Need some help with wheel fitment.

[1milkman]

I have a 1966 c20 that i am planning on bagging, my question is will a 20x9" rim with a 5 & 3/4 back spacing fit? Thanks.

[PGSigns]

I have a 65 C10 with bags and 20X8.5 with 5.5 back spacing and front is ok but the back needed wider tubs to clear the tires on a fleetside. Are you going to convert it to trailing arms? I'm not far from you if you want to look at my bag setup and how my wheels fit.
Jimmy

[1milkman]

Thanks for the response....but i realize that i left out a very important part....these wheels will require the use of a 2" thick adaptor. The front suspension has been converted to disc brakes i believe from a siverado and currently has leaf springs in the back from the same vehicle.

[Captainfab]

Fitment will depend on just what differential is under your truck, since they are not all the same width. Is it the original Eaton HO52 or is it the 14 bolt from the same truck as the front disc brakes?

[Lowl!f3]

Take measurmenrs of the width and figure the back space you will need. Measure 100 times before you order something you cant use. Test fit with used old tire of equal measurements. $30 trash tire.

[PGSigns]

A better idea of what is under it will tel us what we need to know to help you out. Not sure why you would need a spacer, My wheel are close to the ones you are thinking about and 2" would put them out the wheel well and past the side of the truck. Mine has the 73 to 87 brakes on it so should be close to yours. Offer is still open on looking at one of these all ready on bags.
Jimmy

[1milkman]

The previous owner i believe used both the front and rear suspension from a silverado thus converting it to five lug. The rims that i am interested in are six lug which would require an adaptor. A local tire shop here has a set of gently used rims for one heck of a deal. I appreciate the offer PGsigns and i just may take you up on that one weekend if possible.

[1milkman]

I am pretty sure after taking some measurements that i have plenty of room in the rear. The front on the other hand i don't think will work with adaptors but would a six lug rotor be possible?

[PGSigns]

We need to figure out what parts are under it. There are a lot of ways to get to where it is now. It may be by the time you make the truck six lug the rims are not as good a deal any more. Also you need to find out the inner diameter of the hub hole in the wheel. Some are kind of small and require turning down the front hubs and the rear axles to get them to fit. I have 20X8.5 on the 65 and will not run them when I get it done. They are to tall for how I want it to sit when aired out. The inner fenders and the lip on the front fenders sit on the top of the tires. Plan is to go to 17" wheels and a set of tires to get me the look I want.
Jimmy

[Captainfab]

If your truck has been converted to 5 lug, then it really isn't a C20 anymore, which would be 8 lug.

[1milkman]

When i take a straight edge down from the edge of the front fender and measure back to the face of the stock rim i have 6 & 1/4 ". Well Captainfab if i can get these Cadillac rims cramed up under there i guess we can consider a hybrid!

[PGSigns]

Well that is not the place you have problems with when you bag it. The truck will sit down on the tires and mine sit right on the inner fenders and the last inch or so of the front fenders where they bolt to the inners. Depending on what front spindles and a arms that are on it and what drop spindles will fit them you may be able get 6 lug front rotors. I have a set on the 65. Now you would just have to figure out the rear. That could be as easy as putting a stock C10 rear in the truck. Then you are back to 6 lug. I can tell you the front fit OK using late model GM wheels on the 65 but I did have to machine the rear axles to allow the hubs to fit over them.
Jimmy

[1milkman]

PGSigns i greatly appreciate all the info. I have been on numerous forums in the past and it seems everyone on here is very helpful. As far as the rear axle i think i can handle any alterations that i may encounter as i have been a machinist for 26 yrs. I am not sure what rear end is under there as i have mostly dealt with vw's in the past but i know it is five lug and has ten bolts. Thanks again for all the help...I pick the wheels up in about two hours!

[PGSigns]

Going to six lug if it is a ten bolt would be best to swap back to a 64 to 66 12 bolt and then if it has the 1.25" rotors on the front just order a set of rotors from one of the vendors here. The are not available from parts stores.
Jimmy