Info needed: Streetable CMP truck

[Hanno Spoelstra]

Originally Posted by Lang

There are lots of anecdotal figures on what people can and can not do with tires, gear ratios and engine speeds. There is nothing subjective about it - just straight maths.

The subjective bit is when one bloke thinks it OK to sit on 3,000rpm all day long while another is horrified if it goes over 2,500rpm on an over run down hill. More than worries about engines exploding is the fact revs-is-fuel.

There are lots of calculators on line. I find this one pretty quick and easy. Their 3rd gear number is just standard 1:1

https://spicerparts.com/calculators/...rpm-calculator

This tells the story, even with a modern efficient design quite clearly every extra rev is costing you money.

Thanks Lang, helpful indeed to calculate rpms at a given speed.

For a C15, cruising at a speed of 80 km/h, with a 6.16 to 1 ratio rear differential and 844 mm diameter tyres, the engine will rev at 3096 rpm.