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Discussion Starter #1
seems like this topic comes up every time someone puts a set of adapters on their C3 to use a later Corvette wheel. Some guys have run adapters for thousands of miles with no trouble and other guys swear up and down that you won't make it out of your driveway before you have issues. Here's a really rough cross section of a stock wheel and a large backspace wheel on a stock hub and spindle. What's your take and why?

 

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I've been running adapters for almost 10 years. No issues.

I think results vary and depend almost completely on:

Offset / Backspacing
Hub-Centric / Not
Driving Style

I like deep dish wheels, that have a smaller backspacing. Typically called a RWD offset wheel. This moves the weight distribution towards the center of the rim instead of the outer edge as seen on many FWD offset wheels. Newer cars, even RWD, tend to have the larger backspacing. Maybe the larger the backspacing, the more likely bearing wear will be.

There are two different kinds of adapters. Hub-centric are machined to fit spot on over the lip on the outer edge of the hub. This perfectly centers the adapter and puts the bulk of the weight on the hub itself instead of the studs...which are further from center on the hub. That too could contribute to bearing wear.

Finally, driving style. I'm a cruiser. I like torque, medium speeds, and mildly curvy to straight roads. I'm easier on my suspension and bearings because I am not an aggressive twisty high speed autocross driver. I think the more aggressive a driver is in turns, affects the wear of the bearings, and in turn, other suspension components.
 

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I'm sure it does decrease overall bearing life, heck driving or not driving your car wears bearings. So why not drive it with the look you want?

I saw all the guys taking their trucks and jeeps with 2"-3" spacers driving them for daily use and weekend off-roading without issues over years. D_B is spot on too, driving style will add to bearing life, with or without spacers.
 

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I'd think that under ideal conditions, the load (weight) should be split pretty equally between the bearings, with maybe a slight bias toward the inner larger bearing. Adding a spacer would move the center of weight outboard, loading the outer bearing more.
That said, with no more weight that we're looking at, (maybe 1500 pounds on each end= 750 pounds each wheel?) that it's not really going to make a huge difference. Maybe a reduce the bearing life a little. The major stress is probably going to be on the wheel lugs anyway.
 

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This is a fun topic, there's so many logical answers

didya know that many high level drag cars of the rail and flopper variety run adapters? Look in the pits at your next event, pay attention when the wheels are off. They're all over. Here's a place that makes em

http://www.wheeladapter.com/index.php

But moving beyond the quality of the spacer, what about bearing geometry/loading for a corner carver?......

One might say that trips to steak houses and strip clubs isn't going to be as hard on a C3 as the track use they were designed for. (although the trip home from the strip club could be another story) So the bearings are able to take that punishment in the form of poor geometry instead of sustained lateral Gs.

Others might point out that we cheer anyone with 10-12" deep dish old-school wheels, and they're also horrible for bearing geometry/load. If we'd had the internets in the 80s this thread would be about deep dish cragars eating up wheel bearings on daily drivers.

To me, the real catch of spacers is the need to remove the wheel to check spacer torque. That's probably to blame for more spacer failures than anything else.

I think the popularity of dubs has created more high quality spacer options for musclecar enthusiasts but also opened the floodgates for cheap chineese junk. Don't be the guy who'll only spend 80 on a set of spacers then complains their junk. Of course they are.

Counterpoints please..... :cheers:
 

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Assuming the spacers are machined exactly and the tire is in the same place and has the same mechanical qualities, no change.

Most of the time this won't happen.

I've been running high offset rims for years (3in bs on 10in wide rims), but don't drive many miles. The only problem was the rear axle failed by fatigue. I'd had the emergency brake lock up on that axle which probably started the crack years earlier. The wide tires no doubt grew the crack faster.
 

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Moot point. For every five folks who post and say not to use them, five more will post and say they're fine.

No debate if you run stock wheels.

I run stock wheels.

:buhbye:
 

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Moot point. For every five folks who post and say not to use them, five more will post and say they're fine.

No debate if you run stock wheels.

I run stock wheels.

:buhbye:

As far as after market wheels, yeah, run the risk if you want the wheels.

However, there are a lot of folks who have or want to install late model Corvette rims on a C3. These guys have to use adapters...no debate.

So...it's 'kind' of like stock wheels, since they are stock...just not a stock application. LOL.
 

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I've heard that adapters are fine so long as your 'vette isn't silver...
:laughing:

Good thing mine's pewter now then. :laughing:

All I know is everybody has an opinion on them.
Yet NOBODY has any proven tests.

Here's what I DO know:
Those that are afraid of them, despise them.
Those with no experience with them, have the largest opinion.
Those that use them, have no issue with them.

Complaints (or rumor) of failure are few and far between.
Out of those that experienced bearing failure....how do you verify the bearings where not aged and ready to fail already or wheren't cheap offshore parts?

This thread will be nothing but opinions and arguement because the only way to confirm if there is any issue with adapters would be to build brand new arms with all new identical quality parts and reconstruct testing over and over to confirm the validity of the parts wether they fail or not....and no one is going to do that.

My opinion.....any additional wear to the bearings or arms from using adapters would be so minimal over time that you would not know if bearing failure was due to the use of adapters or just normal failure. Moving the wheel mounting surface outward an inch or two is not going to produce the kind of force needed to cause premature bearing failure. (Not to mention my C6 wheel/tire combo is lighter than my old stock wheels-less sprung weight)

Now if my bearings fail within the next year, I may change my opinion on that. ;)
 

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I just wanted to comment on the drawing....

Love the detail! :thumbsup:

Right down to the cotterpin in the axle nut. :partyon:

The set up in the picture is going to fail though.
No lug nuts!
 

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seems like this topic comes up every time someone puts a set of adapters on their C3 to use a later Corvette wheel. Some guys have run adapters for thousands of miles with no trouble and other guys swear up and down that you won't make it out of your driveway before you have issues. Here's a really rough cross section of a stock wheel and a large backspace wheel on a stock hub and spindle. What's your take and why?

You have to make that call on your own based on your current Corvette.

The variables of Moment (spacer size 1/2"?, 2"?, 3"), amount of torque being delivered to the wheels (stock motor?, aftermarked crate?), and the age of your current bearings, how often you drive it, all come in to play.

The bigger the moment (more spacer you use), and the greater the torque = the more risk you have of bearing failure.

For example.....

My 1979's rear leaf spring is nearing the end of it's life. I can see some tilt inward of the rear wheels. So I know the bearings are already seeing some stress. I've also recently dropped in a new Crate 355 engine with 190 ft-lbs MORE torque than the stock engine....

If I go and add 2-inch spacers to the mix I'll be upping the moment arm on the bearings by a factor of about 17%. (2"/12" = 0.1666')

So now I've added 17% more moment arm to the bearings, added 190 ft-lbs of more toqure to the bearings, and I know my leaf springs got a sag as well also adding more stress to the bearings.

For me, I'd say it'd be a medium risk of bearing failure.
 

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There are two different kinds of adapters. Hub-centric are machined to fit spot on over the lip on the outer edge of the hub. This perfectly centers the adapter and puts the bulk of the weight on the hub itself instead of the studs...which are further from center on the hub. That too could contribute to bearing wear.
There is ABSOLUTELY no more load on the bearings or studs than without an adapter (assuming the tire is in the same position as drawn). Think about it. Has the load path changed at all?
 

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There is ABSOLUTELY no more load on the bearings or studs than without an adapter (assuming the tire is in the same position as drawn). Think about it. Has the load path changed at all?
I agree 100% the load on the bearings remains the same, and in the same location. As the weight is transfered in a straight line below the hub. To the rim and distributed across the tire.

The rim and the spacer have different stress point, but are strong enough to withstand it. If they were not the rims would break every time you turned a corner.
 

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Discussion Starter #17
There is ABSOLUTELY no more load on the bearings or studs than without an adapter (assuming the tire is in the same position as drawn). Think about it. Has the load path changed at all?
is this the way you see it?



since the forces on the hub flange don't change, neither do the forces at the wheel bearings. Any additional stress is only in the wheel and adapter.
 

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is this the way you see it?



since the forces on the hub flange don't change, neither do the forces at the wheel bearings. Any additional stress is only in the wheel and adapter.
So with a quality set of hub centric and wheel centric adapters, all is good. :agree:
 

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Biggest problem with adapters is that they have to be retorqued ever so often. Some are worse than others.
 
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