Best national tire chain to buy 6 new tires?

Cheryl_B wrote:
I'm sorry, but y'all are overwhelming me. I don't know what I got myself into with this thread. I'm over my head. I just want new tires. How hard can this possibly be? The tire people do know how to do their job, right?

Sure the tire people know how to do their job, but if they don't have the correct tire available, then what? That's what we are dealing with - a 30 year old vehicle with obsolete, barely available tires.

So if you think it can't be difficult, we'll stop right here and you can run down to your corner tire shop and deal with them - and when they tell you they can't get anything that fits, you'll be back here - a bit more humble.

j-d wrote:
....... I've looked at your 16.5 writeup a lot, and sent a bunch of people to it. The chart furnishes the Dual Spacing for say 225/75R16E to replace 8.00 or 8.75/16.5

But what we need now for Cheryl's project is dual spacing for 8.00/16.5 and 8.75/16.5 to see how much gap between sidewalls on 8.75 replacing 8.00 would be. Then would that be enough? I'm trying to find the dual spacing specs for 16.5's and no joy so far. Do you have that info? .......

The minimum dual spacing for an 8.00R16.5 is 9.0" and for an 8.75R16.5, 9.9". That means that the gap between freestanding duals is 1" and 1.15" respectively.

Now I'm going to guess that Cheryl has 6" wide rims, and that means we get 0.3" more to play with.

I'm sorry, but y'all are overwhelming me. I don't know what I got myself into with this thread. I'm over my head. I just want new tires. How hard can this possibly be? The tire people do know how to do their job, right?

Barry,

I've looked at your 16.5 writeup a lot, and sent a bunch of people to it. The chart furnishes the Dual Spacing for say 225/75R16E to replace 8.00 or 8.75/16.5

But what we need now for Cheryl's project is dual spacing for 8.00/16.5 and 8.75/16.5 to see how much gap between sidewalls on 8.75 replacing 8.00 would be. Then would that be enough? I'm trying to find the dual spacing specs for 16.5's and no joy so far. Do you have that info?

I was working on the premise that 8.75's, being 0.75-inch (3/4") wider than 8.00, would narrow the gap by 3/4" (3/8" for outer tire + 3/8" for inner, 6/8" or 3/4") less than 8.00's.

That was when I thought of the 2x4 as a "feeler gauge." At pavement level, it'll have to fit between the sidewall "bulges." If it fits tight, there's about 1-5/8" spacing. Loose, up toward 2". I hope she has 1-3/4" or more now, with 8.00's. Then 8.75's would take it down to 1". That's what I have on the rear tires of our coach. Different chassis, but they're the 225/75R16E that's pretty close to an 8.75R16.5E, and I'd feel Cheryl'd be OK with that. Just keep tires inflated to say 65 PSI so there's a little less bulge. I run 75 but our coach is much heavier, 9200 pounds on the rear axle per CAT Scale.

I'd rather see Cheryl on New, Quality, 8.75R16.5's than pay about the same for used 16" wheels with cheap tires. Firestone Transforce seems to fill the bill for an 8.75R16.5 of decent quality and reputation and relatively low price.

There is nothing "wrong" with 16.5's from a user standpoint.

Cheryl,

Your truck is 30 years old. It's bound to have parts that are going to be difficult to find. Tires is only part of the problem.

JD is right. You have 3 options - none of which is perfect.

If I were in your shoes, I would opt for the 8.75R16.5's, but only after checking the dual spacing. I am pretty sure it won't be according to spec, as most vehicle manufacturers used spacing for the size they supplied and not larger! But it might be enough to live with. If you go this route, you need to adopt a regular inspection procedure for those tires. Duals that "kiss" result in an unusual failure mode, but it is detechable before it is catastrophic.

Looking for more information, I found there are a few 8.00/16.5 tires out there, and a few 8.75/16.5 tires as well, that are NOT Radials. They are the old "Bias Ply" design. You want to save some $ but please don't cut that low. Bias doesn't track as well as radial, they don't last nearly as long, and perhaps the worst: They develop Flat Spots. We had a Dodge van that came with 800 bias tiers. For the first mile every day on my way to work, it felt like the wheels were square. Try to push it out of the garage by hand, it wouldn't budge. Went to 875 radials. They drove smoothly, and I could give it one handed push in the garage and then go chase it down the driveway.

Here's a pictorial of Dually Spacing aka Offset
I hope I can get those spacing specs for the 800 and the 875 tires. The very top of the image is the tread of the tires. Between them, the sidewalls, is the space I want you to check, except down at the pavement.

j-d wrote:
Yeah, You! Dual tires add a level of complexity that 4-wheel pickup and van owners don't have the spacing issues. Then over the years, all different kinds of Wheel Centering, sometimes called Piloting.

When I bought the seven from Pep Boys, we agreed on a price for "all six" and I said I needed a spare thrown in at that price. They did it.

Yeah, You! That's what I needed to hear. I have my marching orders. Will be back when I have more updates. Thank you all for your input. This is allot freakier than I thought it would ever be.

I hope you're all just messing with me. Will be back with the results. I promise.

Yeah, You! Dual tires add a level of complexity that 4-wheel pickup and van owners don't have the spacing issues. Then over the years, all different kinds of Wheel Centering, sometimes called Piloting.

When I bought the seven from Pep Boys, we agreed on a price for "all six" and I said I needed a spare thrown in at that price. They did it.

j-d wrote:
If you'll give me till Monday, I'll go to Discount Tire and try to confirm the dual spacing for the 875 tires vs the 800's you have now.

You mean me? You've got time. I'm not rushing out to get the tires. Even in less of a rush now that I asked this question on RV.net. I don't know why everything is so complicated. I just thought I was going to haggle on the cost of 6 new tires and drive away with a big smile on my face.

If you'll give me till Monday, I'll go to Discount Tire and try to confirm the dual spacing for the 875 tires vs the 800's you have now.

For now, here's simple: find some scrap pieces of boards and see what thickness you can poke between the dual tires where they sit on the ground. If you can find some "Two By" like 2x4... Put it on the thin edge and see if the "2-inch" that's actually about 1-5/8 will slip between. If it will, will it wiggle?

Do that, report back, and please include the tire size info that's molded into one of your actual tires.