Anyone over 280 lbs. have the Penske rear shock upgrade?

[happyPuppy]

Those that do not know much about sag and its importance to rebound , this is a pretty good video.

 

[RadioHowie]

I'm 250 and my suspension was set up by Traxxion Dynamics in GA. They know there stuff.. Ask for Lee

Fubar, that's a pretty good lookin' human you got there in yer avatar.

 

[Wannabe_4x4]

Classic case of not enough rebound damping.

You're talking about in the rear shock, right?

So basically, is it because the rear shock is packing in then? I always thought I had too much rebound, and that it was shooting up too fast, or maybe too much compression and the shock wasn't using the full range of motion, or maybe both.

If I open up the rebound a little (2 clicks at a time or whatever)... how would I know that it's too much or just right when i go through the same exact corner? What am I feeling for in the bike and the suspension to know that I'm not at enough rebound, or too much?

 

[MCRIDER007]

Classic case of not enough rebound damping.

You're talking about in the rear shock, right?

So basically, is it because the rear shock is packing in then? I always thought I had too much rebound, and that it was shooting up too fast, or maybe too much compression and the shock wasn't using the full range of motion, or maybe both.

If I open up the rebound a little (2 clicks at a time or whatever)... how would I know that it's too much or just right when i go through the same exact corner? What am I feeling for in the bike and the suspension to know that I'm not at enough rebound, or too much?

I thought you were talking about the rear shock which seem reasonable since you have added a very heavy spring (which rebounds with more force). The rear shock "packs" when there is too much rebound damping and the shock isn't able to fully extend before it hits the next bump....which is the opposite of what you are describing. How much rebounbd damping is "enough"? Ride through the same corner on the same line at the same speed and turn up the rebound damping until the second bump to settle is gone, any time you feel like you are riding a pogo stick you need more rebound damping. If the bump feels too harsh, you probably have too much compression damping.

 

[Wannabe_4x4]

see the post below

 

[Wannabe_4x4]

So here are my numbers as of 9pm, 2/18/10

fork compression 12

fork rebound 10

fork sag 45mm

front tire psi 40

rear compression 12

rear rebound 20

rear sag 35mm

rear tire pressure 40

ride seems much much better! the bounce is gone. I was getting a little bit of bumpiness when going over certain ripples and cracks. Tried opening compression rebound, but then I started getting more bumpiness/or too much rear squatting. but when I dropped the rear pressure to 40psi, the bumpiness almost entirely went away. I have a feeling the spring tension is too much, since I had to give it a couple extra turns to get to 35mm of sag. I expect that over time, it'll smooth out entirely.

 

[Wannabe_4x4]

2.19.10 update

40 and 42 psi.. that's what gets me. when i run that much air pressure, i get the bumpiness on the cracks and ripples. if i go down to 40 in the back, no ripples.

figured out the initial hard hit was because my spring tension was too loose. I gave the rear shock 2 full turns of pre load, and now that hard initial hit is all but gone. the subsequent dip mildly pogos now, but not like it was doing before.

I'm happy, for now. gotta wait a couple days till the spring settles again with the extra preload dialed in, then i'll report back.

 

[Wannabe_4x4]

:yahoo: I've done it! I hit suspension Nirvana!!!!!! It's like that guy in Waterworld saying he's seen dry land! lol. 7 months of maticulous recording data, tweaking and turning. Happy to report I'm back in "Club 42" as well... 42 psi in the rear tire.

Thank you ALL for the feedback, tips and pot shots. Actually a combination of what everyone was saying applied to my suspension woes. Luckily now after all is said and done, my bike truly feels like it's riding on rails. Grips the road extremely well, and cruised at 65 mph through a tight 35mph sweeper this morning. :clapping:

So here are the final #'s.

I'm a 300 lb. rider with gear on.

Using Michellin Pilot Road tires... not the 2C... just the regular Pilot Road ones.

Complete suspension buildup assembled by Peak Performance in Simi Valley using GP Suspension parts. Running a Penske 8983 adjustable rear shock (valved and set up by GP), and .97 springs upfront with new valves from GP Suspension in Oregon.

Front Fork:

Compression Dampening - 12

Rebound Dampening - 12

Preload - Zero lines showing... nut is flush with the cover (only the hex pattern is above the cover)- amounts to 48mm of sag while I'm sitting on the bike

Front tire pressure - 40 psi at 6:00 AM measured in a 60 degree F. garage

Rear shock

Compression - 13

Rebound - 22

Preload - hard to say, but added about 4 or so full turns from what GP set it at - amounts to 35mm of sag while sitting on the bike. When I was setting this, it was a matter of hitting tight sweepers at speeds of 40-60 mph. If I felt like my body weight was on my wrists, I backed off a half turn on the preload till the bike felt level under the g forces of the turn. When the bike felt lower and squatting in the back, I turned the pre load 1/2 turn tighter till it felt level again.

Rear tire pressure - 42 psi at 6:00 AM measured in a 60 degree F. garage

Like Ashe says... gotta do the SAG first! Without that, I was messing with the compression and rebound, when it turns out all I had to do was add a turn or two of preload.

 

[Big-D]

I run 40psi in the front and rear, but I'll take the advice and run them up to 42psi and see what happens.

Boy................there sure are a lot of Fat Guys :haha: on this forum!!