tire pressure - again

[Effy]

I know, I know, this has been brought back more times than the living dead. My question is very simple. My tires on my 16k# coach are Goodyear g670s. I like them. The sticker inside says to run them at 83 psi. And I do. But the ride is rough. Smooth on smooth roads but hit a pothole or concrete road and the feedback will rattle your teeth. My coach is light and in talking with my dealer he says I can run as low as 75 psi to soften it up. Looking at Goodyear’s rating table, there is a marginal difference in weight at the wheel between 85 and 75 PSI. Talking 300 lbs. Now I have never weighed all 4 corners and doubt I ever will. I mean a very small change in weight at a corner is so small, it might be attributed to filling up with gas or emptying the tanks, to loading the refer or a cooler. Not to mention shifted weight. Heck even a person moving around. That’s a constant in RV’s. So my question, to soften the ride, can one safely reduce the psi 5-8 ? Now I will say the gap between my duals is about 1.5”. It would scare me a bit to lower this too much as I know I don’t want these to rub. I know I’ll get a ton of blasts about how unsafe all this is without weighing and breaking out an abacus. But I can tell you I will run different psi in my truck depending if I am hauling, going on a trip etc. Changing Psi 5-8 really does not seem to be a big deal based on road feel. I mean I have to imagine it changes that much on its own going from hot to cold climates, low to high elevations etc. Blast away.

[et2]

MH manufactures don't make tires, they leave that up to the tire manufactures and buy what fits their platform. I would say that the correct inflation data is the responsibility of who made the tires as they have done all the research to keep their products safe and reliable. Mine was delivered from the dealer over inflated even from the placard posted by Fleetwood. My coach was all over the road. I weighed it and inflated per the tire mfg graph plus about 5 lbs to adjust for cargo variations. Now rides like a dream and is within 8 lbs of what is posted on the MH placard.

If the tire mfg has a printed graph depicting weight vs pressure it is probably a prudent decision to believe it is correct. I'm sure if inflated correctly ( per the data) those claiming it's going to blow hitting a chuck hole are being chicken littles. Not inflating per the weight recommendations on the graph ( meaning actual under inflation or over based on the weight) can put the tire in a condition that could cause problems.

Sure filling it full of air will probably save you a few cents in fuel and perhaps better wear. The trade off is handling and beating the snot out of your suspension and every nut & bolt and nail on the rig, " and you". Me, I'd rather enjoy the ride.

[jadatis]

As long as you did not weigh , we have to do with the GAWR's and GVWR of your motorhome.
If you give them here and also configuration ( thought I already saw dual load axle rear) and sises maximum load and loadkind of tires, read from sidewall . Also speedcode can be handy ( N stands for up to 140km/87m/h).
Give all that and I will answer with a picture of my filled in calculator.

[J-Rooster]

Executive wrote:
The most common CAUSE of blowouts is under inflated tires.

If you're looking for someone to agree with you to run your rig in an unsafe condition, you're not going to get it here, at least not from me. While you may never four corner your rig, (I assume you're too cheap) at least weigh it on a CAT scale and know your axle weights.

I'm wondering though, you say, "The sticker inside says to run them at 83 psi." What sticker are your referring to? I've never seen a sticker that says to run tire pressure at an oddball number.

The lower PSI on your tires will certainly soften the ride. Why not run them all at 20PSI..:h

Good luck to you, if you choose to run your tires as you've described, please make sure your insurance is up to date....just sayin....Dennis

I agree with this post! Under inflated tires, (low tire pressure) causes heat build up inside the tire and that is not good. My Michelin and Winnebago manuals both said to run my tire at 85 lbs. psi rear and 90 lbs. psi front! Didn't work for me, tire squirm! I now run 100 lbs. psi all around. My ride is a little rougher at 100 but my tire wear is excellent. My first set of tires lasted 10 years running 100 lbs. all around, and I'm currently on my second set of tires. I weighed my coach one time (WSP Truck Scales, Federal Way, Washington State) when my coach was brand new, fuel of fuel, propane, water, and all my stuff and my coach was 500 lbs. overweight! I've never weighed my coach again, and it's been over 10 years. IMHO, experiment with different tire pressures each time you go out RVing, record the tire pressure and how the coach was responding to the different amounts of air thats what I did it took a little time but my coach is now dialed in! Good Luck with your tire pressures.

[artguys]

Effy...the transition area between the bead and sidewall on a tapered bead tire is a major stress point...for this reason maintain max air pressures.

[Effy]

If I can't lower, then I may start down the rabbit hole of practical solutions to soften the feedback. Like I said, most of the time it's fine, but bad roads and potholes are rough. I have looked at airbags, spring compression, shocks etc. Not sure which the most practical solution would be with the best results. And I am not going to spend absurd amounts either. I mean there are only so much you can throw at it before it's more practical to trade up.

That said I have read a LOT of posts on here about folks have backed off PSI from max to settle things down a bit. Hence why I asked. Max is Max under Max condtitions. I just need to see where I am with respect to max conditions.

I want to be safe, rest assured. I carry precious cargo. Still at 83 psi, but man it can be rough at times.

[Ivylog]

I'm glad you finally got it. In fairness to Dennis and myself if I'd gotten here sooner there were two things that bothered me too. 1. "Now I have never weighed all 4 corners and doubt I ever will." and 2. "Where does one go to weigh an RV?". Made it pretty easy to assumed that you never have weighed even each axle but you are willing to take a salesman advice over the sticker. 83 sounds like it was accurate for when the rig came off the line without any dealer/owner added items. I doubt that after weighing you will be able to go lower than 83 BUT until then we are all just guessing.
I've weighed several times at closed weigh stations in OR and I've been able to put one side off the scale so I can calculate the corner weights.

[enblethen]

We are able here in WA to weigh our rigs at truck weigh stations when they are closed and in some locations while they are open.
Yes, you can go to some truck stops that are equipped with scales. Some do not like to weigh MHs because you want four corner weights. Some truck scales are not set up to do four corner weights.You can live with front and rear weights as you said a couple hundred pounds different between front corners and rear corners shouldn't be a problem.
When we see a weigh station that is closed we pull through to get weights. We then put it in our log book for reference down the road.

[Daveinet]

Just so you know, Dealers and the manufacturer are notoriously wrong. RVs get re-configured so many times, they really don't know what it weighs. Also, who knows what you typically haul in it when you are fully loaded.

Some of the reason you are getting the answers you are getting is because it is so well known that under inflation is such a huge cause of blowouts. It is a big deal, and those who have been around for a lot of years will concur with reports read on here. Personally if I were riding with you and had to choose between slightly under inflated tires, or towing twice your rate limit, I would choose towing twice your weight limit. Under inflation is that serious.

Yes, the F53 is known to ride stiff, although that has improved in more recent years. It would be interesting to know what your GVWR is, compared to your actual weight. As you mention your coach is pretty light, that may be part of the problem. There are better ways to address the problem, although not cheap. MorRyde is one option. Sulastic spring shackles is another option. Some have been able to just change shocks. A little searching here should give you what others have done to the late model F53.

[Effy]

lanerd wrote:
Effy... you're a senior member and have been around here for a long time and I'm sure you've read many a posts that deal with this subject. You're sounding like a newbie!:E You are obviously aware that weighing your coach is a must, to determine the correct air pressure...guessing that 5 - 8 pounds won't make any difference is just that...a guess. Come on, you're giving us senior members a bad name.:W

Go to any big truck stop....Flying J, Pilot, T/A, Loves, ect... and they will have a scale that you can use for a nominal fee. Usually the local dump will have a scale (but won't provide you with written results) and will do it for free. Moving companies.....Mercury, Nationwide, Atlas, Allied.... will also have scales. For others just check your yellow pages or google for your town. It's not that difficult.

Hey man, cut a fella some slack, I can try and fly under the radar once in a while can't I? I have stopped taking my meds.. maybe that's having an impact.

In all seriousness as much as I hate to admit it, you guys are right. I should weigh it and do it right. I know. Maybe I was just hoping a lot of you would jump on the happy pill train and say sure - rainbows will fly out of your muffler if you lower psi.

I get it.

Set up something to weigh and see what min can be. I plan on lowering it if I can and be in the threshold. That f53 will rattle your bones on bad road. Wife won't let me get a pusher, just about died on that hill a few times. I can't bring it up again for a while.

[lanerd]

Effy... you're a senior member and have been around here for a long time and I'm sure you've read many a posts that deal with this subject. You're sounding like a newbie!:E You are obviously aware that weighing your coach is a must, to determine the correct air pressure...guessing that 5 - 8 pounds won't make any difference is just that...a guess. Come on, you're giving us senior members a bad name.:W

Go to any big truck stop....Flying J, Pilot, T/A, Loves, ect... and they will have a scale that you can use for a nominal fee. Usually the local dump will have a scale (but won't provide you with written results) and will do it for free. Moving companies.....Mercury, Nationwide, Atlas, Allied.... will also have scales. For others just check your yellow pages or google for your town. It's not that difficult.

[diazr2]

When I owned a class C I would run the tires 8lbs down in the front and would run the back at 5lbs down. Made a difference to me. But when gas went through the roof I pumped them back up for added millage. Never had a problem ether way. Sure could tell the difference though. When I had them pumped up I would ask Eileen if she had her teeth guard in.

[Effy]

It's a 2013 coach with no mods. I understand some road feedback is inherent in the F53 chassis. I get that. But my dealership (could be wrong - don't kill the messenger- that's why I ask you guys) said that 83psi on the sticker at the captian's chair, would be max psi. And yes I looked at it 5 times, it says 83. My other units say 85 but they have Conti's - this has G'years. Anyway, dealer told me lowering it 5 or so would soften with no issues. Again, that's them saying that not me. I come here to ask to see if that's a good idea. If you guys said, yep sure Lower it a few I would be fine with it. But so far the overall response is that I seem to be some kind of cheap idiot and should be given lashes for even considering it. And why haven't I weighed it? I am expecting a torch and pitchfork weilding mob to arrive at my house and claim my keys. I am just telling you what was told to me and looking to you guys for answers. And come on guys, I bet EVERY one of you has run your tires off by a few PSi either intentional or not. It's impossible not to unless you drive in a vacuum or measure it daily. Sure I want to be right and safe but some of the doom and gloom is little overkill.

[Schertz]

Fair Question regarding tire pressure issues....

The condescending sarcastic responses from some responders is NOT FAIR.

I may never exceed beyond full member status on this forum - because I am usually not willing to make inquires and get condescending responses.

[artguys]

Key words by the OP...when I hit a bump. Not many here who would have needed to have driven for years on bias-ply tires can remember the transistion to radials. The most notable was how smooth riding the new radials were until you hit a "bump". Add to that the OP's tire and wheel combination are stiff riding to begin with and he has his answer...all else applies, as in don't reduce the pressure etc.

[azrving]

What other things may be wrong that are giving you the bad ride? Wrong shocks etc?