The best wheel offset calculator...

[Chiketkd]

Stumbled across this tonight when trying to figure out the change in characteristics after I install the '93 RX-7 wheels I secured today:

http://marksink.com/tire_wheel_offset/offset.html

This calculator can be very helpful for people looking to figure out whether aftermarket 17" or 18" rims will work with the SVX.

For my calculations I used the following specs:

Stock SVX wheel specs are: 16x7.5 with a +55mm offset

Gen 3 RX-7 wheel specs are: 16x8.0 with a 50mm offset

New characteristics:
"The clearance from strut housing to the inside of the wheel will be 1mm LESS
The outside edge of the wheel will EXTEND an extra 11mm"

I know these wheels will work great w/o rubbing issues as SVXRide AutoX's with them on his '92 LS-L. They weigh 16lbs each (stock SVX rims weigh 20lbs), so I'll shave 16lbs of unsprung weight after installation. However, I won't be able to put them on until Winter is over, as the seller included some barely used Dunlop Sport SP9000 max performance summer tires.

-Chike

P.S. A handling plus of installing these wheels is that the front and rear track on my car are widened by 22mm.

[Chiketkd]

Here's another example:

My friend Svxfiles got some 17" lightweight Locos from Dayle a few months back.



The specs for the Locos are: 17x7" with a 38mm offset

New characteristics are:
"The clearance from strut housing to the inside of the wheel will be 23mm MORE
The outside edge of the wheel will EXTEND an extra 11mm"

So the front and rear track on Tom's SVX will also be 22mm wider and there will be a greater clearance between the inside of the rim and the strut.

-Chike

Cool find. This means that maybe those 18 X 8.5s will fit, if the offset is 42mm, it'll be the same clearance on the inside. Super.

PS: Merry Christmas

[Chiketkd]

Originally posted by justiceSVX
Cool find. This means that maybe those 18 X 8.5s will fit, if the offset is 42mm, it'll be the same clearance on the inside. Super.

PS: Merry Christmas

Everything will technically fit, but understand that each wheel will stick out 26mm more our approx 1 inch. This shouldn't be a problem with the front wheels, but on the rears, you may have to use some -ve camber to prevent the top of the tire from rubbing against the upper fender.

-Chike

why not bump out the rear fenders a tad? It'd make the SVX look even more serious.

[Chiketkd]

Originally posted by justiceSVX
why not bump out the rear fenders a tad? It'd make the SVX look even more serious.

It would, but turning the top of your wheels in a little (i.e. -ve camber) would be a lot cheaper than fabricating a wide-body kit for your SVX.

-Chike

[Chiketkd]

I learnt today when I spoke with the seller of the RX-7 rims is that with the max performance Dunlop Sport SP9000's, the wheel & tire combo weigh ~38lbs each!

My all-season M+S Bridegstones with the stock wheels weigh 47lbs each on my digital scale, probably due to the extra reinforcements built into the tire.

This means I'll be shaving 8.5-9lbs per corner when I install these new rims and tires - or a total of 34-36lbs!

-Chike

[Mr. Pockets]

Originally posted by Chiketkd
P.S. A handling plus of installing these wheels is that the front and rear track on my car are widened by 22mm.

To be more accurate, wouldn't you say you'll have improved grip, not necessarily improved 'handling,' from the wider tires and track?

Your car will tend to wander a little more at speed, I would guess.

[oab_au]

Originally posted by Mr. Pockets


To be more accurate, wouldn't you say you'll have improved grip, not necessarily improved 'handling,' from the wider tires and track?

Your car will tend to wander a little more at speed, I would guess.

Not to mention Torque steer, and diving around, under hard braking.

Harvey.

[Chiketkd]

Originally posted by Mr. Pockets
To be more accurate, wouldn't you say you'll have improved grip, not necessarily improved 'handling,' from the wider tires and track?

Your car will tend to wander a little more at speed, I would guess.

Improved grip is true which is what I was equating to handling. However, I do understand the -ve that you have pointed out. Grip is definitely the more accurate term...

Originally posted by oab_au
Not to mention Torque steer, and diving around, under hard braking.

Harvey.

I understand the slight increase in brake dive, but I'm not sure I get the increased torque steer Harvey? Our cars use equal length half shafts front and rear (to the best of my knowledge), so I've always found torque steer to be non-existent under hard acceleration at the dragstrip.

-Chike

P.S. Either way guys, after completing these winter mods, I'll turn my focus to some mods in the handling department in the Spring/Summer. Namely Mychailo's stiffer springs, urethane bushings, and some thicker sway bars.

Originally posted by Chiketkd

It would, but turning the top of your wheels in a little (i.e. -ve camber) would be a lot cheaper than fabricating a wide-body kit for your SVX.

-Chike

I'm not referring to a body kit... musclecars push out their 1/4 panels a tad all the time to fit the right rubber.

[Chiketkd]

Originally posted by justiceSVX
I'm not referring to a body kit... musclecars push out their 1/4 panels a tad all the time to fit the right rubber.

You're referring to 'tubing' right? If so, then yes, any bodyshop can bang your rear 1/4 panels out a tad to fit the slightly larger wheels...

-Chike

P.S. Still would be cheaper though to do a 4 wheel alignment. However, wider rear fenders would look awesome!

[svxfiles]

Originally posted by Chiketkd
Here's another example:

My friend Svxfiles got some 17" lightweight Locos from Dayle a few months back.



The specs for the Locos are: 17x7" with a 38mm offset

New characteristics are:
"The clearance from strut housing to the inside of the wheel will be 23mm MORE
The outside edge of the wheel will EXTEND an extra 11mm"

So the front and rear track on Tom's SVX will also be 22mm wider and there will be a greater clearance between the inside of the rim and the strut.

-Chike

Dayle told me they had an offset of 45mm.
Nice looking car by the way, Oh, wait...

[Chiketkd]

Originally posted by svxfiles
Dayle told me they had an offset of 45mm.
Nice looking car by the way, Oh, wait...

That's weird, Dayle lists the wheels as having a +38mm offset on his site.

http://store.yahoo.com/svx-motorspor...es/moriii.html

-Chike

[svxfiles]

I'm going to take them off this week to install my 245/45/16s on factory wheels for the winter. So I guess now, I'll have to measure them.
But I would not have bought them if they were 38mm. Stock is 55mm, right?