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Old 04-02-2019, 06:37 PM   #1
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THOR #14905
Max Tire for Class C and suspension questions.

What tire can I fit?!

I just purchased a 2019 Thor Quantum RS26 (Class C). We have only put a few hundred miles on the RV, but already have needs for improvements. We drag the rear coming up our driveway so I did helper bags and skid wheels, still drags a bit. I have the white-knuckle handling which really is terrible, this must be fixed asap.

I am considering one of two options: Option 1- upgraded sway bars and steering dampener, perhaps add a leaf spring, and then some good all terrain tires like BF K02 or similar with a larger contact surface and taller profile. It would be nice to have more ground clearance as well as dirt traction for a remote site we visit often. I would hope these improvements would get rid of the wandering and swaying, as well as give us a bit more traction and clearance. In this case what I the largest tire people have been running without rubbing? This is a $1k-$3k fix plus tires.

Option 2 - Drive down to weldtec (only 2 hours away) and drop big money on a 4-6" lift and tires to match. This likely solves all problems other than an empty wallet. This is a $7k fix plus tires, if I understand it correctly.

Any feedback from people with rear world experience on tire sizing on a stock height as well as bolt on suspension mods vs. fully modified? My main concern is just getting a comfortable ride without overspending if not necessary, ground clearance is an easier topic to sort through and only an issue very rarely. Handling is always an issue and needs correction asap.

Thanks for the help!
Seth
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Old 04-02-2019, 08:57 PM   #2
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THOR #10400
I spent less than $5500 for 4" lift, tires, and upgraded steering stabilizer. Didn't get new springs in rear, just 4" blocks at Weldtec. Not sure you would want full AT tires, most importantly get a heavier load rating. The size tires I got are probably the largest you're going to fit on it w/o issues. I assume you've already gone through my thread covering this...
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Old 04-02-2019, 09:37 PM   #3
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I spent less than $5500 for 4" lift, tires, and upgraded steering stabilizer. Didn't get new springs in rear, just 4" blocks at Weldtec. Not sure you would want full AT tires, most importantly get a heavier load rating. The size tires I got are probably the largest you're going to fit on it w/o issues. I assume you've already gone through my thread covering this...
Thanks for the pricing info- very helpful. Why did you go with the blocks instead of their custom leaf springs? Cost is much higher of course, but wondering if you had any other insight.

Yes, absolutely looking for a heavier load rated tire and maybe not full AT but at least something more aggressive than stock.

Did you run your larger tires on your rig prior to the lift? Did they rub at all prior to your lift, and how did the tires alone impact the performance/ride?
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Old 04-02-2019, 09:51 PM   #4
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Although the custom springs would help I'm sure with ride, my main objective was to get more clearance for the levelers with the taller tires and lift. I was concerned about too much lift in the rear, which would make the ramp of my Outlaw at a steeper angle for loading/unloading MCs, and that the springs might add a bit more ride height over the blocks. The front leveler clearance was really the issue. So all that and another $2k didn't make sense. Read through my thread and you'll get answers to tire questions and more.
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Old 04-03-2019, 12:12 AM   #5
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Originally Posted by azadv View Post
Although the custom springs would help I'm sure with ride, my main objective was to get more clearance for the levelers with the taller tires and lift. I was concerned about too much lift in the rear, which would make the ramp of my Outlaw at a steeper angle for loading/unloading MCs, and that the springs might add a bit more ride height over the blocks. The front leveler clearance was really the issue. So all that and another $2k didn't make sense. Read through my thread and you'll get answers to tire questions and more.

I read through your thread again and still couldn't find the answer. It looks as if you drove your RV with the bigger tires from PHX to SD, but there was no mention of if you had any issues with that size at stock height. No rubbing during turning, or during compression? Did they impact the handling in any way? Thanks again for your feedback.
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Old 04-03-2019, 12:23 AM   #6
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No rubbing issues. No adverse impact as far as I could tell. Tires alone were not any cure for handling issues, probably very little to do with any of that. Here's what I said in response to your question in that thread:

"I did install the Nexans before I drove the coach to San Diego for the lift at Weldtec. I had only driven it home from dealer, to my kids houses locally, and to the tire place with the OEM tires before that, maybe a total of 50 city miles, so I can't really make a valid comparison between OEM and larger Nexan AT's. I wanted to sell the OEM's with as little miles on them as possible to offset the cost of the new tires, 'cause I'm cheap that way. I can tell you that on the trip from PHX to SD (about 400 miles) the coach was kinda squirrely on the highway and when big rigs passed me (I usually only go 55/60mph regardless of the speed limit cause I don't give a sh*t and I have time) there was a lot of sway and swerve, and it sucked to the point of being a wee bit scary. On the way back to AZ there was noticeable improvement in ride quality and negative effects of big rigs passing me subsided to the point I wasn't all tense seeing them come up from the rear, it turned into a non-issue. Then I installed the Fox steering stabilizer to replace to puny OEM one and things got even better.

Tire clearance was close on the left rear in particular, the back side of that tire was close to the fender flare but the right side rear was centered OK. I ended up taking off the flare and removing some material and reinstalling the flare to even things out, then I installed some proper mud flaps on both the front and rear. The front tires didn't really have any clearance issues. There are pics in this thread of new tires installed before lift, I put them there to illustrate clearance..."
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Old 04-03-2019, 12:24 AM   #7
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I've got a 2018 Four Winds 26B which is about the same as yours. I got rid of my white knuckle driving by going to the local Ford big truck shop and having them do an alignment. I told them I want it to handle on long hauls on the highway and it drives like a dream now. Cost about $350.

Would be nice to do something about the tail drag but I can't afford a lift kit any time soon!

Good luck with getting the driving issues resolved.
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Old 04-03-2019, 12:32 AM   #8
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Yeah, I think in my case it was the combination of higher load tires (least impact), lift with heady duty custom valved RV Fox shocks and Fox steering stabilizer (most impact), and the alignment performed after the lift/tires.
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Old 04-03-2019, 03:30 PM   #9
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Here's a good write up to help better understand the various handling issues and their solutions.
http://www.rvforum.net/miscfiles/MH_..._%20Primer.pdf

In the case of my class C, it seems to mostly be an issue coming from the leaf spring rear...so a track bar seems to be the most direct way to address it.
but
once i had an alignment done and set the steer axle tire pressures a bit lower based on actual measured weight, I find the handling now to be acceptable.

Also, I do like the idea of these 17.5 inch wheels
https://ricksontruckwheels.com/wheels-ford-e350450.php
since my rear axle is at capacity, and sometimes probably over...
I just haven't pulled the trigger....

for the dragging rear.... I've just learned to live with it. Attack hills at an angle, etc... I've only had a couple times when it really dragged hard....mostly I've been able to avoid...but then I live in the flatlands....
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Old 04-03-2019, 04:21 PM   #10
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Thank you all for the feedback. It sounds as if the 235/85/16 on all six tires is the max size. I would assume there may be room for more width up front, but I could be wrong.
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Old 04-03-2019, 09:03 PM   #11
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I also wanted the Weldtec Lift Kit but I am across the country and could not find any shops who would put their kit on.

I also had the white knuckle driving experience and decided to just deal with it myself. I spent last weekend installing the following on my Outlaw 29H E-450:

1) Hellwig Front and Rear Sway Bars ($562)
2) Roadmaster RSSC Steering Stabilizer ($358)
3) SumoSprings (500lb Fronts and 1500lb Rears) ($427)

After a 40 mile test drive I could not believe the night and day difference it made! It went from driving like a dump truck with a dead elephant tied to the roof to handling like a big SUV.

I may decide to do a trac bar but I am going to wait until we do our first trip of the season and I am fully loaded down. The way it handled during my test ride was good enough that I don't think I will need to do anything else.

I still have a clearance issue with the front levelers and septic drain pipe but I am thrilled that it is a dream to drive now compared to the way it was.

I may go with taller tires when the stock tires wear out to get an extra inch or so to help the front levelers a bit and I will probably change the septic drain.

But for a little over $1300 and about three 1/2 days of time, I was able ot do the work myself and completely changed how my Outlaw 29H handles and rides.
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Old 04-03-2019, 11:56 PM   #12
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THOR #13869
Rickson tire has E450 tire & rim upgrades.
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Old 04-04-2019, 12:57 AM   #13
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Originally Posted by 10scDust View Post
Rickson tire has E450 tire & rim upgrades.
I just read about the Rickson upgrade. I am actually going to call them tomorrow to get a quote.
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Old 04-05-2019, 12:35 AM   #14
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THOR #2791
+caster

On the topic of Ford E450 alignments:

Ford ships all E350/E450 cut aways with identical fixed, non adjustable
caster/camber sleeves, "one size fits all".

The RV builder almost never changes the Ford sleeves, as a result:

If the final RV build is nose down one degree then the runtime caster will be about +3.5 degrees. These units can have a real wandering problem.

If the final RV build is nose level then the runtime caster will be about +4.5 degrees. These units are probably indifferent.

If the final RV build is nose up one degree then the runtime caster will be about +5.5 degrees. These units are probably just fine, possibly excepting the 31 footers.

So, some RVs have a problem and some do not have a problem. JMO.

POPULAR MECHANICS MAY 1973:
START QUOTE:
If too little caster exists, the car will wander and weave,
thus necessitating constant corrections in steering.
END QUOTE:
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Old 04-05-2019, 11:46 AM   #15
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Harvard, thanks for that info.


I bought the camber/caster sleeves for my RV because I wanted to get at least 5 degrees of caster, but when I got an alignment done it was already at 5 degrees so I didn't install them.


My big 32' class C has a lot of weight at the rear, and it could use some more clearance for the rear levelers. I was thinking that it could benefit from helper springs or lift blocks at the rear. But it sounds as if this would decrease the effective caster, so maybe that's not a good idea.
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Old 04-05-2019, 02:43 PM   #16
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Harvard, thanks for that info.


I bought the camber/caster sleeves for my RV because I wanted to get at least 5 degrees of caster, but when I got an alignment done it was already at 5 degrees so I didn't install them.


My big 32' class C has a lot of weight at the rear, and it could use some more clearance for the rear levelers. I was thinking that it could benefit from helper springs or lift blocks at the rear. But it sounds as if this would decrease the effective caster, so maybe that's not a good idea.
In theory you might have a light front end because of the long rear overhang. As such, you may benefit by reducing the front tire pressure to be just enough to carry the weight of the front end. This would have the effect of increasing the caster trail to be the most available trail for that 5* caster angle.

For example, my 2004 E450 28 foot front end runs at about 4350# (max) 4600#.
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Old 04-05-2019, 03:04 PM   #17
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Just an FYI....

I spoke with Heather a Rickson today. Had to leave a couple vmails but she called me back. Very nice and helpful person as well as knowledgable about the application.

The bad news is there is currently ~4 month lead time for the wheels. They are waiting for their materials supplier to give them an update so they can get a better handle on when they can start manufacturing more of the 17.5" wheels.

I am getting into their manufacturing queue now. My tires only have 3000 miles and I am trying to be proactive by installing a better load carrying tire so I can wait 4 months. I am also going to order a 7th rim to have as a spare in case I damage one and need a replacement given they are custom.

She also convinced me to go with a drive / steer tire combination. She said the tires are going to be scaled down 18-wheeler type tires so traction on surfaces like wet grass will not be great. I will either go with Toyo or Yokohama tires with the mud / snow rated on the back and the regular tread on the front.
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Old 04-06-2019, 12:25 AM   #18
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THOR #13869
Quote:
Originally Posted by jabrabu View Post
My big 32' class C has a lot of weight at the rear, and it could use some more clearance for the rear levelers. I was thinking that it could benefit from helper springs or lift blocks at the rear. But it sounds as if this would decrease the effective caster, so maybe that's not a good idea.
On our class C, the rear levelers have room to move up a notch or two.
The bolt holes on the leveling jack cylinders are 1" apart.
I raised ours because they scraped, then on the fronts, there is physically no room to unbolt them and raise them to remount, so they stayed where they were.
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Old 04-06-2019, 12:33 AM   #19
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THOR #13869
Quote:
Originally Posted by Judge View Post
I am also going to order a 7th rim to have as a spare in case I damage one and need a replacement given they are custom.
The seventh rim, as a spare taken with you, may be a good idea.

When renewing, and upgrading our Good Sam roadside coverage, the gal mentioned it covers changing a flat tire for you.
She also said it did not cover if you did not have a spare.
What would that scenario cost...$$$ ?

Look under the rear of yours, may be like ours, I fabbed a tire carrier from a piece of 2" pipe, 2 x 4 channel iron, and fastened it to the trailer hitch after adding a piece to bolt it to.
The pipe fit in an oval hole in the framework, my pivot point.

I have a welder and can put a descent bead, if it is horizontal in front of me, lol.
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At my young age, lol...
You could still maybe see me rolling down the highway, on my motorcycle, pulling a trailer with camp gear, smiling, beard in braids...
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Old 04-06-2019, 12:52 AM   #20
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Model: 2013 31L
State: Florida
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THOR #908
Quote:
Originally Posted by Harvard View Post
On the topic of Ford E450 alignments:

Ford ships all E350/E450 cut aways with identical fixed, non adjustable
caster/camber sleeves, "one size fits all".

The RV builder almost never changes the Ford sleeves, as a result:

If the final RV build is nose down one degree then the runtime caster will be about +3.5 degrees. These units can have a real wandering problem.

If the final RV build is nose level then the runtime caster will be about +4.5 degrees. These units are probably indifferent.

If the final RV build is nose up one degree then the runtime caster will be about +5.5 degrees. These units are probably just fine, possibly excepting the 31 footers.

So, some RVs have a problem and some do not have a problem. JMO.

POPULAR MECHANICS MAY 1973:
START QUOTE:
If too little caster exists, the car will wander and weave,
thus necessitating constant corrections in steering.
END QUOTE:
Harvard
I'm curious....do you sell these bushings yourself? If not, where can they be purchased?
Anyway, I'm curious if you're selling them yourself because I see your posts all the time always about this topic....
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