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Hi all,
I've got a new coil shock (DVO Jade X) to put on my bike and I need to work out what spring to get for it.
Question 1: what weight to get?
This is for a Trek Rail eBike,
60mm stroke (up from the 57.5 fitted as standard) - this should give around 156mm travel at the wheel (up from 150mm)
I've plugged that into the TF Tuned calculator here
Along with my ready to ride weight (+ extra for eBike motor and battery) - 98.5Kg
This comes out with 531 lb/in for plush DH (33% sag) and 564 lb/in for firmer (28% sag) setup
Just interested in whether that sounds reasonable to you, for anyone of similar weight / similar travel bike?? Do you prefer a heavier or a lighter spring than that?
Question 2: What springs fit?
I've measured the shock and the diameter of the spring mount is 36mm
I've found some cheap rockshox springs that (cheap enough that I can buy a couple of different weights to try out)
AFAIK Rockshox springs are 38mm Inner Diameter, so should, I think, fit with One of these
Does that sound right?
However on the TF Tuned page here it says rockshox springs won't work with other brands of dampers. But I can't see why that would be????
Any clues? Is the info on the TF Tuned page correct?
Thanks for any info / help!!!
First things first do you have the frame clearance for the extra travel you are adding! 6mm is enough to be getting tight, especially if you have a large volume tyre.
Yeah I've just checked it, it'll work in high BB/steep mode.
In low BB/slack mode, With all my weight on the saddle, with just the bump stop on the shock, the rear stay brace JUST kisses the seat tube.
I can take the shock down to 57.5mm, I'll probably do that rather than risk it. DVO sell a spacer I believe.
Re-doing the calculations for 57.5/150 gives
590lb/in for firm 28%sag
556lb/in for plush 33% sag
It’s hard to compare like for like as I don’t have the same bike / the mathematical expertise to do a great comparison.
However I have a Transition Sentinel with a cascade link and a Kitsuma coil shock. 57.5mm stroke delivering 155mm of travel. 4 bar - so similar ish to the Trek I guess.
I’m running a 500lb Cane Creek Valt spring - not sure what the sag is but would guess between 25-30%. I wouldn’t want more sag than I’ve got as I think things start to feel soggy / you could potentially bang through the travel to bottom out. I weigh about 76-77kgs in my birthday suit - maybe 80kgs ready to ride at a guess.
Nukeproof extra light springs come with adapters to fit a variety of different size shocks and are sensibly priced. Cane Creek Valt springs are 36mm diameter I believe so one of those should fit I’d think.
Obviously DVO spring will fit too (stating the obvious).
I found the tf tuned calculator way off for my weight on the standard transition link - it suggested 393lbs for the firmer / trail setup. I’d say I need minimum 475lbs probably - but went to 500lbs then to 500lbs with the cascade link.
Other people are getting away with slightly lighter springs on the same bike - but with different shocks. I think ohlins seem to be more heavily damped and stuff like the ext or new RS Super Deluxe coil with HBO give you more bottom out resistance at the end of the travel.
Edit - to add - look on eBay for secondhand springs. There are loads of ones that have been bought to try out and turned out to be the wrong weight. They tend to go for half the rrp or less so it’s a great way to try out different weights for cheap.
Thanks that's very helpful @joebristol.
If you found the tf tuned calculator underestimated then I will probably try 600lb/in initially. I'd rather it was a bit too firm than blew through all the travel.
From a quick Google it would suggest the Rail has a 17% progression rate (if that’s the right term). Mine has 24% as standard and is better for me with the 30% the Cascade Link has. I’d say firmer is probably the better approach.
Have you already bought the Jade X?
Yeah already got it - turned up today. Very few cost effective coil options that don't foul the frame was reason for purchase. Got it for a V good price.
Depending on how it goes with a linear spring I may look at a progressive one in future.
Will go with a cheap linear spring first though to make sure I am in right ballpark.
If the Rail has 17% progresivity, you'll likely need a progressive spring. I know Cane Creek sproings will fit the Jade.
Not sure if a RockShox spring will fit, but I know they are significantly wider diameter (inside and outside) and can foul on the piggyback of some shocks.