4x4 rearends

[WETOWM]

This may be a STUPID quistion but is the front axle housing wider than the rear axle when i look at the fron & rear it looks like the front tires stick out more then the rear

[too much stuff]

Yes the fronts are wider.

[WETOWM]

Never payed to much attention until today when i put the wheels and tires on my frame up resto

[LONGHAIR]

Yes, I have always "heard" that it was a traction thing, so the tires don't follow the same track... but I'm not buying it. That would only come into play when driving in a straight line.
I suspect that it was done to keep larger diameter tires from rubbing at full lock....and they never changed the rear to save a buck

[lowrollin70gmc]

The rear is narrower to help in turning radius, even modern trucks continue this trend to a certain degree.

[ryanroo]

Originally Posted by lowrollin70gmc

The rear is narrower to help in turning radius, even modern trucks continue this trend to a certain degree.

Bingo.

supposed to allow for a tighter turning truck. the rear follows a tighter radius than the front, so the narrower rear helps follow that tighter radius.

i dislike the look and have a rear end that closer matches the front.

Ryan

[69GWC]

I put a 72 rearend in my 69 so now its wider and a closer match to the front I dont like the look of the rear being narrower then the front either.
Posted via Mobile Device

[LONGHAIR]

I would love to hear some legit reason why the width of the rear end has anything to do with turning radius. Wheelbase, yes...track width? not buying it.
Even "if" it could matter in some extreme, a few mere inches couldn't make enough difference.

[ryanroo]

Maybe its not much, but the idea makes sense. imagine a 20ft wide rear axle. during a turn, the inside wheel would move backwards(like a tricycle). under power it would tend to push. so the wider the rear in relation to the front the more tendency it will have to push the front, thereby decreasing the turn radius. under power and with good traction to both rear tires, it will try to push strait and push the front axle until you end up so narrow that there is one tire in the middle. since the rear is static and the tires are always trying to push strait forward the narrower the axle the less tendency it will have to push. this becomes even more noticeable with a locked rear.

[sduckworth13]

Cool, I learned something new today. Thanks for sharing

[skorpioskorpio]

Just as a side note to this, I know you can have an axle narrowed, does any one widen an axle? ...or if you wanted such a thing is it just cheaper to get a custom made one new? I'm asking because, I'm planning out a project where I am going to put in a Porterbuilt cross member and am thinking of widening the front end by a couple inches and using higher offset rims to push the steering center closer to the center of the rim and would like the rear to have the same width and rim offset, meaning probably 3 inches wider.

[lowrollin70gmc]

Back to original topic:

I also went to a wider rear axle in an 11.5 AAM at 68.25WMS vs my stock Dana 60 63" WMS. Even with the wider rear, swapping out the closed knuckle D44 and it's lack of steering angle more than made up what I lost with the rear axle.

For comparison, my front axle is a dodge D60 so it is actually narrower than my rear at 67.5WMS. It isn't very noticable and will correct itself when I swap to slide over front discs and gain about a 1/4 per side plus the 1/8 spacer I have extra.

For reference, the black wheels have a decent amount of backspacing and wouldn't clear my rear wheelwells flexing on the stock axle.

Stock front and rear with 16x8 "standard" offset (4 inches?) 315/75/16


Stock Rear Axle, D60F 17x8 "late model" offset (5-6 inches?) 315/70/17


2005 11.5AAM


And my front end sits higher: the D60F has larger tubes/spring mounts, the Cummins weighs less than my last motor, and I rub the top of my apartment's garage door opening so it's staying at this height until I move. I can't even run my 37s unless I leave it outside. But I don't mind how it sits and she drives beautifully even up to 95.

[71K20chevy]

CASE CLOSED!!!

[blasher]

Can someone please summarize the measurement differences in rear axle widths. I have a ‘69 K10 but I think the axle is a few years newer. How can I tell if I have the older narrower axle or a newer wider axle? I can’t read any of the axle tube stampings. I think they’re buried under layers of rust and paint. Thanks in advance.

[Redcap]

Originally Posted by blasher

Can someone please summarize the measurement differences in rear axle widths. I have a ‘69 K10 but I think the axle is a few years newer. How can I tell if I have the older narrower axle or a newer wider axle? I can’t read any of the axle tube stampings. I think they’re buried under layers of rust and paint. Thanks in advance.

Measure them?

[blasher]

I know I've seen threads on here that answer my question but the search function doesn't work for me in this section. I get this error message: (Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 35 bytes) in /home/admin69/public_html/vboard/search.php on line 1160) Does anyone else get this search error?

I Googled the internet and learned: “1963-69 were the narrow 6 lug 12 bolt, and 1970 and newer should be 1.5 inches wider.” I’m still not sure what the total measurement is backing plate to backing plate. That’s the question that I was trying to ask above.

[blasher]

Alright, I got it. Google found the older thread on this site for me: (http://67-72chevytrucks.com/vboard/s...d.php?t=547192)

So, backing plate to backing plate should be either 56.5” or 58”.