Safe to just use ramps on one wheel on each side?

[grthigpen]

Hi, is it safe to use 2 single tire ramps on the rear of a DP, one on each inside tire only? thx

[gemert]

No, the duels work together to hold the weight of the coach. If you are only supporting on one tire on each side I'm betting that each tire will be supporting almost twice as much as it is designed for. Not a good idea.

[harleyjt]

I assume you are talking for an extended period. Regardless, that's not at all recommended as you effectively double the load on the supported tires since the other ones are suspended in mid air.
jt

[Tony Lee]

There is dynamic loading and there is static loading and while it may not be recommended to drive at 90mph on just one tyre instead of two, that isn't the same thing as gently running one tyre up on a ramp that is wider than the tread width and leaving it for a few hours.

BTW I put the ramp under the outer tyre as it is more stable. Again, if the naysyers claim that will bend axles or do other terrible things, it comes down to the huge difference between static and dynamic loads and shocks and if that were the case every time you misjudged and ran over a curb or off the side of the tar, you would be writing off your axle. Doesn't happen so ...

[smiller]

Originally Posted by Tony Lee

There is dynamic loading and there is static loading and while it may not be recommended to drive at 90mph on just one tyre instead of two, that isn't the same thing as gently running one tyre up on a ramp that is wider than the tread width and leaving it for a few hours.

BTW I put the ramp under the outer tyre as it is more stable. Again, if the naysyers claim that will bend axles or do other terrible things, it comes down to the huge difference between static and dynamic loads and shocks and if that were the case every time you misjudged and ran over a curb or off the side of the tar, you would be writing off your axle. Doesn't happen so ...

That's how I see it. The official answer is and always will be that you are technically overloading the tire, but I rather doubt the static load of the vehicle on one tire would do any damage.

[gemert]

Originally Posted by Tony Lee

There is dynamic loading and there is static loading and while it may not be recommended to drive at 90mph on just one tyre instead of two, that isn't the same thing as gently running one tyre up on a ramp that is wider than the tread width and leaving it for a few hours.

BTW I put the ramp under the outer tyre as it is more stable. Again, if the naysyers claim that will bend axles or do other terrible things, it comes down to the huge difference between static and dynamic loads and shocks and if that were the case every time you misjudged and ran over a curb or off the side of the tar, you would be writing off your axle. Doesn't happen so ...

Naysayer is kind of strong. I'm not an expert and am assuming you are so I will bow to your experience that makes you sure that they won't bend an axle or the ramp and cause thousands in damage or an injury. Thanks for the benefit of your experience.

[Ray,IN]

Read what Michelin says about leveling RV's with dual tires on page 5.http://www.michelinrvtires.com/asset...ireArticle.pdf
Then make your own decision.

[FIRE UP]

Originally Posted by grthigpen

Hi, is it safe to use 2 single tire ramps on the rear of a DP, one on each inside tire only? thx

Well Sir,
As you can see, there's varied answers. People can argue or, "discuss" the right or wrong way 'till the cows come home. This is one of those things that logically, the PRIMARY reason for duals, on any vehicle that comes from the factory with them is, because the chassis is intended to be loaded with enough weight to warrant the cost and effort to install them.

In the case of a D/P motor home, (without a tag), I'd say that 80-90% of them are running down the road, very close to the max GAWR of the rear. Some more, some less. With that being said, it means that all four wheels and tires are sharing the total weight back there. Now, cut that in 1/2.

One side is now supporting 1/2 the total weight of the rear. That's ok 'cause, those two are supposed to carry/support that weight.


Now, cut the amount of support in half but, DO NOT CUT THE WEIGHT IN HALF! You are now putting all that weight, intended for two wheels and tires, onto one wheel and tire. Now, is all that weight going to cause damage if you drive up on ONE SINGLE RAMP? Most likely not. Is it not good for it, YEP! When you picture what happens when you do that, one wheel and tire, the one with the ramp under it, is being compressed about twice as much as it would if both tires and wheels were on ramps.

And, the un-weighted tire and wheel, actually drops by quite a bit, below the surface contact point of the one that's doing all the supporting. What that means is, you're actually torqueing the end of that axle tube upwards because all the weight is at the outer-most point of support.

Now we could go on and on about it but, that's the story. You're simply not supporting the weight properly and, while it may not break or bend components right in front of you, you're still not doing what's best for the tires and wheels, suspension etc.

But the real point here is, WHY WOULD YOU DO IT IN THE FIRST PLACE??? I mean, the answer is phenomenally simple, CARRY FOUR RAMPS! Yes, I know, there sometimes can be storage problems. But, in the photos below, you'll see the ramps I built a month or so ago and, based on their design, they store on top of themselves. That provides for using way less space. There's actually (5) ramps and, (4) large Jack blocks and, (2) front tire blocks, (which can also be used for any other position too but, I call them front blocks).

I may be fortunate to have that kind of space for that little lumber yard but, also, it's a priority for me. We often are in situations where lumber is needed. With the kind of weight I'm carrying back there, right close to 17,000 lbs., I wouldn't even dream of only putting one ramp on each side. I kind-a look at it this way, if I damage something, knowing that I could have prevented it, I'm the one who's got to fix it and, pay for whatever's needed for parts, simply because I was lazy. AIN'T HAPPENING!
Scott

[gemert]

Originally Posted by Ray,IN

Read what Michelin says about leveling RV's with dual tires on page 5.http://www.michelinrvtires.com/asset...ireArticle.pdf
Then make your own decision.

Thanks for the injection of common sense!

[gemert]

Originally Posted by FIRE UP

Well Sir,
As you can see, there's varied answers. People can argue or, "discuss" the right or wrong way 'till the cows come home. This is one of those things that logically, the PRIMARY reason for duals, on any vehicle that comes from the factory with them is, because the chassis is intended to be loaded with enough weight to warrant the cost and effort to install them.

In the case of a D/P motor home, (without a tag), I'd say that 80-90% of them are running down the road, very close to the max GAWR of the rear. Some more, some less. With that being said, it means that all four wheels and tires are sharing the total weight back there. Now, cut that in 1/2.

One side is now supporting 1/2 the total weight of the rear. That's ok 'cause, those two are supposed to carry/support that weight.


Now, cut the amount of support in half but, DO NOT CUT THE WEIGHT IN HALF! You are now putting all that weight, intended for two wheels and tires, onto one wheel and tire. Now, is all that weight going to cause damage if you drive up on ONE SINGLE RAMP? Most likely not. Is it not good for it, YEP! When you picture what happens when you do that, one wheel and tire, the one with the ramp under it, is being compressed about twice as much as it would if both tires and wheels were on ramps.

And, the un-weighted tire and wheel, actually drops by quite a bit, below the surface contact point of the one that's doing all the supporting. What that means is, you're actually torqueing the end of that axle tube upwards because all the weight is at the outer-most point of support.

Now we could go on and on about it but, that's the story. You're simply not supporting the weight properly and, while it may not break or bend components right in front of you, you're still not doing what's best for the tires and wheels, suspension etc.

But the real point here is, WHY WOULD YOU DO IT IN THE FIRST PLACE??? I mean, the answer is phenomenally simple, CARRY FOUR RAMPS! Yes, I know, there sometimes can be storage problems. But, in the photos below, you'll see the ramps I built a month or so ago and, based on their design, they store on top of themselves. That provides for using way less space. There's actually (5) ramps and, (4) large Jack blocks and, (2) front tire blocks, (which can also be used for any other position too but, I call them front blocks).

I may be fortunate to have that kind of space for that little lumber yard but, also, it's a priority for me. We often are in situations where lumber is needed. With the kind of weight I'm carrying back there, right close to 17,000 lbs., I wouldn't even dream of only putting one ramp on each side. I kind-a look at it this way, if I damage something, knowing that I could have prevented it, I'm the one who's got to fix it and, pay for whatever's needed for parts, simply because I was lazy. AIN'T HAPPENING!
Scott

More common sense. I love this forum.