chevynut
06-03-2016, 09:56 AM
I saw this on Ridetech's site and compared it to my own coilover spring rate calculator with different results. I can't find the formulas they use, but I don't think theirs is correct. As you change spring angle or the car's weight, the preload should change but it doesn't. The spring rate changes, but only in certain increments which makes some sense as they probably round up or down.
http://www.ridetech.com/tech/spring-rate-calculator/
I also downloaded the spreadsheet and it's worse imo. For some reason they want you to measure the wheel rate first, then calculate spring rate. That makes no sense to me and I don't understand how a guy with a custom application is supposed to use it.
www.ridetech.com/info/wp-content/uploads/2016/02/spring-rate-calculator.xls (http://www.ridetech.com/info/wp-content/uploads/2016/02/spring-rate-calculator.xls)
It's not that hard to do the calculations to arrive at a spring rate. One thing I did notice is that in their spreadsheet they square the motion ratio but NOT the shock angle factor. I understood you have to square both of them and my spreadsheet does that. The difference isn't that significant at low angles.
My spreadsheet calculates the exact rate needed (not increments of 50) using the car's weight, unsprung weight, shock angle, motion ratio, and shock parameters, as well as the desired adjuster nut height. I round up or down depending on whether I want to go softer or stiffer. I will be trying to gather feedback from customers who I've used the spreadsheet for.
Ridetech is right about one thing...most guys over-spring their cars and then complain about how bad the ride quality is with coilovers. I try to use the softest spring possible since coilovers have a pretty limited stroke.
http://www.ridetech.com/tech/spring-rate-calculator/
I also downloaded the spreadsheet and it's worse imo. For some reason they want you to measure the wheel rate first, then calculate spring rate. That makes no sense to me and I don't understand how a guy with a custom application is supposed to use it.
www.ridetech.com/info/wp-content/uploads/2016/02/spring-rate-calculator.xls (http://www.ridetech.com/info/wp-content/uploads/2016/02/spring-rate-calculator.xls)
It's not that hard to do the calculations to arrive at a spring rate. One thing I did notice is that in their spreadsheet they square the motion ratio but NOT the shock angle factor. I understood you have to square both of them and my spreadsheet does that. The difference isn't that significant at low angles.
My spreadsheet calculates the exact rate needed (not increments of 50) using the car's weight, unsprung weight, shock angle, motion ratio, and shock parameters, as well as the desired adjuster nut height. I round up or down depending on whether I want to go softer or stiffer. I will be trying to gather feedback from customers who I've used the spreadsheet for.
Ridetech is right about one thing...most guys over-spring their cars and then complain about how bad the ride quality is with coilovers. I try to use the softest spring possible since coilovers have a pretty limited stroke.