Date:         Wed, 23 Jun 2004 15:22:47 -0700
Reply-To:     Ryan Press <ryan@PRESSLAB.US>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Ryan Press <ryan@PRESSLAB.US>
Subject:      Re: Towing a Vanagon with a Vanagon?
In-Reply-To:  <00a301c4596a$5587b8e0$6ff7db0c@MAIN>
Content-Type: text/plain;charset=iso-8859-1

Read comments inline:

Robert Fisher said:
> A semi is a specialized system (with specialized sub-systems; brakes,
> suspension, etc) designed for hauling huge loads. A Vanagon is not a semi
> tractor, nor does it have anything close to 300 horse, not to mention 15
> forward gears, ten tires, etc. I don't understand why people keep
> insisting
> on the illogical comparisons between semis and Vanagons. It's like
> comparing
> a kid's toy model rocket with a Nasa booster; yeah, they're both rockets,
> but so what?

I was simply stating that the ratio may not apply to all situations.  The
Vanagon is in no way similar to a vehicle designed specifically for towing
purposes.  I apologize for implying that a Vanagon is like a tractor
trailer.


> As far as the formula below goes, I took its application to be a simple
> dead-weight trailer or vehicle that was not assisting the tow vehicle in
> any
> way (i.e. brakes). Assigning the number 35 to the formula is probably
> shorthand for a more complicated formula; horsepower relates to torque,
> which relates (in design) to the capabilities of the frame, braking
> system,
> etc. in the common American production vehicle. In other words, a 'rule of
> thumb'.

The key to accelerating any vehicle is the amount of torque during the
acceleration period.  Horsepower is fine for overcoming a constant load,
i.e. wind resistance.  To figure out acceleration, the integrated torque
and the gear ratio are the primary factors.

This is why tractor trailers have low HP and high torque.  The HP is there
to overcome constant drag: tires, wind, etc.  This drag is probably not 25
times greater than an automobile as the weight ratio between the truck and
the auto would imply.

The large amount of torque accelerates the load and also carries the load
up hills.


> There's no way it's "all about torque", as in 'Never mind the speed,
> brakes,
> suspension or condition of the vehicle, we've got tons o' torque!" I don't
> buy it.


Nor did I intend to imply that brakes, suspension, etc. are irrelevant.
This is silly.  Just the other day I stated my brakes on my Vanagon were
insufficient to tow a small motorcycle trailer.

I was only commenting on the horsepower to weight ratio.

Ryan