When you've turned the wheel once it takes up any 'slack', after that the ratio
of tailshaft to wheel will be OK. The other thing is, with one wheel on the
ground the other wheel will only turn 1/2 as much as with both on the ground (as
I neglected to realise initially). Remember Rob isn't trying to calculate an
exact ratio, he's trying to decide between two (3.89 and 4.22).
Certainly, if you were trying to calculate an exact ratio 4 wheels on the ground
is more accurate but it requires more effort and you still have the problem of
deciding what fraction of a turn the tailshaft has made (ie how do you decide
what .89 of a tailshaft turn looks like?) This of course can be largely
ovecome (even using the one wheel off the ground method) by simply turning the
wheel 10 times instead of once.
Vic Hughes
geewillie wrote:
> This test has never produced reliable results for me. However do the same
> test with all four wheels on the ground will always get a true ratio. This
> will not be errored by slippage that can occur with one wheel off the ground
> ( excluding locked rearends). It's more accurate but not easier.
> Gene
> ----- Original Message -----
> From: "Robert Wiseman" <robman@telocity.com>
> To: "Alpines" <alpines@autox.team.net>
> Sent: Wednesday, November 29, 2000 6:16 PM
> Subject: Temp & Gear Ratio
>
> > Well tonight I did investigating.
> >
> > #1. Temp Gauge/Sending Unit.
> > When I turn on the ignition, the gauge jumps to 90.
> > I have the same volts reading at the gauge and the sending unit
> > Someone suggested that I remove the sending unit, suspend it in
> boiling
> > water and check the gauge. No Change.
> > Ran engine 15 min. Drove around block several times. No change in
> > gauge.
> >
> > Does this mean I need a new sending unit?
> >
> > #2. Trying to determine my gear ratio in the rear end.
> > Jacked up one wheel, marked the drive shaft, and the wheel
> > Turned wheel 1 rotation.
> > Drive shaft turned not quite 2 rotations.
> > Did the same with my spare rearend. Same result.
> >
> > What does that tell me about my gear ratio.
> > or should I have jacked up both wheels?
> >
> > Thanks,
> > Rob
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