From: mydeuceandwillys@aol.com
Date: Sat Jun 03 2006 - 05:04:14 PDT
Where you a test pilot in a former life? Yikes i would be worried if i
understood that, But you are correct all the same everything is the way
it should be for sure, But its fun to screw em up and see if we get
away with it, You could get extended handles on those calipers?7 or 8
ft? maybe alittle bent on the end ? Randy
-----Original Message-----
There can be a problem even when supposedly the same size tires are
From: Patrick Jankowiak <recycler@swbell.net>
To: Military Vehicles Mailing List <mil-veh@mil-veh.org>
Sent: Fri, 2 Jun 2006 21:55:54 -0500
Subject: Re: [MV] 900X20 TIRES
used front and rear, although it won't break anything.
When doing 55, having the 1100x20 street tires on front and 1100x20 NDT
on rear, I can engage and disengage the front ok, but in fact if I
disengage it for 1/2 second and re-engage it, it takes 4 seconds to
'click' in, meaning that the driveshaft speeds differ very slightly due
to the tire sizes, inflation at the time, and probably wear.
Does not the front engagement spline in the transfer have 6 teeth? that
would make it 4 seconds for one tooth, and because each tooth is
occupying 1/2 the size of the space of 1/6 of the circumference and
only has to slide half as far to click in, then there is 48 seconds for
one revolution, meaning that the rear driveshaft is turning 2500RPM and
the front is turning 2500.0208333 RPM (assume faster for the argument,
same difference either way) disengaged.
The driveshaft difference is then 0.0208333RPM which is 7.499988
degrees per minute and also is 0.1249998 degrees per second.
The 6.72 gear ratio reduces this to 0.0186011607 degrees per second at
the axle.
An 11.00x20 tire (I think) has a circumference of 128.8 inches, and so
1 degree is 0.35 inch.
Therefore the front and rear tires are forced to slip relative to each
other by 0.00651 inches per second at 55MPH. I had a hard time
measuring this to confirm it officially because the calipers kept
getting knocked out of my hand as I had them down too near the road to
be sure and accurately measure the slippage along the tire's contact
patch.
I can see that this is a major source of friction anyway and I better
go back to the matched 11.00x20 NDT's on the front right away.
PJ
===Mil-Veh is a member-supported mailing list===
To unsubscribe, send e-mail to <mil-veh-off@mil-veh.org>
To reach a human, contact <ackyle@gmail.com>
Visit the searchable archives at http://www.mil-veh.org/archives/
This archive was generated by hypermail 2.1.4 : Tue Jul 18 2006 - 21:47:04 PDT