FAQ: Wheel & Tire, Lug, Bolt Pattern, Offset, Center Bore Info

A question that's been bugging me since I learned the Riv bolt pattern: I happen to like the stock wheels, and want to keep them. But I'd need to find a couple of center caps, then deal with the problem of occasionally losing one. So my answer would be to buy a set of '97--'99 Camero center caps which bolt on and would suit me fine. Found a place online that sells them but doesn't list a bolt pattern. Asked around and got 2 opinions--either 4.5 or 4.75. IF it's 4.5, that would be 1mm larger (looks like 1/16"), and I could probably fit them. But I don't know. Any advice?

Looking to order a set of hub centric rings for my Riv, and didn't think to measure the hub in millimeters. They measured 2.75", but that's right in the middle of the millimeters options when ordering. I can choose 69.50mm or 70.10mm for the ring ID. 2.75" = 69.85mm. Does anyone know what our hubs OD is in millimeters for sure?

Diameter of our hubs is 70.3 mm. I have an extra set of plastic rings if your wheels have a bore dia of 72.62 mm.

See previous page for my experience ordering hub centric rings.

Aaron, thanks for pointing me here. I used the search and this didn't show for some reason.

My KMC rims measured 2 7/8". I want to call it 73mm, but I'm just laying a tape measure across it. Could be 72.62.... dunno. I'd give them a try if you want to let them go. I was thinking about ordering a set of aluminum rings. Maybe I'd better try measuring again in MM's.

Use a caliper if possible. The rings are accurate to 1/100 of a mm, and should fit very tightly in the wheel, and securely over the hub. I'll give you the plastic rings. Pay me later if they work out for you. Ship to your work address?

I checked the wheel again at noon, and they are actually just a hair under 2 7/8, like maybe 1/32 less. I'll bet 72.62mm is right.

I swapped the KMC's off for the season last weekend, so a test fit will be easy. I'll PM ship info, but yes, to my work address, thanks.

I tried searching to see if this was posted already. Quite possibly, my 'Search-Fu' is weak.

I stumbled across this site while looking for info on what other wheels would fit my Riv. I'm actually surprised that something like this exists for free. Very nice of them to create this database and make it available to everyone. Kudos to them.

Wheel Bolt Pattern Cross Reference Database

THUMBS UP !!! Great site and thanks for sharing

okiedrifter wrote:

RIVIERA 86-89 14 X 6 5X115 12mmX1.5 70.3
RIVIERA 93-on 15 X 6 5X115 12mmX1.5 70.3
RIVIERA FWD 79-85 15 X 7 5X120.7 12mmX1.5 70

stock wheels are 15"? I thought they were 16"?

charlieRobinson wrote:

okiedrifter wrote:

RIVIERA 86-89 14 X 6 5X115 12mmX1.5 70.3
RIVIERA 93-on 15 X 6 5X115 12mmX1.5 70.3
RIVIERA FWD 79-85 15 X 7 5X120.7 12mmX1.5 70

stock wheels are 15"? I thought they were 16"?

P225/60R-16 Yes 16"

In the OP, the spec is for "93-on".

This was probably taken from a source written in 92-93, before the 95 Riv was introduced. At the time, it was correct!

Cliff's notes: beware of any spec or part for a "93-on Riviera".

2010-2011 LaCrosse wheels are 5x120mm, although some databases do show them as 5x115, same as Riviera.

What's the weight of the 12 spoke OEMs like on my riv? I know i've seen it posted on here somewhere before. Trying to do weight comparisons. And what about the offset? Will a 40-45mm offset throw something off? Thank you!!!

OEM wheels + tires weigh about 50 lb per (not 100% sure on that)

If you get a larger wheel, usually you're going to see a weight increase because the larger size tire will be heavier, even if the wheel design is lighter.

Mr.Riviera wrote on page 1 that our OEM rims have +32mm offset. The rims are 6.5 or 7" wide, depending on the style.

The offset you choose depends on how wide of wheel (or tire) you get. If you stay with +32 offset, using a wider wheel or tire will "grow" both inward and outward an equal amount, so if you go from 7" wide to 8" wide wheels, you'll gain 1/2" on in and outside edges of the wheel/tire, using +32.

For the same 7" to 8" increase, if you choose a wheel with more offset, like +45mm, you'll gain all of that 1" on the inside edge, keeping the outside edge looking the same as stock. Yes, there's more of a chance the tire could rub at fully locked steering.

If you go negative, say +19mm offset, and go from 7" to 8" wide wheels, the inside edge doesn't move, but the outside edge will go out a full 1". Extreme negative offsets are what started the term "roller skate" as applied to cars with wheels that stick out.

It's worth mentioning that as a wheel grows wider, if the offset doesn't change, the spokes will move inward from the outside rim, causing a deep-dish effect. Increasing the positive offset helps to keep the spokes in about the same position relative to the outside rim, so the look of the wheel doesn't really change, even though it gets wider.

http://www.latemodelrestoration.com/item/LRS-1007SCK/1994-04-Mustang-Chrome-Sc-Style-Wheel-17X9. I'm really wondering if these will fit.

I would imagine 'rollerskate' wheels would increase drag, no?

Yes, but so to wider wheels in general. There is aero drag under the car as well as on the sides, and then there is more rolling resistance.

What tire pressure yall runnning at? OEM specs say 30psi all around. My tires are rated for up to 50psi.

Has anyone tried the 17" Buick LaCrosse wheels from 2007/2008? Wondering if the bolt patter and offset are compatible.

The listing I've seen says they are 5x115, but I see that some later LaCrosse wheels are 5x120.

Thanks
Al

charlieRobinson wrote:

What tire pressure yall runnning at? OEM specs say 30psi all around. My tires are rated for up to 50psi.

i run 42 up front and 46 out back. I also have different tires front v.s back and they are 245/45/18 so not quite comparable to stock.

When i did have the 16's on the car i would run 35 front and 38 rear. Much more than 35psi and traction became a problem for me, under even normal driving.

I like my rears a bit overinflated to try and get better mileage and to help balance my handling.

al_roethlisberger wrote:

Has anyone tried the 17" Buick LaCrosse wheels from 2007/2008? Wondering if the bolt patter and offset are compatible.

The listing I've seen says they are 5x115, but I see that some later LaCrosse wheels are 5x120.

Thanks
Al

The Lacrosse bolt pattern is 5x120, though some incorrectly assume (and list) them to be 5x115. One of our members actually tried a set to find they wouldn't fit.

Mr.Riviera wrote:

charlieRobinson wrote:

What tire pressure yall runnning at? OEM specs say 30psi all around. My tires are rated for up to 50psi.

i run 42 up front and 46 out back. I also have different tires front v.s back and they are 245/45/18 so not quite comparable to stock.

When i did have the 16's on the car i would run 35 front and 38 rear. Much more than 35psi and traction became a problem for me, under even normal driving.

I like my rears a bit overinflated to try and get better mileage and to help balance my handling.

I have been running 31 in the front and 33 in the back, cold. I also like more in the back as I find it helps with cornering. Haven't noticed a difference in mileage from 30psi all around though.

You may want to consider load in addition to pressure. Our cars are front heavy, so they need higher pressure up front to counter the weight. I run 45 front/ 40 rear for summer 45 profile, 40 front/ 35 rear for winter 60 profile. You can run higher rear pressure, but you'll have a smaller contact patch and less grip in exchange for slightly increased MPG.

Maybe, but then why does OEM specs call for 30psi all the way around? You think theyd consider curb weight prior to putting a number on this, yeah?