Having been reading the Jupiter thread regarding changing rear axles and overdrives, I note that my Javelin feels pretty undergeared. Having calculated my mph per 1000 rpm,allowing for slightly oversized radial tires, as just over 16, at a top speed of 80 mph, which I see in contemporary road tests, the engine rpm would be 5000 rpm. With the standard tires it would be nearer to 6000 rpm. I am not surprised that a few crankshafts broke. We checked my speedometer with a GPS unit and it is about 1.5 mph slow. I was quite surprised that it was that close. After reading the Technical Manual, prepared by JCC, I find that there were alternative axle ratios listed on page 34. The standard Javelin is 4.875:1, but with a change to the crown wheel and pinion, a ratio of 4.44:1 would be possible.
Is it feasible to make this change, and are the alternative crown wheels and pinons avaiable?
Javelin Rear Axle ratios
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Robin Fairservice
- Posts: 322
- Joined: Mon Feb 13, 2006 9:11 pm
- Your interest in the forum: Learning about Jowett cars
- Given Name: ROBIN
- Location: Prince George, BC, Canada