Richard A. Boris wrote:
> I validated that my tachometer is reading correctly and checked the
> speedometer to a MGB traveling next to me. The condition I have is in
> forth gear, 4000RPM at 60 MPH. Does anyone know what the rear end ratio
> is? In the next few weeks I will be installing the entire banjo axle
> with a 3.909 ratio.
60000
----------------------- = MPH/1000 RPM
Axle ratio * (revs/mile)
MPH/1000 RPM (4th Gear)
TIRE -------------------------------------------
SIZE REVS/MILE 4.55 4.3 4.1
3.91
-------------------------------------------------------------------
560x14 853 15.459 16.358 17.156 17.989
165x14 854 15.441 16.339 17.136 17.969
560X15 814 16.200 17.142 17.978 18.852
165x15 820 16.081 17.016 17.847 18.714
Rich ... assuming 165X14 tires, you have a 4.55 diff fitted ... just a WAG
on my part, as tire diameters and hence REVS/MILE vary ... but, it does
provide a ROM.
The ratio is stamped on top of the diff ...
BANJO REAR GEAR RATIO
-----------------------------------------------------
4.55:1 9 pinion/41 ring gear teeth
4.30:1 10 pinion/43 ring gear teeth 1500/1600 'A'
4.10:1 10 pinion/41 ring gear teeth 1622 'A'
3.91:1 11 pinion/43 ring gear teeth 'B'
... if its a 4.55 ratio you should find 9/41 stamped on the diff ...
however, it is possible that someone fitted a new set of gears to the
carrier so ya may want to count the teeth.
Give me a shout if you'd like to part with the 4.55 diff.
Safety Fast! ... larry.g.unger@lmco.com
'61 MGA 1600 MkII
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