C20 17.5 wheels and disk brakes...

[jocko]

While there's lots of diameter there to play with, am assuming the narrow 5.5 width might result in the inner taper of the wheel, or possibly, the inner flat part of the large dia wheel, not being able to clear a caliper. Has anyone done front disks with stock 17.5s? Just curious. Thanks.

[oem4me]

Good question. I'll piggyback on your question and ask the same about the rare 19.5 X 5.25's.

[jocko]

ttt. still curious if anyone has attempted this.

[Classic v6 GMC's]

Bringing this back to the top for 19.5 wheels.

[jocko]

ttt for any of the tall skinny C20/30 wheels with disk brakes added (not locking rims, talkin bout 17.5/19.5 steelies. Anyone done this?

[aotte1]

Not an exact answer, do know the original 16x5.5 6 lug, 3 nub wheels, work on a 1978 Dana 44 front axle, with disks. Have a 17.5 6 lug will try to put it on same Dana axle with factory disk brakes. These are all 1/2 ton applications. Not sure how the 8 lug SRW disks design differ, along with 2 and 4 wheel drive applications. Will examine both 17.5, 6 and 8 lug wheels for BS and rim design for differences. I think the 19.5s have a different BS, then the 17.5s.

Les

[buds56]

In the early 80's I had a 71 GMC 3/4 4wd with disc front brakes with 9.50 x 16.5 tires and 4.10 gears.

I had bought a car about 3-400 miles away and needed to pick it up. I worked in a salvage yard and had to watch every penny.

We had an old (58 or 59) 8 lug truck in the yard with a set of 7.00x17's with tubes and split rims, the tires were like new tread wise but very old Firestone "gum dipped" highway tread.

In hindsight this wasn't real bright on my part (I seem to remember them being a bit dry rotted, but heck they had tubes in them) but I put them on my truck because they were so tall compared to my 16.5's I figured my fuel economy would improve similar to putting 3.73's in the truck for the road trip.

They fit on the truck fine and I had no problem on the trip
Just one example of some of the stupid stuff I did when young

[Classic v6 GMC's]

Well I found the answer I needed for my 57 van. I took one 55-59 19.5 and one 60-68 19.5 and tried them on the front of a 2008-ish Chevy van. They both fit.

[jocko]

No way! That's good news. Don't suppose you have a 17.5 lying around you could check?

[Classic v6 GMC's]

Originally Posted by jocko

No way! That's good news. Don't suppose you have a 17.5 lying around you could check?

I do not have regular access to the van but next time I do I will try a 17.5 wheel.

[jocko]

that would be great, thank you. So, a 2008 would be lug centric but same bc, if I'm not mistaken - with slightly different (metric) studs(?) Any details on the swap you're thinking about or are you just using the 2008 as a basis for comparison for caliper interference?

[Classic v6 GMC's]

Originally Posted by jocko

that would be great, thank you. So, a 2008 would be lug centric but same bc, if I'm not mistaken - with slightly different (metric) studs(?) Any details on the swap you're thinking about or are you just using the 2008 as a basis for comparison for caliper interference?

Yes they are lug centric but same bolt pattern. The swap uses 2003 and up chevy 2500 parts and I wanted to make sure the old wheels would clear the caliper before purchasing.
Here is the link to the bracket kit for the swap.
http://www.thehollisterroadcompany.c...converion.html