Rebound adjustment help please

[capo1000]

Played around with my rear suspention yesterday...Trying to get it set up for me solo...Then Ill work on 2-up.

Im 200 lbs. Got the preload up to where theres 2 lines showing, and it feels good. Im trying different rebound settings and heres where I need some help. I had it about 2-1/2 turns out from full hard. Felt good over the bigger bumps, and series of smaller potholes, jagged pavement...Felt like it recovered nice and no packing.
What I did notice was when Id come over a crest, a "hump" in the road it felt like the rear wheel would pop up and almost come off the ground....Should I soften the rebound or harden? Or maybe the preload is too stiff? Im not sure because the bike really feels good everywhere else.

Any help would be appreciated. I did a search and know its been discussed before. Im just confused on which way to go with what Im experiencing.

Thanks,
Bill

 

[st1300r]

I'm forgetting the typical rebound setting.
Search the threads and look for Raven's description of rebound setting and why seat of the pants adjustment can fool you.

 

[capo1000]

I'm forgetting the typical rebound setting.
Search the threads and look for Raven's description of rebound setting and why seat of the pants adjustment can fool you.

Got that already..But thanks...Said to start at 2 turns out. He mentions "oscillating" and the rear feeling like is packing over series of bumps as a reference on adjusting. Mine isnt doing either....Just this "hop" sensation. Im not sure if this is a sign on to much rebound or too little. I can just keep messing with it but Im hoping someone has experienced this and can make some suggestions

 

[invader]

I had to set mine to about 1.5-1.75 turns out for the wheel hop to disappear.

 

[capo1000]

I had to set mine to about 1.5-1.75 turns out for the wheel hop to disappear.

Thanks Invader....So you feel the hop was due to the rebound being set too hard? Mine was at 2-1/2 out...I reset to 2 turns out for now and will mess with it more this week. Im starting to think I have to soften it up

 

[Spencer]

.

Once you have your pre-load set for 35mm of total sag then get someone to help steady your bike upright and push down between the bars and on the seat as hard as you can. Adjust the rebound until both ends come up at the same rate. The bike should rise level. If the back is coming up slower soften the rebound, quicker then stiffen it up. Balancing out the chassis will give you the best overall handling no matter what your feeling on the road. Each bike will be different so you can't use someone else's settings as anything but a starting point.

.

 

[capo1000]

.

Once you have your pre-load set for 35mm of total sag then get someone to help steady your bike upright and push down between the bars and on the seat as hard as you can. Adjust the rebound until both ends come up at the same rate. The bike should rise level. If the back is coming up slower soften the rebound, quicker then stiffen it up. Balancing out the chassis will give you the best overall handling no matter what your feeling on the road. Each bike will be different so you can't use someone else's settings as anything but a starting point.

.

Thanks Spencer!

 

[wjbertrand]

Sounds to me like the rear end is kicking a bit when unloaded upon cresting a rise? If so I think you might need to dial in a bit more rebound until you feel like you've snubbed that out. I weigh a bit more than you 210lb and I usually have the rebound backed out about 1/2 to 3/4 turn from full hard.

You're not going to get a real compliant ride out of the OEM shock as I feel the compression damping is a bit too high. What the bike really needs is a bit more spring rate and a reduction in compression damping to ride really well. Unfortunately that means an expensive aftermarket solution.

 

[Clem]

If it feels good, 90% of the time, I wouldn't change much. Maybe add a bit more rebound but I'd guess that the compression is what is tossing the bike. I've got a pretty big bump on my regular ride that pretty much sends the bike airborne, I just get up on the pegs and it isnt too bad. I tried total soft and it was about the same, hence the guess that its compression. IMHO, full soft is not so good for even mildly spirited riding.

It only gets so good with the stock set up. It sounds like I'm about where Jeff is (3/4 to 1 out IIRC but a bit lighter)with the addition of having lowered the front 2mm. I might go another 3mm someday.

 

[capo1000]

Sounds to me like the rear end is kicking a bit when unloaded upon cresting a rise? If so I think you might need to dial in a bit more rebound until you feel like you've snubbed that out. I weigh a bit more than you 210lb and I usually have the rebound backed out about 1/2 to 3/4 turn from full hard.

You're not going to get a real compliant ride out of the OEM shock as I feel the compression damping is a bit too high. What the bike really needs is a bit more spring rate and a reduction in compression damping to ride really well. Unfortunately that means an expensive aftermarket solution.

Thanks Jeff....Looks like I was decreasing rebound when I should have been increasing. I know the ride will only get so good with the OEM shock. Right now it feels pretty damn good exept for the occasional hop I get at certain speeds when cresting a rise

 

[Marshal_Mercer]

With all due respect to what Jeff suggested, go slightly less rebound damping (counter-clockwise). Try the same bump. Subtract rebound damping until the back end no longer kicks up.

Marshal

 

[dduelin]

I have to agree with Marshall. If it feels like the rear wheel is not tracking the road surface after a bump or rise the rebound is too hard. If the rebound is too hard the wheel can't move fast enough to stay on the road as the bike is thrown up into the air by the bump. Remember the stock shock is only adjustable for rebound damping, not compression damping. The force transmitted to the chassis from the bump after compression damping is what it is and can't be changed. What can be changed is how fast the wheel can rebound from the compression force. If the wheel leaves the surface of the road past the bump the rebound is too slow.

I used to run rebound damping 1/2 to 3/4 turn out from full hard and thought I had the right setting for a long time until I took Lee Parks Total Control course and we checked our rebound like Spencer described. I had to be talked into trying this setting for a while. 1 1/2 to 1 3/4 out from full hard is best for me on the stock shock. This will feel like too little rebound but it was the best for managing traction by keeping the rear wheel on the ground under most conditions.

 

[bikeopath]

Bill,

I had the same issues with the stock shock. Riding many of the same roads you do I understand the dilema.

Working only on your description of the issue, and my personal observations, you need to SOFTEN rebound damping. This will allow the rear wheel to follow contours of the road surface more quickly, especially over high amplitude, low frequency bumps.

Try the shock on 1 turn, and pre-load at the softest setting.

What did I do? After awhile I got frustrated with the stock shock. Chucked it for a Penske from Lindemann Engineering. Compression and rebound adjustable. and rebuildable. Their solution takes the same tack as Race Tech (whose front end kit I also installed). More spring and less damping.

HOLY CANOLI! It's a completely different bike. If you've ridden race bikes (I know you have) then let me say the ride is soft and compliant, just like a racers. Just flat out works.

Remind me next time I see you, and we'll swap mounts, so you feel what I mean.

 

[wjbertrand]

With all due respect to what Jeff suggested, go slightly less rebound damping (counter-clockwise). Try the same bump. Subtract rebound damping until the back end no longer kicks up.

Marshal

From the OPs description he has the rebound turned well out already. I am referring to kicking up as occurring after compression when the rear end re-extends after or at the crest of the rise when the suspension is unloaded. If re-extension (rebound) is too rapid, the back end can kick back up through the seat, again after the initial compression. Back when I was racing dirt bikes, where you are standing with your butt just above the seat, the seat would come up and slap my butt upon unloading of the rear suspension if I had too little rebound dialed in. Adding more always solved it.

If he is describing that the rear end is leaving the road, i.e. the rear is not extending back out quickly enough after the bump, then I would agree there's too much rebound damping. I doubt this is the case based on his description of the current setting. Also, from his reply, it sounded as though he's already been working in the direction of reducing rebound without satisfaction.

 

[Marshal_Mercer]

From the OPs description he has the rebound turned well out already. I am referring to kicking up as occurring after compression when the rear end re-extends after or at the crest of the rise when the suspension is unloaded. If re-extension (rebound) is too rapid, the back end can kick back up through the seat, again after the initial compression. Back when I was racing dirt bikes, where you are standing with your butt just above the seat, the seat would come up and slap my butt upon unloading of the rear suspension if I had too little rebound dialed in. Adding more always solved it.

If he is describing that the rear end is leaving the road, i.e. the rear is not extending back out quickly enough after the bump, then I would agree there's too much rebound damping. I doubt this is the case based on his description of the current setting. Also, from his reply, it sounded as though he's already been working in the direction of reducing rebound without satisfaction.

Hi, Jeff:

I know what you mean, having done the dirt bike thing myself.

In the original statement, it was said that "....it felt like the rear wheel would pop up and almost come off the ground".

Marshal

 

[wjbertrand]

Hi, Jeff:

I know what you mean, having done the dirt bike thing myself.

In the original statement, it was said that "....it felt like the rear wheel would pop up and almost come off the ground".

Marshal

Yeah, you're right and I did see that, but with his description of the current setting...........

 

[capo1000]

Thanks for all the input guys....

The rebound felt fine before I increased the preload to (just over) 2-lines out from full hard. The bike feels better now in the twistys and not harsh...Didnt feel bad before...Just a little too soft at times when riding aggressive.
So now that I increased the preload a total of about 2-2 1/2 turns I get that hop on the crests where a few times it felt like the rear wheel almost came off the ground. I made a few adjustments and decreased the rebound about a half turn total (twice, 1/4 turn each time)
Maybe those 2 small adjustments werent enough to make a noticeable change. I set it back to 1-3/4 turns from hard and next time I get out, I'll try adjusting both ways. I know Im close....The bike feels pretty damn good otherwise.
On those crests, the impression I get is the suspention is coming back up to fast.....So Ill try the harder setting first.
Tony (Bikeopath) Id like to feel how your bike rides with that Penske shock!
I like my bikes set up pretty stiff, and wouldnt want to go softer on the suspention. I also want to see if I get better tire wear with the preload increase. I definately noticed the bike handled better with the new setting, and not harsh over the bumps/potholes/jagged sections.

Ill keep you guys posted

 

[capo1000]

Found this info. on SportRiders website......Lots of good stuff there


LACK OF REBOUND DAMPING (REAR SHOCK)

?The ride is plush at cruising speeds, but as the pace increases, the chassis begins to wallow and weave through bumpy corners.
?This causes poor traction over bumps under hard acceleration; the rear tire starts to chatter due to a lack of wheel control.
?There is excessive chassis pitch through large bumps and dips at speed and the rear end rebounds too quickly, upsetting the chassis with a pogo-stick action.


TOO MUCH REBOUND DAMPING (REAR SHOCK)

?This creates an uneven ride. The rear suspension compliance is poor and the "feel" is vague.
?Traction is poor over bumps during hard acceleration (due to lack of suspension compliance).
?The bike wants to run wide in corners since the rear end is "packing down"; this forces a nose-high chassis attitude, which slows down steering.
?The rear end wants to hop and skip when the throttle is chopped during aggressive corner entries

 

[MidLife]

So now that I increased the preload a total of about 2-2 1/2 turns I get that hop on the crests where a few times it felt like the rear wheel almost came off the ground. I made a few adjustments and decreased the rebound about a half turn total (twice, 1/4 turn each time)

With increased preload, wouldn't you have to increase the rebound adjustment instead of decreasing it?

 

[Marshal_Mercer]

With increased preload, wouldn't you have to increase the rebound adjustment instead of decreasing it?

Oddly enough, no. The shock's pre-load setting does not change the shock's spring compression/extension rate. One would change the rebound setting if 50 or more pounds (22kg) weight (mass) was added or subtracted, though; more for more, less for less.

The steps I take to calibrate suspension(s) are: set the front and rear spring sag; set the front and rear high-speed compression damping (none on the ST); set the front and rear low-speed compression damping (none on the ST); set the front and rear rebound damping (rear only on the ST).

Marshal