Modification of Wheel Simulators on MB Sprinter

[wbob]

I am the owner of a Thor Freedom Elite 24fe. I suspect that my concern may also be applicable to other Thor models on the Sprinter chassis using wheel simulators. I noticed a few months ago that the wheel simulators were starting to gouge the brass tire valve extension on the rear dually wheels. If you are one of those owners, I suggest you check your tire valve extensions. I cannot envision a situation where this, over time, would not lead to the extension being worn through causing a sudden loss of air pressure to that tire. The extensions are made of brass and that is a soft metal.

The original holes in the simulators are very difficult to align with the valve extensions so that they do not come in contact with the metal surrounding the holes. Putting on the simulators after removal was a one hour job to try and align the extensions with the holes for minimum metal to metal contact. Unfortunately, I found it impossible to get it perfect. Also, tire monitor sensors could not be attached without an additional extension, something I didn't want to do. I live in a state that requires yearly safety inspections requiring that a rear wheel(s) be removed to check the brakes. The technicians always mess up whatever alignment I have achieved.

My solution was to make the holes larger. I know some of you will say that the holes should be smaller. For my purposes, I decided that appearance was not as important to me as peace of mind and ease of installation. The size of the hole also makes it easy to align the extensions. With the simulator installed on the wheel, my fingers can fit inside the cutout to attach and align the extensions the way I want. Before, I had to guess at the angle, install the wheel cover, and then start over when the angle of the extension was wrong. Additionally, I can install my tire monitor sensors without having to use any additional extensions.

The 1st attached photo shows the steel wheel without the simulator and the MB (or maybe Thor) tire valve setup. The 2nd photo shows the wheel simulator in place without the center hub and the 3rd photo shows the simulator with the center hub in place. The valve extensions do not flex (solid) and there is no chance of metal to metal contact with the edge of the cutout.

You may also want to examine your front valve extension. On my model the extension was attached to a rubber tire valve and it did flex quite a bit. The flex can cause the extension to contact the edge of the simulator hole also gouging the brass. The solution for the front is to replace the original rubber tire valve with a metal valve stem that cannot flex.

[paulwadley]

How did you enlarge the holes on the simulators?


Paul

[wbob]

Originally Posted by paulwadley

How did you enlarge the holes on the simulators?


Paul

I used a Sharpy to outline the holes on the back of the two simulators. I tried free hand but didn't like it and had to remove the marker with a scrubbing pad. The problem for me was the bowl shape the simulator. I finally used card templates that insured that all four holes were the same. I determined the hole locations by aligning with the location of the valve stem on the wheel. To be accurate and ensure I didn't cut in the wrong place, I did this separately for both the passenger side and driver's side.



The cutting was easy. I just used a small cutoff wheel trying to stay inside the markings. Finally, I used a deburring tool to smooth out the edges of the holes. Someone also suggested a jig saw with a metal cutting blade and I am sure that would work. Not everyone has these tools and there are probably metal fabricators nearby that can easily do the job (you will have to outline the holes for them). I suggest that they not use a plasma torch as the heat will most likely ruin the chrome on the simulator.


I'm using this reply to post two pictures of the tire valve extensions on one of the simulators. It was returned to me in this condition after the state inspection.

[Bob Denman]

I got a safety alert from Tiffin over this issue. they are working on a permanent fox for it. In the meantime: they said to remove the covers...

[wbob]

Originally Posted by Bob Denman

I got a safety alert from Tiffin over this issue. they are working on a permanent fox for it. In the meantime: they said to remove the covers...

Good for Tiffin! It is definitely a safety issue! I have received nothing from Thor. If I am speaking out of turn and some of you have been alerted by Thor, please let us know.



I am planning a trip from PA to Michigan early next week to have hydraulic levelers installed. That was exactly how I was going to make the trip - without the simulators. Meanwhile, I had a little time and decided to just complete the project. I see no reason to remove them now.

[2013NHSiestaowner]

I own a 2013 Thor Siesta with 50K mi. The only issues I've had have been valve stem failures. I like the idea of opening up the holes in the simulators to minimize that set of problems. I also want to install TPS sensors which also require additional clearance. Which systems have you used and what is your preference? Thank you.
Peter

[powerboatr]

only issue i see is the valve stems are not now 180 degrees out from each other. does it effect wheel balance when both wheels are on? not sure
but my frieghtliner book states to place wheels with stems 180 degrees out from each other


but my wheel have internal balance beads so it probably does not matter.




your fix is a fix. good thinking


they sell a rubber bushing for lots of wheels that hold stems away from metal parts that might or could be used to fill the gap if you want
https://www.shinyrv.com/


https://www.shinyrv.com/product/dual...free-shipping/ for the sprinter wheels not sure how it would work on the simulators