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Suntour Epicon SAG and travel settings

clydefrogclydefrog Posts: 162
edited April 2012 in MTB workshop & tech
Hi, I was looking at information about setting the correct SAG on the Suntour Epicon fork that came on my new bike. In the manual it says to do this you need to firstly set the forks travel to it's maximum setting. Is this really necessary? It's something I don't have the tools for and looks like a lot of work, and also potentially damaging if you make a mistake whilst doing it. Should I just set the air pressure and leave it at that, and not bother doing any of the sag adjustment, or should I just set it to the recommended SAG % for the current travel setting?

Also if I want to change the air pressure in my fork, do I need to completely bleed out the air already in it and then inflate it, or when I attach my shock pump and start inflating will the needle on the gauge bump up to show the current PSI of the fork and I can just inflate it a bit more?

Thanks.

Posts

  • Greer_Greer_ Posts: 1,716
    1. Set sag for your current travel setting. I think sag only has to be set at max travel for u-turn forks.

    2. a) If solo air, you can inflate from whatever pressure its currently at

    b) if dual air - look here viewtopic.php?t=12629675
  • clydefrogclydefrog Posts: 162
    Greer_ wrote:
    1. Set sag for your current travel setting. I think sag only has to be set at max travel for u-turn forks.

    2. a) If solo air, you can inflate from whatever pressure its currently at

    b) if dual air - look here viewtopic.php?t=12629675

    Well like I said the manual says "Forks which come with travel adjust option have to be set to the maximum travel." but I am really not up for doing this for the reasons stated. It also mentions this in the same section "63-100mm travel --> 15-20% sag120-180mm travel --> 20-25% sag" so if my travel is 120mm which I think it is (max is 140mm on this fork), I was just going to try and get the sag to about 20% by adjusting the air pressure.

    By solo air do you mean you only inflate one side? That's what the Epicon is, you only inflate the left side. Cheers.
  • Greer_Greer_ Posts: 1,716
    You can check the travel by deflating the chambers then measuring travel with a tie wrap or O-ring around the stanchion. Solo air has one valve on the top left leg which fills both the +ve and -ve chambers at the same time, dual air has two separate valves (one at the top of the left leg (+ve) and one at the bottom(-ve)) to give greater adjustability.

    By travel adjust I think it means U-turn which is travel adjust on the go (by flicking a switch) not internal travel adjust which the epicons are. If you set sag for 140mm then changed the travel back to 120mm, you would have to deflate the chambers so its pointless. Set the amount of sag for 120mm which is usually 15-20%. Hope that explains it a bit more
  • clydefrogclydefrog Posts: 162
    Greer_ wrote:
    You can check the travel by deflating the chambers then measuring travel with a tie wrap or O-ring around the stanchion. Solo air has one valve on the top left leg which fills both the +ve and -ve chambers at the same time, dual air has two separate valves (one at the top of the left leg (+ve) and one at the bottom(-ve)) to give greater adjustability.

    By travel adjust I think it means U-turn which is travel adjust on the go (by flicking a switch) not internal travel adjust which the epicons are. If you set sag for 140mm then changed the travel back to 120mm, you would have to deflate the chambers so its pointless. Set the amount of sag for 120mm which is usually 15-20%. Hope that explains it a bit more

    Yeah it's strange that you'd have to do all of that to set it to 140mm, but then do it all again to change it back to 120mm anyways for the proper height. Why would it not mean the internal travel adjustment though, when that is the only way of doing it on the Epicon? Surely they still count that as a travel adjust option as well as some quick adjust thing like the U-turn (if any suntour forks have that)?
  • Greer_Greer_ Posts: 1,716
    Hopefully someone else will come on and agree with me, but its just what's done. If you're running the forks at 120mm, you set the travel for that. The extra 20mm travel has nothing to do with it if you're not using it. You will reduce the amount of sag if you use the same pressure at 120mm as 140mm which defeats the purpose of setting it at the correct sag.

    Some manuals have to be taken with a pinch of salt - it just doesn't make sense to actually do what you are interpreting from the manual.
  • clydefrogclydefrog Posts: 162
    Greer_ wrote:
    Hopefully someone else will come on and agree with me, but its just what's done. If you're running the forks at 120mm, you set the travel for that. The extra 20mm travel has nothing to do with it if you're not using it. You will reduce the amount of sag if you use the same pressure at 120mm as 140mm which defeats the purpose of setting it at the correct sag.

    Some manuals have to be taken with a pinch of salt - it just doesn't make sense to actually do what you are interpreting from the manual.

    I think you're probably right and I can just set it to the correct sag % for 120mm travel by using that cable tie method and adjusting the air pressure. I've just sent an email anyways to one of the suntour servicing guys asking the same thing to see what they say, but either way I will not be taking that thing apart and doing all of that stuff if that's what they say you're meant to do. Thanks for the help.
  • clydefrogclydefrog Posts: 162
    By the way what did you mean by this
    Greer_ wrote:
    You can check the travel by deflating the chambers then measuring travel with a tie wrap or O-ring around the stanchion.

    I can see what the travel is set at just by measuring the length of the stanchions from the seals to the tops with no load on it (it is 120mm by the way).

    I understand I'm meant to set the sag on these by firstly setting the pressure to 73psi, then putting a tie around the stanchion by the seal, riding forward on level ground then getting off and measuring the distance from the seal to the new position of the tie. I should then adjust the air pressure until the distance from the seal to the tie position is around 20% of the total travel (120mm).
  • supersonicsupersonic Posts: 82,708 Lives Here
    You need to take apart to adjust travel - there is no need to do this. The instructions mean for EXTERNAL travel adjust ie a crown top knob - you fork doesn't have this.

    Set sag at 25% of travel and see how it feels.
  • clydefrogclydefrog Posts: 162
    Yeah they must be, anyways I've set the sag at about 20% sitting on the bike, but then I also stood on it too and obviously that changed the amount of sag quite a bit. I've now set the pressure to about 150psi (from the original 100) which means if I'm sat down it won't reach the 20-25% sag but stood up it will, I'm going to have to experiment with it a bit more and and also try out the rebound adjust.
  • Greer_Greer_ Posts: 1,716
    Yep its meant to be set in the 'attack' position. If you find yourself bottoming out, put a few more psi in, or else remove some for better small bump compliance. A good bet for the rebound is just halfway. It will all take a bit of playing about with to get them working perfectly :)
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