Firestone Excludes Thor

[mhbell]

I wanted to put Firestone Ride Rite air bags on my motor home. For some reason Firestone and Air Ride both say will not fit Thor Motor Home or all Except Thor. Can anyone tell me why. My motor home has the Ford F-53 chassis. Why do they exclude Thor. The F-53 chassis is the same as other motor homes. I would sure like a answer. I have contacted Thor, Firestone and Air Ride and have received no answer from any of them. I do know of others who have done it. Can anyone shed some light on this?
M H

[FW28z]

Doesn't sound right to me. Mor/Ryde does all of the chassis work for Thor as well as most of the industry. Can't imagine doing anything different for Thor than any one else.

However, anything is possible, and Mor/Ryde I would think would have the answer if anyone would.

[Chance]

If correct, there may be many reasons it's not sold for some specific applications. I did a quick search and found a RideRite model for 2014 F53 chassis. Below is installation instructions.

http://riderite.com/-/media/www/ride...lManual_EN.pdf

The first thing I would check is whether there is enough clearance on either side of the frame to install the air bag assemblies. It's possible that some motorhomes may be built in such a way that it precludes the installation.

[mhbell]

Originally Posted by Chance

If correct, there may be many reasons it's not sold for some specific applications. I did a quick search and found a RideRite model for 2014 F53 chassis. Below is installation instructions.

http://riderite.com/-/media/www/ride...lManual_EN.pdf

The first thing I would check is whether there is enough clearance on either side of the frame to install the air bag assemblies. It's possible that some motorhomes may be built in such a way that it precludes the installation.

The only thing I can think of would be if the body brackets were it mounts to the frame were in the way. Not is not the problem if any in my case. I also have 10 1/2 inches from the tire to the Frame with no obstructions above the axle. I have ordered a set the Firestone Ride Rite 2170 for my ford F-53 chassis. Still waiting for a answer from Firestone. So far they have evaded the Question as to why Thor motor homes are excluded. I know several who have installed them on Thor Motor homes. Maybe Firestone has a vindetta or something against Thor.
Mel

[Chance]

Mel, the instructions for the model I pulled up show the air-bag assemblies mounting ahead of the axle and not directly on top of it. Hopefully that won't make a difference on your installation. Also don't forget to check vertical clearance since you'll need to run the air lines out the top of each air spring.

[EA37TS]

Thor did a frame extension on some of the F53 chassis Class As. For instance on my Challenger they took the 242 inch wheelbase and extended it to 252 inches.

The question then becomes did the manner in which the extension was accomplished create a situation whereby the ride rite system cannot be mounted to the frame without weakening one aspect or another of the frame rail extension?

The installation instructions specify using 2 existing holes on the frame rail. With the frame rail extension done by MorRyde, are those holes still in the correct location for mounting the air bags?

[mhbell]

Originally Posted by Chance

Mel, the instructions for the model I pulled up show the air-bag assemblies mounting ahead of the axle and not directly on top of it. Hopefully that won't make a difference on your installation. Also don't forget to check vertical clearance since you'll need to run the air lines out the top of each air spring.

Thanks Chance
I have plenty of room to install them. a good 4 inches at the top. I have been in contact with another person who has a Identical motor home and installed the air bags on his with no problems Following the instructions. I will do the same even though the bags will be a little bit ahead of the axle. Should get my air bags next week as I have ordered them.
Mel

[Chance]

Originally Posted by dstankov

Thor did a frame extension on some of the F53 chassis Class As. For instance on my Challenger they took the 242 inch wheelbase and extended it to 252 inches.

The question then becomes did the manner in which the extension was accomplished create a situation whereby the ride rite system cannot be mounted to the frame without weakening one aspect or another of the frame rail extension?

The installation instructions specify using 2 existing holes on the frame rail. With the frame rail extension done by MorRyde, are those holes still in the correct location for mounting the air bags?

Are you thinking they would move the rear axle back on existing frame rails and then add additional rail length only at back end?

On the Axis I saw the frame was cut and extended in middle of wheelbase, plus there was an extension at rear too. On E-Series frame moving axle back on existing rails is not an option, so maybe that's why it's done that way.

On the F53 by virtue of it having straight rails it may save them some work if they can relocate the leaf spring mounts instead of cutting and welding frame. It's hard to say.

You may be able to look under your motorhome and see how they did it on yours.

[EA37TS]

Originally Posted by Chance

Are you thinking they would move the rear axle back on existing frame rails and then add additional rail length only at back end?

On the Axis I saw the frame was cut and extended in middle of wheelbase, plus there was an extension at rear too. On E-Series frame moving axle back on existing rails is not an option, so maybe that's why it's done that way.

On the F53 by virtue of it having straight rails it may save them some work if they can relocate the leaf spring mounts instead of cutting and welding frame. It's hard to say.

You may be able to look under your motorhome and see how they did it on yours.

They appear to have added a section towards the front of the frame.

When I looked under my coach three things jumped out.

First, on my Challenger the springs are on the outside of the frame and there does not appear to be enough clearance between the tire and frame for an airbag. I did not measure this with a tape measure.

The upper leaf of the springs are just about level with the lower edge of the frame rail.

The rear area/axle is mounted to a sub-frame assembly which is bolted to the main frame rails with I believe nine bolts (I saw 3 on the side, 3 on the bottom and I assume there are 3 on the top). This joint appears to be in the area, forward of the axle, where the air bag should be mounted, or very close to that area.

Now, I'm not sure if this layout is specific to the 22.5 inch chassis.

[mhbell]

I just crawled under mine again and checked everything. My Frame has not been Lengthened. The clearance from the frame to the tires is 10 1/2 inches You only need 8 according to Firestone instructions. Yes the Spring hangers are outboard of the frame like all F-53 Truck frames up to at least 2010 as I recall. The air springs set on the springs so there is still plenty of room. The springs are 4 inches wide and from the outboard edge of the spring to the tire is 3 3/4th inches. which would be 5 3/4th inches from the center of the spring on the inboard or frame side and 5 3/4th inches on the outboard or tire side. The max Diameter of the air bag is 6.60 inches which would be 3.30 inches on each side of the spring. from the center of the spring to the edge of the spring is 2 inches leaving a overhang of the air bag of 1.30 inches. Plenty of clearance. I think someone forgot to do there math at Firestone. BTW I ran a vin check on my frame and it was made in Detroit Michigan in 2006.
Mel

[EA37TS]

Yesterday I sent an inquiry to Firestone asking why the Thor F53 chassis was excluded from the Ride Rite system.

A few minutes ago I received their response from tech support.

They state that:

Begin quote

"Thors usually have brackets and different things in the way on the frame where our brackets go that interfere."

End quote

So this is in context, the question I asked was:

"Can you tell me why the Ride Rite system excludes F53 chassis used by Thor Motorcoach? I have a 2015 Thor Challenger."

So we now have the answer.

[Chance]

Originally Posted by dstankov

.....cut....

The rear area/axle is mounted to a sub-frame assembly which is bolted to the main frame rails with I believe nine bolts (I saw 3 on the side, 3 on the bottom and I assume there are 3 on the top). This joint appears to be in the area, forward of the axle, where the air bag should be mounted, or very close to that area.

Now, I'm not sure if this layout is specific to the 22.5 inch chassis.

What you describe is very interesting to me because I've never seen a truck or large motorhome utilize a subframe to mount the rear axle. I've seen a few that were converted to full rear air suspension like those used on semi trucks, but the entire air suspension including trailing-spring-bar-mounts were bolted directly to the frame rails.

Dave, can you tell if the subframe looks like it came that way from Ford or is it something that Thor either added or had some other company add for them? And can you tell why it was likely added?

[mhbell]

Originally Posted by dstankov

Yesterday I sent an inquiry to Firestone asking why the Thor F53 chassis was excluded from the Ride Rite system.

A few minutes ago I received their response from tech support.

They state that:

Begin quote

"Thors usually have brackets and different things in the way on the frame where our brackets go that interfere."

End quote

So this is in context, the question I asked was:

"Can you tell me why the Ride Rite system excludes F53 chassis used by Thor Motorcoach? I have a 2015 Thor Challenger."

So we now have the answer.

They should amend their statement to say Some models of Thor instead of saying "Exclude Thor". I have pictures of the air bags installed on a Hurricane 31D with no modifications. F-53 Chassis.

[EA37TS]

Originally Posted by Chance

What you describe is very interesting to me because I've never seen a truck or large motorhome utilize a subframe to mount the rear axle. I've seen a few that were converted to full rear air suspension like those used on semi trucks, but the entire air suspension including trailing-spring-bar-mounts were bolted directly to the frame rails.

Dave, can you tell if the subframe looks like it came that way from Ford or is it something that Thor either added or had some other company add for them? And can you tell why it was likely added?

The sub frame is without a doubt Ford based on the labels (part number stickers) I saw attached.

It appears that Ford is able to assemble the rear axle assemblies on the sub frame and then determine the chassis wheel base by using different length front frame rails. The attachment point is approximately 2 or three feet in front of the rear axle.

With that said, sub frame may not be an appropriate term. Rear frame section may be slightly

The attached diagram is the Ford parts list for the frame rails on my coach based on VIN. You can clearly see the front and rear sections. The rear axle and suspension is mounted to the rear section.

[mhbell]

Originally Posted by dstankov

Yesterday I sent an inquiry to Firestone asking why the Thor F53 chassis was excluded from the Ride Rite system.

A few minutes ago I received their response from tech support.

They state that:

Begin quote

"Thors usually have brackets and different things in the way on the frame where our brackets go that interfere."

End quote

So this is in context, the question I asked was:

"Can you tell me why the Ride Rite system excludes F53 chassis used by Thor Motorcoach? I have a 2015 Thor Challenger."

So we now have the answer.

I received the same message. They need to do their homework. That is not true in all cases. I have pictures with proof. for the F-53 chassis on hurricane 31D models..

[EA37TS]

Originally Posted by mhbell

I received the same message. They need to do their homework. That is not true in all cases. I have pictures with proof. for the F-53 chassis on hurricane 31D models..

I agree. It appears Firestone found it easier to do a blanket exclusion rather than to determine which specific models should be excluded. Must cost more to manufacture a specific mounting bracket than the revenue lost by excluding the entire Thor line from sales.

I will say that Firestone is not the only ones doing this. When I looked at (I believe) the Saf-T-Plus system applications there are numerous part numbers that say "F53 except Thor".

[mhbell]

Originally Posted by dstankov

I agree. It appears Firestone found it easier to do a blanket exclusion rather than to determine which specific models should be excluded. Must cost more to manufacture a specific mounting bracket than the revenue lost by excluding the entire Thor line from sales.

I will say that Firestone is not the only ones doing this. When I looked at (I believe) the Saf-T-Plus system applications there are numerous part numbers that say "F53 except Thor".

The sad thing is the 2170 Air bags and brackets fit without modification. I wonder how many, passed up getting air bags because of not knowing, checking the dimensions, or the exclusion. I know of one man who was about to sell his Daybreak motor home because he thought he could not install air bags. I know of another person who now hates firestone because the air bags would not fit. he says he will never again buy anything 3rd party for his motor home.

[EA37TS]

I just received a clarification email message from Firestone

It appears that on some Thor models there is a body mount that is positioned where the Ride Rite upper mounting bracket has to be installed.

Apparently Firestone has had so many problems with installation on enough Thor models (mounting and damage caused by incorrect installation) that they decided to reduce their liability and exclude the entire product line. In this manner liability installation of the product on a Thor Motor Home rests solely on the owner.