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I have a Scott 720 plus with an OEM FOX Nude shock (120 travel, switches down to 85 then locked via twinloc). Even at 30%+ sag the rear shock never gets much more than 60% through it's travel.
From what I have read it comes fitted with the smallest volume spacer available and that cannot be removed.
Have tried the obvious of undoing the twinloc cable (no difference) and checking I get full travel with the shock deflated (I do).
As it is the rear shock feels softer than the front (Fox 34, where get 90% travel) and it feels like the bike could be better balanced.
Any other ideas?
Have you deflated then repressurised per the manual?
With the shock pump attached to the rear shock valve, pump your desired pressure
into the shock. Once the pressure is achieved slowly compress and decompress your
shock through 25% of its travel 10 times. This will equalize the positive and negative air
chambers and will change the pressure on the pump gauge, if needed add or reduce
pressure and repeat.
Note the compression/decompression of the rear shock through the travel must also
be done if the pressure is reduced!
The volume spacer can be removed - you'll find it on the inside edge of the aircan, at the threaded end. The first thing I would try is to deflate the shock, set it to open mode and then compress - the o-ring on the shock body should go almost to the very end.
What weight are you and what psi are you setting the shock at?
Good shout but yes I did that (every 50psi as per the EVOL specific instructions).
I might however try deflating, equalise then work back up. I have had the bike a couple of years and only now am riding harder am really puzzled why not using any more travel.
The full spec is below if that makes any difference to advice
2017, Nude4, DPS, A, Trunnion Evol LV, Scott, Spark Plus, 165, 45, 0.2 Spacer, CL+, RM, Climb F, PMS-3275C/PMS-3275C Logo
https://www.ridefox.com/fox17/help.php?m=bike&id=568 is where Fox have the volume spacer tables. My shock is a 2017 model which is helpfully not listed. On basis of being 165/45 and LV though the 2018 table says no spacer makes the CR too low.
Settings at the moment are 210psi. I am 80kg, set it up at 30% sag with a backpack, tools and couple of litres of water.
Will go deflate and setup again now to double check,
Just checked and it was ~195psi (allowing for a bit of leakage when putting shock pump on). Sag is bang on 30% without helmet, bag etc.
When I totally deflate I can get full 45mm travel out of it.
45mm is spot-onso it's set-up. I would start by deflating by increments of 5psi/ride and go from there.
Had a very quick play on 185psi. Travels more, sag is just over 30%. It makes the front feel firm though so will have to have more of a play when have more time and the right weather.
" bike a couple of years "
and have you had the shock serviced in this time?
If not might be worth getting a service done.
I have same bike and one thing I will say it's very good and one of the best bikes I've owned . I was told the shock tune is very progessive for pedal efficiency . I'm 15st 9 and have about as much as 35/ 40 percent sag to achieve full travel . The bike with this setting still pedals well and you have lock out for climbs . Also for the fork I found 5 volume spacers in and took 3 out .
Where are you setting sag? Fully open or in traction?
Think I took 2 spacers out of the forks and it works far better for me.
BearBack not sure what you are asking? Sag measured (for rear shock) by sitting on the saddle and dangling my legs. Twinloc open.
Plenty of content on MTBR re this were I found the same issue with the shock on a Spark.  I wasn't getting full travel from my 57mm stroke as per the instructions  but when I got into it I found it was actually a 45mm stroke shock, and the travel ended way before the O ring was pushed off - considerably more.
Secondly, some suspension Guru's have found - validated by some obscure text on Scotts website that Open mode is supposed to be soft and used for descending so not supposed to be open all the time. Â Ride the bike in the majority in the Traction mode and only open it for rough descents. Â When you get your head around this, run a bit more sag it all comes together and just works.
That does sort of make sense.
I probably ride 60% of the time with the shorter travel / increased compression damping anyhow. Plus 30% open (as you say proper descents) and 9% fully locked out climbing. The other 1% I am sliding down a trail on my leg/back/face.
Had two thoughts about the open mode being soft and running more than 30% sag.
Firstly that reduces the effective travel, when on the worst descents I would have thought you would want as much travel as possible (whilst retaining some sag to maintain tyre contact on dips)? Rear is 120mm effective travel, so at 40% sag it leaves 72mm travel (without considering downhill your weight may be further back and therefore it sags more). That said it is a very progressive setup (frame pivot and shock combo) so maybe that is still enough for trail use? I have to say even at ~80mm total travel I have not ever felt it was too little.
Secondly with twinloc I am not sure how much the sag reduces when on the 'traction control' middle setting? The rear certainly sits higher on middle setting so will have to experiment to get best compromise. Unsure where it sits on full lockout.
Not sure on the second point, but on the first point thats the same for any shock/bike with sag. Â I appreciate you feel you're getting cheated out of travel but in reality your are not - as you say its about the wheel falling into dips as much as rising over obstacles.
The trick is with setup - using rebound and compression adjustment to get the "best" scenario of forcing the suspension to rise or resist reactivity to the trail - and this does actually differ from trail to trail, but most of us find the best middle ground and leave it there.
" Sag measured (for rear shock) by sitting on the saddle and dangling my legs. Twinloc open."
NO NO NO NO!! Doing it you way prob means you running to much pressure.
You need to be in the "ready/attack" position, as in on the pedals, standing in a natural position that you would be if to ride go over some rough ground (centre of the bike).
You should also set the forks in this position. Did you sit on your bars to set fork sag?
It helps to kept the bike balance.
I didn't set pressure on basis of sag sitting down dangling legs, that is just how I measured sag.
Do you set pressure using sag?
Yes basically. Sag & Press are connected. Pressure and rider weight affect sag
Say your put 175 psi in your shock and got 30% sag (and you weigh 75kg)
And I get on it, (say I weigh 100kg) I would be more like 35% or more and I prob go through the travel/bottom out quickly, and not feel very supportive.
If I put press in and set up sag to 100kg rider, say 200psi (and slow rebound) then you get on, you prob find it at 25% it feel bit harsh not get full travel etc.
Also throw in how you like to have you bike feel, you can have sag from 25% to 35%
would check out some vids from fox/rock shox etc
https://www.youtube.com/results?search_query=set+up+sag+mtb
Once sag is set correctly and you find you blowing throu travel or not getting full travel, then yes have a play with adding or taking away spacers etc.
You might of set sag correctly and I got the wrong end of the stick, but I would start all over again and set front and rear sag again and go from there.
Talking of rebound, I found my 100mm Spark RC prefers quite a lot of rebound damping - about 5 clicks from centre IIRC. Â Once I added that it felt like a different - more comfortable and controlled - bike,