Wheels. Offset and spacers. Check my math.

[Calvinator]

I have 1996 GP SE with stocker 16" wheels:

 

I picked up Center Line 17" wheels for cheap:

 

And thanks to this forum, there was some guidance on fitment & brake clearance.  I will need spacers for these wheels and I have been calculating.

 

Stock wheel = 16x7 25mm offset.

Centerline wheel = 17x7 38mm offset.

 

The offset difference is 13mm.  Meaning the Centerlines are 13mm closer to the suspension than the stockers.  I'm going the wrong way, I want to move the wheels outwards towards the fenders for a better stance and clearance.

 

Here is my math:

 

To move the Centerlines outwards to match the stockers, I need 13mm (.5 inch).

 

I want to move the wheels further towards the fenders, say another 13mm (.5 inch).

 

This means I need a 26mm spacer.  26mm just happens to be 1inch.

 

 I will be buying a billet aluminum spacer adapter hub centric type.

 

 

 

 

In summary, to get these 17x7 38mm offset wheels stanced correctly, I'm going with a 1" spacer.  May consider a 1.25" on rears only.

 

Anyone with some pics of wheels with a 1" spacer and similar setup ???

 

THANKS

 

 

[jake91]

I know GOT2BGM runs a 1in bolt on spacer on his Z for his 3rd gen Monte wheels

Edited March 22, 2017 by jake91

[jman093]

1996 GP with 17x7.5 Bonneville SSEi wheels using 1" spacers.

 

[GOT2B GM]

1.25" spacers on the rear, 1" spacers on the front

 

[Calvinator]

Thanks for the pics, I think I am heading in the right direction.

 

I won't be able to do another test fit for a week or so.  I don't know how long the stocker wheel studs are.

 

When the 1" spacer is bolted on to the wheel hub, do the stocker wheel studs extend through the 1" spacer?  If the stocker wheel studs poke through the 1" spacer, I would have another issue because my wheel's hub surface is flat. The poking through stocker wheel studs will be in the way.

[GOT2B GM]

Worst case scenario, you'll have to shorten or install shorter wheels studs

[55trucker]

Thanks for the pics, I think I am heading in the right direction.

 

I won't be able to do another test fit for a week or so.  I don't know how long the stocker wheel studs are.

 

When the 1" spacer is bolted on to the wheel hub, do the stocker wheel studs extend through the 1" spacer?  If the stocker wheel studs poke through the 1" spacer, I would have another issue because my wheel's hub surface is flat. The poking through stocker wheel studs will be in the way.

Are we referring to *spacers* or *adapters*?

 

spacers are just as the name implies, they are not usually more than 1/2" thick and they free are of the hub, extra long studs would be needed, but adapters are machined to either hub centric, lug centric or (preferably) both. Adapters have to be thick enough to support the machining of the lug openings down to a safe/strong depth but still allows the stud & the nuts to disappear into them so they are less than flush with the surface so the wheel will mount.

[Calvinator]

Adapters that are 1" to 1.25" thick that bolt to existing wheel studs.  The adapters then provides new wheel studs and 70.3mm hub flange.

 

I would buy the billet aluminum with the pressed in studs.  I've been shopping and researching.  I called the Adaptit USA company and they offer everything I am looking for.  

 

The adapters will cost me $200.  The Wheels were $150.  225/55R17 Firestone Firehawk Tires will be $500.    All in I would be $850 and I would have nice 17" aluminum polished wheel, new tires, stanced, and will give me 5-6 years of service.

[jman093]

Thanks for the pics, I think I am heading in the right direction.

 

I won't be able to do another test fit for a week or so.  I don't know how long the stocker wheel studs are.

 

When the 1" spacer is bolted on to the wheel hub, do the stocker wheel studs extend through the 1" spacer?  If the stocker wheel studs poke through the 1" spacer, I would have another issue because my wheel's hub surface is flat. The poking through stocker wheel studs will be in the way.

 

Yes, they are longer than an inch and will extend past the spacer. The SSEi wheels I posted have area cut-out in the area of the hub flange where the stud extended into the wheel, so it was not an issue. If your wheels do not have material cut out of that area of the hub, you'll have a problem.

[Psych0matt]

Adapters that are 1" to 1.25" thick that bolt to existing wheel studs.  The adapters then provides new wheel studs and 70.3mm hub flange.

 

I would buy the billet aluminum with the pressed in studs.  I've been shopping and researching.  I called the Adaptit USA company and they offer everything I am looking for.  

 

The adapters will cost me $200.  The Wheels were $150.  225/55R17 Firestone Firehawk Tires will be $500.    All in I would be $850 and I would have nice 17" aluminum polished wheel, new tires, stanced, and will give me 5-6 years of service.

 

 

If it were me I'd flip the wheels and buy something that looks better and fits a little closer. That's just me though (I don't think those wheels will look good).

[l67ss]

Xxrs are cheap and fit well

[Calvinator]

I'm only into these wheels for $150 and selling them off is an option.  If I stick with these wheels, I'll be at $800-900 spend on them.  Certainly other options at that price.

 

I do like the polished wheel.  I have 4 other cars that all have black wheels, love that look, but wanted a change of scenery for this car.

 

I'll keep test fitting and looking at other options.

[Calvinator]

OK, the plan has been updated:

 

Today I was able to test fit many wheels I have available to me:

1) 17x7 Centerlines with 38mm offset.

2) 18x8 Vogue wheels with 42mm offset (on my monte carlo)

3) 18x8 Infinity G35 coupe wheel with 30mm offset.

4) 17x7.5 Infinity G35 sedan wheel with 38mm offset.

 

After many trade-offs, my plan is:

 

a) I will keep these center line wheels

I will be adding 1.25" bolt-on hubcentric spacers to front and rear hubs of this Grand Prix.

c) The spacers will add the necessary clearance to clear brake calipers and suspension.

d) The spacers will move the wheels/tires 3/4" outwards (toward fender) vs. the stock wheel setup.

 

Going to be 2 weeks before I get this all done.  I'll upload pics as I go.