Hey guys, I have dug and dug trying to find this info and I swear I have seen it on here before but I can not seem to find it now. I have my 32 frame on the jig right now. I am going to be running fenders on my 32 roadster. I am going to be running a 40 ford rear axle (Columbia) and a 40 rear crossmember. Question is, how far back does the 40 crossmember need to go back to center it in the wheel wells? I would like to replace the crossmember instead of cutting up my nice 32 one and splicing the 40 in the center of it...but that is not out of the question. I do plan on running the stock fuel tank and I know there is not a lot of room to go back with a crossmember. What I am working with: Original 32 frame with original crossmember in (currently) 40 ford rear with 40 spring 40 for rear crossmember to use running fenders Any help will be greatly appreciated!
Position the rear axel 3" down from the frame and 17 3/4" from the bottom rear fender hole on the frame to the center line of the rear axel.
I used a 40 front spring in the stock 32 rear crossmember , got it lower but rear wheels are not centered , but then 32s weren't centered from the factory .
FWIW If you want the rear wheels to center in the rear fender as the original, the center of rear axle should be 74" from the center frame hole for the cowl tension bolt. I'd recommend using the 40 crossmember as it will fit the 40 rear spring without relief grinding. I have not done that modification but I have ground a relief to a 40 spring. Just place the center of the rear crossmember an equal distance as the center of the rear shackle on the rear end housing to the center of the banjo. Also, front axle center line is 32" from the same location. You will note: this results in the 106" original wheel base. Hope this helps. Jack
Centering the 32 back wheels is like centering 56 F-100 front wheels. Sounds like a good idea but looses something on completion.
As the tire goes up or down in the wheelwell or fender, it will look different in each situation. You should mock up YOUR situation and see what looks best. If you are going real low it will look different than a more reasonable ride height. And some tire diameters will make it more noticeable than others.
I think they look best slightly forward of center...adds a dynamic feel to the car, somewhat like the way a cartoonist indicates forward motion of a vehicle. Dead center, the two arcs look wrong with the bigger arc of the fender looking like it is trying to match the tire and failing, like: (c Also, the dead center looks to me very static as though the car has just plopped down and is sitting there perfectly still.
That's a whole lot of change to get exactly right without a mock-up. The 40 crossmember is a lot deeper than the 32 and needs flattened, as you flatten it the spring center pin moves towards the engine. I'm thinking you'll need a mock up to get it how you want it. Slide the ass end under the body with the spring, and wheels on it. Use a spreader to get 45* on the shackles or at least know the difference. Get ride height and pinion angle the measure from center pin on spring to body mount holes. And spring height to frame reference. It's going to be easiest to adjust ride height Up via spacer on spring, so keep that in mind.
Here is a stock 32 with a 7.50-16 (to me the wheel looks a little too far forward)... and the same car with a reverse eye spring and a few leaves removed (now it looks better)... I agree that you need to do a mockup. I did a flattened 40 crossmember on my RPU with a 40 spring. I mocked it up just how I wanted it to sit and then built the chassis to suit. See post #3 in this thread... http://www.jalopyjournal.com/forum/showthread.php?t=642590&highlight=neal+10+year+plan Neal
I agree with Pete and Bruce .. If its a tick forward to far its live able but if you have ever seen a car with the wheel a tick to far back it's very un-pleasing to the eye... Neal's pic shows pretty much perfect as it gets...
We just completed a similar build. I chose not to remove the original crossmember and just modify (not cut up) the center section to adapt the 40 spring. I have done many of them but the Kennedy Boys showed me how to do it the right way. You would be hard pressed to tell what was done simply by looking under the car. There are several threads on here that show different methods but it is not difficult. Using the 40 crossmember is a lot of work for very little improvement in my mind. The end result of our build was a tire wheel fitment like shown in Neal's second photo. I like your build plan with the Columbia. Did you know they have Columbia's for stock 32 springs?
OK . . . you asked ! When you use a dropped axle, and roll caster into it, the front wheel moves rearward slightly. To lower the front of the car, one of the things I do is raise the center of the crossmember. When I fab the new center part I move the spring & axle forward some, that helps bring the front wheel forward where it should be. Just one of those little things that makes the whole car look better.
So instead of using a Model A front cross member you alter the 32 cross member in a similar way but put an angle on the cross member where the spring sits to push axle foward?
My sedan looked very much likes Neal's picture above- the rear end moves rearward as you lower the car so that helped center the rear on its own. I installed a flattened 40 rear x-member in mine, and ended up only moving it about 3/8 inch rearward. I trimmed the front flange of my fuel tank with some tin snips which was very simple and helped with tank to crossmember clearance. For what it's worth- I regret removing my original crossmember now that I look back on it. If I did it again, I would retain the 32 x member and either grind the '40 spring, or modify the center of the 32 crossmember to work with the straight 40 spring. But I was working with a perfect original chassis.... On a side note- how freaking cool is it to have a hotrod legend like PWood participate on this forum to share his immense knowledge with us? I, personally am greatful! Thanks Matt
Built a few '32 chassis and I've found moving the axle centerline rearwards 3/4"-7/8" usually gives the best side view. The diameter of the rear tire influences the final location and a mock up is the only way to get it dead on. By using a rear fender and frame horn cover you can mount the rear fender to see how it will look at final assembly. Frank
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