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1967 - 1972 F-100 & Larger F-Series Trucks Discuss the Bumpsides Ford Truck

Wheels - Backspace and Offset?

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Old Mar 27, 2019 | 02:30 PM
  #1  
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Wheels - Backspace and Offset?

I need help understanding backspace and offset.

I am installing a DJM lowering kit on my 1969 F100. It will drop the front 3" and the rear 4".

Planning to buy new wheels and tires.

Do I need to worry about backspace and offset when buying new wheels?

What width wheels and tires will work well with my truck without any rubbing issues?

I am not leaning toward and certain size wheels or tires. I was just basically trying to eliminate (or at least reduce) the gap between the top of the tire and the fender well.

Any advice would be helpful.

Thanks!
 
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Old Mar 27, 2019 | 09:36 PM
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I'm sure you'll get a lot of help here Fleetwood. I'm pretty sure I've seen talk from quite a few members that have performed the DJM install.
Is there anything in their instructions about backspacing or offset requirements? They may not talk about tire size, leaving that up to the end-user to determine what fits on their particular truck and what they like the look of. But often there are physical limitations to just how much wheel can hang out behind the hub/wheel flange and things like king-pins, springs and spindles/knuckles and such.

Are you also wanting to know what the terms mean? Or do you have that down and are just asking about DJM specifics?

Paul
 
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Old Mar 29, 2019 | 11:01 AM
  #3  
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Originally Posted by Fleetwood271
I need help understanding backspace and offset.

I am installing a DJM lowering kit on my 1969 F100. It will drop the front 3" and the rear 4".

Planning to buy new wheels and tires.

Do I need to worry about backspace and offset when buying new wheels?

What width wheels and tires will work well with my truck without any rubbing issues?

I am not leaning toward and certain size wheels or tires. I was just basically trying to eliminate (or at least reduce) the gap between the top of the tire and the fender well.
I did an axle flip in back and DJM beams in front for a -3 and -5.25 drop, respectively. I used new steel wheels from Wheels Vintiques, Series 62... rears are 15x8 with 4-inch BS wearing 275/60-15s. Fronts are 15x7 with 3.5-inch BS and 225/70-15 tires. The truck sits level and no rubbing whatsoever. I should have gone with 235/60-15s in front for a lil rake. Whenever I carry a load, the rear is lower than the front by a hair.

As a rule of thumb, backspacing should be half the wheel width for these trucks...an 8-inch width in the rear commonplace. However, a 9-inch width would be perfect but there doesn't seem to be decent wheels with that width.

I suggest searching Bump articles online for different wheel/tire combos then work with a local retailer (or online company) to determine the required specifications.

.
 
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Old Mar 30, 2019 | 07:48 PM
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Originally Posted by 1TonBasecamp
I'm sure you'll get a lot of help here Fleetwood. I'm pretty sure I've seen talk from quite a few members that have performed the DJM install.
Is there anything in their instructions about backspacing or offset requirements? They may not talk about tire size, leaving that up to the end-user to determine what fits on their particular truck and what they like the look of. But often there are physical limitations to just how much wheel can hang out behind the hub/wheel flange and things like king-pins, springs and spindles/knuckles and such.

Are you also wanting to know what the terms mean? Or do you have that down and are just asking about DJM specifics?

Paul
Thanks for your response. I've been out of town and not able to respond.
I have not opened the boxes from DJM yet, but I doubt if they give and direction pertaining to what size wheels to use.
I understand the terms, I just need to know what size wheels and tires would work well on my truck, after the DJM drop. Or, will any tire/wheel combo that worked before it was lowered, still work after it is lowered?
 
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Old Mar 30, 2019 | 07:51 PM
  #5  
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Originally Posted by HIO Silver
I did an axle flip in back and DJM beams in front for a -3 and -5.25 drop, respectively. I used new steel wheels from Wheels Vintiques, Series 62... rears are 15x8 with 4-inch BS wearing 275/60-15s. Fronts are 15x7 with 3.5-inch BS and 225/70-15 tires. The truck sits level and no rubbing whatsoever. I should have gone with 235/60-15s in front for a lil rake. Whenever I carry a load, the rear is lower than the front by a hair.

As a rule of thumb, backspacing should be half the wheel width for these trucks...an 8-inch width in the rear commonplace. However, a 9-inch width would be perfect but there doesn't seem to be decent wheels with that width.

I suggest searching Bump articles online for different wheel/tire combos then work with a local retailer (or online company) to determine the required specifications.

.
Thank you for your response. I appreciate the info. So based on your experience, if I go with the same wheels/tire sizes you did, I should be fine, right? No rubbing issues?
 
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