>I think I have it figured out. My original speedo is a
>factory OD calibrated one for a 3.89 gearing. When I
>installed the 4.22 rear it will be off and has
>nothing to do with the cable. So the choices are to
>either swap the speedo head for a 4.22 or find an
>original 3.89 rear for a S2. Sound correct? Brent
Yes, regrettably, the Rootes method (and possibly most English cars) for
getting the speedo to match the tranny and rear end was to have a different
speedo for each application. Other cars, like our Ford running breatheren,
do it by having interchangeable gearing at the tranny where the cable comes
out.
There is a chart in the SAOC Guide that lists all Alpines and lists the
exact speedo for that application. The problem is that they simply are not
readily available anywhere.
The second problem is that tire diameter also plays a part in the accuracy.
So, the only real way to get this done right is to take out the speedo and
count exactly how many times the cable goes around (with your tranny, your
rear end and your tires) over 1/100th of a mile (52.80 feet) and send the
speedo to a speedo repair shop with that information.
Note that there are two parts of the speedo that are inaccurate, the speed
needle and the odometer. If you don't care about the odometer, they can
recalibrate the needle only based upon the magnetism needed. If you want
both accurate, they will have to find different gears for the inside, or
hange a converter box off the end. If you have the stock set up, and your
speed needle is off, your odometer should not be off and the magnetism
reset is probably all you would need - unless you want the exact speed
because your tires have changed the odometer too.
Good luck. I'm still running my stock speedo with my OD and 3.89 and
Michelin XZX's, just knowing that a read of 65 is about 45 and a read of 95
is about 65 - and hoping that "about" is good enough not to get a ticket.
One of these days I'll get it fixed.
Jay
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