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View Full Version : Wheel spacers and adapters FAQ


MYBAD79
03-29-2011, 05:13 PM
Wheel adapters come in thickness 5/8" (15mm) and up, the good ones are "hubcentric" as shown on the photo below.

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These are not hubcentric (Note there is no lip centering the rim):

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Here's a photo that shows how the lip fits into the rim (same way your axle's lip fits into the rim):

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When using adapters that are less than 1" thick the original wheel studs may protrude past the mounting surface.

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Make sure your rims have these "pockets" between the holes for the studs - if there are no pockets cut down the old studs so that they're below the mounting surface.

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Excuse the bad English on some of the photos.... the hub centring rings can be custom machined or ordered from a number of places online, I think 1010tire used to sell these made from aluminum....

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mrvette
03-29-2011, 09:58 PM
25? years ago I dealt with the issue of HUB vs LUG centric wheels....never realizing it was a issue....bolt the wheel on and drive....

so I was putting a set of basket weave wheels off a '79 Firebird on to my '70 Lemans/GTO convertible...found out why the wheels always bounced when they balanced fine...the freeking LUG nutz were some shank deal instead of the most obvious cone on the like with any steel wheel....so I had to buy the correct lug nutz to fit the damn wheel.....fine, and it cured the problem...

I not much on the super high prices of aftermarket wheels, and so tend to buy second hand and then 'stock' for the brand....

I let VBP make up their mind how to make the wheel adapters for my car, 16 years ago....'89 vette wheels on a '72....2.5" thick, and so they work, never an issue...used to be '92 vette rims, but changed out for the more unique '89 look....

AND for the life of me, I can't understand why the stilly issue in the first place, just make ALL wheels lug centric, and get over it already...

Dualies in rear excepted...

:hissyfit:

BBShark
03-29-2011, 10:47 PM
Nice write up Karsten.

I recently saw a topic at another forum that stated that using spacers to adapt wheels (of a different offset) will put increased load on the bearings. Nothing could be further from the truth yet it seems to be a popular bit of mis-information.

mrvette
03-29-2011, 11:45 PM
Nice write up Karsten.

I recently saw a topic at another forum that stated that using spacers to adapt wheels (of a different offset) will put increased load on the bearings. Nothing could be further from the truth yet it seems to be a popular bit of mis-information.

Hey, long as the wheel/tire centerline is the same, sure, no problem...but you move that centerline out a inch or more....I say there is a problem...not so much on a solid axle.....but on say a C3 rear???

:hissyfit:

BBShark
03-30-2011, 12:06 AM
Hey, long as the wheel/tire centerline is the same, sure, no problem...but you move that centerline out a inch or more....I say there is a problem...not so much on a solid axle.....but on say a C3 rear???

:hissyfit:

Exactly, if the tire doesn't move, nothing changes.

Twin_Turbo
03-30-2011, 12:47 AM
and if it moves there's still the difference between cornering and straight line loads. They don't all change equally & for the worse depending on what side the wheel moves.

mrvette
03-30-2011, 01:46 AM
Hey, long as the wheel/tire centerline is the same, sure, no problem...but you move that centerline out a inch or more....I say there is a problem...not so much on a solid axle.....but on say a C3 rear???

:hissyfit:

Exactly, if the tire doesn't move, nothing changes.

and if it moves there's still the difference between cornering and straight line loads. They don't all change equally & for the worse depending on what side the wheel moves.

But when fitting super wide wheels on anything close to a stock C3 rear, I can't see how in hell to get more than 3/4 inch to the inside for clearance on the stock sway bar....much less the T-arm....then another maybe 1/2? inch to the frame.....and that demands moving the ebrake we all know about....

so if we keep the same centerline, that means a later C4 wheel takes a 2.5" adaptor to keep same centerline....but that's a wheel/adaptor issue, keeping same centerline....

you move that tread centerline outward very much and you increase loading on the lower struts and the output shafts.....

NO?? as well as the hubs....??

:hissyfit::drink:

edit....lemme put it another way...most easily gotten is 3/4 inch tread to the inside....so 3/4 to the outside, a 9.5 inch wheel width....

if going to 11" wheel width....how in hell to keep from grossly overloading the hubs and suspension??

clutchdust
03-30-2011, 04:08 PM
Nice write up Karsten.

I recently saw a topic at another forum that stated that using spacers to adapt wheels (of a different offset) will put increased load on the bearings. Nothing could be further from the truth yet it seems to be a popular bit of mis-information.
Exactly. I've been arguing that with people for years. I've been running 3" adaptors on my '81 or 10+ years now, at first with c4 wheels, now with c5 wheels. I've evn tracked the car on multiple occasions and had no problems. I know especially on the back that the wheels are a good 1.5" wider than original equipment but the inside edge of the tire is still in the same location. Plus with the -1* camber I run I'm pretty sure the load is so close to original that the difference is negligible. If I have a bearing failure at this point <knock on wood> I don't believe it would be remotely traceable to offset as I've never done a rear wheel bearing on this car since I got it in '96.

mrvette
03-30-2011, 05:24 PM
Nice write up Karsten.

I recently saw a topic at another forum that stated that using spacers to adapt wheels (of a different offset) will put increased load on the bearings. Nothing could be further from the truth yet it seems to be a popular bit of mis-information.
Exactly. I've been arguing that with people for years. I've been running 3" adaptors on my '81 or 10+ years now, at first with c4 wheels, now with c5 wheels. I've evn tracked the car on multiple occasions and had no problems. I know especially on the back that the wheels are a good 1.5" wider than original equipment but the inside edge of the tire is still in the same location. Plus with the -1* camber I run I'm pretty sure the load is so close to original that the difference is negligible. If I have a bearing failure at this point <knock on wood> I don't believe it would be remotely traceable to offset as I've never done a rear wheel bearing on this car since I got it in '96.

Sounds to me like you kept the same wheel/tire centerline, or pretty close, anyway......

what makes me think of that is some years ago, back when I did mine, seeing a bunch of kids with imports and reverse wheels on them all running stupid tires all leaned in at top /\ looking.....the IRS all freeked out.....

:drink:

enkeivette
03-30-2011, 05:50 PM
Nice write up Karsten.

I recently saw a topic at another forum that stated that using spacers to adapt wheels (of a different offset) will put increased load on the bearings. Nothing could be further from the truth yet it seems to be a popular bit of mis-information.

Ya, doesn't matter if the wheel extends far enough to reach the hub or it's extended by an adapter. It's all metal. And metal is generally pretty stout. Haha.

I put quite a bit of power through them. No problems.

mrvette
03-30-2011, 06:54 PM
Nice write up Karsten.

I recently saw a topic at another forum that stated that using spacers to adapt wheels (of a different offset) will put increased load on the bearings. Nothing could be further from the truth yet it seems to be a popular bit of mis-information.

Ya, doesn't matter if the wheel extends far enough to reach the hub or it's extended by an adapter. It's all metal. And metal is generally pretty stout. Haha.

I put quite a bit of power through them. No problems.

Funny how shit happens, I just got back from Discount Tire bought 2 new front 255/50/17 to fit the '89 vette rims on my '72, 2.5" wheel adapters.....

they pulled off the wheels, saw the adapters and almost refused the work, I calmed them down as they are of course ten lug nutz to get to the rotor, and so solid as hell, stronger than the wheels....they finally agree with me, so no sweat, I commented there are too many damn lawyers running ever show in town these daze....tires made in SE Asia, hate to admit....

:banghead::censored::hissyfit:

Arthur Brown
03-31-2011, 01:14 AM
discount tire will not work on cars with spacers, store policy so I heard. Unfortunately these guys don't know the difference between spacers and adapters so they're giving you a hard time because they're afraid to loose their job over this.

MYBAD79
03-31-2011, 01:59 AM
Had the same discussion with the guys at Discount Tire, told them that for example RH cup wheels come with adapters (these are Porsche cup replicas), it's their design.... RH is one of the leading wheel manufacturers and if they trust this design then it sure is good enough for me...

Companies like TechArt , Powertech and RH even have these adapters tested and certified to the strict European standards, most of their adapters are approved by the German TUV which means they went thru excessive testing ... ask Marck how he feels about the TUV ... :lol: