305/35r20 on 9.5" rim rubbing

Norm Peterson

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I can definitely get a 275 on there. I put the fronts on the rear to see how it looked.
It was on a 8.5 in rim, no clue what the offset is.
Measure that wheel's backspacing, from the innermost face of the inside flange to the mounting face on the back side of the wheel center (do not measure from the tire bulge). Subtract half of 9.5" from that and convert to mm. That'll be close enough for discussion purposes.

The 9.5" comes from 8.5" wheel width (which is measured between the bead seats) plus two flanges at half an inch apiece.


Norm
 

Pentalab

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I didn't put the passenger side on. But the rears were centered with the stock rims.

If you didn't install the pass side, does it rub on driver's side...when you drive around with oem tire on the pass side ?? It's not rubbing..just sitting there in the driveway, with the wider rear on the driver's side, so when does the rubbing occur ?

What u need, is a pix taken from behind the rear..such that you have eliminated the parallax of the wheel well (at the 9 + 3 o'clock). Then we can see exactly how much is sticking out past the wheel well. Even mine has a tiny bit of sidewall out past the top of the wheel well, but the axle would have to rise one helluva lot, b4 it hit, non issue.
 

408Stang

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Lots of people run 305's on their cars but most report a little rubbing.... What your showing is quite a bit of overlap though.... I agree with other people here: Check your axle for being centered. Because you have an adjustable Panhard bar, it's possible for it to be way off.

I run 295/35/20's in the rear and 285/35/20's in the front... I'm lowered about 2" from stock and I have zero rubbing, even on a track. However, I also am using a watts link rear suspension and Michelin Pilot Super Sport tires. Your drag radials are designed to have a big cushy sidewall. You might not have the same issue with a performance tire with a stiff sidewall. You also have your suspension moving in an arc due to the Panhard bar. If it's compressed / lowered then I the axle is pushed to one side unless the Panhard has been adjusted for the lowering.
 

Rusnak_322

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Measure that wheel's backspacing, from the innermost face of the inside flange to the mounting face on the back side of the wheel center (do not measure from the tire bulge). Subtract half of 9.5" from that and convert to mm. That'll be close enough for discussion purposes.

The 9.5" comes from 8.5" wheel width (which is measured between the bead seats) plus two flanges at half an inch apiece.


Norm



The 8.5" tire has a +32mm offset. there is a number cast in the back of the rim.

Lots of people run 305's on their cars but most report a little rubbing.... What your showing is quite a bit of overlap though.... I agree with other people here: Check your axle for being centered. Because you have an adjustable Panhard bar, it's possible for it to be way off.

I run 295/35/20's in the rear and 285/35/20's in the front... I'm lowered about 2" from stock and I have zero rubbing, even on a track. However, I also am using a watts link rear suspension and Michelin Pilot Super Sport tires. Your drag radials are designed to have a big cushy sidewall. You might not have the same issue with a performance tire with a stiff sidewall. You also have your suspension moving in an arc due to the Panhard bar. If it's compressed / lowered then I the axle is pushed to one side unless the Panhard has been adjusted for the lowering.


With the stock rims on the car (and 1" spacers) you can tell that it is centered. I think the fact that my car is so low and the offset of the 9.5" rims along with the narrowness of the rim are killing it for me. I just went with this for looks, I don't need the traction of a wide drag radial. So I am going to sell the tires and get some 275/35 for the rear. the thing with my car being so low and black, you cannot see how wide a tire I am running unless you bend down and look. I was following my wife when she was driving it and you really cant tell.

I almost want to jack up the rear and run the big tire. I had a hot rod 55 Chevy right after high school and still love that look.
 
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Rusnak_322

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Ok,
Went with a 275/35 on the rear. Had to get smaller lugs as well.

I am happy with them, I was nervous about red wheel. I am a little conservative.

1db2bac187170b941343bc1c3b3c881f.jpg


b08711c266c5ce3d0c6988325bcd8e97.jpg





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Rusnak_322

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Saw the tires on Craigslist!!!!


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I think I am asking a decent price. $450 Obo.

Those tires look killer, I wish I could make them work.



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Wlkn Tal

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I'm running foose nitros 20x10 wheels that has a +40 offset and was looking to go with MT ET street S/S 305x35x20. My car is lowered on FRPP K springs, am I going to rub? I thought I would be ok, currently hace 295x30's on there no issues
 

Gabe

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I'm running foose nitros 20x10 wheels that has a +40 offset and was looking to go with MT ET street S/S 305x35x20. My car is lowered on FRPP K springs, am I going to rub? I thought I would be ok, currently hace 295x30's on there no issues

You'll rub in the back over bumps with those wheels and 305/35/20's on the back.
That's my same set-up, and I had to raise the back of the car about an inch to stop the rubbing.
Hated the "solution" and I now have the back of the car lowered again since I'm running my SVT 18s again ... looking into different options though, cuz I really hated raising the back of the car.

This was rubbing:

20160128_Niche6b.jpg



Like this:

20160131_tire-rub.jpg




This wasn't rubbing:
(ass up higher)

20160820_a.jpg


20160514_no-plate.jpg
 

Wlkn Tal

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First word that comes to mine is $hit! Doesn't seem to be any other viable options out there either, only other size is 275-40-20, it might look funny because it so tall
 

Gabe

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First word that comes to mine is $hit! Doesn't seem to be any other viable options out there either, only other size is 275-40-20, it might look funny because it so tall

285/35/20
It's what I wish I went with.

I went with the 305/35/20 on these wheels because somebody else had the same tires in the same size on the same-size/offset wheels and he said he had no rubbing issues, even though he was lowered.
Come to find out he really isn't lowered that much.
So I got screwed, and I can't easily afford to keep swapping tires, when they're $300 a piece.
So, I spent a couple hundred on the new rear springs and adjustable perches so I could lift the car, and now I can (fairly) easily lift or lower the back, depending on which set of wheels/tires I want to run.
But it's still a pain in the ass, and I would've gotten different wheels if I knew I couldn't run the tires I wanted to run.
I had the same rear tires on 20x10 wheels in 2015, but the offset was 48mm, not 40, and I had no issues.
 

Gabe

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There's also a definite fit, the 285/30/20 but this size has almost no sidewall.
It's what my fiancee's rear Alcoa wheels (20x10 with 37mm offset) had on them when we got them:
(car's lowered in the back only, using Ford Racing "L" springs)

2014-08-30_Manch90a.jpg


2015-10-15_wheels1.jpg
 

redfirepearlgt

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Vossen 20x10.5 (+45mm offset/7.52" BS) with Nitto 555 G2 305/30/20's and BMR 1.5" drop drag springs. No issues with rubbing and the wheels stay just inside the wheel well. Keep in mind that the wider the wheels are the more noticeable your centering will be.

Your 275 choice looks real nice on that 9.5" wheel. Good choice.
ba6keSB.jpg
 
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redfirepearlgt

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Strange single adjustable. Also, Dylan at BMR directed me to purchase the GT500 drag spring version due to the additional weight of the blower kit already effecting the factory height of the front end. By his experience with setups like mine, others have used this setup and achieved only an additional 1" drop since the GT with a blower is not as front end heavy as the 07-09 GT500 so the springs will sit higher while retaining the same spring rate. Just quoting the expert on that, the proof will be in the pudding. I can go no lower than a 1" front drop because I will drag in and out of the driveway. The 13 was running a Roush spring setup that was 1.25R/1.00F and it just barely cleared. I've done the trig based on a 1.5" rear end drop with the BMR GT drag springs, so I know no more than 1.00-1.125" front drop will clear as well as reduce the rake just slightly which is fine with me.

I will post measurements with photos before and after when I get the chance to get this all done because I know there are others who have struggled with similar issues. Dylan has had luck with people running blower setups using the GT500 front drag springs to gain the additional 1" drop successfully but he has no photo feedback to provide. I hope to resolve that for him.

I can't wait. While the car sits almost level with only about a 1/8th inch rake on the front end, the gap on the wheels wells as you have noticed is apparent when looking from more than a glance.
 
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