RB SmartWeigh results April 02, 2021, 06:14:14 pm Since I'm totally loaded and on my way, I thought I'd get a 4 wheel weighing to see if I have a good load balance.I was weighed with full water, gas, and propane, and empty grey and black tanks. I also have BigFoot levelers installed (one pump, 10" foot pads)My loaded 2021 RB weighs 13100 lbs. Front axle is 3900 lbs, rear is 9200 lbs. The axle weights are perfectly even side to side. It came with Hankook Dynapro HT LT225/75R16E tires. They're rated for 2680 lbs single and 2470 lbs dual. I figure all this to mean I can add up to 1400 lbs to get me to the GVWR of the E450. If I put it directly over the front axle, the max would be 730 lbs and the rear axle can hold another 680 lbs, although I don't really have that much stuff to add. The Smart Weigh lady says this weight distribution shows I should probably travel with a full water tank or the vehicle will be off on side to side balance. My question that SmartWeigh and Google don't seem to be able to answer is to what PSI do I inflate my tires? I can't find a Hankook load/PSI chart. LD's sticker says 75PSI front and 80PSI back, but it also says 5000 lb GAWR front axle and 9600lbs rear axle. I'm not at those weights. Can anyone direct me to an inflation chart for this tire? Or suggestions on the proper inflation? I've been running 70 front and 75 back. Is that enough?Linda
Re: RB SmartWeigh results Reply #1 – April 02, 2021, 06:41:32 pm Hankook would be the ones to publish a tire inflation chart, and I can't find it with a quick google search. The only Hankook chart I could find was for larger truck/bus tiresTire Inflation TablesPerhaps there is some warranty information from Hankook in the paperwork that came with your LD? I'd look in there for a phone number. Perhaps they could point you in the right direction.Sorry I can't be more help,Rich
Re: RB SmartWeigh results Reply #2 – April 02, 2021, 06:46:32 pm "I figure all this to mean I can add up to 1400 lbs to get me to the GVWR of the E450."The way I read your post is that you are striving to reach GVWR (GrossVehicleWeightRating). You do not want to exceed that rating, stay below it if you can. It is a guideline to help you to NOT overload the rig. "LD's sticker says 75PSI front and 80PSI back."If those tires came with the rig I'd go by LD's recommendation. Those are the exact air pressure readings that I use on my 30'IB.
Re: RB SmartWeigh results Reply #3 – April 02, 2021, 07:21:41 pm Until you can find an actual Hankook tire pressure chart, I suggest looking at your LD Owner's Manual tire weight-pressure chart, all tires of this type, size, and load rating have very similar air pressure ratings. Have you contacted the dealer where the tires were purchased or Hankook directly?Larry
Re: RB SmartWeigh results Reply #4 – April 02, 2021, 07:56:34 pm Hankook LT 225/75R/16E tires are standard on E-450 chassis, and, as far as I know, Hankooks are OEM on Transits and may also be on other Ford truck models. The tire specs, i.e., construction, weight ratings, etc., are very similar/essentially the same as other E-rated same size light truck tires. You might want to call Hankook per Larry’s suggestion, but if you are comfortable with the ride quality and handling, and if frequent checks of the tires show no unusual or excessive wear, I suggest sticking with 70 front and 75 rear. 1 Likes
Re: RB SmartWeigh results Reply #5 – April 02, 2021, 08:13:18 pm I still need to weigh mine (soon) and would love to find a place that can weigh all four wheels. We have lots of CAT Scales around but I don't think they offer that.
Re: RB SmartWeigh results Reply #6 – April 02, 2021, 09:33:57 pm I forgot about the LD Owners Manual. Looked in it and it suggests 75 rear for my weight, but 55 for the front, which seems way low. I think I'm going to try 65/75 and see how that handles. I don't have 5000 miles on her yet, so there is no obvious tire wear. Going to have to go by handling characteristics for the time being.Quote from: Lazy Bones - April 02, 2021, 06:46:32 pm"I figure all this to mean I can add up to 1400 lbs to get me to the GVWR of the E450."The way I read your post is that you are striving to reach GVWR (GrossVehicleWeightRating). You do not want to exceed that rating, stay below it if you can. It is a guideline to help you to NOT overload the rig. I didn't mean this to be I'm trying to achieve GVWR, only that I *could* add more weight, even though I can't think of any more stuff that I need to take along.Thanks, Linda 2 Likes
Re: RB SmartWeigh results Reply #7 – April 02, 2021, 10:02:21 pm "I think I'm going to try 65/75 and see how that handles."Good start! You should be looking for performance, comfort and above all, gas mileage. Sooner or later you will find the sweet spot that satisfies all desires. As to the 'full' water tank, many of us do not want to carry the weight, 8lbs per gallon. Shifting cargo will help balance the load. 1 Likes
Re: RB SmartWeigh results Reply #8 – April 04, 2021, 12:00:15 pm Linda, I had the similar weights on our 2010 rear bath and going by the LD manual and many miles of travel I found that 65# front and 75# rear worked the best for handling. This has also held true for our new 2021 rear bath with the similar weights. As we do a lot of dry camping we quite often travel with a full water tank. We don't worry about gas mileage unless there is a drastic dropping change that would indicate problems with the drive system. We do keep tabs on the tire pressures via the TST color tire monitor system. 1 Likes
Re: RB SmartWeigh results Reply #9 – April 04, 2021, 12:43:15 pm When you did the 4 wheel weigh - were you sitting in the drivers seat? Small difference, but if you're trying for exact weights.As Colin Fletcher said "If you look after the ounces, the pounds take care of themselves".You are 300# over my 2013 31 IB with full gas, propane, no water and no me. Joel
Re: RB SmartWeigh results Reply #10 – April 04, 2021, 12:53:41 pm Joel, and I believe you should also have any passengers and critters on board, right?So how does one get a SmartWeigh?
Re: RB SmartWeigh results Reply #11 – April 04, 2021, 01:20:43 pm Quote from: joel wiley - April 04, 2021, 12:43:15 pmWhen you did the 4 wheel weigh - were you sitting in the drivers seat? When our rig had 3000 miles on it, the front end was aligned and weighed. The rig was fully loaded, with full water tanks.To duplicate the weight of the passenger, driver, and a loaded refrigerator, bags of gravel were placed in both front seats and another bag in front of the refrigerator, which was empty at the time.Near the shop was a place where all four wheels were weighted individually, allowing setting the tires to the recommended pressure.Larry
Re: RB SmartWeigh results Reply #12 – April 04, 2021, 01:30:12 pm I always travel with a full water tank, as I like my great tasting water (or is it tasteless?) at home. I have found some terrible tasting water on the road, specially in my tea! 1 Likes
Re: RB SmartWeigh results Reply #13 – April 04, 2021, 01:36:35 pm Quote from: LazyMike - April 04, 2021, 01:30:12 pmI always travel with a full water tank, as I like my great tasting water (or is it tasteless?) at home. IWe always travel with a full tank, you never know if water will be available, it's happened twice to us in camps where the water was off for some reason. The tank is always filled at home, it's part of our emergency supplies.Our LD has a high-grade water filter to clean up the drinking water. Larry 1 Likes
Re: RB SmartWeigh results Reply #14 – April 04, 2021, 01:58:33 pm Hmmm. When I used SmartWeigh back in August 2019, they specifically told me what tire pressure to use based on my weight results. Right now I run the front tires at 70 lbs (based on heavy full storage in the overheard cab) and 80 lbs on the rear.I will be getting a weight update in the late fall since I have downsized items and added others and the overhead cab is only half full now.
Re: RB SmartWeigh results Reply #15 – April 04, 2021, 01:58:55 pm Re: 'Smart Weigh'. Try these links:SmartWeigh · Escapees RV ClubThe Best Way to Weigh Your RVhttps://www.youtube.com/watch?v=oZhHwshUCssA few RV (generally larger) shops which specialize in suspension services may offer four-corner weighing; these are not very common, but check locally.Oregon's roadside weigh pads are generally open; if the pad is large enough and free of obstacles, one can sometimes maneuver the rig to get accurate weights of each corner. I've done this a couple of times. (Getting just front and rear axle weights is usually not difficult when using these pads, but it can be a challenge to get each corner.) 1 Likes
Re: RB SmartWeigh results Reply #16 – April 04, 2021, 08:24:33 pm Quote from: joel wiley - April 04, 2021, 12:43:15 pmWhen you did the 4 wheel weigh - were you sitting in the drivers seat? Small difference, but if you're trying for exact weights.As Colin Fletcher said "If you look after the ounces, the pounds take care of themselves".You are 300# over my 2013 31 IB with full gas, propane, no water and no me. JoelYep Joel, I and my 2 cats were aboard. Also about 50 lbs of canned goods, a 38lb bag of cat litter, 4 cases of canned cat food, my sewing machine, 10 lbs of hand weights, about 30 lbs of assorted tools and lots of other stuff. I'm fully packed for snow birding, not just weekending. I guess that's the difference between the 27's and the 31's. I get to pack stuff into my space, you get the extra space.I'm actually surprised at the evenness of the side to side weights. The Smart Weigh lady was very complimentary of Lazy Daze, saying they and Airstream are practically the only manufacturers who take weight balance into consideration.Linda 1 Likes
Re: RB SmartWeigh results Reply #17 – April 04, 2021, 08:30:46 pm Quote from: debinvenice - April 04, 2021, 01:58:33 pmHmmm. When I used SmartWeigh back in August 2019, they specifically told me what tire pressure to use based on my weight results. Right now I run the front tires at 70 lbs (based on heavy full storage in the overheard cab) and 80 lbs on the rear.I will be getting a weight update in the late fall since I have downsized items and added others and the overhead cab is only half full now.Deb,They gave me tire pressure charts for a bunch of tire manufacturers, but Hankook, the stock Ford tire doesn't seem to have a chart. and the owner's manual doesn't mention it since this is sold as an unfinished chassis.Linda
Re: RB SmartWeigh results Reply #18 – April 05, 2021, 02:30:03 pm I don't think of looking to the tire manufacturer for psi by weight. If they are load range E I would go with the psi in the LD book. In my case the previous owner had it weighed. According LD manual I should have around 62 front and 67 rear. I tried more but felt I felt the bumps too much. I do 63 and 68. PS Tire manufacturer can not know all the specs of your vehicle to come up with any thing of value.
Re: RB SmartWeigh results Reply #19 – April 05, 2021, 06:08:02 pm Quote from: StevenJill - April 05, 2021, 02:30:03 pmI don't think of looking to the tire manufacturer for psi by weight. If they are load range E I would go with the psi in the LD book. In my case the previous owner had it weighed. According LD manual I should have around 62 front and 67 rear. I tried more but felt I felt the bumps too much. I do 63 and 68. PS Tire manufacturer can not know all the specs of your vehicle to come up with any thing of value.It should be weighted with your gear and full water, gas, and propane tanks, do not assume the previous owners loaded it the same as you do. Everyone is different.Larry 2 Likes
Re: RB SmartWeigh results Reply #20 – April 06, 2021, 01:21:15 am Linda,Hankook says to use the tire pressures specified in the vehicle's owner's manual. The sticker on the chassis is applied by Ford and lists inflation pressure at the full Gross Vehicle Weight Rating and maximum axle weight ratings, since Ford can't know how its cutaway chassis will eventually be used. Those are safe pressures but may be unnecessarily high, resulting in a harsher ride.The owner's manual supplied by LD will likely give you tire pressures for a given axle weight, front and rear. So, if your LD was weighed at it's traveling weight (vehicle, fluids, cargo, passengers) then go to the LD manual, enter the chart with your axle weights and read the corresponding recommended pressures.Set those pressures when the tires are cold (in the morning before sun hits them). If you travel to a significantly different elevation or a new climate or after a change in weather (summer to winter for example), set them again to the pressures specified by LD based on axle weight. Tire pressures represent a differential from the current ambient air pressure so you do not use a different pressure due to changes in elevation or temperature. You simply set the same pressure again in the new conditions.You should never go lower than the pressure specified in the LD manual for your axle weight. But you may decide to go a bit higher either to get somewhat better handling (a slightly higher pressure will mean a stiffer tire that likely will perform better in corners though it will be less comfortable and may wear differently) or to provide a cushion against the possibility of a higher load. And you should never go higher than the tire's maximum pressure rating imprinted on the sidewall (likely 80psi for all tires of the size used on LD motorhomes). Personally I would not vary the pressures side to side to compensate for side to side weight variations as different pressure changes the handling characteristics of a tire. Better to adjust loading to balance the weight.I used to worry a lot about these calculations but then, via weighing, learned we usually run very close to the maximum weight rating of our chassis and of each axle. So I now just set the pressure to correspond to the maximum axle weight ratings, which on our 2003RB means 65psi front and 80psi rear. Those also happen to be the pressures on the Ford sticker, which, as I said, corresponds to the maximum allowable axle weights. (Your 2021 chassis has different weight ratings so has different maximum tire pressures for each axle, apparently 75psi front and 80psi rear based on your post.)But since you are running below the maximum weight ratings my suggestion would be to use the pressures in the LD manual, perhaps rounding them up to the next increment of 5psi for safety's sake, and then just stick with that unless you change the loading of your motorhome.I try to check and set tire pressures the morning of each traveling day. This means that they are set for the current elevation and weather conditions and keeps me informed of any recent changes that might indicate damage to the tires or valves. And, if you have a tire pressure monitoring system (we don't) this provides a manual cross check of the information provided by the TPMS. I personally think checking tire pressures is the best thing you can do to ensure the safety of your motorhome. 4 Likes
Re: RB SmartWeigh results Reply #21 – April 06, 2021, 07:08:41 am Quote from: Larry W - April 05, 2021, 06:08:02 pmIt should be weighted with your gear and full water, gas, and propane tanks, do not assume the previous owners loaded it the same as you do. Everyone is different.Larry That is kind of funny Larry. I am not assuming I am loading the LD the same as the previous owners, that would be silly. However I am figuring that I am not loading much more if more at all and that the psi I am inflating to is plenty judging by the feel and look.
Re: RB SmartWeigh results Reply #22 – April 06, 2021, 05:53:47 pm I always ran 62 front, 76 rear on my old michelin LTX' per the guy I bought my first LD from, he seemed to be the kind of guy that tried many pressures for ride vs MPG. I have the Agilis Cross Climate Michelins now & they seem to ride better & are less noisy. Heat in the summer here in texas causes more failures especially on inside rear. I think im going to bump it up to 65 front , 78 rear. (maybe 80 on the inside rear) ( I Rarely run close to GWVR)
Re: RB SmartWeigh results Reply #23 – April 06, 2021, 06:35:38 pm Micky, tires on the same axle should be aired to the same pressures. 1 Likes
Re: RB SmartWeigh results Reply #24 – April 06, 2021, 06:45:49 pm Especially tires next to each other in the dual pair, should be the same as possible to share duties at a 50% partner. RonB
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