Top Speed June 14, 2003, 11:53:25 pm Yahoo Message Number: 23410I am seven days into a cross country (and back hopefully) trip in my 2000 26.5 RB. I have made my way from the SF Bay Area through Arizona and New Mexico and I am currently sitting in a very nice park in Austin TX. Before my trip several people told me that I should keep my top speed under 65MPH. I thought that this was mainly for fuel economy, and also for safety. On the road, I was in many places where the speed limit is 75MPH, and at 65 you have big rigs riding on your rear bumper and passing. I found myself doing 70 - 75MPH a lot. I do have a heavy foot. Other than fuel economy (I still am averaging around 11mpg) is there any reason to stay under 65 MPH ?Is 75MPH too fast for the LD ? It still felt fine at 75 and had a nice ride.What is the recommended top speed ?On a different subject, my wife really wanted to take route 66 as much as possible. This sounded like a great idea, but if you ever think about taking route 66 from CA east, DON'T do it. I am still trying to figure out where some of the screws that I found on the coach floor go. You can't really even call that a road. It is more like an old asphalt junk yard.In Arizona there are some nice sections, but you should really do some research before following "historic" route 66 signs.Thanks for any info,Charlie G.
Re: Top Speed Reply #1 – June 15, 2003, 04:17:22 am Yahoo Message Number: 23417Charlie,I have many times driven 70 mph or more with our LD when we were on the interstates and were more interested
Re: Top Speed Reply #2 – June 15, 2003, 01:31:44 pm Yahoo Message Number: 23426QuoteOther than fuel economy (I still am averaging around 11mpg) is there any reason to stay under 65 MPH ?Is 75MPH too fast for the LD ? It still felt fine at 75 and had a nice ride.What is the recommended top speed ? Charlie,On a trip to the Life On Wheels Conference in Moscow, ID, from Colorado in 2000, I got in the habit of doing 75MPH for much the same reasons you mentioned. The ride was fine but I did notice that any condition requiring a quicker that normal road maneuver produced a much tighter grip on the steering wheel than the same maneuver would have produced at 65MPH (22' Front Lounge, Chev 454 chassis, &Bilstein shocks).While at the "Life On Wheels" conference I attended a "Radial Tire Safety" course. The instructor recommended adding 10 PSI to your 'normal' tire pressure if you will consistently be traveling at speeds greater than 65MPH. I don't recall the exact reasoning but seem to remember it had to do with load limit versus speed, which probably boils down to heat buildup and dissipation. 'Normal' tire pressure was the manufacturer's recommended inflation for your particular tire/load range/weight/wheel configuration combination. It was also pointed out that inflation pressures higher than these recommended values would make the tires more vulnerable to road impacts and hazards.On my return trip, I inflated my tires to +10PSI (I normally run 60 PSI in the front, 50 PSI in the rear which is both Lazy Daze and Michelin recommended for my tires). I found the ride to be noticeably harder which to me supported the increased vulnerability to road impacts and hazards statement. Also, when I thought about it, I was really just more comfortable traveling at 65MPH and enjoyed the trip a lot more.So, I now keep inflation at the recommended values and set the cruise control to 65MPH. I too would be interested in hearing other's thoughts on this subject ... !… Wayne
Re: Top Speed Reply #3 – June 15, 2003, 02:14:54 pm Yahoo Message Number: 23431Wayne: It is the tire manufacturers which mandate increasing tire pressure by 10 psi to go over 65 MPH. My bridgestones also mandate that above 70 you have to decrease load by 10%.Living
Re: Top Speed Reply #4 – June 15, 2003, 05:31:45 pm Yahoo Message Number: 23437Certainly tire care and handling are to be considered when contemplating driving a motor home over 70 mph. IMO a more important part of the equation is increased stopping distance. Speed can be a killer when you get a surprise obstacle such as a deer, a tractor, a person, or an accident over the ridge. It's easy to over run the braking distance of a 7 ton motor home. Sometimes faster may be better, other times 60 mph and 30 minutes longer on the road gets the distance needed all in one piece. Tom.
Re: Top Speed Reply #5 – June 15, 2003, 06:38:59 pm Yahoo Message Number: 23438QuoteCertainly tire care and handling are to be considered when contemplating driving a motor home over 70 mph. Based on your comment about stopping, I wonder if anyone has any data on the stopping distance for the late model 26.5 ft. LD's with ABS.The only truck data related to stopping distance that I have been able to find is for tractor trailers. I've been reluctant to put the LD into a panic stop by utilizing the ABS but maybe I should.Malcolm
Re: Top Speed Reply #6 – June 15, 2003, 09:17:21 pm Yahoo Message Number: 23447John M. wrote: Tires have a decrease in their load carry capacity as speed goes over 55mph. Running fast requires one to know weight and tire pressure as both will decrease the tires ability to carry a specific weight; this should be of more concern then stopping distance. John M.John, You are absolutely correct, UNTIL, you absolutely need to stop to avoid a disaster. Then, stopping trumps all other considerations. Tom.
Re: [Life With A Lazy Daze RV] Re: Top Speed Reply #7 – June 15, 2003, 09:19:46 pm Yahoo Message Number: 23448John is absolutely correct. I wonder today, with the price of gasoline, why people want to go over 55. Maybe an environmental consideration??
Re: Top Speed Reply #8 – June 15, 2003, 10:21:30 pm Yahoo Message Number: 23449ABS vehicle owners have been having more accidents than those without ABS vehicles; it is perplexing the insurance companies. The consensus seems to be that people who use ABS for the first time
Re: Top Speed Reply #9 – June 15, 2003, 11:02:51 pm Yahoo Message Number: 23452I'm certainly no rocket scientist, but I know that there are very, very good reasons for big rig trucks and vehicles pulling boats or trailers, etc. to be required to drive at 55 mph. Although a LD is not a big rig, it is certainly bigger and heavier than your standard passsenger vehicle. If the phrase "the bigger you are the harder you fall" is true, then I would guess "the bigger you are, the harder it is to respond in an emergency" would also be true!I had myself believing that motor homes were required to drive slower than the average car or light duty truck (we have only had our "previously enjoyed" RK for two months.) Goes to show what I know, huh. Call me fat, dumb, and driving way under 75! Does anyone out there know if there is a legal basis for keeping the lead out of our shoes when driving our precious, pretty LD's?Linda
Re: Top Speed Reply #10 – June 15, 2003, 11:21:57 pm Yahoo Message Number: 23454QuoteDoes anyone out there know if there is a legal basis for keeping the lead out of our shoes when driving our precious, pretty LD's?Linda,Other than the desire to keep your driver's license, I know of no special legal speed limits or restrictions applied to an RV the size of a LD. But, that experience may vary state by state ...... Wayne
Re: Top Speed Reply #11 – June 16, 2003, 11:05:42 am Yahoo Message Number: 23464QuoteOther than fuel economy (I still am averaging around 11mpg) is there any reason to stay under 65 MPH ?Is 75MPH too fast for the LD ? It still felt fine at 75 and had a nice ride. I haven't read all the responses, so this may be redundant.- Mileage is a big reason. If you really see no difference, this is unusual, and prompts me to think you may not have fairly tested. - Your kinetic energy is proportional to the square of your velocity, but impact damage is directly proportional. Your brakes are stressed X4 when you double your speed, and attempt to stop.- Your tires run cooler and have a lower likelyhood of failure at lower road speeds. Not all LT tires are designed for sustained driving above 65 mph - verify yours are.- Some states consider you in the same classification as commercial vehicles restricted to reduced speeds. CA does not.Still, with the right tires, your LD is designed to drive at those speeds continuously.Steve
Re: Top Speed Reply #12 – June 16, 2003, 02:05:56 pm Yahoo Message Number: 23472"Before my trip several people told me that I should keep my top speed under 65MPH. I thought that this was mainly for fuel economy, and also for safety."Those are exactly the main reasons to drive 65mph or under. Another is that many motorhomes don't handle well at highway speed because the manufacturers rarely care about weight and balance and other important issues. Many require many aftermarket devices just to handle half as well as your LD does with stock equipment!"On the road, I was in many places where the speed limit is 75MPH, and at 65 you have big rigs riding on your rear bumper and passing." Not only do big rigs do this but also so do many other vehicles! The speed limit is the MAXIMUM legal speed but not the required speed. On most interstate highways there is only a maximum and minimum speed posted. Typically the minimum speed is 45mph. Even when you travel at 70-75mph you'll still have people riding your rear bumper until they can pass you because often the 18-wheelers and many other vehicles are doing 85-95+mph. Even here in Fl when I drive at 80mph (10mph over the posted speed limit) in my car on the interstates people ride on my bumper until they can pass! Just because others want to go faster that doesn't mean you have to, unless you want to! "Other than fuel economy (I still am averaging around 11mpg) is there any reason to stay under 65 MPH ?"Yes, your safety! I agree with Steve in believing that if you're still averaging 11mpg at 70-75mph you're most likely calculating incorrectly! If you got 11mpg at 70-75mph you either calculated wrong or you had a great tail wind, where traveling downhill most of the time, or both! We all like to check every tank to gauge our fuel economy however doing so is very inaccurate and is never done when the EPA and other testing facilities establish the fuel economy for a given vehicle. The correct way to calculate fuel economy is listed in your Ford E Series owner's manual and should be done over the course of several tanks of gas and filling each tank at the same pump rate and number of automatic click-offs. You also should never fill beyond a couple auto click-offs or you'll end up wasting fuel because the tank is designed to fill only to a certain point just like your propane tank. Filling beyond that often leads to loss of fuel on the road as it rapidly expands while warming to the air temp. Never "top off" the tank!"Is 75MPH too fast for the LD ?"Not at all, however it does require many considerations including stopping distance, fuel economy, tire pressure, etc. The faster you travel the more likely you are to be involved in an accident and also to be seriously injured if one should occur. When driving with LT tires that aren't speed rated, and most aren't, you need to increase the pressure when driving at sustained high speed. High speed driving increases the tire temperature and lowers the load carrying capacity of them. All LT tire warranty, maintenance, and safety manuals will have warnings in them about driving at sustained high speed. The first will require an additional 10psi pressure above the recommended pressure for the load being carried when traveling at 66-75mph. The second level of speed (76-85mph) requires not only the additional 10psi pressure but also a 10% reduction of the load carrying capacity of the tires. You should never drive on non-speed-rated LT tires above 85mph! I suggest you read your tire manual for specific information or contact the tire manufacturer for that info. I'm sure many tread separations are due to people not following those speed/inflation rules and/or improper leveling methods over stressing the tires."What is the recommended top speed?" From the tire standpoint only that would be 85mph. You really need to evaluate for yourself what the proper speed to drive is for you. Although the LD will handle fine at higher speeds, that shouldn't be your only criterion for determining a safe travel speed. The fact is that speed kills and your odds of getting into an accident and of serious injury in one rise exponentially with increased speed.All that being said, I have driven my 26.5MB as fast as a sustained 80mph and I can tell you the fuel economy at that speed was a horrible 8.4mpg! At 70mph you gain about 1mpg, and at 75mph about .6mpg! Not only is the fuel economy bad but also the ride with the required additional 10psi is harsh! Especially for those riding in the rear! I was observing the required pressure and weight restrictions and won't ever drive at that speed again! I prefer to drive at a top speed of 60-65mph and let others pass me! The increase in safety and fuel economy is worth the little extra time it will take to get to my destination. Regardless of how fast you drive someone will always want to drive faster and will ride your rear bumper until they get a chance to pass!Have a great trip!Mike R.
Top Speed Reply #13 – June 16, 2003, 11:51:19 pm Yahoo Message Number: 23488Thanks to everyone for all of the feedback about top speed. I actually feel the most comfortable driving between 65-70Mph and the LD seems to be the smoothest at that speed.A few people responded that I must be calculating my gas mileage incorrectly to average 11MPG at 70-75MPH. Most of my trip has been in the 65-70MPH range, and I have averaged the mileage over 5 full tanks at this point. I had a low of 10.34 MPG and a high of 10.91 MPG. My LD is a diesel so that is why it is probably a little higher than some people expected. It is also really nice to buy diesel here in Texas where it is usually around $1.32 a gallon.I did have a question about tire pressure. I know I need to weigh the rig, preferably at each wheel independently. I have not done this yet, so I have been driving with all the tires inflated to 80psi. Other than the rough ride, is there a problem with doing this ?Thanks again for all the info.(Now in San Antonio) Charlie G.
Re: Top Speed Reply #14 – June 17, 2003, 01:48:17 am Yahoo Message Number: 23490Charlie,If you want to drive about 15 miles north on I35 (back towards Austin) to New Braunfels, there is a gra
Re: Top Speed Reply #16 – June 17, 2003, 11:10:50 am Yahoo Message Number: 23495"I know I need to weigh the rig, preferably at each wheel independently. I have not done this yet, so I have been driving with all the tires inflated to 80psi. Other than the rough ride, is there a problem with doing this?"Charlie G., If you want the official information regarding this from a major tire manufacturer and possibly the manufacturer of the tires on your LD go to the links section of this group and download the Michelin RV Tire Guide. It will answer all your questions on tires and how to weigh the rig to get individual wheel weights even if the scale doesn't have that capability. You should also download the load/inflation charts and use them. There are tire guides there from both Michelin and Goodyear, the Michelin is the better one, and load/inflation guides from Michelin and Bridgestone/Firestone. Most LT tires of the same size and load rating use the same pressures regardless of manufacturer though at time Michelins differ.There ARE problems with driving with tires inflated at to high a pressure and at 80psi you could possibly be in an over inflated pressure depending on your load. The problems are not just ride or wear related! With a diesel engine your front axle could well be at the maximum GAWR but even as such 80psi is 15psi over what is needed for the GAWR. It is fine to go over that pressure by about 5-10psi without being bad for the tires, though the ride comfort could suffer.Gus got what is often bad advice from someone he trusts. Mechanics often feel you should ride with more air in tires than is needed. Although inflating tires on delivery trucks like UPS or FedEx to the maximum pressure is usually fine since they often leave with a full load, reduced slowly during the day, and then often return with a full load after their pick-ups, it's a bad idea for most vehicles where the weight is more constant. The guide will let you know why and is official information from a manufacturer that constantly tests tires under various conditions. That's something the mechanic that advised Gus doesn't do! We also have no idea what the load was on Gus' tires during those miles he reports and if it is close to the maximum load for the tires. We also don't know what he considers a rough or comfortable ride either and that is subjective. What he considers acceptable you or someone else may consider extremely rough or harsh!Mike R.
Top Speed Reply #17 – June 15, 2003, 08:12:55 pm Yahoo Message Number: 23442Tires have a decrease in their load carry capacity as speed goes over 55mph. Running fast requires one to know weight and tire pressure as both will decrease the tires ability to carry a specific weight; this should be of more concern then stopping distance. John M.
Re: [Life With A Lazy Daze RV] Re: Top Speed Reply #18 – June 16, 2003, 11:41:16 am Yahoo Message Number: 23465Must "weigh in" on the speed conversation, since so far there has been no mention of driver reaction time. There is awfully good data that RT increases as people get older (of course, not any of us...but those other people : - ) !! The faster those other people drive, the less time there is to react in an emergency. Couple that with decreasing RT, and an emergency can become a disaster. We do a great deal of driving the west and in the prarie states. There is a real issue of wind. Sudden gusts require quick responses. High speeds don't leave much margin for error in these situations. Have seen a good many rigs, of all types and classes, turned over along the side of the road. Am trying to train my heavy foot to lighten up...or I just set the cruise control.Safe and happy travelingBobbi
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