Do you know what your wheelbase ratio is?

[Roadtrek 1]

See this article for more details, it explains why this is important....

https://axleaddict.com/rvs/Why-RV-Wheel-Base-Ratio-Is-Important

You don't want to have your RV drive "like a house"....and be challenging every time you're behind the wheel....as in this video below....

Space is important, but.....

https://www.motor1.com/reviews/140845/thor-outlaw-rv-why-buy/

Apparently, a longer wheelbase is an advantage.

 

 

 

Edited April 6, 2019 by Roadtrek 1

[Kirk W]

Longer Is Safer

To a great degree, this is also true for the wheelbase of a vehicle that tows a trailer RV. While I have never seen a formula for determining the proper ratio between tow vehicle wheelbase and trailer length, there really should be one. I can assure you that even when towing a small travel trailer, the longer & heavier the tow vehicle is the less impact wind and road conditions have on the handling. 

[Roadtrek 1]

9 hours ago, Kirk W said:

Longer Is Safer

To a great degree, this is also true for the wheelbase of a vehicle that tows a trailer RV. While I have never seen a formula for determining the proper ratio between tow vehicle wheelbase and trailer length, there really should be one. I can assure you that even when towing a small travel trailer, the longer & heavier the tow vehicle is the less impact wind and road conditions have on the handling. 

Kirk, I would agree and found this for you; 

https://www.transwest.com/kansas-city/7-features-you-should-look-for-when-shopping-for-a-towing-vehicle

When I originally posted this article on wheelbase, I was primarily speaking of RVs of any size.  The article gives people a calculation to determine their ratio.   RVs with a relatively short wheelbase for their overall length are difficult and fatiguing to drive requiring a lot of steering corrections....

In general, I think it's more risky to tow a vehicle such as a trailer than just driving a single vehicle...

[trailertraveler]

13 hours ago, Kirk W said:

To a great degree, this is also true for the wheelbase of a vehicle that tows a trailer RV. While I have never seen a formula for determining the proper ratio between tow vehicle wheelbase and trailer length, there really should be one.

The RV Consumers Group developed a guideline years ago for the relationship between tow vehicle wheelbase and trailer length. It is discussed in this article which I have linked to a number of times on this forum. The article also discusses a second guideline,  

Quote

The distance from the coupler to the rear trailer axle should be no more than twice the wheelbase of the tow vehicle.

 

[FL-JOE]

I read several related articles a few years ago to learn about this ratio between wheel base and overall length when it comes to motorhomes.  We were in the process of shopping for our first gas coach for past timing.  We had driven a Jayco product that was hard to even keep in a lane of traffic.  It turned out it was way under the recommended ratio.  Ended up with a gently used Thor Challenger 37GT that had a better ratio but still tired you out after 300 or 350 miles a day.

IMHO that ratio is the most important thing but type of suspension runs a close second.

[Kirk W]

Thanks to all of you for posting links to those articles. Actually two of them I had previously seen but had lost the links to. I especially like the one from RVCG as it addresses both types of towing. The other factor that can have a great impact on the handling when towing a small travel trailer is the issue of 1 axle or 2 axles. Because it costs less, the lower priced, short, lite weight travel trailers typically come with only 1 axle but handling is much improved for the same towing combination if the trailer has 2 axles because of the effect the trailer rocking has on the tow vehicle. The second axle lessens that effect. 

[Roadtrek 1]

5 hours ago, Kirk W said:

Thanks to all of you for posting links to those articles. Actually two of them I had previously seen but had lost the links to. I especially like the one from RVCG as it addresses both types of towing. The other factor that can have a great impact on the handling when towing a small travel trailer is the issue of 1 axle or 2 axles. Because it costs less, the lower priced, short, lite weight travel trailers typically come with only 1 axle but handling is much improved for the same towing combination if the trailer has 2 axles because of the effect the trailer rocking has on the tow vehicle. The second axle lessens that effect. 

Kirk,  just curious, I've seen some trailers with two wheels one in front of the other on each side vs. dual wheels on one axle.... I don't know which is more secure? 

Could you please tell me about that?   Which can handle more weight? 

[Kirk W]

3 minutes ago, Roadtrek 1 said:

I don't know which is more secure? 

Offhand, I can't think of any travel trailers that have a single axle with dual wheels. Having 2 axles and tandem wheels not only increases the weight carrying capacity, but it also improves handling and control because tandem axles increase the ground & aft as it travels over rough roads. 

I can't recall ever having seen dual wheel configured tires on any fifth wheel either, while 3 axles are becoming more common with the increased length and weight, especially with toy haulers. 

[mptjelgin]

Newmar outfitted their big fifth wheel trailers with tandem wheels.  They had eight tires on two axles.  They were very well built trailers that weighed north of 20k pounds.

[Jaydrvr]

33 minutes ago, mptjelgin said:

Newmar outfitted their big fifth wheel trailers with tandem wheels.  They had eight tires on two axles.  They were very well built trailers that weighed north of 20k pounds.

The substantial over engineering and ample tire/wheel/axle capacity is what attracted us to the Newmar fiver. Jay

 

Edited April 7, 2019 by Jaydrvr

[Dennis M]

4 hours ago, Jaydrvr said:

The substantial over engineering and ample tire/wheel/axle capacity is what attracted us to the Newmar fiver. Jay

 

Same here and it's still going strong after 14 years and 100k miles plus.

[jenningsr85]

My motorhome is 28'5" long, wheel base is 158.7", what is my wheelbase ratio %?

[fly2low]

.46 or 46%

less than ideal

[Kirk W]

5 hours ago, jenningsr85 said:

My motorhome is 28'5" long, wheel base is 158.7", what is my wheelbase ratio %?

Convert the length into inches which is 341". Next divide the wheelbase by the length.

158.7  /     341     =       46.5%

[rls7201]

So much to do about so little.

My 33' MH, 190" wheel base, 13' of overhang, on a 17,000 chassis would be considered by some as a disaster waiting to happen.
It drives great for an office building on wheels. 
Only one gadget added to the suspension. A front Pan Hard Bar. Toe is set correctly and no rags for tires.
I'll still work part time in the front end business and am very fussy about the way my vehicles drive.

Richard

[Kirk W]

12 hours ago, rls7201 said:

So much to do about so little

Yup. Much like the wearing of a mask or a seat-belt.

[KimberlyJames]

Nice article!

[rls7201]

On 8/2/2020 at 6:38 AM, Kirk W said:

Yup. Much like the wearing of a mask or a seat-belt.

And what does wearing a mask or seat belt have to do with chassis frame ratio and driveability?
What are your qualifications for determining driveability? Please share them.
How many hundreds of vehicle of various configuration have you experienced and corrected their short cummings.
Or are you just repeating what others have said?
 

Richard

Edited August 10, 2020 by rls7201

[Ray,IN]

I agree, this ratio is vital to successful towing. Remember the old 1/2T 10 passenger Ford extended vans? They were notorious for poor handling, both alone and towing a trailer.

On 8/1/2020 at 6:37 PM, rls7201 said:

So much to do about so little.

My 33' MH, 190" wheel base, 13' of overhang, on a 17,000 chassis would be considered by some as a disaster waiting to happen.
It drives great for an office building on wheels. 
Only one gadget added to the suspension. A front Pan Hard Bar. Toe is set correctly and no rags for tires.
I'll still work part time in the front end business and am very fussy about the way my vehicles drive.

Richard

Richard, this is the original  article about wheel-base ratio: https://rv.org/blogs/news/short-wheelbases-and-accidents-go-hand-in-hand

[Alie&Jim's Carrilite]

21 hours ago, Ray,IN said:

I agree, this ratio is vital to successful towing. Remember the old 1/2T 10 passenger Ford extended vans? They were notorious for poor handling, both alone and towing a trailer.

Richard, this is the original  article about wheel-base ratio: https://rv.org/blogs/news/short-wheelbases-and-accidents-go-hand-in-hand

Near the end of the article, it mentions that 5th wheels don't have as much issue due to the 20-25% pin weight.  Unfortunately that is no longer true.  DRV has moved the axles forward do that the standard 350/3500 pickup can carry the pin.  Our 46ft, DRV weighed 21420 empty with a pin weight of just 2830.... 13.4%.  That was with full propane and 2 batteries.  Towed like crap empty.  We loaded as much of our personal belongings into the front of axle area to transfer weight forward.

[Ray,IN]

On 8/12/2020 at 9:01 PM, Alie&Jim's Carrilite said:

Near the end of the article, it mentions that 5th wheels don't have as much issue due to the 20-25% pin weight.  Unfortunately that is no longer true.  DRV has moved the axles forward do that the standard 350/3500 pickup can carry the pin.  Our 46ft, DRV weighed 21420 empty with a pin weight of just 2830.... 13.4%.  That was with full propane and 2 batteries.  Towed like crap empty.  We loaded as much of our personal belongings into the front of axle area to transfer weight forward.

Our last 5er was a Dutchmen Grand Junction, when I changed to bigger diameter tires I had the rear axle moved back 3". Although the 5er towed fine before the axle move, it towed better afterward.