Hi every one, new here. I'll give a short intro; I have been a mechanic of one kind or another for 40+ yrs. I have a 94 flareside, 99 sd.that I put a cummins in. At this time I am building a 48 f1, 351w,5spd.,9 in posi.rear. My question is about the rear diff. it is 1 in. longer from spring to wheel bolt surface. I want to put 10in wide wheels on.Anyone have idea of what back space, and off set it would take to clear the outer part of fender? Thanks

 

Welcome to the forum!

 

The largest rear tire that will fit comfortably in the 48-50 F-1 stock bed/fender I found to be a 265 width (this was with 15" wheels on 8 inch rims). Is your 9" from a 1972 or earlier truck? Are you thinking wheel tubs?

 

I have Cooper Tire Cobra Radial GT 235/60 15R on Appliance Production Slotted D Mags 15x8-1/2, 5 lug on 5-1/2", 3-1/2" Backspacing with a 9" rear end with no problem... I think you could get 10's on the rear with the right offset but I haven't tried or know the right combo.

 

Welcome to the forum. I have a 9" rear end from a 72 F100 with 295/50 R15 tires, with 10" smoothie's with 5 1/5" backspacing from what I remember. Here are some pics. As you will see they fit without a load but I wouldn't want to put a lot of weight in it, Im sure they would rub. So Im thinking if you want this width tubs would probably be a good Idea.I hope this gives you some idea of the fit with 295/50 R15s. PS the truck is a 50 F1 EDITT. I just found my notes from when I ordered my 10" wheels. the note indicate they are 4 1/2" back space not 5 1/2 ", ????? so please measure your trucks space carefully B4 you order . Sorry.

 

Thanks all for the replies, the 9'' is out of a 79 f150. I measured from the spring to the wheel mounting surface is about 12'' thanks again

 

Just some misc information on 9" axle widths The 1972, 9" im using is 61.25" and the 1979, 9" you are using is 65.25". Another way to get 10' wheels in without wheel tubs would be to widen your rear fenders. You might check with AX if you are interested in this method of widening your wheel space. Or there's lots of stuff in the advanced search thread on the blue banner at the top of the main page. Ive seen several projects on fender widening that came out beautifully. And that info should be in advanced search feature. Just another FYI, if you click on the FAQ button which is also on the blue banner but over on the left side of the main page, This FAQ button has drop down menus and list the how to's of this site and I found it to be very helpful. Well it's past my bed time, and Im sure Im just rambling by this point so Ill just say goodnight,

 

The reason that I asked about the year of the 9" is the greater width from 1973 on in the trucks. The 1972 and earlier rears were essentially the same width, wheel mounting surface to wheel mounting surface, as the original rear under the 1948. I do suggest that you locate one of the earlier 9" axles, much easier than custom backspaced wheels or widening the fenders. IIRC with the earlier rear you will end up with essentially a zero offset since that rear like the original rear pretty much centers the wheel mounting flange in the stock wheel well. If you keep the suspension up high so that the fender lip will not contact the wheel, you do have other possibilities.

 

Here is a pic if the rear of my truck to show the track of mine

 

Thanks for the pic from the rear, looks good. I remeasured the rear I took out, and the one I put in (79 9'') it is only 2'' longer over all. I am trying to fill in the wheel wells to hide that extra 1'' of axle tube without hitting the fender. thanks again