Dually Wheels--Teach me!

[roll_the_dice]

OK, so I am starting to think about my next project...1964 GMC 1 ton Dually. Since I need new tires, I want to update the wheels at the same time with chrome or polished aluminum. I have read these trucks were hub centric and the hub bore was 4.56" with 8x6.5" lug pattern. I have also read GM trucks older than 2000 were the same hub size. Is that true?

I found an inner rear steel wheel with the correct hub bore and bolt pattern. On the outer wheel, do they still need to be hub centric? I found an outer wheel that is 4.60"...would this work? I am assuming the front wheel just needs to be the right bolt pattern or do I need to worry about the correct hub size also?

I think I have decided on 16" or would it look better with 19.5"? Subjective I know.

My plans on the truck are to put a flatbed on it (unless I find a stepside bed I can alter).

What am I missing or haven't thought about? Dually's are new to me...here she is before I do anything to it...blank canvas. And I am doing the build as cheaply as possible..I will sell this eventually for the next next project...a 50's truck.

[jayoldschool]

And I am doing the build as cheaply as possible.

Then keep these wheels. They look great. Paint them, that's it. I wouldn't even change the tires until it's ready to hit the road, do all the other work first. Unless they don't hold air.

[roll_the_dice]

Originally Posted by jayoldschool

Then keep these wheels. They look great. Paint them, that's it. I wouldn't even change the tires until it's ready to hit the road, do all the other work first. Unless they don't hold air.

Cheaply as possible within reason, but I still want a certain look. It will be one of the last things I do...but I don't want tube tires so they will be changed eventually even if I change them to steel wheels without going chrome/polished. Steel wheels that fit the hub and lug size are $85 each shipped...so cheap enough if I go the painted route.

[roll_the_dice]

In my head I am going to do a cheap version of this...I love the rear fenders, so this is my vision.

[jayoldschool]

It would be cool to find a roll back tow bed for it!

[roll_the_dice]

Originally Posted by jayoldschool

It would be cool to find a roll back tow bed for it!

That was my first idea/want...but my truck is 133" WB. I don't think it is big enough and at only 1 ton...not sure if it is stout enough. Eventually I would love to do a C50 or bigger into a rollback or wedge car hauler.

[bigmoe]

A stepside would be cool! You'd have to widen the fenders.

http://www.2040-cars.com/chevrolet/s...o-3500-846455/

[roll_the_dice]

Originally Posted by bigmoe

A stepside would be cool! You'd have to widen the fenders.

http://www.2040-cars.com/chevrolet/s...o-3500-846455/

That was option #2...which is very cool. I have some feelers out looking for a 9 foot bed...so if I can find one, this would be the route I like a lot! I think the 9 foot bed is going to be hard to find though.

[roll_the_dice]

Any insight for my questions in the first 2 paragraphs above?

[Captainfab]

I have honestly never dealt with any of the original running gear on a C30. If the hubs do in fact measure 4.56", I don't know if a wheel with a 4.60" bore would be an issue. As far as I know switching out the original wheels to newer non-split ring wheels isn't a problem. One thing I would suggest first, before you get too far along, is checking the differential gear ratio. Some of the C30's came with 5.13 gears, but most likely 4.57's. Either one is not very highway friendly. I would suggest first deciding if you really want to keep that differential. A swap to a Dana 70 or a 14 bolt with higher gears might be a consideration.

[roll_the_dice]

Originally Posted by Captainfab

I have honestly never dealt with any of the original running gear on a C30. If the hubs do in fact measure 4.56", I don't know if a wheel with a 4.60" bore would be an issue. As far as I know switching out the original wheels to newer non-split ring wheels isn't a problem. One thing I would suggest first, before you get too far along, is checking the differential gear ratio. Some of the C30's came with 5.13 gears, but most likely 4.57's. Either one is not very highway friendly. I would suggest first deciding if you really want to keep that differential. A swap to a Dana 70 or a 14 bolt with higher gears might be a consideration.

Thanks John!

I didn't think the 4.60" bore would be bad but wanted to verify. I have the SM420 trans... I currently have the Eaton HO72 in the truck...I think it is 5.14 ratio? You are right...I need to decide the rear end first before I decide wheels...

Would you think a 14 bolt or Dana 70 would still be a good fit? I was looking at different rear ends today after doing some searches. I found a Dana 70 4.10 gear ratio fairly local to me. What gear ratio would you think with the SM420?

[Chuck73080]

Originally Posted by roll_the_dice

Thanks John!

I didn't think the 4.60" bore would be bad but wanted to verify. I have the SM420 trans... I currently have the Eaton HO72 in the truck...I think it is 5.14 ratio? You are right...I need to decide the rear end first before I decide wheels...

Would you think a 14 bolt or Dana 70 would still be a good fit? I was looking at different rear ends today after doing some searches. I found a Dana 70 4.10 gear ratio fairly local to me. What gear ratio would you think with the SM420?

You have the same rear and trans as the '66 LWB I just bought. Although my knowledge is very limited compared to most of the people here, I have been researching the same subject you have. My truck was originally ordered with split rims as it appears yours may have been. The prior owner changed mine over to 16" tubeless wheels from a later model C30 and mounted 225X75R16 tires which are only 29.3" diameter and would turn the 283 4,126 RPM at 70 MPH.

So, I opted for a Dana with 3.54 gearing, which should drop my RPM at 70 MPH to 2842. Whatever you do I would suggest running tubeless tires as most major tire shops in my experience won't work on split rims from a liability stand point. Granted my experience is based on 46 years driving big trucks, but the 6 years I pulled refrigerated container chassis with split rims between OK and CA was a nightmare of tire problems with split rims. Of course this was with Dayton hubs which are THE WORST to deal with.

Here is a link from Spicer to calculate gear ratio/tire diameter/RPM/speed

https://spicerparts.com/calculators/...alculator#less

I've spent hours with it and frankly it is an indispensable tool IMHO.

Like I said my 225X75R16 tires are only 29.3" diameter, 225X85R16 are 30.4" and 235X85R16 are 31.7". Keep in mind that each time you increase tire size it normally increases load carrying ability, which will increase the price and higher load rating which generally translates to poorer ride quality. You also need to watch the section width of the tire, you never want the sidewalls of your duals to run against each other under load.

Your truck looks great, I'll be watching your progress.

My truck was originally ordered with the big West Coast Mirrors, but the prior owner had them replaced by a single mirror when 4-5-6 Chevy Trucks repainted it in 2015.

My wife thinks my truck is ugly so I'm going to use dual SS 6"X8" mirrors and SS mounting arms from Brother's, a complete chrome grill/headlight bolt in assembly from 4-5-6 Chevy Trucks, a chrome bumper from LMC and SS simulators rather than chrome wheels.

I always wanted a stretched dually chassis with a Hodges bed, and that is why I fell in love with my truck on first sight, although at 10 feet it would have to be a very SHORT car.

Good Luck

Chuck73080
https://www.youtube.com/watch?v=maXSPBlGQl4&t=10s
https://www.flickr.com/photos/184381...57653616824764

[allchevy58]

On my 64' C30 I wanted 06' dually wheels so I had adapters made from Motorsport Tech 2" 8X6.5 4.460" to 8X6.5 4.595" tall pilot 14mm1.5 studs for the rear and same without the tall pilot for the front. Put on LT235/85r16 tires, with 514 gears I didn't even try to go on the highway. Bought a HD70 out of a 77' Chevy C30 dually, installed 354 gears and the mileage was terrible and terrible on hills. Changed to 4:10 gears and it is perfect, 3,000 rpm at 70 mph. My truck is pretty heavy being 12' flatbed. The HD70 brought outside of the tires right to edge of the flatbed, looks nice. Bolted right in, had to shorten back half of driveline. I had to have new adapters for the HD70 for hub centric, so if you decide to put 06' dually wheels on the original rearend, I have those adapters available.

[Captainfab]

The trans being a 4 speed really doesn't play much of a part in selecting the rear gear. That is unless you want to go with a really high rear gear and have to use 1st gear all the time. If you will be running a 283, don't be too concerned about the highway rpm's. The 283's like rpm's and need the rpm's to build their torque. They don't have much low end torque. In that case the 4.10's would be fine. Now if you are upgrading to say a 350, then you can get away with a higher rear gear, say like a 3.73 or 3.54. The size of tires do play a part in selecting the rear gear. A 14 bolt, Dana 60 or 70 would be a good choice.

Originally Posted by roll_the_dice

Thanks John!

I didn't think the 4.60" bore would be bad but wanted to verify. I have the SM420 trans... I currently have the Eaton HO72 in the truck...I think it is 5.14 ratio? You are right...I need to decide the rear end first before I decide wheels...

Would you think a 14 bolt or Dana 70 would still be a good fit? I was looking at different rear ends today after doing some searches. I found a Dana 70 4.10 gear ratio fairly local to me. What gear ratio would you think with the SM420?

[roll_the_dice]

Originally Posted by Chuck73080

You have the same rear and trans as the '66 LWB I just bought. Although my knowledge is very limited compared to most of the people here, I have been researching the same subject you have. My truck was originally ordered with split rims as it appears yours may have been. The prior owner changed mine over to 16" tubeless wheels from a later model C30 and mounted 225X75R16 tires which are only 29.3" diameter and would turn the 283 4,126 RPM at 70 MPH.

So, I opted for a Dana with 3.54 gearing, which should drop my RPM at 70 MPH to 2842. Whatever you do I would suggest running tubeless tires as most major tire shops in my experience won't work on split rims from a liability stand point. Granted my experience is based on 46 years driving big trucks, but the 6 years I pulled refrigerated container chassis with split rims between OK and CA was a nightmare of tire problems with split rims. Of course this was with Dayton hubs which are THE WORST to deal with.

Here is a link from Spicer to calculate gear ratio/tire diameter/RPM/speed

https://spicerparts.com/calculators/...alculator#less

I've spent hours with it and frankly it is an indispensable tool IMHO.

Like I said my 225X75R16 tires are only 29.3" diameter, 225X85R16 are 30.4" and 235X85R16 are 31.7". Keep in mind that each time you increase tire size it normally increases load carrying ability, which will increase the price and higher load rating which generally translates to poorer ride quality. You also need to watch the section width of the tire, you never want the sidewalls of your duals to run against each other under load.

Your truck looks great, I'll be watching your progress.

My truck was originally ordered with the big West Coast Mirrors, but the prior owner had them replaced by a single mirror when 4-5-6 Chevy Trucks repainted it in 2015.

My wife thinks my truck is ugly so I'm going to use dual SS 6"X8" mirrors and SS mounting arms from Brother's, a complete chrome grill/headlight bolt in assembly from 4-5-6 Chevy Trucks, a chrome bumper from LMC and SS simulators rather than chrome wheels.

I always wanted a stretched dually chassis with a Hodges bed, and that is why I fell in love with my truck on first sight, although at 10 feet it would have to be a very SHORT car.

Good Luck

Chuck73080
https://www.youtube.com/watch?v=maXSPBlGQl4&t=10s
https://www.flickr.com/photos/184381...57653616824764

Thanks! Great information...I already have the spicer website bookmarked! What engine do you have in yours? Since mine is a GMC, I have the big block V6 305E. My truck is matching numbers and I am the 2nd owner with 60k miles. Only surface rust and is in really great condition. I am keeping the engine and trans...my wife wants me to keep the rear end (money...jeesh), but it is 5.14 I believe...Not sure how to convince her on a new rear end.

Originally Posted by allchevy58

On my 64' C30 I wanted 06' dually wheels so I had adapters made from Motorsport Tech 2" 8X6.5 4.460" to 8X6.5 4.595" tall pilot 14mm1.5 studs for the rear and same without the tall pilot for the front. Put on LT235/85r16 tires, with 514 gears I didn't even try to go on the highway. Bought a HD70 out of a 77' Chevy C30 dually, installed 354 gears and the mileage was terrible and terrible on hills. Changed to 4:10 gears and it is perfect, 3,000 rpm at 70 mph. My truck is pretty heavy being 12' flatbed. The HD70 brought outside of the tires right to edge of the flatbed, looks nice. Bolted right in, had to shorten back half of driveline. I had to have new adapters for the HD70 for hub centric, so if you decide to put 06' dually wheels on the original rear end, I have those adapters available.

That's great information on the Dana 70! I found a Dana 70 with 4.10 gears for $350...but when I asked the guy to measure the width between brake backing plates he said 59 inches which can't be right. He is about 4 hours from me...so I am not sure I want to drive down there to double check him. Do you know what should the measurement be?

Wonder if anyone would be interested in my Eaton HO72 if I swap it out.

[roll_the_dice]

Originally Posted by Captainfab

The trans being a 4 speed really doesn't play much of a part in selecting the rear gear. That is unless you want to go with a really high rear gear and have to use 1st gear all the time. If you will be running a 283, don't be too concerned about the highway rpm's. The 283's like rpm's and need the rpm's to build their torque. They don't have much low end torque. In that case the 4.10's would be fine. Now if you are upgrading to say a 350, then you can get away with a higher rear gear, say like a 3.73 or 3.54. The size of tires do play a part in selecting the rear gear. A 14 bolt, Dana 60 or 70 would be a good choice.

Thanks again John...I have a 305E v6...so I think the 4.10 gears would be good? Here is a picture of the rear end I found. He didn't know if it were a Dana 70, I assumed it was. It came out of an 1988 C30.

[duallydude63]

i have a 63 on a newer frame i had to widen the the fenders 4 in" (stepside) !!!

[allchevy58]

The original rearend measures 46" on the outer side of backing plate and Dana 70HD measures 55" on the outer side of the backing plate. Is his rearend out of a single wheel or dually? They are different width I was told. I cut off the old shock mounts and welded new brackets for the shock facing forward. Mine didn't have rear shocks, yours probably doesn't either but it makes a world of different in the ride.
I built a 383 for mine and it runs pretty good with 4:10 gears.

[roll_the_dice]

Originally Posted by allchevy58

The original rearend measures 46" on the outer side of backing plate and Dana 70HD measures 55" on the outer side of the backing plate. Is his rearend out of a single wheel or dually? They are different width I was told. I cut off the old shock mounts and welded new brackets for the shock facing forward. Mine didn't have rear shocks, yours probably doesn't either but it makes a world of different in the ride.
I built a 383 for mine and it runs pretty good with 4:10 gears.

Great pictures! Thanks for the help! He told me it was from a dually.

These were the pictures he sent me of the rear end...

So if the track is wider, that just means the rear end is wider, but it will still work?

If this will work, I think $350 is a decent price...you think?

[Captainfab]

Measuring backing plate to backing plate is NOT the way to measure a differential to determine track width and or fitment. There are way too many variables with brake widths and hub configurations plus the backing plate is far from flat. You must measure the WMS to WMS.

[allchevy58]

Originally Posted by roll_the_dice

Great pictures! Thanks for the help! He told me it was from a dually.

These were the pictures he sent me of the rear end...

So if the track is wider, that just means the rear end is wider, but it will still work?

If this will work, I think $350 is a decent price...you think?

I paid $300.00 at a junkyard with the sway bar, I'd recommend getting that too. Sway bar links and all, bolts right in, just drill holes for the links to frame.

[Chuck73080]

Originally Posted by roll_the_dice

Thanks! Great information...I already have the spicer website bookmarked! What engine do you have in yours? Since mine is a GMC, I have the big block V6 305E. My truck is matching numbers and I am the 2nd owner with 60k miles. Only surface rust and is in really great condition. I am keeping the engine and trans...my wife wants me to keep the rear end (money...jeesh), but it is 5.14 I believe...Not sure how to convince her on a new rear end.

That's great information on the Dana 70! I found a Dana 70 with 4.10 gears for $350...but when I asked the guy to measure the width between brake backing plates he said 59 inches which can't be right. He is about 4 hours from me...so I am not sure I want to drive down there to double check him. Do you know what should the measurement be?

Wonder if anyone would be interested in my Eaton HO72 if I swap it out.

Our trucks sound very similar although mine had 4 or 5 owners over it's 62,000 miles I have copies of all the transactions since it sold new. I bought a Blueprint Engines 396 SBC stroker that dyno'd 506HP@5600/534TQ@4100, Centerforce billet flywheel/12" dual friction clutch combo. for the SM420.

The Dana sounds like a good deal. it looks to me like a dually rear, the wheel on the left is obviously an outside dually wheel. I think the measurement difference is between backing plate width and wheel mounting surface width.

Go for a day trip, the worst you could be is wrong and gas is cheap. Just be prepared to bring it home with as many parts as you can get. If the wheel base is the same, grab the drive line if you can, spare parts are either usable or trade goods. Since you don't have your wheels and tires yet, you can adjust your tire diameter to dial in your cruising RPM. the 4.10 with that 235X85R16 tire would be 3042RPM@70.

Let us know how it turns out.

Good Luck

[roll_the_dice]

Originally Posted by Captainfab

Measuring backing plate to backing plate is NOT the way to measure a differential to determine track width and or fitment. There are way too many variables with brake widths and hub configurations plus the backing plate is far from flat. You must measure the WMS to WMS.

Thanks...I texted the guy and am waiting on WMS measurements.

Originally Posted by allchevy58

I paid $300.00 at a junkyard with the sway bar, I'd recommend getting that too. Sway bar links and all, bolts right in, just drill holes for the links to frame.

I wish we had a good junk yard here...maybe I will take a look anyway...but good call on the sway bar links. Thanks

Originally Posted by Chuck73080

Our trucks sound very similar although mine had 4 or 5 owners over it's 62,000 miles I have copies of all the transactions since it sold new. I bought a Blueprint Engines 396 SBC stroker that dyno'd 506HP@5600/534TQ@4100, Centerforce billet flywheel/12" dual friction clutch combo. for the SM420.

The Dana sounds like a good deal. it looks to me like a dually rear, the wheel on the left is obviously an outside dually wheel. I think the measurement difference is between backing plate width and wheel mounting surface width.

Go for a day trip, the worst you could be is wrong and gas is cheap. Just be prepared to bring it home with as many parts as you can get. If the wheel base is the same, grab the drive line if you can, spare parts are either usable or trade goods. Since you don't have your wheels and tires yet, you can adjust your tire diameter to dial in your cruising RPM. the 4.10 with that 235X85R16 tire would be 3042RPM@70.

Let us know how it turns out.

Good Luck

I was thinking our trucks are similar for sure! Good thinking on the drive line if the WB is the same!

Yeah, I am waiting on wheels/tires until I figure out the rear end. I think I am going to swap it...don't think I can handle the 5.14 gears!

[urmyboyblue]

Are your wheels 16.5"? I have a 1966 C30 that had 16.5" wheels on it when I bought them. It was cheaper to go to a 16" wheel and buy new tires than to buy 16.5" tires- which there are very few to choose from. I converted my C30 into basically a C20 by shortening it and adding a fleet side bed, a 14 bolt and single rear wheels. I like it that way for sure!

[roll_the_dice]

Originally Posted by urmyboyblue

Are your wheels 16.5"? I have a 1966 C30 that had 16.5" wheels on it when I bought them. It was cheaper to go to a 16" wheel and buy new tires than to buy 16.5" tires- which there are very few to choose from. I converted my C30 into basically a C20 by shortening it and adding a fleet side bed, a 14 bolt and single rear wheels. I like it that way for sure!

According to the sidewall of my current tires they are 18x7. I am planning on going to 16" when I decide on the rear end.