The issue of increasing road speed in MVs is a problem and safety issue both
ways. Too slow and you are a hazard from people running into you or passing
when it is not safe. While increasing the speed raises real safety problems
over braking, tire road contact area and even steering.
My 3 ton Canadian Military Pattern is by any standard today under powered
85hp and has a 4 speed transmission. It does 0-60 MPH in about 12 minutes
on flat ground. The 60 MPH is actual road speed from running (rubber gears)
11:00x20 tires instead of the 10:50x20 tires, the truck thinks it is doing
50. At full speed the truck is moving just about as fast as its short
wheelbase and brakes feel comfortable.
Often it is not a question of a higher top end, but a matter of better gear
ratio spacing. Here in New Hampshire we have a lot of hills so much of the
time I am driving either foot on the floor or no gas at all. On hills on
major highways if I get forced down into 2nd gear very rarely am I using
full throttle. This is where the issue of gears vs top speed come in. On
one convoy run a couple of years ago on the interstate I was leading and for
nearly two solid hours I never shifted gears or had my foot off the floor,
indicated speed ranged from 35-50 MPH (road speed 40-60). On the up hills
the convoys closed up on the down hills and flats it spread out.
I have been looking for years at other transmissions that would fit my truck
but the problem is that the resulting gearing in the middle gears just does
not fit the power curve of the engine.
My point is take a careful look at the weight of the truck as you will be
driving it and where you drive. Look at what the engine RPMs will be and in
what gear for the majority of the driving. Will changing transmissions mean
that you are right at the shift point for your normal driving.
If the truck has the power for more speed then you have to decide does it
have the brakes and handling to be safe going faster. It goes almost
without saying that you have to consider are the tires you running are safe
for extended high speed running at load. My truck with only 4 tires on the
ground and a rally weight of 12,000 lbs. you better believe that I only run
good tires, no weather cracking.
I would be interested in hearing thoughts on effect on the rest of the drive
train of increasing the top speed. Also going back to the original question
what is the top road speed you are looking for?
Philip Waterman
CMP HUP & 3 Ton
Temple, New Hampshire
waterman@tellink.net
----------
>From: David Lorenz <dlorenz@plinet.com>
>To: M422A1Mite@aol.com
>Subject: Re: [MV] M-54 transmission upgrade
>Date: Mon, Oct 25, 1999, 11:52 PM
>M422A1Mite@aol.com wrote:
>>
>> I'm looking to increase the highway speed of my M-54A2. ......
>
>Do you really want to go faster in a military truck that is greater than
>26,000lbs.? ....
>Dave
>
===
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