71-72 C20 question #1

[Poppa Wheelie]

Long time lurker here. I am considering getting a 71-72 C20 for a number or reasons, but I have a lot of questions about them.

I was going to ask about a book or other source to find out more about them, but Im thinking it would just be more fun for board members to answer my questions. There seems to be a lot of knowledge here.

Here is my first question: Did these C20s come with 16.5" diameter wheels? What up with that? I had an 87 K20 suburban that came with 16s. Do most change over to 16's? What are the pros/cons of the different sizes?

[Tinkermc]

Welcome to the Forum and we need to know what year you R talking about?

[hugger6933]

Welcome. Most people change because the 16.5 is a hard tire to find and quite expensive when you do find it. The 16 inch wheel opens up many possibilities for different tire /wheel combos. Jim

[Keith Seymore]

More fun for who?



Here's a link to the GM Heritage Center archive. Choose the info packet for the model year(s) you are interested in and you will find the answer to almost every general question you can think of.

K

http://www.gmheritagecenter.com/gm-h...tion-kits.html

http://www.gmheritagecenter.com/docs...olet-Truck.pdf

http://www.gmheritagecenter.com/docs...olet-Truck.pdf

[Poppa Wheelie]

Holy Kow-ski! Thats a 3/4-ton of knowledge right there. Thanks for the links. Probably all or most of my questions have already been answered, thanks. See, I knew it would be fun to show off your knowledge.

[Keith Seymore]

Originally Posted by Poppa Wheelie

Holy Kow-ski! Thats a 3/4-ton of knowledge right there. Thanks for the links. Probably all or most of my questions have already been answered, thanks. See, I knew it would be fun to show off your knowledge.

You are right. That was fun.



K

[Bigdav160]

I wonder why 16.5"? It seems an odd size.

When did 16" gain popularity?

I understand 16.5" do not have safety ridges and has appeal to some who might have to change a tire while boondocking.

[jocko]

Poppa, I've got a 71 C20 with 16.5s and a 72 C20 with 16s (both originally came with 16.5s). Both wear Firestone TransForce HT tires which are still available. The 16.5, other than being a little bigger diameter, has a more curved shaped lip profile rather than the 16's stepped shape (and how most wheels are today) There are more tire availability options for the 16s than there are for the 16.5s, but there are tires available for the 16.5s. 16.5s were standard on the C20s and 16s were an option I believe. Here they are side by side. The 16.5 shows a little more white (about 1/4" on each side, ha...) 8 lug 16" Chevy or GMC wheels through 87 for the 8 lug crowd all the way down to 1960 (I think), but I know they fit the 67-72 8 lug hubs. My 72's wheels are from an 87 Chev C20. Also note that Ford 8 luggers fit, but they are lug centric, not hub-centric. Doesn't really matter, they both work. Bottom line is based on whether or not you want to go find and buy and paint (or powder coat) the 16s or just go with what you have. They both look good. I thought I'd prefer the 16s, but the 16.5s look and work just fine. They both take the same 3/4 ton cap which is around 12" in dia. 16.5 shown first, then the 16. For reference, the tire sizes are 9.50x16.5LT and LT265/75R16. 3rd pic shows a SPID with optional 16" wheels ordered.

[Poppa Wheelie]

Jocko, thanks for the detailled info, thats exactly what I needed. I previously owned an 87 3/4-ton suburban that of course had 16s. I also have owned a couple of late model 1-tons again with 16's (of course different wheel design). I have been checking into 71-72 c20s and was surprised to find they came with 16.5s. It just seems weird from a modern perspective, and from my not being familiar with them. I have been looking at old aluminum slot wheels and they all seem to be 16.5s.

I had heard that 16.5s had limited availability, so I am glad to hear that there is still decent availability. I am familiar with Transforce tires, as a former mechanic I used to specify them for the c2500 vans for the local TV service. I particularly like the HTs for the front and the ATs for the rear, as the ATs have a more aggressive tread.

I plan to use stock or near stock tires so I am sure I can find something for either rim size. Personally I feel that Chevrolet has always under-tired every truck it ever made. What I mean is that the stock tires look just a bit too tiny for the vehicle. I like to get a tire that has a bit more size and looks more substantial (speedo is usually off but not by much).

Good info on the rim interchange too. I prefer hub-centric rims (just because) but I have used lug-centric rims in heavy loading without problems.

[Sicklajoie]

Originally Posted by Poppa Wheelie

Personally I feel that Chevrolet has always under-tired every truck it ever made. What I mean is that the stock tires look just a bit too tiny for the vehicle.

I couldn't agree with you more. As ugly as this past generation pickup is, it looks even dumber with what looks like donut sized spares all the way around.

[Sicklajoie]

And just for reference, this is my C/20 with 16 x 7 F#rd lug-centric rims on 265/75/16 tires.

[Poppa Wheelie]

Sicklajoie, I had to laugh at your pic of the late model. Massive front end, and tiny little tires. I really hate to see duallies, I mean DUALLIES, with their tiny little 225-whatever-they-come-with(s) on them.

Good to know the "other brand" rims are 7" wide. Again, more substantial.

The tires you guys are running have exactly the look I want.

Hey guys, fantastic photos, fantastic trucks, the stock hub caps look boss, and thanks for such great info and pics.

[Sicklajoie]

You're welcome, keep us posted on what you do and don't be afraid to take pics!