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Discussion Starter · #1 ·
I was looking at the spring calculator on the CaneCreek website to find out what spring rate I should get for my 210x55 CCDB Coil IL but they did not have all the options I needed in their pre-set dropdown lists (no metric shock strokes) so I could not find out what spring rate I needed.


After tinkering with the data sent by my browser to their calculator I finally found out something interesting that might help you if you are in the same situation.


First, go to their spring calculator webpage

CC DBCOIL IL Spring Calculator

Second, hit the dropdown for "Frame Travel", the options are:


or "Shock Stroke" and the options are:


I'll take the Yeti SB130 as an example (and because it's a great bike. LOL) So what we need for our beloved SB130 is either:

136mmx55mm (if you want the Lunch Ride version ... Ohhh Fancy!)

Right!? So how do we enter those values to get a correct answer about our spring rate?

Well, we modify the data sent by our browser to their calculator ;)

Fixed settings are: units(mm)/riding_weight/sag/preload/weight_on_rear
Variable settings are: frame_travel/shock_stroke

Here's a result of a pre-set "variable settings" on the left VS custom "variable settings" on the right! So if you keep your bike at 130mm and order a 52.5mm stroke coil shock, (the default stroke for the SB130), using the drop down preset options ... the closest values are:

frame_travel: 130mm
shock_stroke: 2.0 (that's 50.8mm, it's close but you'll see it makes a difference)

See what I mean? The spring_suggestion value tells us to buy a 500lbs when in reality we would need a 450lbs

Another example ... if you want to get 136mm of travel, because why not if you order a new coil shock you might as well get more travel for the same price!

You want to upgrade to 136mm so you order a 55mm stroke, using the preset options the closest values are:

frame_travel: 135mm
shock_stroke: 2.25 (that's 57.15mm, again you'll see it makes a difference)

pre-set "variable settings" on the left VS custom "variable settings" on the right

The spring_suggestion value tells us to buy a 400lbs when in reality we would need a 450lbs

OK now that you get it, let's explain how to do it yourself :)


We will make a first query to the CC calculator page, then we will edit it in our browser and replace any values we want before resending it to the CC calculator page. Once the CC server will get our query it will do it's maths as usual as if the query "values" were coming from the "user interface" and it will give us a result/response. that way we will get an accurate result! Got it?

How do we feed custom data into their calculator?

- Use Firefox (could work with another browser but that's what I use)
- Go to the CC spring calculator page (IL or CS depending on your shock)
- Right click anywhere on the page and click on "Inspect Element", several panes will open at the bottom of your window.
- Select the "Network" tab

You'll see something like this (just leave it for the moment):

Text Line Font Colorfulness Black

- Now use the calculator as you normally would and enter your weight, etc... if you can't select what you need, ex: a 55mm shock stroke, don't worry select the 57mm instead.
- Once the calculator gives you a final spring rate, look at the bottom of the page where we have the "Network" tab open. You should see a new line with "POST" at the beginning. Right click on it and select "Edit and Resend".

That's where the magic happens, it's the place where you can modify your data manually and enter whatever value(s) you want!

Blue Text Line Colorfulness Font

Colorfulness Line Font Black Parallel

Once you have modified the values, press "Send" on the top right corner then wait a few seconds. You'll get another "POST" line containing the results of you query. just click on it and on the right hand side click on the "Response" tab to get your result!

Text Colorfulness Font Screenshot Multimedia

Voila! now you know how to modify any value so the calculator can give you an accurate rate spring!

Hope you enjoyed this little "hack/trick" and hopefully it will help you and save you some time and money! Now I'll go order a 450lbs knowing it's what I need :)


398 Posts
Why not just use the Fox Spring rate calculator ? or the many others that allow you to input exact stroke length.

They all spit out similar numbers and still could be +/-100 pounds off which is still 2-3 springs off. Good starting point- but they are dated and don't include useful variables like spring curve, riding style and preferences.
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