crop guy wrote: I have asked several different people on the street and keep getting different answers so I'll give yall a try. How much PSI did I need to run in my tires and should they all be the same on my HD36 FS when loaded with 1/2 tank of water, 4 kids, DW, small dog, etc.? The door says 95(?) and the tires say 110(?) I attended part of a tire seminar @ the Rally in Perry, so I realize I should actually go weigh it, but I have NO time.
I have been argued with from ride quality to just plain silly answers but as a person who has spent many millions in tires over the last 30 years your best bet whether on a car or RV or a class 8 truck is to air them up to the max psi cold listed on the sidewall of the tire.
You can argue with me and talk about weights and ride comfort but for blow out protection and unltimate tire life. Check them cold, air them up to the max psi listed on the side wall. The proof of this has been in my pocket book and it talks loudly when it comes to tire cost.
As in the past I will argue with you and tell you that your are still wrong. The manufacturers absolutely disagree with you. Simply look at their sites and see what they say about over-inflation. I'm amazed you still flog this view. Would you say inflate to 120 if that was on the side of the tire and the tire inflation guide said 95 psi for GVWR and the wheels were only rated to 110 psi?
Michelin RV Guide wrote: Overinflation, on the other hand, will reduce the tire’s contact area with the road, which
reduces traction, braking ability, and handling. A tire that’s overinflated for the weight
it’s carrying is more prone to a harsh ride, uneven tire wear, and impact damage.
So, tell us again why you are right.
I have a Tahoe. GM says 32 psi. Tire says 40 psi max on the side. Put 40 in that tire and the ride SUCKS big time and the tires start to show strange wear. How do I know. Well, putting in 35 lbs when we left home a couple of weeks ago to return to FLA in the Tahoe, with the temperature below freezing, I found myself with cold tire pressures of 40 after we arrived in FLA. Sure won't make that mistake again - especially since we have built-in pressure indicators. Very rough ride after we hit the hot weather. Now, I've got them back to 35 in early morning and will get them down to 33 - but we head back north in a few weeks and I'll have to monitor the temperature closely - also with the MH tires.
Don, Bev & Phil
07 Jayco 32SS on Kodiak May 07 Yahoo Kodiak Group
06 HR Amb 40PLQ ISC 330/950 9/05-5/07
04 Winnie Jrny 39W CAT C7 7/04-9/05)
00 Triple E Commander 5/03-5/04
Toad - 07 Tahoe LTZ 12/06 -
04 Colorado Z71 04- 06
Because I have thousands of tires on the road everyday inflated to the max. I have auto-inflation systems installed on over 500 trailers alone, if you multiply that times 8 and that will give you 4000 tires running daily that have few, if any, problems, less blowout and tread failures. (I also have company cars, tractors, yard hostlers and bobtail trucks that are inflated by hand to max psi cold)
Since going to this system ten years ago I have saved literally 10's and 100's of thousands per year in blowout and side wall failures alone.
We track all of our tire wear via computer and 32nds are monitored each time a tire comes to a shop terminal. Every tire carcass has its own life in our system and is monitored from install to scrap.
Our auto-inflation systems are adjusted to to what the cold psi max stated on the side wall. Some are 120psi, some are 115psi and some are 110psi.. we do this religiously and the proof is in the undisputable numbers.
This is not something I just think works, not what I assume works, not a dream I have, but bottom dollar cost savings from less blow-outs and increase per 32nd tread wear tracked with a fervor. These tires are not over inflated, if that were so my cost would have increased and not came down considerably like they have over the last 10 years.
Argue all you want but the numbers can't lie and that is what I go by.
Caseydon wrote: You can't argue with someone who knows more than the people who build them.
I'm just glad I don't have to drive one of his rigs.
The tire manufacturers agree with me, that is why the label them as such, yet giving a buffer to folks that don't run loaded all the time. My motorhome stays very close to 22k, I don't want to chance a blowout on a hot day. Remember Firestone won their case against Ford several year ago because dealerships were leaving tires at 30 psi and under to improve the ride for test drives.
You sure made this personel as I would never directly attack a someone on this message board. I was just passing along what works for me me and what I have learned over the years.
Its your rig and your tires and your choice to run them where you want. I was asked a question on a public forum and responded with my answer.
Caseydon wrote: You can't argue with someone who knows more than the people who build them.
I'm just glad I don't have to drive one of his rigs.
The tire manufacturers agree with me, that is why the label them as such, yet giving a buffer to folks that don't run loaded all the time. My motorhome stays very close to 22k, I don't want to chance a blowout on a hot day. Remember Firestone won their case against Ford several year ago because dealerships were leaving tires at 30 psi and under to improve the ride for test drives.
You sure made this personel as I would never directly attack a someone on this message board. I was just passing along what works for me me and what I have learned over the years.
Its your rig and your tires and your choice to run them where you want. I was asked a question on a public forum and responded with my answer.
Well, once again, why does Michelin say what I quoted from its manual? To lie to us?
Look, the only way I'd even believe a shred of what you claim from your work is if you had a controlled test with tires other inflation pressures (such as the pressures recommended by the manufacturer for the specific weights being carried) and a large sample. ALL conditions would have to be identical.
To me what you seem to be missing is the fact that YOUR work situation may involve conditions where increasing and decreasing tire loads on a regular basis, maybe several times a day, to adjust to the manufacturers recommended pressures is very impractical. I can understand that and then one would really have to go to the pressures for the GVWR (that is the MAXIMUM legal weight). Of course, if you were, by some chance (which let me be clear I'm not suggesting is even remotely the case), running a fleet that often had vehicles over the legal weight and at a weight that would, if the vehicle could carry it legally, require the higher pressure you use, then that would be right thing to do.
Also, your Firestone/Ford example is irrelevant. We are talking using the recommneded pressure - NOT some lower pressure solely for a better ride. If the Ford dealers had inflated the tires to the Firestone recommended pressure, then it is highly unlikely they would have fractured a relationship between Ford and Firestone that went back decades and decades (today, I was looking at sculptures of Ford, Firestone and Edison -in Ft. Myers - as the three were good buds.
BTW, I'm not trying to make this personal. There is nothing to be gained by that by any one. But, again, why don't you call Michelin and ask them to explain the note that I pasted in right from their web site. If we can't believe their statement, why should we believe anything they or anyone else (including you and me) has to say on this topic.
My statement in my previous post was not intended to be sarcastic or ad hominem. It was intended to suggest a certain lack of objectivity. As other posts point out, the broad brush statement "your best bet whether on a car or RV or a class 8 truck is to air them up to the max psi cold listed on the sidewall of the tire" is much at odds with the apparently universal advice of manufacturers to adjust pressures to load. A less absolutist presentation of results with details of service and service conditions, along with inquiry into and presentation of any undesirable effects might make this view more credible.
I've had the experience of driving cars, RV's, and trucks with tires much harder than an inflation table would call for, and I didn't care for the experiences, and hope not to have to do it again.
dcowley doesn't detail the service of the fleets he manages, but apparently many of them are vehicles in commercial transport service. I suspect that the loads carried by these vehicles at times may be not a lot less than the maximum weight ratings of the tires. In such a case, the sidewall maximum pressure would be appropriate, and I'm sure it's not practical to decrease pressures when running light, or even necessary for proper handling, tire life, and safety.
However, it's a common case for a Class C RV to operate at axle weights well below the tires' maximums, for example where marginally adequate Load Range D tires have been replaced with LRE's. In that instance, does the "best bet" pressure jump from 65 psi to 80 psi? If so, why?
In a subsequent post to the one from which the quote above was taken, dcowley does note "The tire manufacturers agree with me, that is why the(y) label them as such, yet giving a buffer to folks that don't run loaded all the time". This would seem to be a departure from the original unqualified statement, and applicable to RV's whose tires have capacity beyond their load.
These auto inflaters that you speak of,are they not designed to keep the tires at a constant pressure? The sales guy who tried to sell them to us claimed you set the desired pressure and that pressure that would remain constant in the tires.This system is however designed to deflate the tires as well should they heat up and cause an overinflation situation.As most RVs are not equipped with an auto inflation system I think we might be comparing apples to oranges.Just a thought.My 36FS weighs in at 18942 pounds empty with 1/2 a tank of fuel and me in it.According to the goodyear site 95 p.s.i.cold is what goodyear recommends.That would be good up to the 22,000 (legal)G.V.W. of your Seneca.Actually I belive all tires at 95 p.s.i.cold is good to 24,000lbs.
http://www.goodyear.com/rv/pdf/rv_inflation.pdf
* This post was
last
edited 04/03/08 09:03pm by billystoys *
View edit history
RMA on under and over inflated tires wrote: MAINTAIN CORRECT PRESSURE
Under inflation or overloading creates
excessive stress and heat, and can lead to tire
failure. This could result in vehicle damage
and/or serious injury or death.
An over inflated tire can cause uneven wear in
the center of the tread. Over inflation also can
make the tire more susceptible to road hazard
damage and pose vehicle handling issues.
This certainly is a controversial and confusing subject.
FWIW, my new 2007 Seneca 33SS was delivered in December 2006 with Goodyear G107 (245/70R-19.5”) tires. They were made in Luxembourg in October 2005.
I had weighed all four corners of the MH, but the Goodyear web site did not list this particular tire, as ‘paulin’ mentioned above. Therefore, I did not have recommended tire pressure verses tire loading information.
The Seneca’s Owner’s Manual states that you should inflate the tires to the maximum listed on the sidewall. The sidewall specified 120 PSI (cold) for the maximum tire loading of 4,940 pounds (single) and 4,675 pounds (dual). The actual weight on each tire was far below the maximum load rating.
While attending a seminar at my Jayco dealer, the presenter said to inflate the tires to the maximum listed on the sidewall (120 PSI).
This seemed to be too high, so I asked my Jayco salesperson. I was told, “There’s a tire dealer right down the street”. Gee, thanks!
I called Jayco Customer Service in Middlebury. They said ditto – inflate the tires to the maximum listed on the sidewall. I said that this couldn’t be right. The tires are nowhere near their maximum loading and the ride was already quite firm.
I asked why Jayco installed a sticker on the driver’s door that listed a recommended tire pressure of 95 PSI? The Customer Service rep didn’t really know, but said that it was understandable that their contradictory information (Owner’s Manual / dealer verses door sticker) “could be confusing”. (Ya' think?) After several more phone calls and several more weeks (!), Jayco’s official word was to use 95 PSI. Yes, this was the pressure reading for each tire when my Seneca was delivered new.
So, the Owner’s Manual, the dealer’s seminar presenter and Jayco Customer Service were all wrong. My salesperson didn’t know and didn’t care. The door sticker is correct (95 PSI).
Interesting that you say your tire sidewall has 120 psi on it as this only goes to 100 for that size with a G rating (unless built later as noted and then it is 110).
Offline
