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Discussion Starter #1
Hey guys,

This the first time I have posted on this site. I have a nice 1970 Cadillac Deville Convertible that I have restored 6 years ago. I am going to repaint it, but I want to get new chrome wheels for it. It is all stock with stock suspension. So I wanted to know what size wheels I can fit on those. I thought 18" was biggest I can go, I wonder if it can even take 20"??

Thanks.
 

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thanks, it was my 2nd car I ever owned. 68 mustang coupe was my first. I still have both of them. My caddy is white with red leather interior. But the paint is having some cracks and flaws and little bit of peeling. I just want to repaint it before my friend's wedding. :)

I have always wanted to get custom chrome wheels for it. So this time I am getting them.

Just wanted to know more info about what size wheels will fit, also offset and width too.
 

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I'm not sure how the wheel well size compares with '75 models, but I saw a '75 DeVille sittin on 22s, and 20s look almost stock. I'd be surprised if 20s wouldn't fit.
 

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davesdeville said:
I'm not sure how the wheel well size compares with '75 models, but I saw a '75 DeVille sittin on 22s, and 20s look almost stock. I'd be surprised if 20s wouldn't fit.
Pimpin :coolgleam

I believe the wheel wells are pretty big in the 70 caddy, only concern I had was the rear ones because of the wheel cover. :confused:
 

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20's will fit no problem diameter wise. If you get a small enough profile you'll be fine. Especialy if it's still stock height. You're stock tires are probablly around 23 inches over all diameter right now. So a 20 with say a 30 series tire will fit nicley. Your main concern will be the width of the wheel. Considering most wheel manufacturers tend to stick with basic back spacing you may run into problems with either the wheel being too wide and hiting the skirt or the back spacing not being deep enough and causing the wheel to rub. With a 20x8 wheel you'll want as close to 5 inches of back spacing as you can get. 4.75" may work too but I would have them test mounted befor you droped the money on them. I've put air bags on a couple of my old Caddy's. They would lay frame with an 8" wide wheel, 10" wide tire, 24" over all diameter and I could still reach my hand up on top of the tire and have 2 inches of clearence befor the tire touched the top of the rear wheel well. Only had and about a half inch between the side wall and skirt but they fit.
 

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Discussion Starter #7
wow, 30 series profile would be pretty thin sidewalls for me. Sounds like the ride would be pretty harsh. I am going to stick with the stock suspension for now since I don't have the money for airbags yet. Would with stock suspension and 20" wheels would make it look like it is standing up too high or it is going to be exactly same ride height since it is same overall diameter as the stockers?

What about 20x9? one wheel shop says it should fit perfectly???

I agree to have it test fit, I'll do that sometime before I decide on a size I want.
 

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20x9 may fit. I just threw 20x8 out to be on the safe side. With the right back space a 9" width could fit. With stock suspension and a similar over all diameter the car should sit at the same ride height. Give or take a half inch depending on the measurments of the tire you choose. Each manufactuerer is a littel different. As far as side walls. to give you an example. A 255/30/20 will equal 10" wide, 3" side wall and 26" over all. Might be an inch or so taller/shorter then stock but that's probablly gona be the closest tire you're going to find to stock. Anything bigger will put in the 28" to 30" range. It's a double edged sword. If you don't mind the car siting an inch or so taller for a more comfortable ride then look into a bigger profile. If you're willing to sacrifice a bit of ride quality for style then the tire size I mentioned might be your best bet.
 

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Discussion Starter #9
Thanks, that is real helpful information. I'll see if I can get a friend who works at wheel and tire shop to test fit the wheels and tires to see how it looks and fit situation. :yup:
 

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Re: Wheel size to fit in 1970 Cadillac Deville

I am tring to find out the offset and bolt pattern for my 1970 deville. the car is in storage and I cant get to it. I have asked around at wheel shops and caddy dealers and none of them know. PLEASE HELP ME!!
 

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18s would look to small, I've seen it, they don't even fill out the wheel well like stocks. I have a friend with a '69, and he put 20s on it, and it has air bags. With the 20s it still has plenty of room to tuck in the back wheels. But he put huge tires on it, so it dosn't turn well at all. their smething like 275s. looks bad too, super low profiles are the only way to go. Or you could do 17s or 18s on vogues, thats a really nice look too.
 

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A 1970 Cadillac Deville's tires are NOT 23" tall.

At minimum from the factory its using a 235/70-15 stock, thats on a 15x8" wheel (7" minimum). That equates to 27.9" tall. The proper 20" tire to use would be a 245/40-20. If you want 22s you can run a 255/30-22.

What tire size do you currently have on the car?
 

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Stock 1970 Caddy rims are 15x7 with zero offset (3.5" backspace). Stock tire size equates to around a 225/75-15 or 235/75-15 in the current tire measuring system.

Dunno how it would play out with larger rims, but I tried fitting some 15x8's from friends Suburban with 235/75-15 tires and they fit the front great but were pressed against the outside of the wheelwell in the rear (even without the skirts). There was room on the inside so if the rears had more backspace than the fronts it would work. These rims were 4" or 4.25" backspace, IIRC.

I looked briefly at putting some big rims on my car, but steered away from it when I couldn't find any tires with a load rating equal to the stock tires. With two people in it, my SDV puts 2880# on the front tires and 2340# on the rear. Add in the weight transferr that occurs when you go around a corner or stop hard and you easily exceed the weight rating of any of the tires I could find.
 

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BluEyes said:
Stock 1970 Caddy rims are 15x7 with zero offset (3.5" backspace). Stock tire size equates to around a 225/75-15 or 235/75-15 in the current tire measuring system.

Dunno how it would play out with larger rims, but I tried fitting some 15x8's from friends Suburban with 235/75-15 tires and they fit the front great but were pressed against the outside of the wheelwell in the rear (even without the skirts). There was room on the inside so if the rears had more backspace than the fronts it would work. These rims were 4" or 4.25" backspace, IIRC.

I looked briefly at putting some big rims on my car, but steered away from it when I couldn't find any tires with a load rating equal to the stock tires. With two people in it, my SDV puts 2880# on the front tires and 2340# on the rear. Add in the weight transferr that occurs when you go around a corner or stop hard and you easily exceed the weight rating of any of the tires I could find.
There are plenty of tires out that cover 1500lbs per corner. What size tires/wheels were you looking at?
 

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Pretty sure it was a set of 22's I was considering. They were on Ebay, but I ended up never bidding because the seller never would tell me the offset, just that "they'll fit"... :rolleyes: I am 99% sure that 22" rims can fit with the proper offset and tire size, but it will be close as heck to get something that won't rub and there was not a chance in #ell that I'd lay out that kind of cash on the 'assurance' of some random Ebay seller.

Anyways, for the load ratings. 1500# per tire, sure I found plenty of those. But, that only covers the car when it's standing still. Factor in weight transferr due to braking or cornering and you're looking at something closer to 2000# per corner up front. Do some really hard stops or turns and you'll go even higher than that. Also, remember that those load ratings are ONLY at the MAX pressure listed on the sidewall. Any less pressure and the load ratings start dropping pretty quickly.

I looked at every tire for that size rim that Tire Rack carried which had the proper outside diameter and a width that would fit and did not find one with a load rating I would feel comfortable with.
 
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