five Report post Posted November 15, 2016 My DD500 will run all day at any speed...a bit thirstier at the higher speeds. However, like many, top speed is limited by my toad to 65. Share this post Link to post Share on other sites
wildebill308 Report post Posted November 15, 2016 This might be a good question for Tire Man. Bill Share this post Link to post Share on other sites
wayne77590 Report post Posted November 15, 2016 Isn't the speed rating the maximum speed that the manufacturer has verified that the tire will perform as specified. Anything over that is a risk. Example would be surface traction. I'm limited to 65 towing by car manufacturer recommendation. Share this post Link to post Share on other sites
manholt Report post Posted November 15, 2016 Never had any problems with toad or tires at over 65 mph. Had a Elk member in Kingman, AZ, and he ran an avg speed of 67 mph between Anchorage, Alaska and Kingman, AZ. I'm an associate member. Think about that some. Average speed = 67 ! He has a 1993 Prevost XL and a Jeep C-7 toad. Share this post Link to post Share on other sites
rossboyer Report post Posted November 16, 2016 Usually the max speed to tow is based on the drive train limit the manufacturer recommends. Share this post Link to post Share on other sites
BillAdams Report post Posted November 16, 2016 No max. towing speed limits on my Jeep! Share this post Link to post Share on other sites
tireman9 Report post Posted November 18, 2016 On 11/15/2016 at 7:57 AM, jleamont said: I will admit....I have walked ours up to 80 before, then I looked down at the speedometer and backed it off. Its easy to get complacent, I just started to keep up with traffic flow on a long and boring highway. I certainly didn't feel like I was going that fast. I use cruise now to stop the itch to pick up the pace. Funny, I have been passed by tour busses pushing 90 and up before, they have the same size tire as me which unless there is something I am missing they are also rated at 75 MPH I bet the bus tires do not have the same load as you do. Tile floor, Residential Refrigerators and solid counter tops are much heavier than a load of people. Bus tires are many times worn out in a couple of years so unless you want to start replacing all your tires at 3 years max I suggest you slow down. Share this post Link to post Share on other sites
manholt Report post Posted November 18, 2016 Interesting thought, but I have a feeling that a Tour Bus comes in at the same or more weight as we do! You got a half bath, fresh and black tank, big comfy adjustable seats, people and their luggage, Over the Road AC/Heat, all on a Prevost (most of the time in US). That chassis and engine is no light weight...as too all that vs mine? In some perverse way, it would be worth while to trade my tires in, because of tread wear, after 3-4 years! Instead of some cracks in sidewall, after 6-7 years! When was the last time, if any, that you passed a Newell or Converted Prevost on the freeway? Only time's for me, is when they enter or exit ! Carl Share this post Link to post Share on other sites
jleamont Report post Posted November 18, 2016 2 hours ago, manholt said: When was the last time, if any, that you passed a Newell or Converted Prevost on the freeway? Only time's for me, is when they enter or exit ! Never! they always pass me like I'm standing still, even at 65. 99% of the time as soon as my coach shifts into 6th gear I either set the cruise or watch the speedometer and keep it under 65. Share this post Link to post Share on other sites
JMWRIGHT Report post Posted November 19, 2016 On 11/18/2016 at 6:11 AM, jleamont said: Never! they always pass me like I'm standing still, even at 65. 99% of the time as soon as my coach shifts into 6th gear I either set the cruise or watch the speedometer and keep it under 65. 1st post - so hello everyone. As the speed conversation goes, I just returned from a 900 i95 trip and did a test on speed / mileage. On my 07 ISL Cummins I used 72-73 on the way and 67-68 on the trip back. Cruise control any time possible, same route. Low amount of traffic either way. Mileage went from 6.4 to 7.1. Just my 2 cents. Mike Share this post Link to post Share on other sites
five Report post Posted November 19, 2016 I'm on my second DP, two different makes and sizes of engines. My experience is that once over 60 MPH, the mileage heads south. Share this post Link to post Share on other sites
JMWRIGHT Report post Posted November 19, 2016 Five, the last leg of my trip is predominately 55-60 and I got 7.4 .... certainly a cost to move a wall of air. Share this post Link to post Share on other sites
manholt Report post Posted November 19, 2016 OK, so you got an ISL 2007...tells me nothing. Make, Model of coach and HP of engine would help! Share this post Link to post Share on other sites
BillAdams Report post Posted November 19, 2016 I am not sure that the make and model is important when the only point he was making was that slowing down improved fuel mileage. I think everyone already agrees on that. Since my employer wants me there sooner than later and is paying for the fuel I use along the way, speed is more important to me than MPG. If I ever retire I will likely slow down (a bit) in hopes of getting the old girl up to 6 MPG! Share this post Link to post Share on other sites
manholt Report post Posted November 19, 2016 Bill. The lowest mpg avg. I had was making an emergency run from Dalhart, TX. to the Children's Shrine Burn Hosp. in Galveston, TX. DPS in front and back. 70 mph avg, 2 drivers, in a 2011 Allegro Bus, 450 Cummins, no toad...6.2 mpg! My normal was 6.8 at 63 on CC. Currently, I get 6.4 at 65 on CC. I get 6.4 at 68 on CC....I tried last year, a tank at 60 mph on CC, spent more time in 5th gear than 6th and got 5.6 mpg! I'm happy at 6.4. Carl Share this post Link to post Share on other sites
jbrunson Report post Posted November 20, 2016 Goodness! I try to cruise around 55 and average 11-12. No clue what happens above 60, but I bet the bottom brows out... flat plane drag is real. Share this post Link to post Share on other sites
wildebill308 Report post Posted November 20, 2016 You guys are making me feel pretty good about my milage. in the last 9,085 miles it is 9.031. Not to bad as this trip was in the west. My little 5.9 300 hp got me over all the hills just fine. I run about 65-68 I don't shift into 6th till 65. I may try bumping it to 70 on the long flat straightaway better known as west Texas. Bill Share this post Link to post Share on other sites
manholt Report post Posted November 20, 2016 WBill. Your 5.9, 300 is more than adequate for the weight your pushing down the road. You and jbrunson are not trying to move all the extra, useless bling , down the hwy. Tile floor, Corian on every thing that don't have wood, dish washer and stacked washer dryer. Then there is 2, 12V batteries and 8, 6V...all that, requires a bigger engine and that requires a heavier chassis! 64 mph in 5th. Bill, if I tried that, I'd be lucky to see the up side of 4 mpg. Your Allison is geared for a 300hp, mine for 425hp and FIVE's Eagle for a 500hp. My biggest problem is a long hill with a lot of traffic, like Northern Calif. and OR. on I-5...in 14, I was less than 250 miles South of Seven Feathers Casino and it took me 7 hours to get there! Share this post Link to post Share on other sites
five Report post Posted November 20, 2016 My DD 500 with the 4000 Allison, gets into 6th gear a little above 55. As for MPG, I wish I got as good as the SilverLeaf tells me I'm getting. When I compute MPG with a #2 pencil (even figuring fuel burned by the generator and Aqua Hot), it's always less than the SilverLeaf. Having said that, I'm looking for lots of improvement....Monday I had the three fuel filters and fuel/water separator changed...to the tune of $410. I changed my own on my Spartan, with it's filter bay...on this Freightliner I couldn't even see them, much less change them. Share this post Link to post Share on other sites
JMWRIGHT Report post Posted November 20, 2016 On 11/19/2016 at 10:38 AM, manholt said: OK, so you got an ISL 2007...tells me nothing. Make, Model of coach and HP of engine would help! 2007 allegro bus quad slide qsp. 400hp Share this post Link to post Share on other sites
