68-69 GM-A rear tires. 295/40-18 vs. 295/45-18

[STREETFIGHTER50]

Just got my AR VN510 wheels. 18x8 with 4.5” BS and 18x10 with 5.97” BS. I’m most likely going with 245/45-18 up front. Trying to decide which rears to go with. Would 295/45’s be too tall looking?

[BAMF68]

I have 18x10 with 6" bs. Running a 295/40/18 Nitto 555g2. Fender lips are not rolled and it's very close.

[cdrod]

The 295/45R18 is almost 2" taller (1.8") than the 245/45R18 and would probably look too tall. The 295/40R18 is a better match at only 0.6" taller than the 245 tire so the sidewall height would look almost the same front to back. A 285/40R18 is only .3" taller than the 245 tire so the sidewall height is nearly identical front to back; if that matters to you.

[STREETFIGHTER50]

I have 18x10 with 6" bs. Running a 295/40/18 Nitto 555g2. Fender lips are not rolled and it's very close.

Sick ride! Sitting properly with them shoes! What are the front wheel/tire specs? Also, what suspension set up?

[BAMF68]

Sick ride! Sitting properly with them shoes! What are the front wheel/tire specs? Also, what suspension set up?

Thanks man!! Running a UMI Performance Stage 5, Viking coil overs. Front set up is a 18x9 with 5.5" back spacing, 275/35. Biggest tire combo for the front, really grips well and no rubbing.

[71OLDS]

Here's some before and after pics that might help you with this. My 71 442 had 305 45 18s in the rear and I changed to 305 40 18s as I'm getting it set up for autocross. Very similar drop in diameter for the 295s you are considering. The 40 series rear levels the car a little more or said another way eliminates the slight rake with the much taller rear tires:
305 45 18s:



and here's the 305 40 18s:

[STREETFIGHTER50]

Thanks man!! Running a UMI Performance Stage 5, Viking coil overs. Front set up is a 18x9 with 5.5" back spacing, 275/35. Biggest tire combo for the front, really grips well and no rubbing.

Does the set up you have eliminate the inner fender wells? I would’ve love to run something wider up front, but my wheels are only 8”. 245/45-18 looks good at the moment. If I could run a 255/45 maybe. Might be too big.

[STREETFIGHTER50]

Here's some before and after pics that might help you with this. My 71 442 had 305 45 18s in the rear and I changed to 305 40 18s as I'm getting it set up for autocross. Very similar drop in diameter for the 295s you are considering. The 40 series rear levels the car a little more or said another way eliminates the slight rake with the much taller rear tires:
305 45 18s:



and here's the 305 40 18s:

Yall got some bad ass verts! Did the ‘71 require massaging back there to fit 305/45s? Those do look tall. Thanks for the before and after pics! You guys got me sold on the 40’s. Looks better and will handle better. Can’t wait to see your Olds finished!

[BAMF68]

Does the set up you have eliminate the inner fender wells? I would’ve love to run something wider up front, but my wheels are only 8”. 245/45-18 looks good at the moment. If I could run a 255/45 maybe. Might be too big.

Nope, factory fender wells. It clears my big sway bar as well.

[71OLDS]

Yall got some bad ass verts! Did the ‘71 require massaging back there to fit 305/45s? Those do look tall. Thanks for the before and after pics! You guys got me sold on the 40’s. Looks better and will handle better. Can’t wait to see your Olds finished!

Thanks - For the 305/45s the lip was cut to the outside and my chrome trim piece was "folded" around the edge. This gave about 1/2" more clearance to the outside. Then to the inside had to "massage" the wheel wells with a BFH and some touch up spray plus the 3" tail pipes had to have flat spots put on them for a little more clearance. Now I'm trying to make room for 325/30/19s on the back for autocross and street. Notching the frame about 3/4" for starters to try to allow a 6.5" BS or even a 6 3/4". The current 305/40 drag radials will be my drag race setup and also are fun on the street sometimes.

For your fronts - my before after pics work for you again! Before is 255/45/18 after is 245/45/18. Both on 18x8. I would strongly encourage the 245/45/18s for several reasons. First the 255s at 27" tall really restrict the turning radius. One thing I've learned with the project I'm working on now (trying for 305/30/19 on the front) is the diameter on the fronts is just as important as the width. My 255s actually hit my sway bar on turn in so couldn't figure out how guys were running 315s on the front with no issues. Well...a 315/30/18 tire is only 25 1/2" diameter. Even though it's 12.8" wide on an 11" wheel, the short diameter gives you more room for width. Also the 245's at 26.7" (and a little thinner) give lots of room for full turning radius. A 255 on an 8" wheel doesn't put much more tire on the ground then a 245 on an 8 so there's no real advantage. Last is the weight. Most 255s are a pound or two heavier than a 245.

-Joe

[Mr Nick]

Would 295/45’s be too tall looking?

I had 295/45/17 rear and 255/45/17 front for a while, and the rears were much taller "looking" than the front. More of a big 'n little drag race type look. I would highly recommend 285/40 or 295/40 on the rear to go along with your 245/45 up front.

[cdrod]

Streetfighter:
You didn't say what car you have so the following info may not be helpful to you if you don't have an A-body. The pics below show the fitment on my '72 Olds 442/Cutlass convertible with a 285/40R18 tire on a 9" rim with a 5.25" backspace (+8mm offset). I have 1.5" clearance on the inside to the frame rail and about .75" clearance to the fender lip w/o out trimming or rolling. I have a 2.5" Pypes exhaust system which is a bit closer than the 1.5" clearance (not shown in these pics). I could go with a wider tire with a 10-11" wide rim and deeper backspace.

Rodney

[STREETFIGHTER50]

Nope, factory fender wells. It clears my big sway bar as well.

Maybe on my next set I might just have to try that out. 18x9 with 5.5” BS & a 275/35 would be awesome to have inside the stock fender wells

[STREETFIGHTER50]

Thanks - For the 305/45s the lip was cut to the outside and my chrome trim piece was "folded" around the edge. This gave about 1/2" more clearance to the outside. Then to the inside had to "massage" the wheel wells with a BFH and some touch up spray plus the 3" tail pipes had to have flat spots put on them for a little more clearance. Now I'm trying to make room for 325/30/19s on the back for autocross and street. Notching the frame about 3/4" for starters to try to allow a 6.5" BS or even a 6 3/4". The current 305/40 drag radials will be my drag race setup and also are fun on the street sometimes.

For your fronts - my before after pics work for you again! Before is 255/45/18 after is 245/45/18. Both on 18x8. I would strongly encourage the 245/45/18s for several reasons. First the 255s at 27" tall really restrict the turning radius. One thing I've learned with the project I'm working on now (trying for 305/30/19 on the front) is the diameter on the fronts is just as important as the width. My 255s actually hit my sway bar on turn in so couldn't figure out how guys were running 315s on the front with no issues. Well...a 315/30/18 tire is only 25 1/2" diameter. Even though it's 12.8" wide on an 11" wheel, the short diameter gives you more room for width. Also the 245's at 26.7" (and a little thinner) give lots of room for full turning radius. A 255 on an 8" wheel doesn't put much more tire on the ground then a 245 on an 8 so there's no real advantage. Last is the weight. Most 255s are a pound or two heavier than a 245.

-Joe

Really good info for the front Joe! I see! Thank you!!

[STREETFIGHTER50]

I had 295/45/17 rear and 255/45/17 front for a while, and the rears were much taller "looking" than the front. More of a big 'n little drag race type look. I would highly recommend 285/40 or 295/40 on the rear to go along with your 245/45 up front.

Yes I’m definitely going 295/40 and 245/45 for this set. Maybe Nittos

[STREETFIGHTER50]

Streetfighter:
You didn't say what car you have so the following info may not be helpful to you if you don't have an A-body. The pics below show the fitment on my '72 Olds 442/Cutlass convertible with a 285/40R18 tire on a 9" rim with a 5.25" backspace (+8mm offset). I have 1.5" clearance on the inside to the frame rail and about .75" clearance to the fender lip w/o out trimming or rolling. I have a 2.5" Pypes exhaust system which is a bit closer than the 1.5" clearance (not shown in these pics). I could go with a wider tire with a 10-11" wide rim and deeper backspace.

Rodney

I have a ‘68 Skylark. My rear tire on it now is a 275/40 with same size/spec wheel as yours. My fenders have been rolled. I do have more space than on the inside than outside. 295/40 might be the max on mine.

[STREETFIGHTER50]

I think it will be tight!

[andrewb70]

295/40 rear and 255/40 front is a nice combination. I ran that on my 70 GTO.

Andrew

[STREETFIGHTER50]

295/40 rear and 255/40 front is a nice combination. I ran that on my 70 GTO.

Andrew

What wheel set/specs? 9” front?

[andrewb70]

18x9.5 6" back spacing in the front
18x10.5 6.25" back spacing in the rear