id like to put my Z06 wheels on the Vette. they are 9.5" wide and have a 56mm offset. i believe i need 3" adapters to get the wheels in the right spot. now ive heard that adapters will kill wheel bearings, and all sorts of diffrent things. id just like to know plain out #1 if 3" is the correct depth, and #2 will it wear things out faster? if it is going to i will get some other wheels for it, but i kind of liked the idea of the vette and Typhoon sharing wheels. much nicer to my wallet :D

 

I feel that adapters, especially as wide as 3" are downright dangerous

 

79P/O, I have used VBP adaptors since '95 on my car 2.5 inch and mating 92 vette rims....17x9.5 tothe front and rear of my car....had various tire combinations through the years....now it's 275/50/17 in rear, by Nitto, and front vary from time to time at 255/50/17......

the way I measure whell offset is a bit differant than engineering drawings...
I just take a straightedge to the outside of the mounting flange, and measure to the wheel mounting plane....stock wheels for my '72 are 3.5 inches offset...
if you measure the '92 rims they are 7 inches offset...SO, to make that 3.5 inches you would use a 2.5 inch adaptor....noting the wheel width goes from 8 to 9.5 inches....so that's 3.4 inch per side net width increase from centerline, keeping centerline very closely the same I came up with 2.5 inches adaptor...works fine....

NOW, using some other companies' adaptor than VBP,,....I make NO comment, I just know waht VBP makes them out of is perfectly safe, as they are a true adaptor, and use ten lug nuts in total to get at the brake drum...
5 for the adaptor, 5 for the wheel...interleaved....now that is totally acceptable engineering wise...only problems is if someone puts their wheels too far to the outside ...moving the wheel/tire centerline out too much like some ricers do, and thereby increasing loading on the bearings/suspension, making the camber look all screwed up....you seen them....the entire car is rendered unsafe....

so my centerline is within about 1/4 inch of being right on...fine....been that way since '95 now....driven daily...

GENE

 

hmm 2.5" may be what i need then. i know my Z06 wheels are corvette offest. Thanks!

 

I don't know what the offset is to ZO6 wheels, you need take a straight edge from weight flange to weight flange on the outside but not on the turned out tie, just the weight mounting flange...and measure to the mounting face....
THAT is what I am calling the offset....if it's 7 inches, fine....if not, you need calculate your own....

now if you look at a tire site, or somewhere in the internet I remember seeing the engineering way of measuring offset, and they use the INSIDE of the wheel mounting bead, where the tire bead rests against...and so that takes into account the thickness of the metal in that area....their way is more accurate for centerline of the tire, but in fact for our purposes my lazy way is fine....

GENE

 

56mm is about 2.2 inches, so a 2.5" spacer would be the closest measurement. but thats 2.2 inches from the front of the wheel. it would be 7.3 inches from the rear of the wheel. so a little over 7 1/4 inches.
[edit]

actually a 2 1/4 spacer would be the closest measurement. as it would be 2.25 if converted to decimals.

it just so happens that i have 2 2.25" adapters for the Z06 wheels to fit on the typhoon... i'll try my math out and see if im right, or if i should have gone to math class on a more regular basis :D


[Modified by '79ProwlerOrange, 7:12 AM 12/11/2003]

 

FYI these are the adapters i bought. 6061-T6 aluminum thats CNC machined for a perfect fit.

Skulte Performance Designs.

 

if you can, post some picts when you put them on the vette!

 

no problem! i may go do it today... :crazy: :D

 

I remember working with VBP in '95, and tried the then listed available 2.25 inch adaptors, and also asked them for 2.5 inch...set of each came in the mail, and I played around with them, finding the 2.25 had to be returned, as the tire was just rubbing the allready altered stock t-arm....meaning the ebrake tab was allready removed....got another set of 2.5 inch adaptors in exchange.....

hope your ZO6 wheels work...

GENE

 

Thanks. i looked at my spacers, and apparently i was on crack. i remember that they are only 1.25" not 2.25" so i can sorta bolt em together and then check what a 2.5" would look like, but thats all. and obviously i wouldnt drive the car with 2 1.25" spacers, id just do it for a quick look.

and i think im going to put it off for a day or 2. its butt cold, and the typhoon is acting funny, so i need to go out with the data logger and see whats going on.

 

keep us posted on how you make out, i'll be going with zo6 rims down the road...

:lurk:

 

will do. as a warning though, its going to look a little strange when i do get pics. the Stock typhoon tire size is 26" while the stock Corvette tire size is 28 1/4" so the wheel/tire will be waaaay too small looking. its a 275/35/ZR18, where as i plan to go with a 295/45/18 for the vette. or maybe i can find a happy medium, and get the speedos adjusted accordingly. :D

 

I've always heard spacers are dangerous. I wouldn't play games with stuff like that, but if you feel comfortable...

 

Spacers are dangerous, but adaptors are NOT.....spacers just move the wheel out a bit using the same lug/stud pattern, typically made from jumk metal, and break up IF the lug studs don't first....

you see, much to MY late learning curve, MOST wheels are what is known as LUG centric, as opposed to axel/flange centric....so it's the lug nut pattern with the conical shaped or the diameter of the shank into the casting that centers the wheel on the hub....NOW if that wheel is taken off that hub/rotor/drum surface and moved outward, all the torque from acceleration/braking/cornering is moved outward on those skinny studs...and with the constant scrubbing caused by the 'spacer' the stucs break....

with a real Adaptor the situation is a bit differant, in the pattern in interleaved and still 5-5 and of course centered, the aluminum is a billet and therefore machined, and therefore stronger than the freaking wheel itself...now the final question is...since the mounting situation is solved by this bullett proof solution....what is done about offset and bearing loading..and that is up to the owner's caluculations with a tape and straight edge on the individual wheels chosen....

you should pay attention to offsets for reasons posted above, as nauseaum...in other threads...

GENE

 

:iagree:

My GS wheels are 56mm offset and I am using VBP 3 inch adapters on all four corners, with no rub at full lock. I am very pleased with the appearance, the tires are flush with the fenders. I wanted to try the 2.5 adapters but chose the 3's instead. I run 275-40-17's on all four. I am glad I went with the 3's instead because I would have had to move the E-brake cable.


[Modified by BLKDOUT, 4:56 PM 12/11/2003]

 

Thank you for enlightening me. I did not know the difference.

 

BLKDOUT, I am fearful for your install as described, as I do not personally know the wheels you are using for sure...but being GS wheels I presume they are 9.5 inches wide at least...and if so, and you did not move the ebrake cable, that offset is too much to the outside IMO...and presents too much bearing loading in the rear...needlessly stressing the suspension and the bearings...most importantly....the wheel/tire combo centerline is about an inch or so to the outside from stock location.....better look into that again...

GENE

 

I've put alot of bad miles on my billet aluminum 2 inch adapters.

I was just thinking about how long they have been on to fit my 11X17 rear rims. They are tough - :) The adapters have out lasted two sets of U-joints one half shaft and one $700 posi unit from Tom's

Gearing is also a TQ multiplier. So my 4.11 rear end should really hurt anything attached to it.

 

I love my VBP adapters !!