Ok, folks, my math-lexia is showing its ugly head again.
I have an O/D tranny for Sonja (my TR4). I have to get my
speedo re-built. There are two rear-end ratios (3.7 and 4.1)
available, and Sonja has the 3.7 rear end. If my numbers are
correct, on any reasonable tyre, that gives me either around 16
or 20 miles/Krev. With the 4.1 rear end, the numbers are perhaps
as high as 18 and 22. My local britcar mechanic seema to think
that my car would be much happier with the 4.1 rear. At a "normal"
cruise (let's say 70 mph) that's either 4400rpm/3500rpm or
3800/3200. Does the extra 300rpm _really_ matter that much, or is
it more the 600 in non-od he's likely thinking about? Or are my
numbers totally screwball??
The relevance to the speedo repair is that I need to know _which_
rear I'm likely to end up with so they can get the right ratio
for that. I can always adjust, but I might as well think ahead
for once if I can. Sooner or later there's probably a rear end
in my future considering how nearly dry it was when I bought the
car.
Any advice out there??
-MM
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