Alignment and steering looseness

[Beau388]

Originally Posted by MLP

All RV manufactures start with a bare chassis. They then add a ton of weight to the chassis. You need to find out how much weight should be on the front end and how much is on the front. With a light front end you will feel the wind and semi passing much more and it will not handle well until the rear is lifted to shift enough weight onto the front to stabilize it. Everything else is a band aid and will not fix it. Then a front end alignment. After that, other things if needed.

Just to be clear Thor MC does not have the certifications from Ford to modify or weld on the any Ford chassis. No bare Ford chassis are shipped directly to Thor MC. If you visit any Thor MC factory, you can see the modified Ford chassis arriving on a special MORryde trailer directly from the MORryde factory. I know the Spartan chassis used by Entegra are also modified by MORryde. I can not speak to whether the Freightliner chassis are modified in any way.

[Judge]

Originally Posted by Beau388

Just to be clear Thor MC does not have the certifications from Ford to modify or weld on the any Ford chassis. No bare Ford chassis are shipped directly to Thor MC. If you visit any Thor MC factory, you can see the modified Ford chassis arriving on a special MORryde trailer directly from the MORryde factory. I know the Spartan chassis used by Entegra are also modified by MORryde. I can not speak to whether the Freightliner chassis are modified in any way.

True.... but I think what we are getting at is the stock Cab & Chassis from Ford gets an alignment at Ford before it is delivered. Then the RV manufacturers (via MORryde) add length, height and weight to the stock chassis that was modified. The end result is the alignment that Ford did is no longer valid after the chassis has been modified and a coach built on it. This is why Thor recommends that all coaches be aligned once delivered and the owner confgures it with gear to get their typical driving weight.

If you talk to shops that specialize in heavy truck alignment, they will tell you chassis modifactions.... something as simple as adding a leaf spring.... needs to be completed before doing an alignment.

[Beau388]

Originally Posted by Judge

True.... but I think what he was getting at was the stock Cab & Chassis from Ford gets an alignment at Ford before it is delivered. Then the RV manufacturers (via MORryde) modify the chassis and add length, height and weight to that modified chassis. The end result is the alignment that Ford did is no longer valid after the chassis has been modified. This is why Thor recommends that all coaches be aligned once delivered and the owner confgures it with gear to get their typical driving weight.

If you talk to shops that specialize in heavy truck alignment, they will tell you chassis modifactions.... something as simple as adding a leaf spring.... needs to be completed before doing an alignment.

Having visited the MORryde factory in Elkhart, they do realign the entire chassis on an alignment plate using CMM and laser precision measurements. This is required by Ford. The entire MORryde work (who, what, when and where) is sent to Ford to be added their data base to aid in future warranty claims. Thor MC does not align any part of the chassis after the house is built on the MORryde modified chassis. The thought is since the coach is not road tested, there will be some settling and chassis realignment during transportation to the dealer. Thor MC recommends the chassis alignment be checked by the owner 500 to 1,000 miles after delivery to the owner because of the potential problems you note.

[Judge]

Aligning at MORryde is fine.... but until the coach is built, I think it is very likely an alignment should probably still be done at delivery.

[Judge]

Originally Posted by chunker21

As a side question, doesn't anyone know what a 550 chassis weighs when delivered to Thor? Mostly a curiosity thing on my part.

So I just put my VIN into the Ford decoder and I was able to obtain this information that is not listed on any of te Ford Cab Chassis brochures and spec sheets.


Curb Weight - Front 3963 lbs 3963.0 min 4250.0 max
Curb Weight - Rear 2993 lbs 2980.0 min 3011.0 max


So the F-550 chassis is about 7000lbs delivered from Ford. It also says they used the 145" wheel base chassis option, which is the shortest of the cab & chassis configs available.

[kwplot34]

Originally Posted by chunker21

I don't remember from your previous posts but have you weighed it and what rationale did you use for those figures? Based on my scale ticket, there is no way I can exceed either axle weight rating without exceeding GVWR. And it would be very difficult to put weight so that I exceeded either axle weight. I was 1380 under GVWR and on the trip I have added HER, our clothes, some groceries, and my hoses etc. I figure I used about maybe 600# of that mostly distributed midships. Using the Continental tire chart that judge provided, I found my axle weights, rounded up to the nearest 5 psi and came up with 80 and 95. That's what I'm got to set today for Saturday's drive. If I come across a CAT scales I'll jump on it. IF this fixes the handling then I'll postpone alignment.

I'll have 4 weeks before the next 3 week trip and several things to do such as replace 2 seater couch, install crossfire, wash and wax, and fix myself some small "warranty items" that are easier for me to do than wait on Thor and CW.

I have not weighed this motor home or the previous one either.
How did I come up with those front and rear PSI, many years of experience and trial and error. When we get a new coach I will set the tire pressure high maybe 5 PSI under max and with the coach loaded for a trip I drive it, see how it handles and rides and watch tire wear. Usually never go lower than 10 PSI on the back but will go lower on the front. When I have nice ride, drives straight, no uneven tire wear and most importantly if the wife is happy with the ride and how it drives I have found my best PSI for my coach and how we load it.
There have been times when I have extra people in the coach and gear and a bigger trailer behind with 2 side x sides like in the fall when myself and a couple friends go to Wyoming to hunt, I will inflate the rear to max and take the front up higher but never max.

[chunker21]

Traveled yesterday with a variety of roads and conditions. Much better drivability. Far less push but that's relative to the speed of the passing truck and shape of the front. Still some oversteer as expected but better. In a few days we'll have the return trip with more varied highway conditions and a better evaluation of tire pressures vs handling. I ended up with front 82, rear 95.

I'll still get it into the alignment shop but the urgency before the next trip is reduced. On the return trip I'll also keep my eye open for the CAT scales.

[Judge]

Took the SV34 in for an alignment today at a respected heavy duty truck shop this morning. I told them I have to do a little back and forth on the wheel when driving down the highway and the steeting wheel was slightly to the right of center. I took it in fully loaded for the most part.

They just called and said the alignment was all within spec. I was a little surprised but the shop is very good so I trust their work. They said all they needed to do was align the steering wheel.

I'm going to stop and get weighed and then adjust my tire pressures accordingly. I know I am pretty close to max weight in the rear so I have been running 105 in the back. I have been running 85 in the front but that was before adding the heavy duty bumper, which added about 250lbs up front.

In any case, at least I know the alignment is good and that is with 12,000 miles.

[Jimmers]

After we scaled ours a couple weeks ago, I increased to 95/105 and noticed a little wandering with ours this past week pulling the big boat.
I may drop down to 90/100 just for the handling.
Prior I was at 85/95 and never had wandering.

[Judge]

In case anyone is interested, here were my alignment specs. They had the front tires @ 90PSI, which would be correct for my front end weight.

[chunker21]

Originally Posted by Judge

In case anyone is interested, here were my alignment specs. They had the front tires @ 90PSI, which would be correct for my front end weight.

Judge if the alignment numbers were correct, what is the 110PSI after reading for? Based on what I've researched and the Continental tire/loading chart you sent, 110 would be far excessive pressure. As I commented earlier, for me 80 should be the correct PSI for my weight. Thursday/Friday we head home and I'm hoping there is a convenient CAT scales on the way so I can get another weigh with the toad.

Jimmers, I started this trip, and thread, based on 95F and 110R PSI. The last leg I reduced it and improved handling a bunch. The improved handling was a benefit but the reduced pressure more accurately reflected my weights. I think the front was arguing with me for being to "tight".

[Judge]

Originally Posted by chunker21

Judge if the alignment numbers were correct, what is the 110PSI after reading for? Based on what I've researched and the Continental tire/loading chart you sent, 110 would be far excessive pressure. As I commented earlier, for me 80 should be the correct PSI for my weight. Thursday/Friday we head home and I'm hoping there is a convenient CAT scales on the way so I can get another weigh with the toad.

The 110PSI was the door sticker pressure for the rear tires. Some vehicles get 4-wheel alignments but not the F-550. That is why there was nothing under the 110 part of the report.

My door stickers has the following max axle weights and max tire pressures:

Front Axle: 7000lbs Max Weight / 95 Max PSI
Rear Axle: 14706 Max Weight / 110 Max PSI


Following the Continental Recommended Weight vs Pressure..... based on my front weight I should be at 90 PSI for the front tires, which is what they used for checking the alignment.

Based on my rear weight, I am at 100 PSI for the rear tires.

I am under for both axle weights but I am over the GVWR fully loaded. I am not worried because the tires are rated for almost 23,000lbs. I am well under the tire ratings and I am under the axle weight ratings. As I burn fuel, I will be closer to being at GVWR. I may ony carry a half tank of water vs a full tank..... but again I am not worried about being over the total weight fully loaded from an axle, brake, suspension and frame perspective.

[Jimmers]

Chunker,
I agree it handled better before I increased pressure.
I will drop pressure and check foot print to see how it balances out.
My axle weights were fairly close but I was over loaded compared to normal travel weight.

[Jph]

Here is a link for Ford commercial vehicles
Fordcommercialvehiclecenter.com
This link will give you truck centers near you. You can click on a dealer to see if and what size motor homes they can handle. Find one that handles big rigs and they will have the equipment and no how to get the steering set up right. I had the same issues your dealing with.
Good luck
James

[HMCSW]

Originally Posted by chunker21

In a previous post I commented that on the way home it felt somewhat loose in the steering. A comment was that it should drive like a Cadillac but of course that's a relative comment not exact. We're on a trip up in the NC mountains and I'll describe the handling as some oversteer tendency and loose. Obvious push by larger vehicles that pass. It's not dangerous by any means but annoying and has an increased workload driving. I know that the chassis are supposedly set/aligned by the Ford factory before delivery to the RV manufacturer and that Thor in this case makes no effort or alignment after the house is built on it. My local Ford dealer is a small one and doesn't have any alignment that can take large vehicles. I do know a truck shop that I used for tire and alignments with my previous DP on a FL chassis.

I have tried finding what Ford recommends or makes on the F550 chassis but having difficulty. Default searches end up with 150-350 which of course is mostly useless. For any here who took their F550 chassis RV to the alignment shop, do you remember what your alignment numbers were before and after aligning? Also what handling characteristics did you have before and how did the alignment fix that?

actually Thor does align when they build the RV. They recommend the buyer get another after loading up with gear.

[Pete'sMH]

Originally Posted by HMCSW

actually Thor does align when they build the RV. They recommend the buyer get another after loading up with gear.

When I bought my Freedom Elite there was a sticker on the door frame that said specifically that it had not been aligned by Thor and that it was the owners responsibility to have it done after loading. I asked my salesman and he said “we usually remove that sticker” and that since Ford aligns it when it’s made we should only need to do it if it handles badly or there is uneven tire wear. I had it done anyway and no changes were needed.

[Beau388]

Originally Posted by HMCSW

actually Thor does align when they build the RV. They recommend the buyer get another after loading up with gear.

I have toured Thor MC plant 750 (twice), 850 and the Entegra RED factories; those plants do not have any alignment facilities. MorRyde does align the chassis after modifications as this is required by Ford, Freightliner and Spartan.

[chunker21]

We got home yesterday and a long day. 500 miles in varied roads, twisty mountains at 15-20mph and interstate at 65. Temperatures up to 100 and the TPMS showed tires in the 115* range and pressure 15+- higher then starting which is normal. Handling was better than the first day with the starting higher pressures but I noticed more push yesterday by passing trucks that the previous travel day with the lowered pressures. Course having a truck pass going 10-20 mph faster has an effect. Still some wandering but much more manageable than the fist day's travel. I'm still going to have it in to the shop for an alignment check but it's not of the first priority of things I want to do before next trip.

Crossfire install, replace theater seats, extend mud flaps, wash and wax, reinforce running boards, and a few others. All in all we're happy with the Omni and nothing "fell off" this trip.

[Scubawise]

Originally Posted by Judge

I would agree that the "looseness" is more of a wandering. I would not say it wears me out or is a white nuckle experience but more of a nuisance. My E-450 Outlaw 29H with the stock suspension was a white knickle drive. After 5 hours of driving it I was worn out. I have driven as long as 12 hours with the F-550 and while tired at the end I was not worn out from keeping it between the lines.

That being said.... I am somewhat like you. I want it to track straight with as little input needed as possible on straight, even roads. I think the alignment will get it where I want it to be. Since Thor does not align the coaches once they are built, I am sure the Ford factory alignment is no longer valid based on the build.

Be careful. I met full time motorhome folks years ago and they belong to a 250 & 350 club. Once these miles are reached they stop driving

[Pete'sMH]

Originally Posted by Scubawise

Be careful. I met full time motorhome folks years ago and they belong to a 250 & 350 club. Once these miles are reached they stop driving

In the RV I’m usually happy with 300 mile days. Not because I’m tired of driving but just because it’s a recreational activity and I like to stop and get set up in time for a nice relaxing dinner and usually a 2 or 3 mile walk with DW and the dog. It took me a long time after retiring to learn to slow down and smell the roses. Now I like it.