# Wheelbase-to-Length Ratio for Motor homes



## LazyRover (Apr 13, 2008)

This is an extract of some words of wisdom by Phred.

*Wheelbase-to-Length Ratio for Motor homes:

Most RVers have never heard the term (or didn't until the RV Consumer Group began concentrating on the subject). The RV Consumer Group, referred to frequently by anybody who knows what they're doing, originated this concept. It refers to one of the most critical factors to be considered in selecting a motor home.

I'll give you the basics. Say the overall length of the MH is 36 feet. That's 432". Say the wheel base is 228". The ratio is calculated as 228 ÷ 432 = .528 = 52.8% (call it 53%).

Anything under 50% is unsafe for highway travel.

50 to 53% is a bit dicey (will wear out the driver causing fatigue and stress).

Only ratios of 54% or more are considered safe.

Lower ratios will wear out your suspension as well as being unsafe.

(Now you know why so many motor homes are a pain in the ass, literally, to drive.)*

Just considering the above premise for the moment and ignoring loading issues....

Does anyone have any opinions as to how this applies to european made motorhomes?


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## DABurleigh (May 9, 2005)

Yes. Similarly.

I agree with the wisdom, at least the physics principles underlying it; I can't vouch for the quantitative/ subjective breakpoints.

It is an irritating thing about the cheaper RVs that they can skimp on wheelbase. Apart from leaving UK RVers subject to the (at least present) legal constraint on 60% overhang, it can create swing-out problems on our crowded roads (though I accept the trade with turning circle), and potentially cause problems if you want to hang a heavy motorbike on the back, etc.

I much prefer a wheel at each corner 

Dave


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## time-traveller (Apr 23, 2007)

I heartily agree with your post LR although I've never before seen it expressed mathematically. Many years ago I found myself the owner of an American RV C-class - I just forget what make but it will be forever engraved on my memory because the rear twin-wheels seemed to be in the centre of the body when viewed from the side. It seemed to me that if it wasn't for the weight of the engine it would have gently pivoted to rest its backside on he ground. And you're absolutely right - it was a pig to drive - quite dangerous really. It seemed to have a mind of its own and would dart from side to side willy nilly - I only drove it a couple of times and needed all three lanes of the motorway at any speed over a good trot. And it was a good substitute for an afternoon in the gym, too. I was thankful when I got rid of it and often wondered if it was really legal, even in the US where anything seems to go.

I've never seen anything even nearly like it on a european chassis, though.



LazyRover said:


> This is an extract of some words of wisdom by Phred.
> 
> *Wheelbase-to-Length Ratio for Motor homes:
> 
> ...


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## sallytrafic (Jan 17, 2006)

Which presumably is why my Renault with a ratio of 72% can corner like a mini but has the turning circle of a VLCC.


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