Rim fitment for 1978 K20

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Brysonsproject

Junior Member
Joined
Aug 17, 2023
Posts
21
Reaction score
5
Location
Washington
First Name
Bryson
Truck Year
1978
Truck Model
Chevy K20
Engine Size
350
Looking into getting new rims. The originals are 16.5 so I have the option of going up to 17 or down to 16. It looked like there wouldn't be any room to get smaller wheels because of the brake calipers so seems like 17 is my only option, but also I don't know much about offset and backspacing, so maybe there is a rim size and offset combination that works for 16 inch rims?
 

Old Guy Bill

Full Access Member
Joined
Sep 10, 2023
Posts
133
Reaction score
394
Location
KY
First Name
Bill
Truck Year
1978
Truck Model
K20
Engine Size
400
There are a lot of options available, steel, chrome, etc.. also depending on how big of a tire you might want.
I‘m building a ‘78 K20 and I’ll be putting on a steel 17” X 9”, back spacing hasn’t been determined yet but it won’t be outrageous with the tires sticking way out past the fenders.
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
29,108
Reaction score
23,981
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
16's fit fine, they were also used originally. Basically with any average rim, you want somewhere around a neutral offset, up to a certain width. In the neighborhood of 4.5" backspace is max before you run into clearance issues.
 

Craig 85

Full Access Member
Joined
Jan 25, 2017
Posts
3,892
Reaction score
4,039
Location
Nashville, TN
First Name
Craig
Truck Year
1985
Truck Model
K30 SRW
Engine Size
454/TH-400/NP205
Around 1981 the 20 and 30 series trucks went to 16 wheels from the 16.5". I would bet the rim centers are the same. My K30 has 16x10 wheels with 4.5" of back spacing. There are no clearance issues to the inside. I also have larger brakes than a K20.

If I remember back to the early 90's when I did the lift and axle swap on my K5, those wheels were 9.75" wide with about 4 3/4" backspace. No clearance issues with the 3/4 ton brakes.

You must be registered for see images attach
You must be registered for see images attach
 

Latest posts

Forum statistics

Threads
42,137
Posts
909,894
Members
33,633
Latest member
satansdad
Top