[still_walkin]

I have a 1986 cadillac deville sedan 4.1L and I have some 18x9 standard 100 spoke rims and I was questioning about fit ment the tire size is 215 35 18 and I wondering if I'm going to have any rubbing issues. I was also thinking about any rubbing so I might go to a lower profile so I was thinking 205 35 18. What you all think.

 

[Stingroo]

Lower profile would be the middle number I thought? Pretty sure the first number is width in millimeters.

And also, those tires and rims will be smaller overall than your stock rims and tires, so there shouldn't be any rubbing. I used this:

http://www.miata.net/garage/tirecalc.html

Stock size (what I assume you have on it now) is 205/75/14
Then I just put your new dimensions in on the right side, and it came out smaller.

It also says it will throw off your speedometer by 8.4%, meaning that when the speedometer says 60, you're really doing 55.

 

[still_walkin]

Ok thanks yeah my stock is 205 75 14 and my other concern was the speedometer , if I went with a small size like 17x8 or 15x7. I know they will fit but witht the 17s will I have the same problem and what size tire do you suggest.

 

[Bowler807]

If you use 255-40-18 tires on those 18 inch rims your tire circumfrence will be the same as the stock size tires. That way the speedometer will not be off and you will still have the low profile look you want.

I have no idea if they will rub or not because of the width, but I suspect you will be OK.

 

[still_walkin]

Ok but cause of the rims won't the new tires be wider. You know how these caddys have the leveling system and I don't want to have it where it rubbs if it gets too low if I ha kave extra wieght in the back or passengers in the back seat as well. But at the same time I was told the less air your riding on the rougher the ride is going to be . But those mdarn factory hubcaps won't stop rattling I tried everything

 

[mysedan]

yes tires will be wider...therefore to counteract that you need a more positive offset (example a +40) then you get the lower pro look you want, the rims you want and no change in speedo readings

or get the other size and deal with a speedo slightly off

 

[still_walkin]

ok so your saying with the 215/35/18 the speedo is going to be off but with 255/40/18 the tire is going to be wider and no problems with the speedo. Which of these is going to get me better ride quality or I'm screwed both ways

 

[still_walkin]

By the other post above saying that the 255 series tires is the same as my stock ones does that apply to width and hieght. But the only difference is the rim size right

 

[mysedan]

ok so your saying with the 215/35/18 the speedo is going to be off but with 255/40/18 the tire is going to be wider and no problems with the speedo. Which of these is going to get me better ride quality or I'm screwed both ways

the 255 is close match to your current tire height...but much wider than your stockers......so to run those with out fear of rubbing you need to + your offset on the rims to accomdate the increased width of tire....so if you have a 14" rim now....going to a 18 is a PLUS4 rim size....and tire has to be lower to keep the speedo corrected....but the lower pro usually means wider tire (the 40 in the tire equation) and then you can run a typical rim with a large li...you need a more flush looking faced rim (the PLUS on offset) to move the rim in deeper on the wheelwell.

see how that work?

The 255 will still give you a DECENT ride...but anytime you go lower pro....your ride quality suffers due to increased stiffness in sidewall strength.

 

[mysedan]

By the other post above saying that the 255 series tires is the same as my stock ones does that apply to width and hieght. But the only difference is the rim size right

it will still be wider...but the height will be the same...there by keeping your RPM's the same....so the sensor that sees the revolutions of the wheel for speedo will pass by at the same time (in laymans terms)

 

[still_walkin]

I understanding what your saying that the 255 series is better for me ride quality wise and offset wise but the reasoning I'm really concerned about rubbing is my caddyys leveling system has a glitch in it . It doesn't level on its own I have to raise it manually. So I don't want to be driving and the back end of the car get too low and have a accident or somethin it usually takes the car 30secs to raise back to height . Driivng on the freeway is no problem but if I have a slight rubbing on the freeway could be hazardous. I could goto the shop with this concern but most are gonna just sell me anything and be on there way. Thnks for the all the help so far.

 

[mysedan]

ah...I didnt read you have a glitch in your system. switch it all out for bags! actually there is some not overly costly alternatives here on the site that will cure that. mine works (for now) but I am saving up to redo the entire thing or switch to bags myself here sooner or later

 

[still_walkin]

Yeah I drove myself crazy trying to figure out what it is. I changed out the compressor and struts and came to the conclusion its either the leveler or the relay. The leveler is gonna be a difficult one to check seeing how I put a system in my trunk and the time to take it out and put it back is a waste of time if its not the problem. I also believe its the realy which I can't find. So basically what I did was I found the compressors postive lead ran that wire to my interior to my center consule then I used a fuse from my fuse box and put a inline fuse on it and when I feel the car is low I usually can tell. Iwill flick the switch and it will raise no problem I have to contsantly do this. When I 1st start the car it usually takes a minute or to for it to get level but during a course from a to b it takes 30 secs. Depending on my load. If you know where the relay is that would be great. I was told its under the drivers steering wheel under the instrument panel but no luck after that. This is why I was so concerned about how close I can mirror. This rims to my stockers.

 

[mysedan]

well I havent looked very deep into my leveler system at all...in fact the farthest I have gotten is basically looking at my lines and junk...because mine still works....mine cycles periodically sure....so I have zero ideas where the relay is...I would guess its closer to the pump and shocks myself...but then again...I really dont know.

A helms would though alot

 

[still_walkin]

Yeah I looked at my wheels today and the rims are wider than the stocks. So I'm gonna jump so other threads to see if anyone knows where it is or someone could chime in. I was also told my suspension need to be updated because of the new tires and the weight I put new sturts x4 about a year ago and I was going to put new springs in the rear to stiffin out the back end . I was going to change out the rack and pinon cause I have a stifffness in my steering . Other than that what else do you sugggest.