Tire inflation valve Freightliner chassis

[Joenew61]

We have a Renegade motorhome built on a Freightliner M2 chassis that we bought last year. This is the first time I needed to top off the tires using the on board compressor. I was able to get 5 out of the 6 tires done, but can't seem to find the valve for the inner tire on the driver's side. For the similar passenger tire there is a pass through from the outer tire (had to buy a straight chuck to replace the angled one that came with the coach). But I haven't been able to find the access to the inner on the driver's side. Anyone have any ideas where that would be located on that chassis? Thanks!

 

[Gary RV_Wizard]

Has nothing to do with the chassis make/model. Simply the type of tire valve and how it is placed with respect to the wheel. And not all wheels have nice access ports either. You may have to get at that valve from the back side. Or go to a truck tire shop and see if they can remount the tire so the valve is at whatever port exists.

 

[Utclmjmpr]

Irf that wheel was not "timed" correctly,, then it will have to be adjusted,, any tire shop will do it.. It will only effect the outer wheel..>>>Dan

 

[Joenew61]

Thanks. I looked again with a light after I posted and saw where it was - very recessed and a little off center, but probably reachable with a long chuck. The problem is even if it was on center, getting the cap off will be really difficult - the pass through is too narrow for my fat fingers to get it from the outer tire opening, and it looks like a really tight squeeze to get my hand between the tires to remove it. It does look like it has an active cap to inflate without removing it. Is that standard procedure for that kind of set up, to inflate through the cap?

 

[Utclmjmpr]

There is no real reason to cap them,, do your self a favor and throw them away.>>>Dan

 

[John From Detroit]

Unless the number of "Access ports" to the inner tire = the number of lug nuts holding it on it is possible to install the outer tire oriented such you can not access the inner valve stem.

The visit truck tire place and re-mount outer dual advice is thus best .

 

[John From Detroit]

There is no real reason to cap them,, do your self a favor and throw them away.>>>Dan

I am told there is a reason for METAL caps Should the valve core leak the cap will hold the pressure) But with plastic caps... Just to keep dirt out

 

[L-M-L]

Thanks. I looked again with a light after I posted and saw where it was - very recessed and a little off center, but probably reachable with a long chuck. The problem is even if it was on center, getting the cap off will be really difficult - the pass through is too narrow for my fat fingers to get it from the outer tire opening, and it looks like a really tight squeeze to get my hand between the tires to remove it. It does look like it has an active cap to inflate without removing it. Is that standard procedure for that kind of set up, to inflate through the cap?

On our FL60 I cannot get to the inner valve cap through the opening on the outer wheel. I found I could use a peace, I believe it's 5/16" fuel hose that fits snugly over the valve stem cap. I put a piece of rod in the hose to make it stiff enough to use. It works for me

 

[CharlesinGA]

For caps, I suggest, and have used, Alligator V2B Inflate Through Valve Stem Cap Gator Auto RV Semi (10 Pack). These are German made, the original inflate thru cap design. There are others, these are higher quality. The grooves around them are NOT threads, you cannot put a cap on top of them, and do not need to. The grooves are designed to lock with grooves inside the foot of valve inflators that have internal grooves, but will work on any inflator foot.

These will keep dust, mud, water, etc out of the valve stems, but will allow you to inflate the tires as needed.

There are also two types of dual valve foot inflators, one straight and one angled, you may want to have both on hand.

Straight/angled end
Milton S-693-12 1/4" FNPT Extended Reach Dual Head Air Chuck,Bronze

Angled/angled end

Milton S-690-12 Twelve Inch 1/4" FNPT Dual Head Air Chuck​

Have a truck tire shop remove the outer wheel and remount it so the hole in the rim aligns with the inner valve stem.

Charles

 

[Utclmjmpr]

When you think of the pressure in a 22.5 tire ( 80 to 100 or more ) that inflation valve has that pressure on it,, so after 20 years of driving trucks I leave them off the duals,, never a problem..>>>Dan

 

[Joenew61]

Thanks for the tips guys. The factory installed metal caps look very similar, but the straight chuck I have seems to be threaded on the inside. It takes a bit of finesses to seat it on a valve cap that is recessed almost 6 inches, and it catches sometimes when I try to remove it. I'll see what kind of access I have to remove the inner cap and see what my options are.

Related question from a rookie here - when inflating the fronts to 120 PSI, from a post winter pressure of around 110, it seemed like they didn't really take the air when the pressure on the onboard compressor was at steady state of 125 PSI. But after the pump pressure dipped down and the compressor kicked on again, for those 20 or 30 seconds or so as it was cycling up is when I was able to put air in. Does that sound right? Also, how much variation between the rear axle tires is considered acceptable? Should I obsess over getting them dialed in exactly when I top them off?

 

[NY_Dutch]

Is 120 PSI the correct inflation based on the axle weight of the coach? Or the max PSI shown on the tire sidewall. The inflation PSI should be based on the axle weight and the tire manufacturers weight chart.

 

[Utclmjmpr]

That is way too much pressure and will cause handling problems ....DAN

 

[Joenew61]

The dealer told me I should inflate to the cold pressure indicated on the door panel. I am attaching pictures of that as well as the tire.

That is way too much pressure and will cause handling problems ....DAN

 

[Utclmjmpr]

The problem with that thinking is the various differences in coach weights,,tire manufacturers provide pounds per vehicle weights for a reason.. As an example:: My coach weight has "gained" 750 pounds of vehicle weight over a twenty thousand mile period ,, and yours will gain also over time and use Using your tire manufacturers pressure tables ,, weigh the coach per excel and make a final determination of proper pressures per excel divided by the number of tires on that axcel.>>>Dan

 

[NY_Dutch]

The dealer told me I should inflate to the cold pressure indicated on the door panel. I am attaching pictures of that as well as the tire.

Those Load Range H tires are just about maxed out for the front axle GAWR at 120 PSI. I think it would be worthwhile to get the actual weights for each tire position, or at least each axle weight to see what inflation the tire manufacturer calls for to support those weights.

 

[CharlesinGA]

Here is the Bridgestone tire size/weight/pressure tables for commercial tires.

Drive it on a CAT scale and get some real weights for it.

Yours are on PDF page 4 which is page 94 as numbered on the bottom left of the page. Your size would be the bottom listing in the top most box.

 

[CharlesinGA]

The factory installed metal caps look very similar, but the straight chuck I have seems to be threaded on the inside. It takes a bit of finesses to seat it on a valve cap that is recessed almost 6 inches, and it catches sometimes when I try to remove it. I'll see what kind of access I have to remove the inner cap and see what my options are.

Those are grooves, not threads, but are designed to interlock with grooves or threads, on the valve stem, to make it easier to keep the chuck on the stem.

Milton did make smooth nuts to replace the grooved ones on the chuck but they have disappeared out of the catalog.

Charls

 

[Joenew61]

Those are grooves, not threads, but are designed to interlock with grooves or threads, on the valve stem, to make it easier to keep the chuck on the stem.

Milton did make smooth nuts to replace the grooved ones on the chuck but they have disappeared out of the catalog.

Charls

Got it - so having a little resistance when pushing them on the flow through valve caps is to be expected.

 

[Joenew61]

Here is the Bridgestone tire size/weight/pressure tables for commercial tires.

Drive it on a CAT scale and get some real weights for it.

Yours are on PDF page 4 which is page 94 as numbered on the bottom left of the page. Your size would be the bottom listing in the top most box.

View attachment 1321266

Looks like I have some math homework now. So the way to interpret the chart above is the numbers in the grid are the maximum weight I should have on each tire at the PSI indicated on the top row. So when I have the rig weighed, if each tire was supporting around 6,000 lbs then I would have around 10% margin at 120 PSI (295/75R22.5 tire).

I did make note that when I picked up the RV last year the TPMS had the steer tires at 118/119, and the dually tires were 110/111. The dry weight of the coach is 28,500, and GVWR is 37,600. Full fuel, water, provisions, passengers would be 3,500 - 4,000 lbs, so that would put the average load per tire around 5,300. Am I thinking about this the right way? If the maximum weight for a tire at 120 PSI is 6610 per above, then what would the target PSI be for 5,300 actual load?