Just had my transfer box ratios changed in my Defender with some higher ratio gears from Ashcroft transmissions which:
"raise your transfer case gearing by 15%, by replacing the gearing in the exising 1.410 ratio transfer box with new geniune Q (quiet) gears, as used in the Disco II."
Can anybody tell me how many rpm I should be doing in 5th at 70mph? (No rev counter yet...)
Thanks
Not 100% sure in which vechicle you are refering but a Disco II with, AFAIK standard gearing and tyre diameter, (tyres are 255/55R18) does
2250rpm (give or take a tad) for 60mph or about 2600 for 70 but I rarely go that fast as it seems to be straining a bit. Much happier hitting the at about 62mph or 2300ish rpm in 5th.All as indicated by the instrumentation of unknown accuracy...
The 'Q' ratio gearset that you have just installed has a 1.211 hi gear ratio (compared to the 1.410 original). This means that your engine revs are going to be 1.410/1.211 = 18% higher than previously for same road speed.
Hope this helps
or 18% lower, but thanks
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