For those that have notched their rear frame rails to the seem, will a wheel with 5.25" backspace fit without rubbing on the frame?
Frame notch and back spacing
- Thread starter Happy camper
- Start date
Just did my notch. From what I have seen just about everyone runs 5.5in bs. 5.25 should assuming you went to about the seam.
One thing you have to also consider is the size of the rims, a 15" Tire will have a bigger section width than a 17" or 18" tire of similar dimensions
I will get flak for saying this but frame notching will reduce the rigidity of your frame by half. The rigidity of box beams is determined by the size of the cross sectional area of the beam. Reducing the cross sectional area like with frame notching reduces rigidity. Moreover, frame notches often require 90 degree joints which are stress risers. The proper way is to move the frame rails inboard while maintaining the same size of cross sectional area.
Welding reinforcing plates on the sides doesn't do much good as its the top and bottom sides that provide vertical bending stiffness. Cut the top and bottom sides in half, you lost half your up and down rigidity on the axle hump. Now on a nice flat and smooth race track this loss of rigidity isn't as much of an issuse as it would be on real roads with bumps and potholes.
Besides all that, performing major frame modifications such as boxing and notching frame rails really requires a chassis jig to kerp the frame straight and square. A typical paved driveway or garage floor is nowhere near flat even for accurate measurements. Even then careful back step welding techniques should be used to avoid heat warping your frame. Too much heat at once and your frame warps, requiring a trip to the chassis rack machine.
Welding reinforcing plates on the sides doesn't do much good as its the top and bottom sides that provide vertical bending stiffness. Cut the top and bottom sides in half, you lost half your up and down rigidity on the axle hump. Now on a nice flat and smooth race track this loss of rigidity isn't as much of an issuse as it would be on real roads with bumps and potholes.
Besides all that, performing major frame modifications such as boxing and notching frame rails really requires a chassis jig to kerp the frame straight and square. A typical paved driveway or garage floor is nowhere near flat even for accurate measurements. Even then careful back step welding techniques should be used to avoid heat warping your frame. Too much heat at once and your frame warps, requiring a trip to the chassis rack machine.
Thank you for your input, while It did cross my mind that I would lose some of the strength in the frame, having it explained the way you did has me thinking it's not such a good idea.
While I agree with what Clone TIE Pilot has said, what is that section of frame rail actually doing? Supporting the rear bumper and one set of body mounts . All suspension is connected forward of where you will notch. I haven't noticed a bit of difference after doing mine. If anything, I would bet it's the same strength as the factory merely because the entire seam is now welded, instead of stitched, or completely missing welds as mine came from the factory.
Given the number of people that have done it with no ill side effects, incluidng myself, I would venture you'll be just fine.
Given the number of people that have done it with no ill side effects, incluidng myself, I would venture you'll be just fine.
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