Help with fox 40 factory float and DHX2 adjustment

PB Forum :: Downhill
Help with fox 40 factory float and DHX2 adjustment
Previous Page |
Author Message
Posted: Feb 15, 2020 at 4:26 Quote
Hi, just purchased a second hand Gt fury World Cup with fox factory suspension, but the bike is bucking me out on jumps. I’m landing very nose heavy every time. The stem is pretty short and my weight is as far back as I can get comfortably. I’ve set the suspension up for my weight with the correct spring and preload and followed the fox guide and set the compression and rebound to the base settings for my weight. Problem is I’m not great at setting up suspension other than getting the sag right. I copied someone else’s settings on my nukeproof mega and it instantly felt good and jumps are a breeze on it. I’m lost especially with the DHX2 as it’s got so many settings. Am I correct in maybe speeding up the fork rebound and slowing the high speed rebound on the rear? Any help is appreciated

Posted: Feb 16, 2020 at 13:00 Quote
Honestly, just try to learn what the different settings do. It´s a good skill to have anyways and the only way to ensure you get things dialed in the way you want/need to.

As for a quick remedy, no high speed rebound is most likely not what is causing your problems.
HSR is only really utilized when your suspension is compressed deeply into its travel where the spring force is highest.
Assuming you have the correct SAG/spring rate this should not be happening on jumps.
I would not touch HSR at all until you´ve actually taken advantage of any other options.
The most likely culprits are either compression settings or your spring rate.
If the spring is too soft, you compress the bike too much on jumps and store too much energy into the spring. This will result in bucking even if you overcompensate by slowing rebound down, as the lift off phase inevitably gets unstable.
The other option being compression. Again, without knowing the details i cannot really help you much, but lots of people tend to run no LSC at all or only very little. Take advantage of it to maintain chassis stability in your bike if you haven´t. It may take only one or two units of adjustment to change the bikes behaviour. Same goes for HSC, even though it will most likely only affect jumping when you have way too little HSC.
That´s all under the assumption your LSR is already dialed in correctly of course.

As for the fork, there shouldn´t be any need to compensate for any suspoension part by adjusting the other to less than ideal settings. Of course they interact but you really should be assessing their performance individually in order to determine how far from the optimal setting you´re willing to stray.
Personally i get my frok dialed the way i need it to behave, then set up the shock to do the same. If then there´s a problem with balance i have a baseline to start and can assess which component is more suited to making the necessary changes. Like, if my shock rebound is already pretty damn slow, it might probbaly be better to not slow it down any further but rather speed up the fork. If the bike feels like the front is diving i can either stiffen up the front or adjust for a little more give in the back, depending on what requires me to stray less from my "optimal" settings.

Posted: Feb 16, 2020 at 13:27 Quote
Thanks for the reply. Looks like I’ve got to spend a long day(if the weather ever gets better here) to play around with it. I’ll have a look at the compression first then, spring is good, requires only a few turns of pre-load to get roughly 20% sag. Just nice to know roughly which direction to take with the suspension settings. It’s possible my technique might need adjusting but I’m reasonably dialed on my mega, didn’t think I would need to change too much for a bit more travel and slacker geo. Thanks again

Posted: Feb 16, 2020 at 14:05 Quote
Spangoolies wrote:
Thanks for the reply. Looks like I’ve got to spend a long day(if the weather ever gets better here) to play around with it. I’ll have a look at the compression first then, spring is good, requires only a few turns of pre-load to get roughly 20% sag. Just nice to know roughly which direction to take with the suspension settings. It’s possible my technique might need adjusting but I’m reasonably dialed on my mega, didn’t think I would need to change too much for a bit more travel and slacker geo. Thanks again

Downhill bikes usually like more sag, 30-35% is fairly normal. If you truly running only 20% then yes it should be bucking you as you won’t have nearly enough rebound damping. DHX2 should only use between 1 and 2 turns of spring preload.

Posted: Feb 16, 2020 at 14:12 Quote
Probably more like 25% but I’ve got a slightly lighter spring in the parts box so I’ll give that a try also. Thanks

Posted: Feb 16, 2020 at 16:18 Quote
First off, preload should never be used to set sag.
Make sure the spring is secure, that´s it. Otherwise get a different spring.

Also, why would less SAG make him get bucked? He´ll just have to adjust rebound accordingly. After all, the FEST guys all run waaaaay too heavy springs and yet their bikes work fine.
Maybe i misunderstood what you were saying though? Did you mean while using the base settings?
I agree though, 20% most likely is way off in terms of sag.

Another thing i´d like to mention is fork SAG.
This seems especially important as your SAG in the rear is, as was said, a little low.
I generally cannot make a fork work with anything more than 15-20% SAG. So if the usually suggested 30% do not work for you, don´t hesitate to ramp things up in the front to get a little less SAG.
The suggested 30% are a good starting point for the rear though. 20% seems really firm and may very well be what´s causing the imbalance.

Posted: Feb 16, 2020 at 21:46 Quote
I used the an online spring calculator that took my weight, suspension travel, stroke, riding style etc and said I should be using a 450 spring but I’ve got a 400 spring I can try. Like I said it’s probably more like 25% sag. The base settings are from the dhx2 user manual where your weight puts you in a table and tells you a base setting for all 4 adjusters to start from. Fork is definately set to 20% sag.

Posted: Feb 16, 2020 at 21:54 Quote
Spangoolies wrote:
I used the an online spring calculator that took my weight, suspension travel, stroke, riding style etc and said I should be using a 450 spring but I’ve got a 400 spring I can try. Like I said it’s probably more like 25% sag. The base settings are from the dhx2 user manual where your weight puts you in a table and tells you a base setting for all 4 adjusters to start from. Fork is definately set to 20% sag.

Here I share you these videos, very easy to understand and vital on understanding how and perfectly setup your suspension.

MTB rear suspension (Ep.2): Forces & SAG

MTB rear suspension (Ep.3): Don't Preload your shock (too much)!

How to CORRECTLY setup rebound damping (MTB rear suspension Ep.5)

Tuning tips: Compression & Rebound damping (MTB Rear Suspension Ep.7)

Posted: Feb 16, 2020 at 23:47 Quote
Thanks for those, I’ll take a look. Setting this up is turning into a bigger project than I hoped. Thanks for everyone’s input

Posted: Feb 17, 2020 at 7:56 Quote
Spring calculators are not a good way to determine the spring weight. There are too many variables going into it and these tools oversimplify things way too much.
I´ve always ever gotten good results by buying some cheap used springs in the rough ballpark of what i might need according to the calculkator or manufacturer recommendation and then testing them.

Posted: Feb 17, 2020 at 17:22 Quote
Loki87 wrote:
Spring calculators are not a good way to determine the spring weight. There are too many variables going into it and these tools oversimplify things way too much.
I´ve always ever gotten good results by buying some cheap used springs in the rough ballpark of what i might need according to the calculkator or manufacturer recommendation and then testing them.

I agree on Loki. Spring calculators are not that good of a tool to setup your suspension perfect. It is better to take your bike out on the trail and test it there, record yourself to see how to spring is behaving.

Posted: Mar 14, 2020 at 20:29 Quote
It's a DH bike...30-35% sag in the rear.

Posted: Mar 15, 2020 at 13:53 Quote
If you’re getting bucked forward, you need to adjust high speed compression and rebound because doing jumps is all about high speed. The easiest way to start adjusting I would turn down your high speed rebound 1 click at a time while sessioning 1 jump. Once your bucking is controlled, ride other jump lines to see if you’re bottoming out or if Your blowing through all your travel. If you are, then you need to turn up your high speed compression. If your jump landings feel stiff, then turn down your high speed comp. as you change your compression, you will find that you will need to change your rebound because they interact with each other.

Posted: Mar 15, 2020 at 14:00 Quote
Thanks for the help, it’s all appreciated. I was originally hoping for better weather to get back out but now waiting for f*cking viruses of Chinese origins to do one so we can get back to normal without using up stretched emergency services sorting my crashed broken ass from the local trails

Posted: Mar 16, 2020 at 10:45 Quote
I had issues with my enduro bike getting kicked sideways off of jumps with my X2 (I have years of jumping experience from BMX and MTB). I eventually just started running the HSR fully closed after watching a Vorpsprung video where Steve recommended running the HSR full closed unless your LSR is fully open. His reasoning didn't have anything to do with jumping but it fixed my jumping issue. So regardless of theory, I think it's worth a shot to try running your HSR fully closed and see if that fixes your bucking issue. Then you can play with opening it back up a click at a time if you want.

You can also play with adding LSR and compression if you want. The X2 and DHX2 both seem capable of running fairly slow feeling rebound without packing up.

Previous Page |

 
Copyright © 2000 - 2020. Pinkbike.com. All rights reserved.
dv65 0.005270
Mobile Version of Website