RACING OFF ROAD ROCKCRAWLER BEADLocK AND NON BEADLocK  WHEELS  BY  MRW

MANUFACTURERS OF "CUSTOM BUILT" MOTORSPORTS WHEELS SINCE 1955

MARSH RACING WHEELS 

16591 LOGAN CAVE ROAD

SILOAM SPRINGS, ARKANSAS 72761

Local --- 479- 524-4157

FAX --- 479-524-5168

www.rockcrawler-mrt.com

mrtwheels@yahoo.com 

WHEN ORDERING DOUBLE BEADLocK WHEELS "EXTREME CARE" MUST BE TAKEN ALSO TO CHECK FOR INTERFERENCE  OF THE BACK BEADLOCK WITH THE BRAKE CALIPERS, VEHICLES  BODY, TIE RODS, STRUTS, OR OTHER SUSPENSION PARTS

THE DISTANCE BETWEEN "A. THE BACK OF A WHEEL" AND "B. THE BACK OF A CENTER" IS THE BACK SPACE OF A WHEEL

5 = IS WHERE TO MEASURE YOUR BOLT PATTERN 

A. INSIDE RIM LIP

B. DISHED CENTER

C. INSIDE VALLEY EDGE

D. CENTER WELD POINT

E. OUTSIDE VALLEY EDGE

F. OUTSIDE RIM LIP

G. VALLEY INSIDE DIAMETER

H. BELL inside DIAMETER

I. CENTER OF AXLE TO OUTSIDE EDGE OF CALIPER

X. BACK BELL DEPTH

Z. FRONT BELL DEPTH "

YOUR BEST BET

When you're ready to buy a new set of wheels, measure the backspacing of the wheels that you know work - the ones on the car-. 

 HOWEVER IF YOU

   plan to purchase a wheel with more or less backspacing or are changing to a different size or width wheel or tire ------------- PLEASE READ CAREFULLY 

The the backspace (sometimes called offset) is the distance from the inside surface of the dished center (B) to the inside rim lip (A). (technologically the offset of a wheel is determined by measuring plus or minus from the center line of a rims width,  and this dimension changes for each rims width. So for simplicity MRW will use the tried and true backspace measuring terminology).  

BACKSPACING DEMONSTRATION 

On a 15x8" wheel this backspacing dimension can be approximately anywhere from 1" to 5" for modifieds or 1" to 4" for stock cars, This holds true for 15X8,  15x10" , 15X12" wheels etc. because in most cases  the only dimension that changes is the width of the 'valley.'( NOTE  in 7"width wheels and under (X) is decreased ).  

While it may appear that the backspacing range should increase with the width of the valley, actually the critical dimension is the distance between the inside rim lip (A) and the inside valley edge (C). In the illustration above you will see that it is labeled (X) and has an approximate dimension of 4". Regardless of the width of the wheel  8" or even wider, X  will  be approximately  4" and Z will be approximately  1.5"  . (There is an exception to this in our 'Wide Back Bell' shells. In this case X is increased to approximately  5".)  

BRAKE : SUSPENSION ASSEMBLY : AND VEHICLES BODY CLEARANCE

-Notice when measuring,-  (H) & the inside depth of the bell must clear the  brake calipers (3) or drum , rim lip (A) See the illustration above. And also the bulge of the sidewall and the outside diameter of the tire must clear the vehicles body, steering and suspension assembly when turned to the extreme left or right at full spring compression, or zero weight = no  spring compression  . This must be determined by your observations and measurements.  

MAXIMUM BACKSPACING

If (I) x2 (times 2) is greater than 12.625" (G), on a 15" wheel obviously your maximum backspacing must be somewhere under 4". Otherwise the caliper will hit the valley of the wheel. See the illustration above. - -  Note: (G) diameter is greater on 16" 17" 18" 19" 20" wheels 

MINIMUM BACKSPACING

The minimum backspacing is determined by the 'dish' of the center and the Back Bell Depth (X). While the typical center is 1-1/4" deep, part of that is the weld surface, leaving only a part of the actual center depth to work with. Also, the actual flat weldable part of the valley is shortened by the curve of the valley wall.

Placing the center at the extreme usable edge of the valley gives only an approximate  3"?  backspacing.

SO HOW DO WE GET LESS THAN 3" BACKSPACING?

By turning the wheel around and putting the Front Bell on the inside. This time when we put the center at the extreme weldable surface of the valley, we achieve and backspacing of approximately 1".

Normally, you don't need to worry about how we do it when you order wheels from us. We've been doing it a long time. We automatically orient the wheel to get the specified backspacing. If it's from 1" to 5", or more.

OTHER COMPLICATIONS

While we fabricated our shells (rims) and centers to exact specifications, the actual 'dish' and 'weld surface' of the centers can be different from the figures given here. For example, the dish of a Wide 5 bolt pattern is less than a 5 on 5 pattern. Some centers are only available in a flat configuration - with no dish at all! A flat center changes the backspacing considerably "

Another complication is the matter of other support and steering members installed on the vehicle. It is possible to build a wheel that clears the hub and brake calipers but still won't work because it bangs into the steering assembly, suspension, or vehicles body when the front wheels are turned. Not good. (See above)

YOUR BEST BET

When you're ready to buy a new set of wheels, measure the backspacing of the wheels  that you know work - the ones on the vehicle- .

HOW TO MEASURE BACKSPACING

1. Place the wheel (without tire) on a flat surface with the outside up (hub side down).

2. Put a ruler down through the center hub hole.

3. Note where the back side of the center plate strikes the ruler - That's the backspace.

THERE IS NO SUCH THING AS A 'STANDARD' BACKSPACING OR OFFSET!

There are too many variations between car and axle manufacturers. 2", 3", and 4" backspacings are popular and common, but not standard. We depend upon you to give us accurate backspacing and wheel measurements. If you don't, you may have just purchased a very expensive set of paperweights. (See drawing diagrams)

HOW TO CONVERT OFFSET TO BACKSPACE 

Zero (0) offset means the dead center of the wheel . 

Plus (+) offset is how far towards the outside of the wheel from dead center = (more backspace) . And Minus (-) is how far towards the inside the wheel from dead center = (less backspace) .

OFFSET TO BACKSPACE EXAMPLE 

1" inch plus offset on an 8" inch wheel Converts to approx. 5 1\2" inch backspace ---------- as you will need to include the 1/2" for width of the lip of the wheel ---------

 1" inch minus offset on an 8" inch wheel Converts to approx. 3  1\2" inch backspace ---------- as you will need to include 1/2" for the width of the lip of the wheel ---------

WHEN ORDERING DOUBLE BEADLocK WHEELS "EXTREME CARE" MUST BE TAKEN ALSO TO CHECK FOR INTERFERENCE  OF THE BACK BEADLOCK WITH THE BRAKE CALIPERS, VEHICLES  BODY, TIE RODS, STRUTS, OR OTHER SUSPENSION PARTS

THE DISTANCE BETWEEN "A. THE BACK OF A WHEEL" AND "B. THE BACK OF A CENTER" IS THE BACK SPACE OF A WHEEL

5 = IS WHERE TO MEASURE YOUR BOLT PATTERN 

A. INSIDE RIM LIP

B. DISHED CENTER

C. INSIDE VALLEY EDGE

D. CENTER WELD POINT

E. OUTSIDE VALLEY EDGE

F. OUTSIDE RIM LIP

G. VALLEY INSIDE DIAMETER

H. BELL inside DIAMETER

I. CENTER OF AXLE TO OUTSIDE EDGE OF CALIPER

X. BACK BELL DEPTH

Z. FRONT BELL DEPTH "

 INSIDE (G) VALLEY WHEEL DIMENSIONS

To copy this form start mouse curser at upper left side of form (below), holding left button down drag (move) curser across form to right side and then down to bottom and release, then right click mouse on any highlighted word and choose copy.---Now go to your E-mail page and right click on your letter, choose paste and fill in the blanks. (Type wheels in your subject line) and send to mrtwheels@yahoo.com  Or E-mail  mrtwheels@yahoo.com and we can email you this form.     You may Call 1-800-643-3625  or 1-479-524-4157 Mon. to Fri. 8:00 am. till 6:00 pm. U.S. Central time to place your order.      Thank you for choosing MRW    

Current Pricing Subject To Change Without Notice - Shipping F.O.B. Siloam Springs Arkansas 72761 - 1/30/2009

OH!-OH! DID YOU FORGET SOMETHING ???? WE NOW HAVE HEADERS, TIRE SIPERS, TIRE GROOVING IRONS, GROOVING , BLADES, CARBIDE OR  NAIL GRINDING DISKS FOR GRINDING, CONTOURING TIRES, TIRE IRONS, MOTORSPORTS BUMPERS,  ROLL CAGES, LUG NUTS, VALVE STEMS, LOW PRESSURE TIRE GAUGES, TIRE BALLAST, TRACTION ADVANTAGE,  STAGGER GAUGE, STAGGER TAPES, BEAD BREAKERS,  MAGNETIC PAINT,  MUD COVERS & PLUGS, RACING APPAREL, RACING OPTICS, TEAR OFFS, RACING GLOVES, NOMEX DRIVERS UNIFORMS, NECK YOKES, ARM RESTRAINTS,  AND MANY OTHER MOTORSPORTS PRODUCTS -----------IF YOU NEED IT WE HAVE IT OR WILL TRY TO FIND IT FOR YOU.--------------DO NOT SEND CREDIT CARD INFORMATION WITH E-MAIL

"click" to see complete bolt pattern reference page

"CLICK FOR" OTHER IMPORTANT INFORMATION   

CATALOG

BOLT PATTERN
#studs on circle

STUD HOLE SIZE

COMMON APPLICATION