Increase or decrease Rear rebound Damping

[bignick1972]

I was wondering if the lacking of a correct rear rebound setting may give me a sensation of not enough power on first gear 2 UP .
Should i increase or decrease the rear rebound damping if i ride with my wife ?

Thanks
Nick

 

[Checkswrecks]

Put the bike on the center stand FIRST.


Then increase, per your owners manual.

 

[WJBertrand]

Rebound damping or spring preload?

 

[Don in Lodi]

Power feeling vs shock set-up? I don't think the two sensations would be related. Two up needs the preload max'd out though. As mentioned, put 'er up on the centerstand before adjusting preload.

Umm, what does the scale say the two-up masses at? O

 

[bignick1972]

What i m asking is about rebound damping not preloaded adjustment .
When accelerate the bike tend to squat. More weight more squatting . What should i do do compensate ? higher rebound damping ?

 

[Kurgan]

When accelerate the bike tend to squat. More weight more squatting . What should i do do compensate ? higher rebound damping ?

I'm confused by what you're describing, overall. Any bike I've had when accelerating hard doesn't squat, the rear end rises slightly, including the Super Tenere. The only time the bike would do anything resembling a squat, would be when I closed the throttle after being WFO and at that point, it's just settling back to where it was, it's not squatting.

 

[steve68steve]

My (potentially flawed) understanding:
Adjustable damping gives you the ability to set how much resistance the shock will apply to the compression or extension of the spring.


Preload adjusts to put you in the proper "range" of the spring - smooth, level, flight should not have the spring nearly fully compressed or completely uncompressed, to avoid bottoming or topping out the spring (leading to traction loss)


So, my spidey sense says adjust the preload and leave the damping alone.... or mabe more weight means compression damping has to be increased and rebound damping decreased.

Hopefully a suspension guru will post and clarify.

 

[tomatocity]

Nick do you have and ES or Standard?

 

[Rasher]

To slow down the squat you need to add compression damping - something not available on the OE shock.

The chances are the adjuster adds a little of both, many shocks with a single "rebound" adjuster will actually add both, but with a fixed ratio like 3:1 rebound to compression.

The problem is rebound is to reduce the speed the shock returns, so by adding more the bike will squat and then stay there, rather than squat and return, in a way a pillion is already adding a load of rebound damping.

Before I replaced my OE shock I would run full pre-load for two-up and then add a bit of rebound damping to prevent wallow, similarly theory for solo - run the suspension as soft as possible without wallowing in bends.

The OE shocks soft spring and lack of compression adjustment means you are not going to get a great setup, and bigger "improvements" are likely to come from riding smoother to avoid upsetting the apple cart - or to buy a better shock.

IIRC I found the OE shock with max pre-load and about 5-6 turns out on pre-load was about the best compromise, at a certain point adding more damping to mine just made it feel very harsh so I settled for a reduced wallow and decent ride quality - but it would still wallow a bit when pushed on faster bends and ground clearance was still limited - a Wilburs shock made a huge difference and solved all these problems.

 

[Checkswrecks]

What i m asking is about rebound damping not preloaded adjustment .
When accelerate the bike tend to squat. More weight more squatting . What should i do do compensate ? higher rebound damping ?

Squatting is compression of the spring, which is all about preload adjustment.
Compression damping is how fast the spring compresses.
Rebound damping is how fast the shock lets the spring extend after hitting a bump.


None of these have anything to do with making the bike faster or slower unless the suspension is limiting your ability to simply keep traction on rough roads or in corners.

 

[Defekticon]

I'm very familiar with the sensation you're referring to, my wife and I did two up on the Blueridge for a few days on the stock shock and it took a great deal of adjusting to get it to the point where we were comfortable. However, the correct solution if you're going to do a lot of two up riding with luggage is to switch out the spring with one that's appropriate for the load that you're carrying on a regular basis.

Cranking the pre-load up will stop the bike from squatting, but be prepared for a very very rough ride for you and your pillion. With the rebound set too fast and the preload cranked up as high as it will go the suspension is VERY hard, you'll feel everything in the road (but the bike will not squat). This is where you need to play with the rebound adjustment and maybe back off a little preload to find where you'll have a good ride that still supports you and your pillion. I swapped out my stock shock entirely, but it's not necessary, you can get there with the stock shock and a stiffer spring.

 

[WJBertrand]

What i m asking is about rebound damping not preloaded adjustment .
When accelerate the bike tend to squat. More weight more squatting . What should i do do compensate ? higher rebound damping ?

This would be related to spring rate and or preload and compression damping, specifically low-speed compression damping. Rebound damping only controls the extension of the shock after it's been compressed. I have an ES so I'm not sure if compression damping is separately adjustable on the standard models. It sounds to me like you could use more pre-load or a stiffer rear spring.

Having said all of that there should be no connection to engine power.

 

[Rasher]

When I did a lot of two up I had a 160 spring fitted to my wilburs (up from the stock 137 - although my suspension guy measured it and reckoned it was closer to a 130)

The shock also has spate low and high speed compression adjusters so I could add just slow speed compression to help control the squat without making the ride harsh, it also had a lot more pre-load adjustment so I could get a good sag even when two-up with all 3 boxes full.

The 160 spring was a good compromise, but in effect this meant still a bit under sprung when fully loaded, and a bit over sprung when I was solo, the wide range of damping allowed me to find a pretty good setup for most eventualities though.

Since the Mrs now has her own bike I have gone back down to a 140 spring, this is really good for me (80kg) and works well even when fully loaded, and even when two-up it is still much better than the OE shock was, if you are doing a lot of two-up I would suggest a better shock with more adjustment options, and talk to a specialist about the spec for you and your use.

 

[bignick1972]

Thanks to all .
Sorry late answer .