C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
Sponsored by:
Sponsored by:

Wheel adapter question

Thread Tools
 
Search this Thread
 
Old Feb 6, 2016 | 12:42 PM
  #1  
hamrad's Avatar
hamrad
Thread Starter
Instructor
 
Joined: Jul 2015
Posts: 121
Likes: 3
From: Maryland
Default Wheel adapter question

1973 base corvette. All stock except below:


I have searched and read for a couple days now. I have got a set of chrome rally wheels that have a 4 1/4 inch backspace. I have installed 255/60 15 tires. They touch both the parking break cable and the leaf spring. Looking an either spacers or adapters. Thinking a 3/8 spacer would work or a 1" adapter. So, for all the experienced corvette owners out there what is the best option? Please don't reply with get new wheels or such. Already have these wheels and tires just have to figure out best option to use them...............Also, what is the minimum amount of clearance from tire to parking break cable and leaf spring that would be acceptable?
Reply
Old Feb 6, 2016 | 01:16 PM
  #2  
fishslayer143's Avatar
fishslayer143
Drifting
 
Joined: Aug 2009
Posts: 1,346
Likes: 160
From: new iberia la
Default

Spacers and longer Lug nuts will work .. ! " adapter is stronger, so question is how much power do you have?
Reply
Old Feb 6, 2016 | 01:32 PM
  #3  
hamrad's Avatar
hamrad
Thread Starter
Instructor
 
Joined: Jul 2015
Posts: 121
Likes: 3
From: Maryland
Default

Power around 300 horses. Just a little concerned the adapter might put the wheels outside the wheel wells. Don't know if this would be an issue or not.


Originally Posted by fishslayer143
Spacers and longer Lug nuts will work .. ! " adapter is stronger, so question is how much power do you have?
Reply
Old Feb 6, 2016 | 02:19 PM
  #4  
Sacred Steel's Avatar
Sacred Steel
Racer
 
Joined: Mar 2014
Posts: 295
Likes: 18
From: Easton Massachusetts
Default

I have the same size tired as you and I think my wheels are 4.5" back space. I used a set of 1" hubcentric wheel adapters and they don't stick out past the wheel well. The adapters bolt on to your existing lug studs. Don't let anyone tell you that spacers or adapters put more load on the wheel bearings because it's not true.




Reply
Old Feb 6, 2016 | 02:37 PM
  #5  
hamrad's Avatar
hamrad
Thread Starter
Instructor
 
Joined: Jul 2015
Posts: 121
Likes: 3
From: Maryland
Default

Looks good. Did you have to trim the studs any? Seems like the 1 inch adapters might have to have the studs trimmed so they won't hit the wheels.


Originally Posted by Sacred Steel
I have the same size tired as you and I think my wheels are 4.5" back space. I used a set of 1" hubcentric wheel adapters and they don't stick out past the wheel well. The adapters bolt on to your existing lug studs. Don't let anyone tell you that spacers or adapters put more load on the wheel bearings because it's not true.




Reply
Old Feb 6, 2016 | 06:05 PM
  #6  
Barry's70LT1's Avatar
Barry's70LT1
Melting Slicks
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Oct 2001
Posts: 2,066
Likes: 1,414
From: Halifax, Nova Scotia, Canada
Default

I have 4.5" BS wheels, I used 1/2" spacers and new, longer ARP studs.

Reply
Old Feb 6, 2016 | 06:13 PM
  #7  
Sacred Steel's Avatar
Sacred Steel
Racer
 
Joined: Mar 2014
Posts: 295
Likes: 18
From: Easton Massachusetts
Default

Originally Posted by hamrad
Looks good. Did you have to trim the studs any? Seems like the 1 inch adapters might have to have the studs trimmed so they won't hit the wheels.
When I put them on and torqued them down, I took a straight edge and ran it across the lugs and a few of them just barely so I ground them down a hair.
Reply
Old Feb 6, 2016 | 06:16 PM
  #8  
Sacred Steel's Avatar
Sacred Steel
Racer
 
Joined: Mar 2014
Posts: 295
Likes: 18
From: Easton Massachusetts
Default

Originally Posted by Barry's70LT1
I have 4.5" BS wheels, I used 1/2" spacers and new, longer ARP studs.

where did you get these? Do you have a link? I was actually looking to go this route with the 1/2 hubcentric spacers but couldn't find any.
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

10 Corvettes to Drive Before You Die!

 Joe Kucinski
story-1

Corvette & Porsche 911: How Two Icons Conquered the Last 25 Years

 Joe Kucinski
story-2

2027 Chevrolet Silverado 1500 First Look: Everything You NEED to Know!

 Michael S. Palmer
story-3

5 Best & 5 Worst Corvette Daily Drivers

 Joe Kucinski
story-4

The Headlights of Every Corvette Generation Explained

 Joe Kucinski
story-5

5 Best & 5 Most Overrated Corvette Track Packages of All Time!

 Joe Kucinski
story-6

Every 2027 Corvette Engine Explained

 Joe Kucinski
story-7

Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette

 Verdad Gallardo
story-8

10 Ugly Corvettes That We Still Kinda Love

 Joe Kucinski
story-9

Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

 Brett Foote
Old Feb 6, 2016 | 10:52 PM
  #9  
Barry's70LT1's Avatar
Barry's70LT1
Melting Slicks
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Oct 2001
Posts: 2,066
Likes: 1,414
From: Halifax, Nova Scotia, Canada
Default

Originally Posted by Sacred Steel
where did you get these? Do you have a link? I was actually looking to go this route with the 1/2 hubcentric spacers but couldn't find any.
Long story, here are the highlights.
The spacers are not hub centric, I made steel inserts for the stud holes to make it a snug fit, and also made a hub insert to make the spacer hub centric. The spacer can't move.

Since the wheels are Lug centric, I didn't try to get spacers that were hub centric to the wheel.
I got the spacers here..... (Canadian Supplier)
http://www.wmsracing.com/wmsweb/perf..._moreinfo.html
Jegs and Summit also have spacers.
I chose "Billet" spacers, reason, precision and strength.

I used ARP studs,
http://performanceparts.com/part/ARP/100-7701
More info - http://arp-bolts.com/kits/ARPkit-detail.php?RecordID=61
They're a bit long, however can be trimmed.
Also the knurl in the stud is a bit large for the hole in the hub. They may have pressed in ok, however I reamed the hub holes a bit (to 15/32" / .46875) to make a still very snug fit.

Last edited by Barry's70LT1; Feb 6, 2016 at 10:54 PM.
Reply
Old Feb 7, 2016 | 11:11 AM
  #10  
69autoXr's Avatar
69autoXr
Melting Slicks
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Jan 2004
Posts: 3,249
Likes: 210
From: Detroit MI
Default

Originally Posted by Sacred Steel
where did you get these? Do you have a link? I was actually looking to go this route with the 1/2 hubcentric spacers but couldn't find any.
You can have spacers made to your specifications from motorsport-tech.com.
Reply
Old Mar 21, 2016 | 07:48 PM
  #11  
rogernison's Avatar
rogernison
Instructor
 
Joined: Mar 2014
Posts: 110
Likes: 10
Default Backspace

Originally Posted by hamrad
1973 base corvette. All stock except below:


I have searched and read for a couple days now. I have got a set of chrome rally wheels that have a 4 1/4 inch backspace. I have installed 255/60 15 tires. They touch both the parking break cable and the leaf spring. Looking an either spacers or adapters. Thinking a 3/8 spacer would work or a 1" adapter. So, for all the experienced corvette owners out there what is the best option? Please don't reply with get new wheels or such. Already have these wheels and tires just have to figure out best option to use them...............Also, what is the minimum amount of clearance from tire to parking break cable and leaf spring that would be acceptable?
Stock C3 backspace is 4" 1/4" spacers should do the job with plenty of clearance.
Reply
Old Mar 21, 2016 | 09:30 PM
  #12  
cagotzmann's Avatar
cagotzmann
Melting Slicks
15 Year Member
Liked
Top Answer: 1
Top Answer: 3
 
Joined: Jun 2011
Posts: 3,123
Likes: 605
Default

Originally Posted by Sacred Steel
Don't let anyone tell you that spacers or adapters put more load on the wheel bearings because it's not true.
I have seen this a few times.

Not that I question your view, but

Do you have the math that shows this to remove the myth once and for all.

Any engineers here that can provide the final math answer.

My first impression is it could, but I'd like to see the math to change my mind.
Reply
Old Mar 21, 2016 | 11:27 PM
  #13  
MCMLXIX's Avatar
MCMLXIX
Racer
15 Year Member
 
Joined: Jan 2004
Posts: 303
Likes: 28
From: los angeles ca
Default

If the center line of the wheel ends up in the same place relative to the hub there is no increase in load on the bearings.
The bearing does not care or know the path the load takes and the amount of load does not change.
A wider wheel and tire will increase the load.
If the wider wheels center line is still on the face of the hub the increase will be minimized.
The length of a lever is still the same whether it is straight or S shaped.
No need for math or enginemanures.
If the outside edge of the tire tread is in the same place on the pavement the length of the lever is the same.
Reply
Old Mar 22, 2016 | 12:42 AM
  #14  
MN80Vette's Avatar
MN80Vette
Drifting
15 Year Member
 
Joined: Sep 2006
Posts: 1,986
Likes: 21
From: Columbus MN
Default

Originally Posted by Sacred Steel
where did you get these? Do you have a link? I was actually looking to go this route with the 1/2 hubcentric spacers but couldn't find any.
Our son, Matt, is a CNC machinist and has made MANY billet hub centric adapter-spacers for CF members. Adapter-spacers (3/8") for Boss wheels (4.5" backspace) are "standard", but he can make them for any brand wheel given the wheel hub ID.




If you don't install longer wheel studs, then you at least need to switch to conical extended lug nuts to grab more wheel lug threads (bolt diameter MINIMUM).


Reply
Old Apr 22, 2016 | 06:31 PM
  #15  
KevinK's Avatar
KevinK
Drifting
 
Joined: Jun 2007
Posts: 1,404
Likes: 1
From: Ansonia/NYC CT
Default

Originally Posted by cagotzmann
I have seen this a few times.

Not that I question your view, but

Do you have the math that shows this to remove the myth once and for all.

Any engineers here that can provide the final math answer.

My first impression is it could, but I'd like to see the math to change my mind.
It's not the spacer that adds load, it's the typically increased width of wheel/tire that does it...
Reply
Old Apr 22, 2016 | 06:34 PM
  #16  
KevinK's Avatar
KevinK
Drifting
 
Joined: Jun 2007
Posts: 1,404
Likes: 1
From: Ansonia/NYC CT
Default

To the OP, 1 inch adapter would be the rout I would go....but....BUT...with 255s, I would replace those old studs for some ARP studs. The ones you can find have a knurl width that is a bit too wide for the holes...so you need to cut the metal a bit...a TINY bit. You might even just try one of those circular rasp files...and then pull the studs through with a good long wrench. I did it without a press, so it can be done!

And BEFORE I did it, I snapped 3 of the 5 lugs on the driver side rear wheel while driving. So trust me, this is something you are going to want to do.
Reply
Old Apr 22, 2016 | 07:17 PM
  #17  
lionelhutz's Avatar
lionelhutz
Race Director
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2007
Posts: 11,153
Likes: 892
From: South Western Ontario
Default

Use the spacers and ARP studs and you'll be just fine.

I find the concerns about having hub centric adapters a little comical. They can't do anything useful unless they are an interference fit that was pressed onto the hub and into the wheel. The same applies with wheels that are supposed to be hub centric.

Think of it this way. Stand your wheel up and put the "hub" of the spacer into the wheel. Now roll the wheel. The spacer will roll inside the wheel center so it's always touching at the bottom of the hole. So, if you car was actually relying on that hub to carry the weight, the hub would be constantly rolling inside the center hole of the wheel wearing out both the spacer hub and wheel center.

It's the same reason the rear wheel bearing on a C3 need to be press fit and not loose fit onto the spindle. Otherwise, the spindle would roll inside the inner race of the bearing destroying both the bearing and spindle with each revolution of the wheel.
Reply

Get notified of new replies

To Wheel adapter question

Old Apr 23, 2016 | 12:19 PM
  #18  
TheSkunkWorks's Avatar
TheSkunkWorks
Le Mans Master
10 Year Member
Liked
Loved
Top Answer: 1
 
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
Default

Originally Posted by Sacred Steel
Don't let anyone tell you that spacers or adapters put more load on the wheel bearings because it's not true.

In and of themselves, spacers or adapters wouldn't change how loads are distributed among the inner and outer bearings. Rather, it's any track width variations at the wheel/tire CLs that would alter these loads, regardless of whether spacers or adapters are used. That said, we're only talking about a minimal deviation in the OP's somewhat less than severe duty application. FWIW, I don't happen to care for spacers or adapters, but would highly recommend anyone using them to install HD studs and to verify sufficient thread engagement. My $.02
Reply
Old Apr 23, 2016 | 01:10 PM
  #19  
GUSTO14's Avatar
GUSTO14
Le Mans Master
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Sep 2003
Posts: 8,812
Likes: 2,029
From: eastern NC
Default

Originally Posted by hamrad
1973 base corvette. All stock except below:


I have searched and read for a couple days now. I have got a set of chrome rally wheels that have a 4 1/4 inch backspace. I have installed 255/60 15 tires. They touch both the parking break cable and the leaf spring. Looking an either spacers or adapters. Thinking a 3/8 spacer would work or a 1" adapter. So, for all the experienced corvette owners out there what is the best option? Please don't reply with get new wheels or such. Already have these wheels and tires just have to figure out best option to use them...............Also, what is the minimum amount of clearance from tire to parking break cable and leaf spring that would be acceptable?
You say that the tires touch the parking brake cable and the spring. Was this with the car off of the ground and the wheels at full droop?

If it was, you may be surprised when you lower the car to the ground to find that you now have clearance between the spring and the tire. Because of the unequal lengths of the half shaft and the strut rod, the wheel moves in an arc and you have less clearance at full droop. At normal ride height and suspension travel, you will have additional clearance. I would want about an inch to call it good. If that is the case then all you really need to do is move the parking brake mount to the top of the control arm.

Good luck... GUSTO
Reply
Old Apr 23, 2016 | 01:38 PM
  #20  
Barry's70LT1's Avatar
Barry's70LT1
Melting Slicks
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Oct 2001
Posts: 2,066
Likes: 1,414
From: Halifax, Nova Scotia, Canada
Default

Originally Posted by lionelhutz
It's the same reason the rear wheel bearing on a C3 need to be press fit and not loose fit onto the spindle. Otherwise, the spindle would roll inside the inner race of the bearing destroying both the bearing and spindle with each revolution of the wheel.
Don't forget the inner race is being compressed/held in place with a 100+ ft lb of torque. If the rolling resistance in the bearing is great enough to overcome the 100+ ft lb on the inner race, then slip fit or press fit is the least of your problems.
Reply



All times are GMT -4. The time now is 10:46 AM.

story-0
10 Corvettes to Drive Before You Die!

Slideshow: 10 Corvettes to drive before you die.

By Joe Kucinski | 2026-06-23 08:31:12


VIEW MORE
story-1
Corvette & Porsche 911: How Two Icons Conquered the Last 25 Years

Slideshow: Corvette and Porsche 911, how two icons conquered the last 25 years.

By Joe Kucinski | 2026-06-23 08:18:33


VIEW MORE
story-2
2027 Chevrolet Silverado 1500 First Look: Everything You NEED to Know!

Slideshow: Is the 2027 Chevrolet Silverado 1500 the best Silverado yet?

By Michael S. Palmer | 2026-06-16 08:01:12


VIEW MORE
story-3
5 Best & 5 Worst Corvette Daily Drivers

Slideshow: 5 best and 5 worst Corvette daily drivers

By Joe Kucinski | 2026-06-15 10:32:13


VIEW MORE
story-4
The Headlights of Every Corvette Generation Explained

Slideshow: The headlights of every Corvette generation explained

By Joe Kucinski | 2026-06-15 10:17:14


VIEW MORE
story-5
5 Best & 5 Most Overrated Corvette Track Packages of All Time!

Slideshow: The 5 best and 5 most overrated Corvette track packages ever.

By Joe Kucinski | 2026-06-09 12:46:45


VIEW MORE
story-6
Every 2027 Corvette Engine Explained

Slideshow: Every 2027 Corvette engine explained

By Joe Kucinski | 2026-06-09 12:16:31


VIEW MORE
story-7
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette

Slideshow: A Jaguar designer's personal project imagines what a modern front-engined Corvette might look like if Chevrolet revisited the golden age of the Stingray.

By Verdad Gallardo | 2026-06-08 19:53:43


VIEW MORE
story-8
10 Ugly Corvettes That We Still Kinda Love

Slideshow: 10 ugly Corvettes that we still kinda love.

By Joe Kucinski | 2026-06-03 10:34:17


VIEW MORE
story-9
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

A lot of money has changed hands at the online auction house over the years.

By Brett Foote | 2026-06-03 10:21:50


VIEW MORE