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I would like to find the spring rate of some manitou travis titanium coil springs..

Any one have a idea how to calculate it vs a steel spring?

Choose steel or titanium for spring material.
 

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I don‘t know if this the actual answer you are looking for, but the spring rate itself you can calculate with the shear modulus of titanium, the wire diameter, the number of active coils and the mean spring diameter.
just google „calculate spring rate“ or so.
 

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I actually have the springs, i want to see what its rate is.
There are spring rate testers. You could make your own with a scale, weights and a way to support the weights and measure. All you are measuring is the amount of weight to compress a fixed distance, usually pounds per inch. A machine shop may have one or see if there is a shop that makes coils near you and see if they measure it for you.
 

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I actually have the springs, i want to see what its rate is.
Then I think you will have to measure it if you want an accurate answer. Which isn't that hard actually. Compress the spring a certain amount (length) when it sits on a scale (zero'd for the weight of the spring first, of course). Then just divide the scale reading with how much the spring was shortened under that load.
The problem will be to compress the spring without it flying off to the side or bend. 😅 But let's say you manage to compess it 1/2 inch and the scale reads 30 pounds. Then the spring rate is 30/(1/2) = 60 lb/in. You will get more accurate results if you manage to compress the spring more substantially, but that will require some sort of rig for it.

Edit: For some reason I was thinking of fork springs that are very long and narrow. A coil for a rear shock will be much tougher to compress, but it's short enough to be stable and you don't have to compress it as much. Let's say 1/4 of an inch should be sufficient. A flat, heavy object on top of the spring and then measure the length with calipers might do the trick.
 
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