i checked the gear ratio on my 53 merc and i spun the shaft 2 turns to make the wheel spin one. so is that a 2:10 rear end? Ive never heard of that. So its time to change, i'd like to go over 45mph " not original trans"
Probably 4:11. If you only let one wheel turn you have to let it go two revolutions as you count the driveshaft turns. A 2:10 ratio would be way fast. You would be idling at 60 mph.
No, 2.000:1, provided it really was exactly two revolutions. Gear designers try to avoid simple round-number ratios, and often favour prime numbers of gear teeth or at least tooth counts that aren't common multiples, in order to avoid unwanted harmonics. So, if you've got 19/37 teeth, say, you'll have a 1.947:1. I'd be very surprised if you had 18/36! You'll certainly be able to go over 45mph. With, say, 26" tyres, a 5500rpm redline, and enough power to overcome aerodynamic drag at that speed you'd be able to go about 213mph. You'd need all week to get there, though.
The merc has a dana spicer 45 rear which should have a tag on one of the bolts of the rear cover. It will have the ratio. 4.11 was a common ratio with a 3 spd overdrive.
9/37 gives 4.111:1 REM/Mo makes a good point. If you only rotated one rear wheel, the other being prevented by being on the ground, say, you would have brought the differential into play, which would have caused the drive shaft to rotate half the number of revolutions it would have if both rear wheels rotated at the same speed. That would have given you a reading of 2.056:1 from a 4.111:1 rear.
Well, i had both rear wheels off the ground bt the passenger side did not rotate. Aslo here is the only id i could find on the axle after being fed grime from a wire wheel. 1A4025
I put a video on youtube showing how to check an axle.. The other wheel needs to be on the ground, and you need to rotate the raised wheel twice. Do not do this with a locker diff. Mart. http://www.youtube.com/watch?v=bkvp3Fq21ZM
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