Free 7 Day Trial RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Free 7 Day Trial ×
 

Go Back   Thor Forums > Thor Tech Forums > Maintenance and Repair
Click Here to Login
Reply
 
Thread Tools Display Modes
 
Old 10-06-2020, 01:11 AM   #1
Junior Member
 
Brand: Thor Motor Coach
State: South Carolina
Posts: 28
THOR #20754
2020 Thor Four Winds 22e duel wheel spacing concerns

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 thatís 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 canít 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 itís worth a shot I guess.. Any advice appreciated. Click image for larger version

Name:	IMG_4384.jpg
Views:	142
Size:	73.8 KB
ID:	26516Click image for larger version

Name:	IMG_4385.jpg
Views:	139
Size:	70.8 KB
ID:	26517

__________________
Bobdole is offline   Reply With Quote
Old 10-06-2020, 01:23 AM   #2
Site Team
 
16ACE27's Avatar
 
Brand: Thor Motor Coach
Model: ACE 27.1
State: Florida
Posts: 7,536
THOR #7035
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.
__________________
Ted & Melinda
2016 ACE 27.1
2016 Chevy Sonic Toad
2020 Chevy Colorado Z71 Trail Runner Alternate Toad
16ACE27 is offline   Reply With Quote
Old 10-06-2020, 01:31 AM   #3
I Think We're Lost!
 
Bob Denman's Avatar
 
Brand: Still Looking
Model: Tiffin Wayfarer 24 BW
State: New York
Posts: 21,752
THOR #8860
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.)
__________________
Bob Denman is offline   Reply With Quote
Old 10-06-2020, 01:36 AM   #4
Junior Member
 
Brand: Thor Motor Coach
State: South Carolina
Posts: 28
THOR #20754
Quote:
Originally Posted by Bob Denman View Post
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 doesnít really address my concern with the tires almost touching. Is that normal? I didnít notice much bulge difference between 66 and 80. I donít think increasing the pressure will help much is my concern.
__________________
Bobdole is offline   Reply With Quote
Old 10-06-2020, 01:48 AM   #5
I Think We're Lost!
 
Bob Denman's Avatar
 
Brand: Still Looking
Model: Tiffin Wayfarer 24 BW
State: New York
Posts: 21,752
THOR #8860
They're simply not supposed to be bulging so much...
__________________
Bob Denman is offline   Reply With Quote
Old 10-06-2020, 02:01 AM   #6
Junior Member
 
Brand: Thor Motor Coach
State: South Carolina
Posts: 28
THOR #20754
Quote:
Originally Posted by Bob Denman View Post
They're simply not supposed to be bulging so much...


I agree and hope thatís all it is. Iím 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 thatís really bad on Thorís 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 ďstarting pointĒ pressure. Just ďtake the air down to 65 all aroundĒ ďThe dealer and everyone you talked to was wrongĒ. That was the exact words. Lol
__________________
Bobdole is offline   Reply With Quote
Old 10-06-2020, 02:45 AM   #7
I Think We're Lost!
 
Bob Denman's Avatar
 
Brand: Still Looking
Model: Tiffin Wayfarer 24 BW
State: New York
Posts: 21,752
THOR #8860
Good luck with finding the right setup!
__________________
Bob Denman is offline   Reply With Quote
Old 10-06-2020, 03:21 AM   #8
Site Team
 
16ACE27's Avatar
 
Brand: Thor Motor Coach
Model: ACE 27.1
State: Florida
Posts: 7,536
THOR #7035
Tire rub? They're going the same speed so they may bump against each other but I don't see any rubbing happening.

__________________
Ted & Melinda
2016 ACE 27.1
2016 Chevy Sonic Toad
2020 Chevy Colorado Z71 Trail Runner Alternate Toad
16ACE27 is offline   Reply With Quote
Old 10-06-2020, 02:11 PM   #9
Junior Member
 
Brand: Thor Motor Coach
State: South Carolina
Posts: 28
THOR #20754
Quote:
Originally Posted by 16ACE27 View Post
Tire rub? They're going the same speed so they may bump against each other but I don't see any rubbing happening.





ďTire touchĒ 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 Iíll be running a little under max load at 75 psi until I can get it weighed on a scale. Updated pictures -Click image for larger version

Name:	IMG_4387.jpg
Views:	40
Size:	47.9 KB
ID:	26523Click image for larger version

Name:	IMG_4388.jpg
Views:	45
Size:	68.9 KB
ID:	26524
__________________
Bobdole is offline   Reply With Quote
Old 10-06-2020, 02:34 PM   #10
Senior Member
 
Model: Newmar Bay Star Sport 300
State: Alabama
Posts: 4,196
THOR #6826
Iím 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 itís 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 wonít be 80 unless you are at the tires upper load limit. Beyond that, I wouldnít worry about the tire spacing.
__________________
Pete'sMH is offline   Reply With Quote
Old 10-06-2020, 02:45 PM   #11
Senior Member
 
Brand: Thor Motor Coach
Model: Hurricane 31S
State: Texas
Posts: 3,104
THOR #6411
Quote:
Originally Posted by Bobdole View Post
ďTire touchĒ 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 Iíll 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.
__________________
Jim & Roy Davis
2016 Hurricane 31S
1961 Rampside in tow
Beau388 is offline   Reply With Quote
Old 10-06-2020, 05:10 PM   #12
Junior Member
 
Brand: Thor Motor Coach
State: South Carolina
Posts: 28
THOR #20754
Quote:
Originally Posted by Pete'sMH View Post
Iím 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 itís 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 wonít be 80 unless you are at the tires upper load limit. Beyond that, I wouldnít 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. Iíve just never seen tires so close before. Every duel set Iíve ever seen had close to a half inch even while sitting cold.
__________________
Bobdole is offline   Reply With Quote
Old 10-06-2020, 07:39 PM   #13
Senior Member
 
Hooligan2's Avatar
 
Brand: Thor Motor Coach
Model: 2016 Siesta Sprinter 24ST
State: Florida
Posts: 514
THOR #2812
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.
__________________
U.S. Coast Guard retired- 1956-1985
Pensacola, Florida
2016 Siesta 24ST
1972 Moto Guzzi Eldorado
Hooligan2 is offline   Reply With Quote
Old 10-06-2020, 09:35 PM   #14
Senior Member
 
Brand: Still Looking
State: Texas
Posts: 5,413
THOR #2121
That doesnít 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. Thatís a quick way to check that you have correct wheel spacing. It also assumes you havenít increased tire size.
__________________
Chance is online now   Reply With Quote
Old 10-06-2020, 09:44 PM   #15
Junior Member
 
Brand: Thor Motor Coach
State: South Carolina
Posts: 28
THOR #20754
Quote:
Originally Posted by Chance View Post
That doesnít 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. Thatís a quick way to check that you have correct wheel spacing. It also assumes you havenít 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 Iím ok looking at the pictures? I measured from center to center at the top of the tire and itís exactly 10 inches. I havenít found this model tire in a chart anywhere to compare. Thor pawns me to Chevy, Chevy doesnít seem to have a clue (at least who I talked with). Havenít heard back from general tire but hoping to get a dual space measurement to base it off of from them.
__________________
Bobdole is offline   Reply With Quote
Old 10-06-2020, 09:52 PM   #16
Junior Member
 
Brand: Thor Motor Coach
State: South Carolina
Posts: 28
THOR #20754
Quote:
Originally Posted by Beau388 View Post
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 Iíve been hoping for lol. I missed it somehow reading through other comments.
__________________
Bobdole is offline   Reply With Quote
Old 10-06-2020, 10:40 PM   #17
Senior Member
 
Brand: Still Looking
State: Texas
Posts: 5,413
THOR #2121
Quote:
Originally Posted by Bobdole View Post
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 Iím ok looking at the pictures? I measured from center to center at the top of the tire and itís exactly 10 inches. I havenít found this model tire in a chart anywhere to compare. Thor pawns me to Chevy, Chevy doesnít seem to have a clue (at least who I talked with). Havenít 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 whatís used on many 30+ feet long motorhomes weighing up to 14,500 pounds.

As recommended by others, drive to scales and weigh it. Iíd guess that the specified 65 PSI is plenty for actual weights front or rear unless you overload.
__________________
Chance is online now   Reply With Quote
Old 10-07-2020, 03:26 AM   #18
Senior Member
 
Hooligan2's Avatar
 
Brand: Thor Motor Coach
Model: 2016 Siesta Sprinter 24ST
State: Florida
Posts: 514
THOR #2812
Quote:
Originally Posted by Chance View Post
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)
Attached Thumbnails
Click image for larger version

Name:	Dual Spacing.jpg
Views:	76
Size:	85.6 KB
ID:	26553  
__________________
U.S. Coast Guard retired- 1956-1985
Pensacola, Florida
2016 Siesta 24ST
1972 Moto Guzzi Eldorado
Hooligan2 is offline   Reply With Quote
Old 10-07-2020, 04:05 AM   #19
Senior Member
 
Brand: Thor Motor Coach
Model: 22E
State: New York
Posts: 249
THOR #12119
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.
__________________
bry899 is offline   Reply With Quote
Old 10-09-2020, 12:34 AM   #20
Junior Member
 
Brand: Thor Motor Coach
State: South Carolina
Posts: 28
THOR #20754
Quote:
Originally Posted by bry899 View Post
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. Thatís odd to me as I know airing down that low would cause the tires to touch sitting for sure at cold. Iím 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.
__________________
Bobdole is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by Thor Industries or any of its affiliates. This is an independent, unofficial site.




All times are GMT. The time now is 03:45 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0 PL2