Shdggsdv

I'm looking at getting a set of 18x8 Boss 338 wheels and 250/45/18 tires

I understand that the e-brake bracket needs to be relocated, but are any other modifications required for these wheels/tires to fit?

Car is a mostly stock 1975 Stingray

mvette76

with 18x8 they should bolt on no problem

donnie1956

No problem on my 78. 18X8 on front and 18X9.5 on rear and had to move the e brake bracket.

Richard454

I'm running the same size as Donnie-

I do have offset trailing arms - Vansteel coilovers and small flares on the rear - so I went w/ the bigger rim on the rear



The Boss wheels are LUGCENTRIC- where as the wheels are centered w/ the lugnuts. The OEM (and many aftermarket)are Hubcentric.

I had som rings made up to fit the bigger hub the Boss's had- I'm just not fond of Lugcentric.

Boss hub- 82.80mm Corvette hub- 70.3mm

I had mine machined out of aluminum- but there are some plastic ones for about $25 for the set of 4.

http://us.hubcentric-rings.com/size-82.8-70.3/




Combo spacer & hubcentric adapter-



DSCN4814 by Richard Hayes, on Flickr

MN80Vette

I agree with Richard on hub-centric vs. lug-centric. I had what I thought was a balancing problem when I put on 18x8 BOSS 338 wheels.



The problem turned out to be the wheels being off just a little bit off center bit because I didn't torque the lug nuts enough before putting weight on the wheels. I didn't trust lug nuts alone to keep my wheels centered on the hub after that. I don't know when Corvettes first had hub-centric wheels, but the C3's did and the new Corvettes and most European cars do too.

Something nobody mentioned yet is that the backspacing on BOSS 338's are 1/2" more than stock wheels. That moves the wheels 1/2" more into the wheel wells than stock wheels. That's why Richard and I have hub centric spacers pictured in his reply (the ones laying on black granite).

Here is a picture that shows how the hub-centric adapter ring fits inside BOSS 338 wheels:



The ring part of the hub centric spacers fits the same way but are part of the 3/8" spacer.

The lug holes in the spacer are recessed to allow for extended cone lug nuts like these:



The extended cone lug nuts (from Jegs, Summit, etc.) allow the use of the 3/8" spacers without replacing the stock lug bolts with longer bolts. Our son is a CNC machinist and makes the hub-centric spacers in the picture. I recently sold the last pair I had, but he can make more.

A set of 4 cost 4x the cost of plastic spacers, but they are billet aluminum, not plastic. Send me a PM if you're interested.

Richard454

MN80vette-

Is your son back to making them?

Richard

MN80Vette

Yes, he is. He had a lot of custom parts to make for a few members of our car club for a while.

Hans4real

There is another option that are very similar to the Boss wheels and those are the Ridler 695s. The nice difference between Boss (nothing wrong or against the Boss wheels) and Ridler is the offset off the back spacing. The Boss wheels (especially the front 18x8s) get too far sucked into the wheel well and look odd. The Ridler's will have more of a full wheel well because off the offset being more towards the outer dimensions. Set up with 18x8s + 245/45s in front and 18x9.5 + 275/45 in the rear makes for a nice setup. You will need to move the rear E-brake cable mount but the look is well worth the small effort.

MN80Vette

Backspace measures the distance from the mounting plate to the back edge of the wheel. The higher the backspace the further into the fender well the wheel will sit. Both BOSS 338 and Ridler 695 18x8 wheels have a 4.5" backspace, so they are going mount the same distance into the wheel well.

Stock C3 wheels have 4" backspace. It's the extra 1/2 inch of backspace that sucks the wheel into the wheel well. Both BOSS and Ridler wheels need spacers to move them further out in the wheel well.

I am assuming the diameter of Ridler hubs are bigger than car hubs (same diameter as BOSS hubs?) so they fit almost any car. If Ridler wheels had the same diameter as C3 Corvette hubs, then Ridler wheels might have too of a hub for some cars. Ridler wheels would still need adapters to get the centering advantage of hub centric wheels.

Shdggsdv

Do you still need to move the e-brake bracket after having a spacer installed?

Richard454

On my rear - the trailing arms came from Vansteel w/ e-brake relocated.

Those spacers are MN80's son's work-I just had the "rings" made for me.

tarheel34

Do you have any more rings and spacers available?

Shdggsdv

As an update here's my girl with the new Boss 338s! Turns out I didn't need spacers. They fit pretty awesomely as they are.

J.D.78

I REALLY like those

Orange1974

Hi, would this setup work on a 65 convertible?

73ls1

I have 4 hub centric spacers made by a Corvette Forum member .They are the same as the ones Richard 454 has. PM me your phone number and I will call you.