2020 Thor Four Winds 22e duel wheel spacing concerns

[Bobdole]

Have a brand new coach. Have been back and forth with Thor and various forums on proper tire pressure. Both the door jam sticker and Thor say use 65 psi front and rear. The overall majority online think the cold max load on the tire should be applied which is 80 all around for my tires LT225/75R16E S. I received the coach from the dealer with 80 in all the tires and that’s what they also recommended. I decided the bring them all down to 66 psi which led me to the next issue. The coach is empty sitting in storage with empty tanks. I took these pics after deflating to 66 psi. The tires are very close to touching at the bottom where they bulge. Obviously the less pressure in the tire, the more bulge decreasing the space between the tire. Should I inflate to the max tire load? Will a brand new Thor motor coach with brand new tires already require wheel spacers? Am I being completely oc here and is this amount of space between the duel tires normal? I can’t help but think bouncing around at interstate speeds will cause rubbing and possibly a blowout. I also doubt inflating to 80 psi would make much difference but it’s worth a shot I guess.. Any advice appreciated.

[16ACE27]

65 is a starting place
80 is an ending place
Take the coach loaded for camping to a CAT scale and get your actual axle weights, then adjust your tire pressures to the actual load on them by the chart for your size tires.

[Bob Denman]

I agree: start at 65, and go find a scale.
My bet is that you'll end up with 80 psi in them.
(Most of these coaches run pretty near their
Maximum GVWR limits.)

[Bobdole]

Originally Posted by Bob Denman

I agree: start at 65, and go find a scale.
My bet is that you'll end up with 80 psi in them.
(Most of these coaches run pretty near their
Maximum GVWR limits.)

Totally understand this and plan to do it. But that doesn’t really address my concern with the tires almost touching. Is that normal? I didn’t notice much bulge difference between 66 and 80. I don’t think increasing the pressure will help much is my concern.

[Bob Denman]

They're simply not supposed to be bulging so much...

[Bobdole]

Originally Posted by Bob Denman

They're simply not supposed to be bulging so much...

I agree and hope that’s all it is. I’m going to air them up to 80 and will take some more pics and upload the result tomorrow. Man I tell you what, if that creates enough space that’s really bad on Thor’s part. Recommending a pressure both on the coach and by direct contact that could create tire rub and blowouts.. Not even a mention of a “starting point” pressure. Just “take the air down to 65 all around” “The dealer and everyone you talked to was wrong”. That was the exact words. Lol

[Bob Denman]

Good luck with finding the right setup!

[16ACE27]

Tire rub? They're going the same speed so they may bump against each other but I don't see any rubbing happening.

[Bobdole]

Originally Posted by 16ACE27

Tire rub? They're going the same speed so they may bump against each other but I don't see any rubbing happening.

“Tire touch” would have been a better choice of words.. Anyhow I filled up one side to 80 and the other to 75. They both somewhat improved by about the same amount of space. It went from around 1/8 inch at the bulge to around 1/4.. I guess I’ll be running a little under max load at 75 psi until I can get it weighed on a scale. Updated pictures -

[Pete'sMH]

I’m guessing your coach is overloaded at the rear. The yellow sticker recommendation (65?) typically is what the tire manufacturer would recommend for your vehicle at it’s maximum allowable weight (GVWR). You absolutely should get weighed, look up the specs for your tire model for that weight and go with that. It won’t be 80 unless you are at the tires upper load limit. Beyond that, I wouldn’t worry about the tire spacing.

[Beau388]

Originally Posted by Bobdole

“Tire touch” would have been a better choice of words.. Anyhow I filled up one side to 80 and the other to 75. They both somewhat improved by about the same amount of space. It went from around 1/8 inch at the bulge to around 1/4.. I guess I’ll be running a little under max load at 75 psi until I can get it weighed on a scale. Updated pictures

Your pictures are for the tires cold at rest. Driving down the road the rear tires will gain 20 to 25 psi when hot. Also at speed the hysteresis of the tire will decrease the size of the tire patch and reducing the tire bulge where it contacts the ground.

[Bobdole]

Originally Posted by Pete'sMH

I’m guessing your coach is overloaded at the rear. The yellow sticker recommendation (65?) typically is what the tire manufacturer would recommend for your vehicle at it’s maximum allowable weight (GVWR). You absolutely should get weighed, look up the specs for your tire model for that weight and go with that. It won’t be 80 unless you are at the tires upper load limit. Beyond that, I wouldn’t worry about the tire spacing.

Yep, sticker is 65 front and rear. Going to weigh in on our way out for next trip. I suspect weight at or near the tire limit by the looks of the bulging even at 80psi in the rear. Leaving at 75 for now and will adjust depending on the actual weight. I’ve just never seen tires so close before. Every duel set I’ve ever seen had close to a half inch even while sitting cold.

[Hooligan2]

Instead of guessing, Go to the specs for your tires and it will list the minimum dual spacing required for your tire. Measure from the centerline of one tire to the other. A little "tire bump" is rubbing and can cause a blowout. Firestone 225/75R16 LRE requires 13.6 inch spacing..

Another check is to look at the rim offset for your rims. 7 inch offset is 14 inch spacing with a tire mounted.
https://www.rvtiresafety.net/2016/12...-changing.html

FWIW-- Hysteresis- Lagging Flux forces generated by a moving magnetic field usually has minimal effect on dual spacing.. particularly at sub-sonic speeds.

[Chance]

That doesn’t sound close to correct. A 14-inch spacing with about 9-inch wide tire would leave 5 inches between tires.


Ford specifications for E-Series wheels is 5.15 inches of nominal offset. Since a 225 MM wide tire should be just under +/- 9-inches wide (nominal), there should be just under 1-1/2 inches of space between tires other than at ground. That’s a quick way to check that you have correct wheel spacing. It also assumes you haven’t increased tire size.

[Bobdole]

Originally Posted by Chance

That doesn’t sound close to correct. A 14-inch spacing with about 9-inch wide tire would leave 5 inches between tires.





Ford specifications for E-Series wheels is 5.15 inches of nominal offset. Since a 225 MM wide tire should be just under +/- 9-inches wide (nominal), there should be just under 1-1/2 inches of space between tires other than at ground. That’s a quick way to check that you have correct wheel spacing. It also assumes you haven’t increased tire size.

I can fit a thumb through all the way around the tire. It appears to be spaced correctly except at the bottom with the bulge. I see you say other than at ground. Is it safe to say that I’m ok looking at the pictures? I measured from center to center at the top of the tire and it’s exactly 10 inches. I haven’t found this model tire in a chart anywhere to compare. Thor pawns me to Chevy, Chevy doesn’t seem to have a clue (at least who I talked with). Haven’t heard back from general tire but hoping to get a dual space measurement to base it off of from them.

[Bobdole]

Originally Posted by Beau388

Your pictures are for the tires cold at rest. Driving down the road the rear tires will gain 20 to 25 psi when hot. Also at speed the hysteresis of the tire will decrease the size of the tire patch and reducing the tire bulge where it contacts the ground.

Thanks, this is the answer I’ve been hoping for lol. I missed it somehow reading through other comments.

[Chance]

Originally Posted by Bobdole

I can fit a thumb through all the way around the tire. It appears to be spaced correctly except at the bottom with the bulge. I see you say other than at ground. Is it safe to say that I’m ok looking at the pictures? I measured from center to center at the top of the tire and it’s exactly 10 inches. I haven’t found this model tire in a chart anywhere to compare. Thor pawns me to Chevy, Chevy doesn’t seem to have a clue (at least who I talked with). Haven’t heard back from general tire but hoping to get a dual space measurement to base it off of from them.

I assumed you had the more common Ford, so if you have a Chevy it may be a little different. My bad for assuming.

In any case, your 22E motorhome is relatively small and light, so if you inflate tires to 80 PSI the ride will likely be too harsh. That size tire at 80 PSI is what’s used on many 30+ feet long motorhomes weighing up to 14,500 pounds.

As recommended by others, drive to scales and weigh it. I’d guess that the specified 65 PSI is plenty for actual weights front or rear unless you overload.

[Hooligan2]

Originally Posted by Chance

That doesn’t sound close to correct. A 14-inch spacing with about 9-inch wide tire would leave 5 inches between tires.
.

My mistake-- Here is Chart for a LT225/75R16 the dual spacing is 10.2 inches..
(bottom line of the chart)

[bry899]

I currently have a 2018 Four winds 22E on a ford E350 Chassis (GVWR 12,500)
My Total Weight is 10,900 lbs fully loaded with all tanks full, including Me and 1 passenger.

80 PSI is too much the ride is hard and bouncy, I keep The tires at 70 PSI
You should have your unit weighed.
I am not sure if my spacing is like yours, but most likely is, If I get a chance tomorrow I will look. I am not concerned of the space and have 20,000 miles on it.

[Bobdole]

Originally Posted by bry899

I currently have a 2018 Four winds 22E on a ford E350 Chassis (GVWR 12,500)

My Total Weight is 10,900 lbs fully loaded with all tanks full, including Me and 1 passenger.



80 PSI is too much the ride is hard and bouncy, I keep The tires at 70 PSI

You should have your unit weighed.

I am not sure if my spacing is like yours, but most likely is, If I get a chance tomorrow I will look. I am not concerned of the space and have 20,000 miles on it.

I had it weighed today. Full gas, full fresh tank, packed for trip nothing in grey/black though. Weight was much less than expected. 4000 front and 6820 rear, 10820 total. Looking at the chart, factoring in an extra 10% puts front around 65 and rear at 50-55 psi. That’s odd to me as I know airing down that low would cause the tires to touch sitting for sure at cold. I’m just going to run 70-75ish rear and 65 front and be done with it. No way am I going to run 50-55 psi on those things. 65 looked bad enough.