How to Determine Your Spring Rates

At RT Pro, we want to make it easy for you to get yourself set up with the best product for YOU. We've took over a decade of experience with development and customer feedback and crammed it in to a simple form for anyone to use.  It's pretty complex on our side, but a simple formula on the customer end. We (including Andy) wrote it so you can trust it. It's been proven over 20k uses to be 95% accurate. Click HERE to fill this form out and submit for instant results and a link to the kit you will need for your model. For inquiring minds, read on to learn how it works.

The weight listed refers to total driver, passenger, accessory and cargo weight. We recommend using your most average weight to figure from since it's obviously how you use the machine the majority of the time.

Plows and other part-time gear/accessories can make this calculation complicated but there is much more effective adjustment in our spring kits than the OEM springs due to proper design. All threaded body type shocks seem to have enough preload adjustment to compensate temporarily for these additions without a spring rate change so the formula below still applies. If the preload adjustments don't give you enough adjustment on Polaris UTV's w/ Sachs OEM shocks (non-threaded body) when adding the temporary or seasonal weight we do offer these Spring Shims which add 1/2" per shim to the preload and are stack-able up to 1".

How it works:

  • This formula has been adjusted to work for all our springs kits for all models. It adjusts base values by model. 4 seat/crew models use a different final "shifting" number.
  • If you have our lift kit or plan to run one, this will take 200 lbs. OFF your total number. If you have offset wheels, wheel spacers or anything that makes the wheel offset 2" or more from the original wheel/hub relationship it adds 100 lbs. to your total. (Anything under 2" PER SIDE doesn't count.)
  • To determine your rate choice you must add up all of the weight you carry on your machine. This should include anything that makes the machine weigh more than OEM weight. This weight should also include average driver/passenger weight (you can play with this weight a little later). Note: Spare tire weight is factored separately by mounting location. We figure 50 lb in bed and 100 lb off bumper due to increased leverage.

If your final number equals under 600 lbs. we will recommend the medium rate springs. Anything over 601 lbs. will work best with the Heavy rates. (The "shifting" number is 800 lb for 4 seat/crew models).

Try it as many times as you'd like. If you end up really close to the 600 lb. line you can play around with the driver/passenger weight a little bit and reconsider your most average loads. If you are still on the line: Think about what you're looking for in a ride. If you consider yourself a moderate driver, err to the lighter side. If you’re an aggressive driver err to the heavy side. Furthermore, if you are the type of person who considers a smooth ride the most important then go on the lighter side. If you would rather have support and height over a "Cadillac" ride then go towards the heavy side.

We can fine-tune your system by simply swapping out some springs from your kit for a fraction of the cost of making you buy a whole new kit. Often it only takes 2-4 springs if a change is even necessary. We offer a "Spring Exchange Program" here which allows the original purchaser of our spring kits to swap out springs at far less cost than buying springs outright to "try out". If you go through our process and still don't feel content with your height or ride just call and talk to one of our friendly techs.

Note: This formula applies to our lift kit and springs ONLY. We make it a strict policy to refuse comments about the performance or relationships of any competitor’s products to ours. We know our parts, are convinced they are the best, and have no time to consider alternatives. It's not worth wagering a guess if something else will or will not work with our products when we have complete kits available.

NO GUARANTEE is made with these calculations. RTP will not be held responsible for miscalculations or liable to send you new springs until your heart’s content. We feel very confident in this formula but this is ONLY an advanced method of guessing. Our policy is to exchange with customers for $70 per two springs plus shipping both ways for an exchange. There is NO exchanging recoated springs.