BAC Forum
General Boards => Technical Support => Topic started by: Harold and Gloria Skipworth on February 04, 2012, 09:15:32 PM
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Being fairly new to the motorhome scene I'm not quite sure of what to expect regarding ride quality. I know that the quality of ride I experience on the rougher roads in the northern states has had an impact on the alignment of some of my slideouts. In particular the PS front slide is saging to the point that the bottom edge of the slide presses down on the top edge of the compartment doors and one corner on the rear of the slide scrapes on the floor inside the coach. The impact that I feel while driving on an interstate hwy if I hit an expansion joint which is a bit lumpy is as if I ran over a brick with my car. As it is it is nearly impossible to keep some of my drawers closed as well as the mirrored wardrobe doors. The unit has 50,000 mi. on the odometer, had a visual inspection of the bilstien shocks, the ride height has been checked and is within 1/8" of spec. I get very little porposing with fairly good recovery. I know that I will have to find a shop to realign on or two slides but have no idea where to go near home. The dealer I purchased this unit from in Aug. 2011 put goodyear 295 80R 22.5 on the rear and michelin 275 70R 22.5 on the front, I complained but they refused to budge. I ended up having to go to 120 lbs in the fronts as I weighed in at 12,200 in front. As I said I did not know what to expect when we got out on the road regarding the harsh ride as the test drive was all smooth roads. Any advice is welcome
2005 Monterey Laguna IV
C-9 400
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If you are running max air prerssure in all tires that would certainly have an impact on the ride quality. If you have the rear weight number maybe you could adjust preessure down a bit if weights allow. In my GY G169 RSA book your 295 size (if they are G169) says each rear side is good for 11350 at 100 psi.
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Harold,
Your slide problem is probably not related to your ride quality complaints. Most of the large slides rest on rollers, and your problem is probably related to one or more of these rollers.
Some of the rollers that Monaco installed were covered with a material that wore away with use. If that is your problem, you can replace the roller with a new roller, or you can remove the roller and install (very tight to press fit) a piece of schedule 40 PVC water pipe that is cut to the length of the roller surface. The PVC pipe fitted roller may not look as good as the factory roller, but it will last longer.
Gerald
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I'd be concerned about the 275's on the front axle. The coach came with 295's and I run 110 lbs in the front for the same coach built late 05 as an 06. That gives me a small saftey margin.
Check the paint lines on the slideout, that will tell if they have dropped or not.
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Harold-
Let us know where you live so perhaps forum readers can help you find a good service facility if you don't want to try and fix it yourself; but Gerald is spot-on with his slideout assessment.
My '06 Monterey Ventura isn't as heavily loaded as your coach, and at ~5500 lb per side up front, I run 110psi. Actually, Goodyear recommends I run 95psi up front for that load. For your 12,200, assuming ~6100 lb/tire load, I would expect 110psi to be about right, but yours are Michelins. The 275 70R's up front is something I would have questioned as you should have and did, and that size hasn't the carrying capacity of larger tires like those on the rear, which is probably why they had to go to a higher pressure. That size tire in a Goodyear maxes out at 6200 lbs of load at 120psi. The factory tires were probably 295/80R Goodyears which max out at 6720 lbs of load.
The ride on my rig isn't bad on 110psi all the way around out of the Factory and Beaver Coach Sales, but I could improve it by dropping down to the recommended 95front, 100rear. I just keep it up for the fuel mileage, and there seems to be no wear consequence apparent.
To better zero in on whether your ride could be improved by adjusting tire pressures down, you should take advantage of any opportunity, at an FMCA rally or elsewhere, to get your coach weighed by the RVSEF (Recreational Vehicle Safety Education Foundation)
http://www.rvsafety.com/custompage7509.html?pg=weighing
and
http://www.rvsafety.com/otherweighingloc.html
They will give you a detailed report and explanation of individual wheel loads specific to your rig, and help you find the optimum pressures for each axle and tire brand, whether you shoot for ride or mileage. Tire inflation tables are also available from manufacturer links off their site, though I couldn't get the table off the Michelin link to download for me.
Another option would be a visit to Henderson's Line Up Shop in Grants Pass, OR, if possible, for at least a consultation with the best in the business in coach ride and handling. It could be the original front tires were worn oddly, and that's why your dealer replaced them. That doesn't mean the dealer resolved the cause of the odd wear. Henderson's could check the alignment for you - not everyone understands how to properly check and align motorhomes.
Joel
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Thanks for the replys, I have set the rears at 110 lbs per an inflation table from goodyear for the actual weight of 22,500 on the rear axle. The fronts have to be 120 lbs for any safety margin with my 12,200 load. I have considered not waiting for the tires to wear and replace the fronts just to be able to drop the pressure to 105 to110 lbs. during the course of drawer slide repairs on the PS front slide under the stove top I noted that I could see the rear roller which did seem to have a covering that looked as if it had come apart. I would have to disassemble some cabinetry to see the front roller. The slide has definitly droped as the rolled partion of the storage bin door hinges before and after the slide does not line up with the lower edge of the slide. We live in northeast Ohio in Andover near Erie Pa. and Youngstown Oh. and I do not know of a shop near here able to help. Fifteen years ago I would have tried it myself but not any more.
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Harold,
With some coaches being a bit heavy and your front tires being near their limits, you should take the time to get your coach weighed. If there's a truck stop nearby and the scale's aren't too busy, weigh the coach twice. Once with the coach positioned so each axle is on its own scale. This is easy as most of the CAT scales have 3 plates. Then position the coach such that only the left or right tires are on the scale and individually weighed. This too is generally easy because one side of the scale typically is open to the parking lot. With these two readings you can determine the weight on each wheel position. The weight of the wheels not individually weighed will be that axle weight minus the weight of the individual wheel that was weighed for that axle. This should be accomplished with the coach fully loaded with your travel belongings and full tanks. If not, make sure to add that amount of weight. Finally, add the weight of each passenger to each front tire weight. Now that you have each wheel position weight, take the heaver of the left and right wheel weight and double it to determine your actual axle weight. Yes your actual axle weight, for tire pressure purposes, is twice the heaviest wheel position not the actual axle weight.
Undersizing your most critical steer axle tires makes no sense. They did at least put Michelin's on, which is a good thing. Personally, I just replaced my front tires and went to the next larger tire.
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Harold
One other thing. Check the maximum pressure your wheels can support. It may be 120 psi.
Gil
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Gil is right about the rims, but you are probably OK at 120 psi. Check your rear wheels (the rim isn't covered), and just inside the outside edge of the rim should be lightly stamped lettering. It probably says Accuride and includes the load range and maximum cold psi of 125.
If no one else on the Forum chimes in with a shop suggestion, you might consider utilizing the website at this link:
http://www.rvservicereviews.com/StateList.asp?state=OH
or
http://www.rvservicereviews.com/StateList.asp?state=PA
But surely some Beaver here has somewhere along the line had experience with a repair facility in the vicinity of NE Ohio or western Penn?
Joel
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The 7.5 inch rim is only rated 120psi
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My rims say 125psi.
There is also a possibility that Harold's dealer may have violated code by installing improper tires on his coach. RVSEF is consulting with Harold to determine if that's the case. He may be due a couple of new tires.
Joel
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Joel,
I'm pretty sure a commercial tire shop can not install undersized tires. I don't know if this is law, due to insurance restrictions, or why this is, but I know it's common practice. The only way a tire shop can do so is if the wheels were brought to them by themselves (without the vehicle).
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I've consulted with Michelin regarding using 295/80R x 22.5 at 95 to 100 psi VS 315/80R x 22.5 at 90 psi and they did not have a problem with either combination as long as I had clearence for the larger tires. I'm still undecided, my rims are good for 125psi so I'm good there. BTW the thing that upset me the most about the install of the 275 tires is that they inflated them to 100 psi which is good for 5625 lbs each or 11250 for the axle. This left me 1550 lbs short for the axle. Fortunately I only went about 50 miles before I discovered it.
Never argue with idiots, they will just bring you down to their level and beat you up with experience.
Harold
hjskip@centurylink.net
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I went with 315s. I think with your axle weight, 295s are more than adequate. 315s don't come cheap, even with the Monaco club discout.
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I'm gonna side with Gil on this, Harold. Run 295 R80's up front at about 95psi, if you decide to change, as long as there is no great left to right load discrepancy. 315's are an inch wider than 295's, and an inch and 3/4 wider than your 275's; that's a lot more than you need, and barring any other problem contributing to the harsh ride, you should notice some improvement going from 120psi to 95 psi. Get your rig weighed for individual wheels, not just axles, to see if you can lower your rear pressures as well, since you are still 1780 lbs. shy of your rear axle max. My Goodyear chart would lead me to think that you may be able to use as low as 95psi back there, depending on left and right side loading; you have to use whichever side is heaviest when determining pressure, and it has to be equal in all 4 tires.
But also have the alignment checked up front, to protect your tire investment.
Joel
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Joel
Sounds all good to me, just waiting to hear back from a local tire dealer. Seem there has been a change to the FMCA connection to the Michelin Advantage program, and they are waiting for an update.
Harold
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The Monaco process change is not until next week. Check the Monaco club site. Check the Monaco price against the FMCA price. The Michelin dealer can give you the FMCA price. The Monaco price is on the club site.
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i wound up going to 295/80R x 22.5 up front with 95# all around, made a dramatic difference. During the process of changing I checked the date code on the 275's and found 04. I got suspicious and checked the rears as well, lo and behold they are 04 as well. I'm thinking about putting up a sign in front of the dealer "Bend over all ye who shop here". :-/
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It was a learning experience, eh? Let's just hope the dealer didn't fudge anywhere else.
Glad you are happy with the tire and ride results, and that the RVSEF was able to assist. Just be sure to get your four corners weighed so you know that 95psi in the back is enough; bumping up to 100psi wouldn't hurt your ride much and may be a margin of safety ;).
Did you take advantage of the Monaco/Michelin program? Have the alignment checked as I suggested?
Joel
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FWIW, I did not check the date codes until a few days after I had 315 Michelins installed by TCI in Orlando. The tires about 13 months old. I assume 315s are not in high demand and have no idea how new a new tire should be.
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the dealer matched the FMCA price without the hassel. The alignment check will come when I get near a shop which is able to do the work.