Tires obsolete....going from 16.5 to 16s...Help!

[fireflymin]

Well, I've got this 1990 Class C....just bought it in April, and have been working on it...very slowly, as time allows.....I just called the tire shop to get a quote on new tires for this rig.....and was told that the 16.5s are very hard to find, and I checked on this and Sam's forum, and sure enough....other posts have indicated that this is true....So; today, I went to the junk yard and found 7- 16 rims, plus the "simulator" covers...Here's the questions.....first ,3 of the rims have holes in the area where you would put your hand through to put the air pressure gauge that are large, and match up to the simulator holes....the rest of the rims have smaller holes, but the valve stem can still be accessed.... they all have the correct 8 holes for the lugs.....then I noticed that the one front wheel simulator has 9 or 10 bolt covers....Can I use it anyways, as they really are not covering the bolts anyways.....Or am I completely needing to rethink this whole process? I'm so confused and disappointed, as I spent alot of time at the u-pick junk yard, in the heat, and thought that I had everything that I needed...just wanted to make this switch smoothly.... In summary, does it really matter on the rims as long as they are all 16s .....and since you cannot see all the rim covers at once, does it really matter that the bolt covers have 8 on one side and 9 or 10 on the other? Any help would be appreciated.....Thanks....

[Kurmudgeon]

Quote:

Originally Posted by fireflymin .... In summary, does it really matter on the rims as long as they are all 16s .....

Yes, it does. Forget about the wheel simulators for the moment, and let's talk about just the wheels. Wheels made for various dual rear wheel chassis are generally specific to the chassis manufacturer. GM, Ford, and Dodge all used DRW axles with different hub diameters, but the same bolt pattern. So the wheels for each have different size center holes. That means different wheels.

The wheels you put on your MH must have the correct size center hole. GM uses the smallest, so any of the wheels will fit a GM chassis. But on these axles the load is supported by the center hole on the axle hub, and if you put a Ford or Dodge wheel on a GM, you are now carrying the entire load on the lug bolts, since the center hole is not supported on the hub. Eventually, the lugs will probably fail. The center hole diameter must match the axle hub you are putting it on. A blowout on a rear dual is nothing compared to the experience of both wheels coming off. Someone here will correct me if I'm wrong, but I believe GM uses a 4.56" hole, Ford a 4.77", and Dodge about a 4.9". Make sure you find the right wheels for your chassis.

The simulators are nothing but decoration hanging on the wheel. So if they will fit and stay on the wheel, and they suit you, that's about all that matters.

[fireflymin]

Just had to get back on here and say thanks again for your input....I had no idea that these wheels were so different.... And the folks at the junk yard, I guess really don't know either......I for sure will be doing some measuring tomorrow......Just took all those rims to the tire store today to have them look and confirm that they were okay.....then gave me a quote on some new tires......Sure would hate to spend all that money on new tires, only to have them not fit on the axle hub......I appreciate your help..

[ccook129]

Firestone Transforce HT

Details: Goodyear WORKHORSE RIB 8.75 -16.5 115/111 10PR SBL - tires-easy.com

[Possum]

A relative works for a major tire company and he recommended that I change over to 16" wheels on my older Chev Chassis motorhome. He claims the 16.5 tire size has been out of manufacture for a couple years and even supposedly new tires are almost past their "best by" dates.

[fireflymin]

Well, this has proven to be an educational experience.....I appreciate all the input..... This morning I went out and measured the inside diameter of the 16.5 wheel that was the spare for my motorhome....then I measured the inside diameter of the rims that I purchased at the junkyard.....I only had one that measured the same as my original... So; I can understand that if I had the ones mounted with the larger diameter axle hub opening, it would for sure be alot of weight for the lugs to carry. I guess it's back to the junkyard with all these wheels....I'm taking my tape measure with me this time! Thanks to all again.

[fireflymin]

As I was heading out for work this morning, another question popped into my head regarding the dreaded rim dilemia......Here it is......When purchasing the correct 16 rims with the right amount of lugs(8), and the correct size axle hub hole....4.56..... Are there special rims for duals or are all rims the same as far as duals go? I'm about to take the rims back that I already purchased to get the correct ones. I'd hate to have to return once again, because I did not check on this.....Thanks

[fireflymin]

This search is wearing me out......I had no idea how complex this was going to get....

[Nick-B]

The Front, Rear Inner and Rear Outer are all the same shape/offset. The Rear Outer wheel just mounts "backwards", same as your old 16.5" rims did.

[fireflymin]

What did you do? I'm having trouble finding 16 rims that will work for my duals....Unless I've been misinformed. I'm still gathering information here....Thanks..I have a 1990 24ft. Ultra by Gulf Stream....class C.

[fireflymin]

So.....All I have to do is find "offset" 16 rims 8 lugs and with the correct size axle hole for a chevy chassis? Hmmmmm? Why am I having such a difficult time finding them?

[Ray,IN]

I suspect standard steel rims from a 1T GMC/Chevy dually will fit exactly. This website will help with measuring and matching your present rims to standard 16" GM rims.

[Nick-B]

Quote:

Originally Posted by Nick-B The Front, Rear Inner and Rear Outer are all the same shape/offset. The Rear Outer wheel just mounts "backwards", same as your old 16.5" rims did.

Fireflymin, I guess I need to be a bit more specific. The rims should be from a "dually" chassis (as Ray mentions) not a standard 16" pickup rim which have a different offset.

Another thing to consider is the rear axle itself. Although you mention that you have a Chevy chassis, the rear axle could be made by Dana rather than GM (common on motorhomes) which could be causing some size confusion.

Hope that helps rather than adding to the confusion.