Rear wheels are sucked in way more than front. K10. Adapters? BAD IDEA? pics inside

[Nasty-LSX]

I know this is normal for k10/k20. Not sure the reason or why GM did this. I was once told it was due to the
turning radius. My question is, Im guessing 1 1/2 inch adapters could correct this weird look. is there any
negative to pulling the wheels out level with the fronts. I dont see why not, But does not hurt to ask.

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[bucket]

There's lots of reasons why GM would have done that, many people have different theories of Ackerman angle, many others say it's for traction reasons.

But the reality of it is, it was to save money. They simply used the same axle housing for 2wd and 4x4 trucks, which makes the rear axle narrower than the front axle on on the 4x4's.

 

[bucket]

And I know someone is going to call me out on it, so here's why I said what I said.

Ackerman angle isn't a good reason, because the track width difference is the same, no matter the wheelbase... like the difference between K5 and a long bed truck.

The traction thing isn't a good reason either. Otherwise, the following GMT 400 trucks wouldn't have had wider rear axles specifically to match the front of the 4x4 trucks.

Also, pretty much all other trucks have a similar track width, front and rear.

 

[Redfish]

My '87 has spacers in the rear to make the wheels line up. I was going to remove them but my Dear Old Dad asked me not to do so. He told me that was something that had always bothered him about his '77 GMC and Mom's '84 Blazer. He apparently hated it more than I realized. It has never bothered me.

The spacers have not had any adverse effect as far as I can tell...other than requiring the removal of a second set of lug nuts every time I need to access the rear brakes. But I don't need to do that very often.

The Truck still carries weight just fine.

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[Redfish]

And I know someone is going to call me out on it, so here's why I said what I said.

Ackerman angle isn't a good reason, because the track width difference is the same, no matter the wheelbase... like the difference between K5 and a long bed truck.

The traction thing isn't a good reason either. Otherwise, the following GMT 400 trucks wouldn't have had wider rear axles specifically to match the front of the 4x4 trucks.

Also, pretty much all other trucks have a similar track width, front and rear.

Some of that logic is based more on opinion than fact anyway. Ford had some great promotional stuff for the first year of the First Gen Bronco. They made it a point to show that the front and rear axles were EXACTLY the same...for Better Traction! There is a wonderful Ford produced video on YouTube for the '67 Bronco and they clearly show that "feature".

I agree with everything you said.

 

[Nasty-LSX]

And I know someone is going to call me out on it, so here's why I said what I said.

Ackerman angle isn't a good reason, because the track width difference is the same, no matter the wheelbase... like the difference between K5 and a long bed truck.

The traction thing isn't a good reason either. Otherwise, the following GMT 400 trucks wouldn't have had wider rear axles specifically to match the front of the 4x4 trucks.

Also, pretty much all other trucks have a similar track width, front and rear.

That makes perfect sense. Thanks. I figured it would not be a big deal to pull them out some.
It will look 10 times better closer to the fender lip. Thanks bucket!

 

[Nasty-LSX]

My '87 has spacers in the rear to make the wheels line up. I was going to remove them but my Dear Old Dad asked me not to do so. He told me that was something that had always bothered him about his '77 GMC and Mom's '84 Blazer. He apparently hated it more than I realized. It has never bothered me.

The spacers have not had any adverse effect as far as I can tell...other than requiring the removal of a second set of lug nuts every time I need to access the rear brakes. But I don't need to do that very often.

The Truck still carries weight just fine.

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Thats awesome Redfish, Would you happen to know how thick your adapters are?

 

[Keith Seymore]

It was for traction, so that the front tires and rear tires were tracking in fresh material (snow or sand).

K

 

[bucket]

It was for traction, so that the front tires and rear tires were tracking in fresh material (snow or sand).

K

I won't argue that it does indeed help with traction to some degree. But that was just A reason, not THE reason.

Most consumers would rather have a wider rear axle to match the front, traction be damned. They don't wish to have a goofy looking rear track width. But, it saved a bunch of time and money to have one rear axle width for all the trucks, which then became "Oh yeah, we did that specifically for traction. Please ignore the goofy look... we did it just to benefit you" sales pitch.

 

[Turbo4whl]

@bucket @Keith Seymore Okay, I'm taking bets here, who is correct? I'll give odds here as the money flows in...

 

[Doppleganger]

Older 4N cars are like this - rears are usually 3+ inches more narrow. The manufacturers official reason was that the front track being wider was more stable and the rears being more narrow was to help with over-steer.

Never stopped people from spacing them out.

 

[bucket]

@bucket @Keith Seymore Okay, I'm taking bets here, who is correct? I'll give odds here as the money flows in...

It's all just speculation at this point. And opinions too of course, lol. I certainly don't have the knowledge that Keith does. But we really need to find someone from the engineering team back in the late 60's to answer it as far as I'm concerned. Then I'll finally shut up, lol.

 

[Keith Seymore]

It's all just speculation at this point. And opinions too of course, lol. I certainly don't have the knowledge that Keith does. But we really need to find someone from the engineering team back in the late 60's to answer it as far as I'm concerned. Then I'll finally shut up, lol.

I know the guy.

Ed Pauly was the suspension engineer for the squarebody trucks.

We lived in the same small town during our time on the program, so we had a lot of nice visits.

I'm not speculating. If I was I would say so, but a lot of squarebody history I don't have to speculate on (like the roof running lights a few threads ago).

K

 

[Keith Seymore]

I know the guy.

This actually happens alot.

My beloved bride - who knows everything (just ask her) and I were driving on Phoenix's Apache Trail up to Roosevelt Dam. It's miles and miles of dirt road and was pretty dusty, so I reached down and put the HVAC system on "max" so it would recirc the inside air.

She quickly reached down and turned it off.

I nonchalantly reached down and turned it back on.

She quickly reached down and"WHAT ARE YOU DOING?!" I proffered.

"It's really dusty out there so I am turning the system to cut down on the dust".

"No you are not" I said. "Recirc is what keeps the dust out".

"No it doesn't" she quietly said.

"BABE!" I said. "I KNOW THE GUY!! WALT WIITALA!! HE DESIGNED IT!!"*

Anyway, so now when we have an automotive dispute one of us will say "I know the guy!"

K

*Walt is a street rodder so I see him at car shows sometimes. I told him this story and he got a kick out of it.

 

[Keith Seymore]

The traction thing isn't a good reason either. Otherwise, the following GMT 400 trucks wouldn't have had wider rear axles specifically to match the front of the 4x4 trucks.

Here's the thing about doing different generations of vehicles:

When the current version came out it was billed as the greatest thing since sliced bread.

So any change you make as a manufacturer has to be "better" than before. And then better again. And then better yet again. At best - It's unsustainable. And it's subject to the whims of the program team and what is "en vogue" at the time.

Think about fuel tank locations as an example. The squarebody had the tank outside the fuel rail, which was frowned upon in hindsight when the GMT400 came out with the tank inside the frame rails.

Be reminded that the previous truck, though (67-72) had the tank inside the pickup cab.

K