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Old 09-26-2016, 08:10 AM   #1
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Dynamax REV Tire Pressure Question

What is the exact tire pressure setting? The door sticker says 65 front 80 rear. The dealer had it set at 75 front 80 rear when I picked it up. I cannot find a specific Dynamax specs sticker anywhere. I know I really need to weigh it loaded but until that happens I would like to know the ideal tire pressure for all purpose use. Best guess between myself, 3 dogs, dog crates, dog pens, food, clothes, etc. I am at 500 pounds. For this trip I can actually fill my fresh water tank at the site so dont need to travel with water for a change.

I know there is another question in my head that I thought of last night but the computer was already off and now I forgot it, so stay tuned. I really do appreciate all the help. My motto is always safety first. Back in 2010 I was in a horrible accident while towing my travel trailer (an 18 wheeler crossed the line and side swiped me on the Mass Pike) and of course I am still paranoid to this day. I just dont leave anything to chance when it comes to something I can control.
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Old 09-26-2016, 08:28 AM   #2
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Follow the door sticker until you can weight the motorhome this is the manufactures recommend air pressure requirement for the unit.


I would also go to a tire dealer or look on line for tire inflation charts for your brand of tires. Once you weight the motorhome when fully loaded as you would travel. You can adjust the tires accordingly to the inflation tables that will support the tire loads.
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Old 09-26-2016, 02:35 PM   #3
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I am able to calculate a save pressure for your vehicle.
But need some data for it

From car: best seperate weighed weigts on tires, second best axle weights, but because mostly nog known , we will have to do with GAWR's and GVWR( Gross axle/vehicle weight ratings).
configurationso howmanny axles rear and single or dual load ( 2 or 4 tires on the axle).
Maximum speed you use and wont go over for even a minute.

From tires: maximum load or loadindex
Loadrange ( probably E-load because of 80 psi) to determine the pressure behind AT.
Speedcode of tires wich says for wich sopeed the maximum load is calculated.

Will give a picture of my motorhome tirepressure calculator to get an idea.
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Old 09-26-2016, 02:44 PM   #4
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Oh my that looks really complicated!!! To answer some of your questions, both front and back are single (no dual in rear). Until I get a feel for the unit I will probably stay around 60 and not go over 65 for a speed. I always drive slow with an RV. Max load on tires is 80 and I feel most of the weight is in the back.
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Old 09-26-2016, 02:45 PM   #5
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Not sure where to find the speed code on the tires?
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Old 09-27-2016, 09:39 AM   #6
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Speedcode is a letter behind the loadindex.On European system tires it is always given but on American system tires not always.
Some Examples
Q= max speed of tire 160km/99m/h
R= max 170km/106m/h .
N= max 140km/86m/h .
Above Q ( R is exeption, but S,T,H,V) the maximum load is calculated for 160km/99m/h, and for higher speed there is a system for highening up the AT-pressure depending on speedcode, that is for normal car tires and XL, for C-tires ( European name for LT) sometimes the maximum load is given for that higher speed, so lower then for Q speedrated.
But again , if you cant find speedcode, we can do without, and I can make a quess by the sises and kind of tire.
Here its about motorhome, but TT's often have ST ( special Trailer tires, wich often have N speedcode , but are calculated in maximum load for 65m/h ( between J( 100km/62m/h) and K ( 110km/68m/h) speedcode) wich makes you think , yudging the N speedcode that max load can be carried at AT -pressure up to 140km/86m/h, and then more heatproduction so unsaver for the tires. In the system for wich I need the speedcode, I correct that and even give the higher advice pressure that would be needed as if it was a Q speedrated tire with even 10% reserve added, for maximum reserve with still acceptable comfort and gripp

This speed thing is for motorhomes and TTralers not that important, because maximum speed of vehicle is mostly lower then maxspeed of tires.
But I still like to know , so I can determine the highest pressure with still accheptable comfort and gripp, gives higher pressure advice , so more reserve for things like , pressure loss in time, misreadings of yudging of weights and pressure , etc etc.
In the spreadsheets I made , the speedcode is not yet worked in , and then even you think it complicated.

But the spreadsheet looks complicated, but if you begin at the top, and work your way down, advice is given.
only blue fields need to be filled in , but if you give me the needed data , I will do the work.
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Old 09-27-2016, 10:07 AM   #7
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Quote:
Originally Posted by Dog Show Gal View Post
What is the exact tire pressure setting? The door sticker says 65 front 80 rear. The dealer had it set at 75 front 80 rear when I picked it up. I cannot find a specific Dynamax specs sticker anywhere. I know I really need to weigh it loaded but until that happens I would like to know the ideal tire pressure for all purpose use. Best guess between myself, 3 dogs, dog crates, dog pens, food, clothes, etc. I am at 500 pounds. For this trip I can actually fill my fresh water tank at the site so dont need to travel with water for a change.

I know there is another question in my head that I thought of last night but the computer was already off and now I forgot it, so stay tuned. I really do appreciate all the help. My motto is always safety first. Back in 2010 I was in a horrible accident while towing my travel trailer (an 18 wheeler crossed the line and side swiped me on the Mass Pike) and of course I am still paranoid to this day. I just dont leave anything to chance when it comes to something I can control.
We have different year REVs so use this as a starting point until you get weighed.

My REV weighed 8900 lbs. on a certified scale. that included wife, dog, full water and propane, some in the waste tanks and half tank of gas.

A local moving and storage company has a scale to weigh their moving vans. You may be able to find one in your area to use. Then you don't have to get in line with the trucks at the truck stops. I went mid afternoon and there was no waiting or hassle. Very easy.

I am currently running 65 psi in my front tires and 72 psi in my rear tires. Ride and handling seem fine.
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Old 09-27-2016, 02:59 PM   #8
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Jadatas, I looked all over the tires and see nothing about speed codes. I only saw a max load of 2680 at 550 kpa.
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Old 09-27-2016, 03:08 PM   #9
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Thanks Bobby. I will check one out near me and see if they have a scale. Thanks for the info on your unit too. By the way, the other thing I really LOVE about the REV is I was able to take it to a local Chrysler dealer who was able to fit it in their truck bay and 1 1/2 hours later the recall was done. I believe they only did the ignition switch and did not have to do the hitch recall. Would have been a PIA with my class A finding a place to take it in, and was so easy to even park it in their lot.

While I have you here, I thought of my other question. The dinette table folds down, is yours the same? Every time I turn a corner it bangs against the way. Is there a way to lock it down?
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Old 09-27-2016, 04:39 PM   #10
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Originally Posted by Dog Show Gal View Post
Thanks Bobby. I will check one out near me and see if they have a scale. Thanks for the info on your unit too. By the way, the other thing I really LOVE about the REV is I was able to take it to a local Chrysler dealer who was able to fit it in their truck bay and 1 1/2 hours later the recall was done. I believe they only did the ignition switch and did not have to do the hitch recall. Would have been a PIA with my class A finding a place to take it in, and was so easy to even park it in their lot.

While I have you here, I thought of my other question. The dinette table folds down, is yours the same? Every time I turn a corner it bangs against the way. Is there a way to lock it down?
My dinette table does not fold. I never used one but I think I would prefer the "dream" dinette.

I have a suggestion although I am not familiar with your dinette. I use foam pipe insulation tubes to keep some things from banking. You may be able to stand a strip or two between the wall and your table. They are available at most hardware stores.
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Old 09-28-2016, 05:03 AM   #11
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Jadatas, I looked all over the tires and see nothing about speed codes. I only saw a max load of 2680 at 550 kpa.
Thats already half of the information, and again, the speedcode is not that important, so for tires info I have enaugh, but if you can give the sises I can google them . For most larger LT tires with E-loadrange in America , maximum load is calculated up to 140km/86m/h wich is N speedcode


As long as you did not weigh , we will have to go from GAWR's and GVWR,
These mostly can be found on the same plate as the pressure advices.
So look again at that doorsticker , mayby the GA/V WR are there too.

2680 lbs maximum load is loadindex 115, but not important, because the maximum load is what counts.
Because 2 tires on rear axle your GAWR rear can maximaly be 2x2680=5360 lbs , so carmaker would advice 80 psi for that.

Front is mostly lower GAWR so can do with lower pressure. And front GAWR is mostly not totally used , even when GVWR is totally used.
My selfdetermined rule for smaller motorhomes is that weight in use on front axle is GWVR-GAWR rear, allows a lower pressure then the car maker gives , because they calculate for GAWR. In case of frontwheel-drive this lower pressure is better for gripp ( in Europe 9 out of 10 motorhomes are of your sise and have frontwheel-drive, example the Fiat Ducato 14 frame ( nephews Citroen and Renault).
But in America this is probably different.

But then they assume the weight to be devided R/L 50/50%, and thats never the case for motorhomes, A weight division of 48/52 is more likely and 45/55 is also weighed sometimes .
The pressure must be enaugh for that tire with 52% ( or 55%) and the other tire on the axle then uses 48/52=92.3% of the loadcapacity that belongs to the calculated pressure, because standard rule is to fill all the tires on one axle to same pressure.
I once determined by reactions about weight and bumping, that below a Loadpercentage ( as I babtised the 92.3% in the example)of 85% discomfort begins by bumping and gripp gets inacaptible, but verry discussable.
45/55%=81,8% so if realy that loaddivision, a little discomfort, but savety first , because tire damage is worse.
Then try to shift some weight.

So best is to weigh per tire/wheel, if its possible.
The way to do that at a normal schale is described on the internet many times.
But in short, drive up to schale with only front axle and weigh, then drive totally on scale to get total vehicle weight, and substact front axle from that to get rear axle, or drive further, so front axle is yust off the schale to weigh the rear axle.
Then repeat the procedure driving with only one side on the schale , depends on if you have space besides the schale to drive over, then substract those values from the axleweights to get the other sideweight.
The road besides the schale must be about on the same hight , otherwise the gravity point shifts sideward to the lower wheel, to much and gives other weights.

Then 9 out of 10 times you weigh crossed weight-differences R/L.
For instance front R52%/L48% and rear R49%/L51%
there are even forms on the internet to fill in and do the calculation.
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