mikebrez Posted June 28, 2018 Share Posted June 28, 2018 Hi! My 1993 Dolphin has been giving me some vibration problems. I've had the tires balanced up the wazoo, including the "road force balance" which is supposed to be something special, and did seem to help. Just had the drive shaft balanced a few days ago, which also helped. The test drive after showed improvement, but a good assessment is difficult to make, as I live in Illinois and there are no good roads here. :( It rides pretty smooth up to about 65 and then starts a general vibration. Doesn't feel like it's up front, as I don't feel it much in the steering. It gets worse at 70. I usually travel at 60 to 65, so you might say, "so what's the problem?" To me, it still indicates that something is wrong & needs fixing. I've been told by a couple of mechanics, who might be making this up, that since it's a light truck with a heavy load, to expect vibration So, what's normal? I feel bumps & imperfections in the road so much more than in a car or in my 4Runner. I assume that's normal. But is vibration at the higher speeds normal? A mechanic who's had much experience with the truck, but not with a house on it, says it should ride smooth. Any opinions, info, and ideas will be much appreciated. Thanks. Mike Quote Link to comment Share on other sites More sharing options...
WME Posted June 28, 2018 Share Posted June 28, 2018 Bent rim?? Quote Link to comment Share on other sites More sharing options...
Maineah Posted June 28, 2018 Share Posted June 28, 2018 All of your wheels are the same try swapping the two outer rears to the front. Quote Link to comment Share on other sites More sharing options...
jjrbus Posted June 29, 2018 Share Posted June 29, 2018 Wouldn't the road force balancing show a bent rim? How many psi are you using in your tires, I see many with 60 or 65 psi, which is like riding on bowling balls. Quote Link to comment Share on other sites More sharing options...
DanAatTheCape Posted June 29, 2018 Share Posted June 29, 2018 I have had a 92 itasca spirit and now have a 93 warrior. I have no vibration issues. Check your wheels for being bent - called runout. Moving wheels around will change that. Also check your front end for worn out ball joints, tie rod ends, control arm bushings etc. Might also check your brake rotors for warpage. . Generally, rotors get warped from being overheated - like using the front brakes all the way down a mountain. Usually easy to detect- does the steering wheel shimmy when you press the brake pedal? It is possible to have a rear axle crooked - not easy or likely to occur though. The rear axles are designed to set in a detent on each side. Not likely at all. I would consider having a knowledgeable friend follow in a car - on a smooth road - check for wheels not turning smoothly, wobble and to see if the rear end is following directly behind the front end. Several things can cause the vessel to "crab" sideways. I agree with your mechanic friend - it should ride smooth Quote Link to comment Share on other sites More sharing options...
mikebrez Posted June 30, 2018 Author Share Posted June 30, 2018 Hi again, Thanks for all the input guys. This gives me more to check out; hopefully something will take care of it. A few things though: -Would a rim need to be bent very much to cause a problem? One does have a slight dent. Tire fits ok & doesn't leak. -I do run my tires at 65 psi, as that's what it indicates on the tires. I was taught by a "tire expert" in an RV course that generally, more pressure is better than too little. I would think that higher pressure would make the ride feel the bumps more, but wouldn't cause vibration? Thanks again' Mike Quote Link to comment Share on other sites More sharing options...
WME Posted June 30, 2018 Share Posted June 30, 2018 Dent does not mean bent. Jack up each corner and spin the tire by hand, use a stick, hold it close to the rim and see what you see. Rare but not unheard of is a broken radial belt. Again spin the tire by hand and look at the tread pattern. Does it run true or does it squirm? Quote Link to comment Share on other sites More sharing options...
Derek up North Posted June 30, 2018 Share Posted June 30, 2018 18 hours ago, mikebrez said: I do run my tires at 65 psi, as that's what it indicates on the tires. 65psi is the MAXIMUM safe inflation pressure and not the recommended pressure for your RV. Try them at 50psi and see what that does for your vibration (and ride comfort). BTW, I'm not impressed by your 'tire expert'. EDIT: Here's another expert opinion that seems to agree with most others. https://blog.tirerack.com/blog/bens-blog/what-air-pressure-should-go-in-your-tires Have you got a label like this on your Escaper? Quote Link to comment Share on other sites More sharing options...
markwilliam1 Posted June 30, 2018 Share Posted June 30, 2018 Do you think you would reduce mileage by lowering your PSI to 50 lbs all around? I run 55 in the front and 60 in the rear, I Get a solid 15 MPGS using this setting but am afraid of lowering the tire pressure would result in poorer mileage! Quote Link to comment Share on other sites More sharing options...
Derek up North Posted June 30, 2018 Share Posted June 30, 2018 It's hard to find precise figures, but there's no doubt that lower tire pressures will increase tire rolling resistance /drag. But I suspect that the difference between 65psi and 50psi would be small compared to the HUGE aerodynamic drag. " Approximately 5–15% of the fuel consumed by a typical car may be used to overcome rolling resistance.[1] A 2003 California Energy Commission (CEC) preliminary study estimated that adoption of low-rolling resistance tires could save 1.5–4.5% of all gasoline consumption ..." https://en.wikipedia.org/wiki/Low_rolling_resistance_tire This is for a "typical car, which is like a Bonneville streamliner compared to an RV! Give it a try for a tank or two and let us know your experience. " Quote Link to comment Share on other sites More sharing options...
jjrbus Posted July 2, 2018 Share Posted July 2, 2018 Over inflated tire increasing mpg is hard to pin down. Most of the testing I have seen is so flawed that it is not even quotable. But Bubba at Bubba's tire and gun shop says he gets 15% better mileage by over inflating his tires so must be true. Mythbusters did a show on it and by increasing the pressure to 60 psi with a recommended 35psi increased mpg by 6%. But that is with an aerodynamic car, not driving down the highway in a brick. So that one is of no help. Popular Mechanics/Science did an article and showed showed no increase and claimed the car handled horribly. Their test was very flawed, not enough data and no control was used, no control in the Mythbusters either. To inflate a tire above recommended psi, one would first have to know what recommended psi is and as near as I can tell no one in the Toyota world knows. There is lots of verifiable data on underinflated tires decreasing fuel mileage and being dangerous. There is also lots of info on the net about over inflated tires being a bad idea. Quote Link to comment Share on other sites More sharing options...
86Dolphino Posted July 18, 2018 Share Posted July 18, 2018 I have all my tires at 65 PSI. (thinking about lowering it to 50 or 55) I just went 230 miles 2 weekends ago on 12.6 gallons and averaged 18.25 miles per gallon. I am really impressed with my MPG. 43 bucks to go from Reno, NV to Mill Valley, CA Quote Link to comment Share on other sites More sharing options...
markwilliam1 Posted July 18, 2018 Share Posted July 18, 2018 I wouldn’t do anything different if your getting “18 mpgs” Wow! Quote Link to comment Share on other sites More sharing options...
Maineah Posted July 18, 2018 Share Posted July 18, 2018 18 MPG at 35 MPH on the highway? The pickups bareilly did that! Quote Link to comment Share on other sites More sharing options...
86Dolphino Posted July 18, 2018 Share Posted July 18, 2018 11 minutes ago, markwilliam1 said: I wouldn’t do anything different if your getting “18 mpgs” Wow! Yes I was very impressed 43 bucks to get to the ocean. I forgot on my first post to say. When I first got my RV I had a vibration a fine vibration from my rear end. It would come up around 50 to 55 that's it. I found my problem was fine dirt/sand build up on the inside of the rims. I cleaned off the dirt/sand and now it rides smooth. I would think tire shops would know to look for that, but you never know. I have a friend that works for a reno volcanizing and I can't say he would know to look for that. So you may want to check Quote Link to comment Share on other sites More sharing options...
86Dolphino Posted July 18, 2018 Share Posted July 18, 2018 1 minute ago, Maineah said: 18 MPG at 35 MPH on the highway? The pickups bareilly did that! I would hit 65 even 70 at times. Now I do have a newer 22re crate motor. Not sure of any extra bells and whistles. Has about 30k on new motor. Tranny was overhauled 10k miles ago too. Tire psi at 65 and I use 87 octane fuel. I did put in new rotor and cap I put in 8.2 high performance wires new OE spark plugs. New air filter Quote Link to comment Share on other sites More sharing options...
linda s Posted July 19, 2018 Share Posted July 19, 2018 If only all our trips could be downhill we would all get that kind of mileage Linda S Quote Link to comment Share on other sites More sharing options...
86Dolphino Posted July 19, 2018 Share Posted July 19, 2018 first part is up hill almost 3000 ft in elevation. next time all record the mileage on the way back. off hand it didn't seem much different. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.