 

A 9.5" rim in the rear should fit just fine right? B

 

Here is a pic of my Sumitomo 245/45/17 on 8" rims. The wheels have a 5.72" backspace with a 1" spacer, so I have a net of 4.72" backspace. Note the face of the tire in relation to the fender lip.

 

 

I haven't taken a pic of the clearance to the UCA balljoint, but have between 1/2" and 1/4" from what I recall. From my wheel thread I mention I could have went with a 3/4" spacer, so I'm leaning towards 1/2" clearance. With the 17" wheel diameter, it doesn't hit the balljoint bump in the UCA but rather the lower portion. You'd really have to get a larger diameter wheel wit an aftermarket UCA that uses a low profile balljoint to avoid this issue. I don't recall what diameter wheels 69gmachine is using to fit his wider rims and tires.

 

The 9.5" wide rims will fit out back just fine. I'm running an inch wider, but things are a little too close for comfort and really pushed the envelope. here is my thread if it helps: http://www.1969stang.com/mustang/forum/showthread.php?t=9551

[RPM 1,190]

Oops, never mind.

 

Bob

Edited December 11, 2012 by RPM

[LindenBruce 27]

Thanks Buening. Maybe I'll go 10" in the back then. I'm going to need as much traction as I can get with a warmed up 428FE under the hood. B

Edited December 11, 2012 by LindenBruce

[69gmachine 15]

I don't want that "pizza cutter" look on the front. B

 

I prefer to call it the "Hot Wheels" look :001_tongue:

[buening 63]

If its not a daily driver and not driven much in the rain, look into getting some softer compound drag radial tires like the Nitto 555. Not the greatest in the rain nor do they last the longest, but better traction at a narrower section width than a wider standard radial tire.

[LindenBruce 27]

I stand corrected 69gmachine:devil2: I will remember that next time, thanks dude. I like those Nittos. This car will never be driven in the rain again as long as I owner her. Daily/weekend driver you bet!!! Hammer down baby:hammer:

[SM69Mach 68]

If its not a daily driver and not driven much in the rain, look into getting some softer compound drag radial tires like the Nitto 555. Not the greatest in the rain nor do they last the longest, but better traction at a narrower section width than a wider standard radial tire.

 

 

This is exactly what I am running. 18X10 with a 305/35 and no buldge what so ever. Its a good weather/weekend car so not worried about either of those issues.

[chillininnh 21]

Here is a pic of my Sumitomo 245/45/17 on 8" rims. The wheels have a 5.72" backspace with a 1" spacer, so I have a net of 4.72" backspace. Note the face of the tire in relation to the fender lip.

 

 

I haven't taken a pic of the clearance to the UCA balljoint, but have between 1/2" and 1/4" from what I recall. From my wheel thread I mention I could have went with a 3/4" spacer, so I'm leaning towards 1/2" clearance. With the 17" wheel diameter, it doesn't hit the balljoint bump in the UCA but rather the lower portion. You'd really have to get a larger diameter wheel wit an aftermarket UCA that uses a low profile balljoint to avoid this issue. I don't recall what diameter wheels 69gmachine is using to fit his wider rims and tires.

 

The 9.5" wide rims will fit out back just fine. I'm running an inch wider, but things are a little too close for comfort and really pushed the envelope. here is my thread if it helps: http://www.1969stang.com/mustang/forum/showthread.php?t=9551

 

In your opinion, what would be the ideal backspace be on a 9.5" wheel on the back?

Edited December 13, 2012 by chillininnh

[buening 63]

I think 6" is about the ideal backspace. I'm running 6.3" net backspace on my 10.5" wheels with the 315s and its pretty tight to the leaf spring. I'd like to see an extra 1/4" or so clearance, although I've yet to have the tires rub the leaf spring but rather the inner wheelhouse at the front lower inner corner. The 6" backspace keeps the tire away from the quarter lip to avoid rolling, but you may have to modify the inner wheelhouse with a mallet. If you don't mind the tire being closer to the quarter lip, you could go with 5.75" to gain a bit of clearance to the inner wheelhouse but you introduce the possibility of rubbing the quarter lip during hard corners.

 

Keep in mind tire selection accounts for a large part of "ideal" backspace. Different width tires will bulge differently as well as a taller tire will find other areas to rub, since its the tire that interferes with everything under there and not the rim. I think a 285 tire with 6" backspace 9.5" wide rim is a safe bet to minimize rubbing, unless you really have the rear lowered. Keep in mind that you can always decrease backspace with spacers, but you can't easily increase backspace. My backspace is 6.8" with a 0.5" spacer.

 

What backspacing are you running chillin?

[chillininnh 21]

My current set up is as follows:

 

Rear 17x9 5.5 BS 285/40

Front 17X8 4.5 BS 245/45

 

Although I'm not real unhappy with the stance I have now, I'm considering lowering the car a bit more and as you mentioned before, the 4.5/5.5 backspace is not tucked in enough to do so. My fender lips aren't rolled and I don't want to roll them.

[buening 63]

How is the clearance to your inner wheelhouse at the front lower corner with your current backspacing? This is the limiting factor for backspacing IMO.

[RPM 1,190]

Chillininnh, that is a really nice pic of your car in the last post. Love the stance.

 

Bob

[chillininnh 21]

Thanks RPM. I'm inclined to leave well enough alone but you know how it is!