X-Fusion set up help.

bellys

Hi my bike has got a X-fusion 02 RLX rear shock. http://www.xfusionshox.com/product.php? ... e72f8bac1f

When i have set my rear sag the shock feels very very stiff.
my sag is set to about 20% of the stroke and with 100psi going of there set up guild i should be about 120psi with 15% sag but this is way to hard. when i am out riding the bike im getting about 98% travel from the shock. this is with small drops/jumps and shallow steps.
if i drop the pressure by 10psi it feels better but the shock bottoms out
one of my mates has commented on how firm it feels and was suprised that im geeting all the travel.

as this is the 1st X-Fusion iv owned is it normal for them to feel firm or do you think i should get it look at.

nicklouse

so how do you have the compression damping set? set the sag and play with compression setting. an if new it may loosen up in time.

FBM.BMX

What frame do you have?

Bearings still good?

Correct tune for your frame?

bellys

so how do you have the compression damping set......

this is full open. as there is 3 settings open part open and closed.

if that sounds right.

The Rookie

2 bikes recently reviewed in MBUK (MAY have been MBR) had the x-fusion rear shock and were roundly slated for its performance, I'll check to see if I can find the article (group test) as I recall the complaint was similar to this, very stiff in the initial part of the travel offering little comfort on small square edge hits, then blowing through the mid range far to quickly and not holding the bike up. (Note this is from memory!)

Simon

bellys

FBM.BMX wrote:

What frame do you have?

Bearings still good?

Correct tune for your frame?

http://www.bikeradar.com/forums/viewtop ... t=12797125 its brand new here you go the bike

bellys

The Beginner wrote:

2 bikes recently reviewed in MBUK (MAY have been MBR) had the x-fusion rear shock and were roundly slated for its performance, I'll check to see if I can find the article (group test) as I recall the complaint was similar to this, very stiff in the initial part of the travel offering little comfort on small square edge hits, then blowing through the mid range far to quickly and not holding the bike up. (Note this is from memory!)

Simon

if you can find it that would be good ta.

FBM.BMX

The Beginner wrote:

very stiff in the initial part of the travel offering little comfort on small square edge hits, then blowing through the mid range far to quickly and not holding the bike up. (Note this is from memory!)

IMO, this is due to two things.

The air can volume and frame leverage ratio curve.

OP - Any idea what the leverage ratio curve is like? No doubt being a rockrider, designed by euros as a trail/xc bike, will be very progressive, starting with a low leverage ratio for taughtness (firm ride in sag region), then getting higher through the travel (blowing through). Cubes in particular are bad for this.

As the bike goes through it's travel, the leverage ratio is increasing, it's progressive, air springs are good in these circumstances as they are progressive rather than linear (like a coil). Higher volume air can is less progressive, lower air can volume is more progressive. I bet the air can volume is too large and not progressive enough for the progressive suspension design, in the OPs case and the magazine tests..

This is the exact reason why people have problems with DHX air shocks on progressive trail frames.

I rekon these would fit and explains things further - http://www.pinkbike.com/news/tech-tuesd ... -2011.html

So IMO, the shock is working as it should, just isn't progressive enough for the suspension design, which is the manufacturers fault for speccing an inappropriate sized air can (but would you expect anything better from a rockrider?).

supersonic

The NEUF frame does indeed have a quite marked increase in leverage ratio through the travel, starting from 20% sag of about 2:1 and ending at full travel at 3.6:1

FBM.BMX

supersonic wrote:

The NEUF frame does indeed have a quite marked increase in leverage ratio through the travel, starting from 20% sag of about 2:1 and ending at full travel at 3.6:1

That's a massive increase. Based on this information, this is where the problem lies. You would need to tiny air can volume to battle this.

bellys

supersonic wrote:

The NEUF frame does indeed have a quite marked increase in leverage ratio through the travel, starting from 20% sag of about 2:1 and ending at full travel at 3.6:1

just been reading on this site http://www.bikerumor.com/2011/07/28/rev ... ear-shock/ and it could be some thing to do with the anit bobbing system.

there comments were........... X-Fusion compression damping’s occasional harshness when descending, the O2 really is best suited to bikes with some level of anti-bob built into their suspension design

supersonic

I think the initial shock stiction, seemingly high LSC and lack of HSC amplify the feeling too. Not the best shock...

Is a bizarre sus design, very odd axle path and anti squat numbers.

supersonic

X-Fusion compression damping’s occasional harshness when descending, the O2 really is best suited to bikes with some level of anti-bob built into their suspension design

Hmmm, that's sorta the opposite of what WMB reviewd the shock as! Harsh to start and blow through the travel was the concensus.

supersonic

I'd look for a second hand Float R with a light compression tune. Then use shock spacers as mentioned above to tune progressiveness.

The Rookie

Comments from the Group test in MBR (sorry SS) May 2011 on £1200 full sussers
Ghost ASX 4900 - Cranking hard compresses the suspension easily, even though it has a similar BB height we grounded out the pedals more often, this left no choice but to increase the rear air pressure to get the bike to ride higher. Rear suspension has a habit of dropping into its travel nid corner
GT Sensor 3 - The action of the shock is so firm in te initial part of the stroke that as soon as you hit the brakes or go light on the back end the GT feels like its locked out losing any small bump sensativity at the rear and forcing even more weight onto the front end.
KHS XC 604 - Put simply the rear suspension does not work

Simon

bellys

thanks for that simon.

thanks for your input every body look like i might change it.