Hi folks. I recently bought a Rockshox Monarch plus rc3 Debonair to replace the crap Fox CTD shock on my 2015 Specialized Stumpjumper EVO 29er. It was advised that I get a low compression tune with a medium rebound. I weigh 103kg and mainly ride big hills and long trails with a fair amount of technical descents . My problem is when I inflate my shock to 300 psi I achieve 40% sag and going by what most people say I should be aiming for 30%. My shock pump dial only reads 300 psi so I have to pump in more air than I would like to achieve 35%. With this setting it ramped up considerably and can only achieve two thirds of the travel on big hits and feels wooden. I opened the air can up to discover four volume reducers fitted so I took out two and fitted it back on the bike. Again I had to pump to 100 psi then cycle the shock. 200psi and cycle again to balance the positive / negative chambers. At well over 300psi I still can't achieve 30% sag so settled on 35%. The shock still ramps up very quickly and full travel is not achievable. Somebody suggested filling the negative chamber with the maximum amount of reducers so I did this and its not really made much difference. My gut feeling is that the air can is too large and more air pressure is used to fill it up, especially for us bigger built riders...trouble is its advertised for Stumpjumpers who usually have smaller air cans fitted because of the 3.1 leverage ration and linear action. There is a lack of aftermarket shocks for this model especially in the 195x46 size. Has anyone on here had the same experience? or is there somebody that could give me a few pointers? thanks for reading guys and any help would be most appreciated. Ray.
I purchased mine from TFTuned and they sent a MM tune which has been pretty much spot on, Im 90kg fully kitted, run it 210psi on TF's recommendation which is pretty much spot on, exactly 30% sag,no volume reducers, very supportive and use just about all travel when needed.
Is it a Stumpy though? Not sure different compression tunes would affect sag air pressures.
Is the l/m tune on the monarch the same as the tune on the stock fox one?
I'd be reluctant to go for a different tune from the recommended one.
>300 PSI is more than I've run on any bike and I'm not far off your weight
Either way id give tf a ring and see what they think
Nothing written on the original shock but it is an autosag shock so never had any problems with sag
If you still have the shock, there should be a 4 letter code somewhere
Or you can use the serial number
.... Enter it here and you'll get the tune info
https://www.ridefox.com/help.php?m=bike
The compression shouldn't make much difference to the sag as damping affects the speed of movement. I would try putting a band in the negative air chamber and try again.
The only number I could find at the bottom of the shaft (where it screws into the yoke is 425954 but that doesn't bring anything up. I just received a full pack of volume reducers and filled both positive and negative chambers and achieved proper sag at 295psi. Still high but it feels better doing the bounce test. If this rain/sleet goes off soon I will go out and test it out. Thanks lads.
Depending on the leverage curve, the correct t sag is t always 30%
Settled for 32mm sag at the moment and it feels kinda like the shock it replaced. Going to give it a few runs and tweaks to see how it goes. I have sent an email to TF Tuned to see if they can advise or change the characteristics if need be
Intrigued to know what the effect of bands in the neg chamber have.
Currently running 2 in the pos (I think anyway, it's the bit under the piggy back air chamber) and shock feels ok but could do with a bit more mid stroke support
FWIW I'm 81kg knitted up and running 220psi and 30% sag on a Nomad
I could never get mine feeling right, it was stupidly soft in the start/middle and still didnt get through all the travel, or set up to pedal decently and was rock hard and only used about 80% travel...
Just seemed to have too much progression and mine was on a bike from new so it was the manufacturers specified tune etc
carlos - MemberIntrigued to know what the effect of bands in the neg chamber have.
having a large negative air chamber means you have less breakaway force required to get the shock into its travel. This means you have to have more pressure to keep the same sag. This has the net effect of giving the shock more ramp/midstroke support. However, this isn't always a good thing depending on rider weight/bike leverage curve.
I had a good opportunity to tune and test the Monarch over the weekend and after a fair amount of faff I settled for three reducers in the positive chamber and two in the negative. Works out at 310 psi for 30-32% sag and I just about reach full travel on biggest hits. It holds up well climbing when in the mid or high setting and just about mimics the Fox shock it replaced but ramps up slightly more at the end of the stroke. After talking to TF Tuned they stated they could have tarted my shock up like a Cockney tart at ascot by doing a push tune and adding a Fast Black coating along with new decals. They also stated Fox shocks are far more tuneable and ultimately more reliable than any Rocksox fork or shock. I have to take their word for that.
maybe an avalanche upgrade for the monarch lol
Yoiks....