20" fitment on 70 chevelle [Archive]

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ness01

02-04-2008, 01:28 PM

I am looking to purchase a new wheel tire setup for a 70 chevelle. here are the specs...

Rear: 20" x 10" - With tire (305/35/20), the overall diameter/height is going to be about 28.4"

Front: 20" x 8.5" - With tire (245/40/20), the overall diameter/height is going to be about 27.7"

Can anyone tell me if can tell right away if this fitment will actually fit a 70 chevelle with stock suspension settings? spacers?

Thanks

JayR

02-05-2008, 09:15 AM

Should fit fine if you get backspacing just right but if you don't lower it, she'll look like a Jr Donk with 20s all the way around. I would suggest dropping it a few inches and putting 19s up front.

DHARROD

02-05-2008, 11:01 AM

Here are some sources that helped me .. my guess is you'll be nearing a 6" backspace... 5-3/4 may work
Front .. 4-7/8 or 4-3/4 (talk to your rim mfg of choice).

https://www.rsracing.com/tech-wheel.html
http://www.wheelvintiques.com/pdfs/wheel_fitment.pdf
http://www.chevellestuff.com/tech/wheel_offset.htm
http://www.chevelles.com/forums/showthread.php?t=185801&highlight=backspace+measurement

Blown353

02-05-2008, 01:11 PM

The back should be OK in width and height... tire width is getting tight at a 305 so make sure your backspace measurements are correct. Tire height may be a problem if you lower it... That's a pretty tall tire and it might rub at the top of the wheelhouse.

In front, I don't see a problem with width or height... at stock ride height. However, those front tires are quite tall so if you lower it I would expect to have the tire rub at the peak of the fender and also the front lower edge of the fender.

DriverzInc

02-05-2008, 03:13 PM

ness01

02-07-2008, 09:53 AM

That rear will be okay, but yes, the front is a little tall. Might consider going to a 19x8 front, like JayR suggested.

We have the perfect fitment for that car, just give us a call and we can talk about it, or PM. Backspace is key when fitting tall, and wide tires under these cars. We can help!

How about if I were to decrease the front tire profile to 245/35ZR20 (overall diameter of 26.69 = 1 inch decrease)? What do you think?

71OLDS

02-07-2008, 10:09 PM

I can give you some feedback on my 71 Olds 442 conv. I'm sure we're not exact but I can provide some real numbers. Currently I run 305/45/18's on a 18x10 rim. BS = 5.5, diam = 28.8. Front = 255/45/18 on 18x8 rim. BS = 4.5, diam = 26.97.

Had Hotchkis springs on the front, no issues. Rear Hotchkis springs too but air bags allowed for height to be adjusted slightly. Had to roll wheel well lips and message inner fenders on one side. Pushing it on size w/305s in the rear (without mods) but got it to work. This was with stock front suspension and brakes.

Now considering uping to 20s. A few new issues. Added coil overs and B-body spindles w/Baer 13" rotors to the front. This pushed the front wheels out about 1/4" to 1/2" If I get new rims may go w/245 or 255/35/20 w/18x8 rim and probably 4.75 BS....or maybe even 5 BS..need to push rim inwards. Height around 26.5" to 27" should be OK, taller could be a problem.

For the rear adding the 12" Baer rotors caused issues too. The thicker rotor (from stock drums) required 1/2" longer studs and pushed rear rims out about 1/4" to 1/2". Considering 20x10 w/ a 305/35/20 (28.58" on Nitto drag radials) and probably a 5.75 or even 6 BS. Car is not "rolling" yet. Once it is can get exact measurements but this may help w/your #s. I think your suspension and/or brake selection should be accounted for when choosing BS and height.

-Joe

DriverzInc

02-08-2008, 10:35 AM

How about if I were to decrease the front tire profile to 245/35ZR20 (overall diameter of 26.69 = 1 inch decrease)? What do you think?

If you must run that 20 front, and a 19 is out of the question, then yes, that will be a better fitting front tire. It's the same tire I put on the front of my Impala, back in the day.

http://i37.photobucket.com/albums/e99/Hensons/Impala_IntroWheels008.jpg
http://i37.photobucket.com/albums/e99/Hensons/Impala_IntroWheels002.jpg

rocketman

02-08-2008, 03:48 PM

I would run either 18/20's or 19/20's to give it alittle balance

71OLDS

02-08-2008, 05:42 PM

DriverzInc

02-11-2008, 12:52 PM

It was a 245/30/20 front, and I bent a rim after only one month. Won't do that ever again. I am currently running a 245/35/19 on the front of my chevelle, with a 285/30/20 rear, and it's a little harsher than the 17's that were on it before, but I can deal with this set up. Suspension is set up right though which makes the real difference. Global West uppers, lowers, with springs, and gas shocks. I plan on upgrading to Vari-shocks from Chris Alston's so I can dial in the ride a little better.

http://i37.photobucket.com/albums/e99/Hensons/Chevelle_SuperSpokeBrushed002.jpg

http://i37.photobucket.com/albums/e99/Hensons/Chevelle_SuperSpokeBrushed010.jpg

slownova

02-11-2008, 12:59 PM

i have a 19x8 and a 22x11 on my 70 chevelle. i wouldn't trade them for anything. stock wheel wells also

gionni

02-12-2008, 12:08 AM

i have a 19x8 and a 22x11 on my 70 chevelle. i wouldn't trade them for anything. stock wheel wells also

do you have pictures of your chevelle???

slownova

02-12-2008, 10:58 AM

its the same car you commented on on pro-touring :cheers:

gionni

02-13-2008, 12:00 AM

yep, i have seen it later... ;)

Jmartorana

02-13-2008, 07:01 AM

Jon,

How harsh was the ride w/that 245/35/20 on the front? I was thinking a 40 series in a 19 might be better for the front but I like the Nitto 555 and they don't make any. My current 255/45/18s are real smooth. Will I be feeling every pebble on the road w/the 35s?

-Joe

Joe

I just did poly bushings and went to 18" rims w 235 & 275/40's series tires from 15 and 60's and the ride was very different (harsh). Initially I thought it was from the change in bushings but I reduced the tire pressure from 48 psi down to 35 psi and it made a world of difference cruising around.