18's on a Cutlass

[White92Cutlass]

Will 18x8 5x114.3/5x100 wheels with a 40 offset fit a 93 Cutlass Supreme without issues? Thanks!

[intern8tion9l]

i would think so

[Andrew]

i think you would want less offset

[Breakdown]

i think you would want less offset

 

 

Standard Cutlass offset is +42mm IIRC.

[GOT2B GM]

FWIW Eagle 077's are +38mm

 

[Andrew]

for some reason i was thinking 1st gens had a 25ish offset

[GOT2B GM]

1st gen GP xlaces are +25 mm

[GnatGoSplat]

GP xlaces are designed to fit flush with the flares. They'll stick out on a Cutlass. 40mm should look about right on a Cutlass, but wheel/spoke design will determine whether they'll clear the front calipers. There's really no way to know in advance whether they'll clear except for trying it or finding someone who has tried it.

[Breakdown]

for some reason i was thinking 1st gens had a 25ish offset

 

Andrew x-laces are the exception.

 

 

1st gen 16 inch alloys are +42mm

1st gen 16 inch x-laces are +25mm

2nd gen 16 inch alloys are +52mm

 

 

As stated by Shawn (Gnat), the key here is the backspacing.

 

 

To give you an accurate impression of what you're up against.

 

 

Your factory rim looks like flat spokes at the back with a small margarine container glued on to the back. That extra 1/2" or whatever of protusion allows the rim to clear your brake calipers. Offset is not the be and and end all of clearing the brakes.

 

If you go to look a the rims and the rear part is flush where the hub mates with the wheel . . . or less than 1/2" it won't fit.

[pwmin]

GP 5-spokes are also +25 IIRC

[White92Cutlass]

If the wheels don't clear the front calipers, would it hurt anything to shave the calipers down a little bit to make them fit?

 

Also, what will going from 16's to 18's do to the speedometer and gas mileage?

 

Thanks.

[GnatGoSplat]

No, it shouldn't hurt to shave the calipers down a little. Most likely, it'll be the brackets and not the calipers themselves that need to be shaved. I shaved the brackets down on 2 of my cars with no problems.

Speedometer should stay about the same if you use tires that are the same overall diameter to the original. Mileage may theoretically decrease a tiny bit due to 18" wheels being heavier, but I don't think it will be enough to notice.

[AWeb80]

These will work fine. I thought 077's were +44........maybe the second gen wheels are +44

[GnatGoSplat]

These will work fine. I thought 077's were +44........maybe the second gen wheels are +44

 

077s are +38. The factory 16" pie cut Cutlass wheels were +44.

[White92Cutlass]

No, it shouldn't hurt to shave the calipers down a little. Most likely, it'll be the brackets and not the calipers themselves that need to be shaved. I shaved the brackets down on 2 of my cars with no problems.

Speedometer should stay about the same if you use tires that are the same overall diameter to the original. Mileage may theoretically decrease a tiny bit due to 18" wheels being heavier, but I don't think it will be enough to notice.

 

Any suggestions on an tire size that won't mess with the speedometer much? Current tires are 225/60/16.

[Breakdown]

Factory is either:

 

245/45R18

 

or

 

225/50R18

[GnatGoSplat]

Any suggestions on an tire size that won't mess with the speedometer much? Current tires are 225/60/16.

 

245/45R18 is almost an exact match in diameter, but wider. I have that size on my 89 and they initially rubbed a bit on turns, even with spacers that pushed my offset to 37mm. 245/40R18 are slightly smaller (by 1"), cheaper, and easier to find. They also might fit better without rubbing. I have 235/45R18 on the 94 convertible that actually look and fit perfectly, but that's kind of a rare size. Some people also run 225/45R18 which is not too far off. Slightly smaller diameter than 225/60, but same width.

[White92Cutlass]

Thanks for the help, guys! Just bought a brand new set of 18 inch Motegi MR4's.