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2200rpm @70mph 2800rpm @80mph also correct by gps on 31" tyres
Gary, I have 31" tyres and also noticed speedo was correct at 50 and 60 compared with my recently purchased gps (£51 Navman on EBay in conjunction with my existing Palm Tungsten T2).
With our 33" tyres, stock gears (4.10's) the Bullet was pulling about 2,250RPM at 80, which was fine in theory for MPG, but in practice it was to high as it needed to much go-pedal to get there so MPG still suffered, and towing heavy trailers was no fun either.
Last week I put a 4.88 geared diff in the back, and she know pulls 2,750 at 80, and the thing accelerates like a 'bullet' train (sic!!) but I think its to low geared as the MPG isn't any better just because of the higher revs at cruising speed, although it would tow trailers great. I think we need either 4.37 or 4.56 gears for the optimum balence of performance and MPG on 33's.
Looking at peoples numbers 2,5K rpm would be nice at 75-80 MPH.
4x4toys.co.uk - Keeping you on and off the road...
Since the speedo drive is taken off the gearbox output speed, tyre size is irrelevant to the speedo reading.
Where it does make a difference is speedo accuracy.
(Mine reads ~3250 at an indicated 90-ish)
90ish! Is that the slowest you go?
I know what you mean, RPM to actual speed over the ground is what we were after, ignoring the what the speedo is saying, we need to get the powerband of the motor back to relate to cruising speeds, which is what tossing bigger tyres on effectively messes up by changing the gearing.
4x4toys.co.uk - Keeping you on and off the road...
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