Tire pressure on georgetown with 22.5 tires.

[Modmike]

Originally Posted by toolman_57

Here's a link posted by another member for their 364tsf: http://www.forestriverforums.com/for...ts-100442.html

Here's the text:
2016 Georgetown 364TSF CAT scale results
Hello fellow owners,

I took possession of my 2016 364TSF last Friday. When I got home I filled it with gas and headed to the CAT scales. it has all the options except for washer/dryer combo. Here are the results for those who are curious:

Straight from the dealer, full tank of gas, no driver;

Front Axle: 6,768 LBS
Rear Axle: 12,125 LBS
Total 18,894 LBS

Corner weights:

Left Front: 3,373 LBS
Front Right: 3,395 LBS
Rear Left: 5,974 LBS
Rear right: 6,151 LBS

GVWR 22,000 LBS
Curb weight 18,894 LBS

Cargo Capacity: 3,106 LBS

Based on this info, for the Michelin XRV 255/80R22.5 G
Front should be 70 PSI
Rear should be 70 PSI

(This is with only gas, no passengers, and nothing on the hitch).
I had mine weighed (weight slip isn't with me today) and with tow dolly, passengers, water, etc., my numbers came out to 75 PSI front and 85 PSI rear.
At 90 PSI mine was just way too "bouncy" and hard to handle--much better after I lowered the pressure.

I'm assuming that no one is running 70/70 however.

That was me. I hope to load it in the next 2 weeks and re weigh. I expect to end up in the 75-80 psi range.

[ramair]

we full time and have our 378XL loaded and we run 95lbs in the front and 100lbs in the rears. Rides smooth and have had issues. this year may change a little because we traded in out Chevy Cruze 3000lbs and got a new Ford Taurus which weighs 3900 lbs so gonna check things out and make any adjustments if any.

[Modmike]

You may be running way too much pressure.

Unless you are adding tongue weight to your hitch you do not add the weight of the toad to your axle weight.

If you are adding tongue weight, which is typically no more than 500 lbs, then you add 250 to rear axle corner weight.

The easiest is just to go to the scales with your toad and weigh your axles.

[ramair]

Originally Posted by ramair

we full time and have our 378XL loaded and we run 95lbs in the front and 100lbs in the rears. Rides smooth and have had issues. this year may change a little because we traded in out Chevy Cruze 3000lbs and got a new Ford Taurus which weighs 3900 lbs so gonna check things out and make any adjustments if any.

made a mistake when typing the above, guess my brain thinks faster than my fingers type. we have had NO Issues running those pressures.. Sorry for the confusion...

[tkarper14]

Originally Posted by RubberNail

You can Google the 2016 Ford F53/F59 specifications and find the recommended inflation for the MAX GVWR with factory tires. For 19.5 tires they show 15k-20.5k at 82 psi, for 22k 95 psi, and for 22.5 tires, 22k at 90 psi, 24k at 100 psi. Obviously weighing the coach and using the corresponding pressure is a better solution.

I am not picking on this particular post, but it includes a lot of good information stated in other replies. Therefore, I am using it as the basis of my questions.

Why is it a better solution to weigh my coach and adjust the tire pressure accordingly? What could possibly go wrong with keeping them inflated to the 100 psi printed on the sticker by the driver seat? What if I am running a lower air pressure based off weight and I decide to purchase something while out and about that weighed a few hundred pounds? Would I have to re-weigh and adjust pressure as needed?

Being new to the Class A experience (had Class C for years), I would think the sticker is the correct pressure. I am willing to change my thinking if there are good reasons to do so.

[RubberNail]

The issues are tire wear and coach handling. Both are at their best when the tire contact to the paving produces a uniform pressure throughout the contact area, ie, the tire surface is not trying to curl one way or the other. True for cars and RVs. I would likely run the sticker pressure UNTIL I could weigh the coach. For me, the weighing is not some much for tire pressure as to discover. Have weighed many RVs, some several times. Always a surprise to me as to how MUCH STUFF I manage to carry - usually between 2500 and 3500#s, and where it winds up being carried. I would suggest to any RV owner that they weight their coach "as stored" and "as camping" just to know what they are dealing with. Then if you have any issues, may want to adjust tire pressures accordingly and see if that improves the situation, before spending money on other upgrades.

[toolman_57]

Originally Posted by RubberNail

The issues are tire wear and coach handling. Both are at their best when the tire contact to the paving produces a uniform pressure throughout the contact area, ie, the tire surface is not trying to curl one way or the other. True for cars and RVs. I would likely run the sticker pressure UNTIL I could weigh the coach. For me, the weighing is not some much for tire pressure as to discover. Have weighed many RVs, some several times. Always a surprise to me as to how MUCH STUFF I manage to carry - usually between 2500 and 3500#s, and where it winds up being carried. I would suggest to any RV owner that they weight their coach "as stored" and "as camping" just to know what they are dealing with. Then if you have any issues, may want to adjust tire pressures accordingly and see if that improves the situation, before spending money on other upgrades.

I did my tire pressure adjustment after the first trip--was running the sticker pressure (90psi) all around and was finding it very difficult to stay straight on bumpy roads--it felt like I was bouncing up and down in the front. I found some other forums/threads that mentioned that I should check my tire pressure against the tire mfg recommendations for weight. When I did I found that my front axle weight led to a 70psi (minimum for the tires) inflation. I was worried that this was weigh to low (mis-spelled pun-ishment). I went with 75psi on the front and 85psi on the back to be safe (didn't get side-to-side measurements) and have been MUCH happier with the ride and control. Folks have advised me that this might lead to premature wear but I'm pretty sure the tires will age out way before I max out the mileage. Since doing this I've driven about 11,000 miles and can't even see any wear on the tires (about 14,000 miles on the coach).

[tkarper14]

Ok both replies make sense to me. We have only made three runs so far for a total of 150 miles and no load. I thought the handling was excellent. Seems like I need to make a fully loaded trip before making any changes.

Thanks for the info.