# spool ratio

**URL:** <https://forum.deltamotion.com/t/spool-ratio/383>\
**Category:** Motion System Design\
**Created:** [February 23, 2016, 3:43pm UTC](https://forum.deltamotion.com/t/spool-ratio/383 "2016-02-23T15:43:26Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![bripet3](https://forum.deltamotion.com/letter_avatar_proxy/v4/letter/b/58956e/32.png) [@bripet3](https://forum.deltamotion.com/u/bripet3)\
**Post date:** [February 23, 2016, 3:43pm UTC](https://forum.deltamotion.com/t/spool-ratio/383/1 "2016-02-23T15:43:26Z")

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I would like to ask for some advice regarding if and when getting a ratioed spool is needed.

We plan to use the Bosch Rexroth 4WRLE 25 valve (as we have these on the shelf) with a 150id cylinder and 100od rod. Would it be essential to get the valve adapted with the equivalent spool ratio?  
This machine will only operate for a few weeks so it would be nice to keep the valves generic for future projects.

The rig is with the rod pointing up lifting a load.

What would the effect of having a 1:1 ratio spool give me vs a ratio spool on the control and motion?

Thanks in advance for everyones input.

Pete.

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**Author:** ![Peter\_Nachtwey](https://forum.deltamotion.com/letter_avatar_proxy/v4/letter/p/f17d59/32.png) [@Peter\_Nachtwey](https://forum.deltamotion.com/u/Peter_Nachtwey)\
**Post date:** [February 23, 2016, 6:03pm UTC](https://forum.deltamotion.com/t/spool-ratio/383/2 "2016-02-23T18:03:23Z")

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I would use 1:1 valve you have on the shelf for two reasons.  
The rod is pointing up.  
the system is moving slow.

The main advantage of using a 2:1 valve is that cavitation can be avoided but that only happens when the rod is facing down or a horizontal load with a heavy mass needs to decelerate quickly.  
Your applications meets none of these conditions

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**Author:** ![bripet3](https://forum.deltamotion.com/letter_avatar_proxy/v4/letter/b/58956e/32.png) [@bripet3](https://forum.deltamotion.com/u/bripet3)\
**Post date:** [February 23, 2016, 6:28pm UTC](https://forum.deltamotion.com/t/spool-ratio/383/3 "2016-02-23T18:28:23Z")

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Thank you Peter for your quick response,

Much appreciated  
Pete Britten