Choosing a spring for RockShox Super Deluxe 185x55

K78

New Member
Jan 17, 2023
96
52
Manchester
About to order a spring for my shock and want to make sure I choose the right one.

I think my frame is single pivot/Dw Link which would mean a 450lb spring, but tbh I’m not 100% sure.

Thanks

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RiderOnTheStorm

Well-known member
I recently fitted a RS coil shock on my bike (cannondale moterra) and used the MRP spring calculator which gave me very good results. My desired sag (25%) was spot on.

Mountain Bike Spring Rate Calculator

Also, besides choosing the appropriate spring rate for your desired sag, getting the correct L/M/H factory tune for the shock is essential. I saw that the RS shock you picked has the MM380 tunes, medium-compression, medium-rebound, with a 380lb lockout.

To find the Compression (HSC) tune you need for your bike, calculate the avg leverage ratio (suspension rear wheel travel divided by shock stroke).

(M)edium compression tune is ideal for a ratio of 2.5 while (L)ight tune would be ideal for a ratio closer to 2:1. A higher leverage ratio (~3) would need a (H)igh tune.

Rebound (HSR) tune is based on your shock's spring rate. The stiffer the spring, the more rebound dampening force is needed to control the return of the shock after a compression. For example, heavier riders needing a higher spring rate and using higher leverage ratio suspension design would likely require a High rebound tune.
 
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K78

New Member
Jan 17, 2023
96
52
Manchester
I recently fitted a RS coil shock on my bike (cannondale moterra) and used the MRP spring calculator which gave me very good results. My desired sag (25%) was spot on.

Mountain Bike Spring Rate Calculator

Also, besides choosing the appropriate spring rate for your sag, getting the correct L/M/H factory tune for the shock is essential. I saw that the RS shock you picked has the MM380 tune. medium-compression, medium-rebound, with a 380lb lockout.

To find the high speed compression (HSC) tune you need for your bike, calculate the avg leverage ratio (suspension rear wheel travel divided by shock stroke).

(M)edium compression tune is ideal for a ratio of 2.5 while (L)ight tune would be ideal for a ratio closer to 2:1. A higher leverage ratio (~3) would need a (H)igh tune.
That is a huge help. I just emailed the frame builder to ask about leverage ratio.

That works out at 2.7 so that shock should be good?

That calculator recommends a different spring rate than the TF tuned one.

7kg of the 175lbs is motor and battery 60% of which would not be over the back wheel. Don’t know if that makes a difference?

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El Topo

Member
Jul 23, 2022
110
37
Germany, Bavaria
Thank you for the informative reply. I think I somewhat understand that part.

- HSC would be high (+1?), because of the 2.72 ratio.
- HSR would be high (+1/2?) because I would choose a 550-600lbs spring (linear).
- HBO would be low (-1/2?), because of using a progressive spring?
- What about rebound?

To find the Compression (HSC) tune you need for your bike, calculate the avg leverage ratio (suspension rear wheel travel divided by shock stroke).

(M)edium compression tune is ideal for a ratio of 2.5 while (L)ight tune would be ideal for a ratio closer to 2:1. A higher leverage ratio (~3) would need a (H)igh tune.

Rebound (HSR) tune is based on your shock's spring rate. The stiffer the spring, the more rebound dampening force is needed to control the return of the shock after a compression. For example, heavier riders needing a higher spring rate and using higher leverage ratio suspension design would likely require a High rebound tune.


But what about that one? Is there a factory tune, that is particularly suited for a Dengfu E10 and its leverage curve, which has been designed around a 210x55mm shock?
Also, besides choosing the appropriate spring rate for your desired sag, getting the correct L/M/H factory tune for the shock is essential. I saw that the RS shock you picked has the MM380 tunes, medium-compression, medium-rebound, with a 380lb lockout.
I will be 95-98kg geared up, and won't ride hard, if that is of any importance.
 
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