I have a jayco motorhome on a Ford E450 chassis, original. Tires Michelin 225/75 with load factor E. max load of the tires is 9880lbs, my actual rear axle weight 9270 (static and motorhome empty with no water, fuel tank 1/3 full) according to Michelin that is asking for tire failure ( had 2 already) because the dynamic loads (going down the street, bumps - uphill - downhill- sideloads) will be over the tire limit. That's the reason the law requires pass, cars and light trucks to have a 16% reserve capacity; mine is down to about 2%. with full fuel and water tank, little bit of staff loaded for vacation or putting anything on the trailer hitch (boat or even loaded bike rack) I am overweight for the existing tires and max rear axle weight I know that is not an issue Ford has to deal but jayco.but I would very much appreciate your expertise about what to do (is that motorhome a risk to drive, maybe unsafe?) is there any means to increase the max rear axle weight on that E450 chassis? any way I could put on a different tire size (enough room on the rim / wheel-well;that would increase the max tire load about 1000lbs - but is that legal and doable, especially. With the dual tires. I am looking forward to your answer. Ford E-450 + jayco.
The Bear II said
09:37 AM Feb 11, 2016
If you have dual tires (4) on the rear axle wouldn't the load be spread over all four tires.
9880 X 4 = 39,520 lbs.
Howard said
01:16 PM Feb 11, 2016
Bear, I believe what he is saying is the total of the four rear tires has a total rating of 9,980 pounds. That would be about right for an E load range tire - 2,470 pounds per tire. And the LT225/75R16 with load range E is a common tire on Class C motorhomes.
jncrowe, you would likely need to upgrade your rims if you upgraded tires to a higher load range. The rims have ratings too and they are usually rated for something close to the tire capacity. It's possible that they are rated for higher, but then you might still be limited by the rim ratings even if you upgrade to a G load range tire.
Assuming you upgrade both tires and wheels, you would need to find the same tire size with a higher load range OR find a different size tire with a higher load range. In either case, you would need to make sure the rims will work with your axle and hubs and you will need to make sure the diameter of the tires is the same or nearly the same as the stock tires. It's certainly legal to make those changes, however it would be best to contact the chassis manufacturer to get options they recommend (sometimes the information is included in the chassis owners manual, but I wouldn't count on it). If you make the change, you will likely exceed the Gross Axle Weight Rating (GAWR) and perhaps the Gross Vehicle Weight Rating (GVWR).
If the tires are overloaded, certainly there is a higher risk of tire failure and that is, of course, a safety consideration. If you are unable to replace the tires and rims for whatever reason, keep your speed down. Lower speeds increase the capacities of the tires, while higher speeds decrease the capacity due to the higher heat generated.
It's not an easy issue to resolve, and that's why we try to educate folks on these issues before they buy. Best of luck to you.
Barbaraok said
03:15 PM Feb 11, 2016
You don't say what year your motorhome is nor the model.
I have a jayco motorhome on a Ford E450 chassis, original. Tires Michelin 225/75 with load factor E. max load of the tires is 9880lbs, my actual rear axle weight 9270 (static and motorhome empty with no water, fuel tank 1/3 full) according to Michelin that is asking for tire failure ( had 2 already) because the dynamic loads (going down the street, bumps - uphill - downhill- sideloads) will be over the tire limit. That's the reason the law requires pass, cars and light trucks to have a 16% reserve capacity; mine is down to about 2%. with full fuel and water tank, little bit of staff loaded for vacation or putting anything on the trailer hitch (boat or even loaded bike rack) I am overweight for the existing tires and max rear axle weight I know that is not an issue Ford has to deal but jayco.but I would very much appreciate your expertise about what to do (is that motorhome a risk to drive, maybe unsafe?) is there any means to increase the max rear axle weight on that E450 chassis? any way I could put on a different tire size (enough room on the rim / wheel-well;that would increase the max tire load about 1000lbs - but is that legal and doable, especially. With the dual tires. I am looking forward to your answer. Ford E-450 + jayco.
9880 X 4 = 39,520 lbs.
Bear, I believe what he is saying is the total of the four rear tires has a total rating of 9,980 pounds. That would be about right for an E load range tire - 2,470 pounds per tire. And the LT225/75R16 with load range E is a common tire on Class C motorhomes.
jncrowe, you would likely need to upgrade your rims if you upgraded tires to a higher load range. The rims have ratings too and they are usually rated for something close to the tire capacity. It's possible that they are rated for higher, but then you might still be limited by the rim ratings even if you upgrade to a G load range tire.
Assuming you upgrade both tires and wheels, you would need to find the same tire size with a higher load range OR find a different size tire with a higher load range. In either case, you would need to make sure the rims will work with your axle and hubs and you will need to make sure the diameter of the tires is the same or nearly the same as the stock tires. It's certainly legal to make those changes, however it would be best to contact the chassis manufacturer to get options they recommend (sometimes the information is included in the chassis owners manual, but I wouldn't count on it). If you make the change, you will likely exceed the Gross Axle Weight Rating (GAWR) and perhaps the Gross Vehicle Weight Rating (GVWR).
If the tires are overloaded, certainly there is a higher risk of tire failure and that is, of course, a safety consideration. If you are unable to replace the tires and rims for whatever reason, keep your speed down. Lower speeds increase the capacities of the tires, while higher speeds decrease the capacity due to the higher heat generated.
It's not an easy issue to resolve, and that's why we try to educate folks on these issues before they buy. Best of luck to you.