GP Suspension Penske shock ride report

[dcarver]

Last weekend installed the triple adjustable Penske. First thing noted was the rear of the bike is waay higher than it used to be. As in maybe 1 or 1.5 inches taller. It used to take some effort to get the bike back on the center stand, now it's just a breeze away. My Rifle windshield is waaay to short now, and when on the side stand the lean angle is atrocious, and my pillion is smashing my helmet more than ever when braking and cornering due to sliding downhill on the seat.

On the other hand, the bike is simply railing around corners.

Here's the problem.. I'm pretty good at setting up MX suspension, but have never set up street suspension. And, as of right now, I haven't read through the extensive Penske manual on set up either.. I just simply bolted the shock up and went riding. No sag adjustment, nada, zilch, zero.

So, this is the starting point of my learning curve. Here is what I THINK I know, and I will read the manual tomorrow as time permits, but thought I'd start this thread to see if other suspension guru's (Jeff Ashe, MarkJenn, TWN, come to mind) have basic tenets to live by for 'Suspension Tuning for Dummies'..

1. Raising the rear end ride height places more 'weight' on the front tire, thus adding to traction.

2. It also makes you look and ride like a stink bug. I no longer seem to fit the 'comfort' spot in the Bill Mayer saddle.

My initial question is this, and YES, I will RTFM tomorrow - but for now, can I 'lower' the rear ride height easily without disturbing the other settings like sag, compression, and rebound damping?

Like TWN, the ride is 'firm', and similar to my MX suspension meaning the harder you ride it, the better the suspension performs. Problem is I don't ride THAT hard THAT often.

Well, looking forward to the replies, and the Penske manual is packed for reading at lunch tomorrow..

 

[danvforce]

Dave from GP sent me a email after they shipped my shock saying they set my ride hight 2 1/2 turns to high when iI received the shock I loosened the lock nut, screwed in the hight adjustment locked the nut and it was good to go. it still sits higher than before and turns in alot quicker. The rear of the bike doesn't seem to sit that much higher than before. You should be able to make the adjustment from below without removing the shock.

 

[twowheelnut]

Ditto Dan... The Wilbers RH adjuster is at the lower damper mount and secured by a lock nut. I'm not certain that you can leave the lower mount bolt in place to make the adjustment. It looks like - from what I can tell on the Penske site - that this is the same location for yours.

Know that by lowering the rear ride height you will generally improve straight line stability at nominal speeds and lessen turn in, while increasing the tendency to understeer (run wide on the corner or push). Plus, you'll lessen the load on the front tire which causes lift and instability at, um, ultra-legal speeds. The up side is that you'll lower the COG and for general riding, I think that's a good thing.

But you claim it's riding 1 - 1.5" taller? Sheesh, that seems a lot to me. Edit: Thinking about it, you have changed from stock, so maybe that is reasonable.

 

[dcarver]

But you claim it's riding 1 - 1.5" taller? Sheesh, that seems a lot to me. Edit: Thinking about it, you have changed from stock, so maybe that is reasonable.

Thanks guys, exactly the info I was hoping for!

TWN, It really is THAT different. I'm starting to think that my stocker with 45k was simply gone, kapoot, making all these difference very stark.

 

[Randy]

And rest easy knowing that adjusting ride height has nothing to do with sag, compression, or rebound. So, if you were to do this again, are you saying that you would have measured the ride height before removing the stocker????

 

[Wolfhound]

I had to lower my rear Penske a bunch after getting it back from GPS.. . . . Didn't like humping the tank . . .

 

[snikr]

I know when I first put on my Wilber shock my FJR sat about a 1/2" higher. As for handling it made it better for me but I wasn't sure that the added height made the difference or was it the better shock. All I know is that I'm happy with it so I didn't play with it. I can't wait to try out the bike after GP serviced the shock and put on a better spring (Dave did say the old one wasn't as bad as most of the springs from Wilber).

Tom

 

[drjfjr]

The easiest way to find out the difference in ride height would be to measure your old shock from center of hole to center of hole. Then measure the new shock on the bike from center of bolt to center of bolt when the bike is on the center stand and compare. Both shocks would be in the extended position and you can compare.

 

[markjenn]

I also got the "we adjusted RH out 2.5 turns too much" email from Dave at GP Suspension for my 8983. So I adjusted it shorter as instructed, then compared the shock length of the old Yamaha shock to the new Penske. I was surprised that it was only slightly longer - I don't have my notes in front of me but it was something like 2 or 3mm longer which isn't much.

The whole reason I bought the 8983 over the Ohlins was because I wanted more ride height to help with the pegs dragging, so I decided to compromise and adjusted it back out about 1.5 turns (i.e., now about 1 turn in from how I got it from GPS) and bolted it up. The bike is definitely taller in back, but it isn't a huge change and I doubt it is anywhere near a 1.5" change. The centerstand is somewhat easier and the bike leans slightly further on the sidestand, but it's not a big difference. I do think that if I adjusted it higher I might start to have stability issues on the centerstand though.

The bike sits taller now due to the ride height change, but a bigger factor is just that the spring is so much stiffer. I had done the preload spacer on the Yamaha shock and left it in the Hard position all the time and I still think the bike rode way too low in the back - it almost felt like a cruiser sometime. (I weight about 225 BTW.)

It sure sounds like yours is riding much higher in the back that this. I found the ride height change fairly subtle, nothing terribly dramatic like you're reporting.

AFAIK, you can adjust the ride height with the shock in-situ - I certainly hope so since I wasn't planning on pulling the shock every time I wanted to fiddle with this. Typically the way these things work is that you loosen the locknut and then turn the shaft which rotates in the shock body. At least it has worked this way on other shocks I've done like this (e.g., Ohlins).

- Mark

 

[madmike2]

TWN, It really is THAT different. I'm starting to think that my stocker with 45k was simply gone, kapoot, making all these difference very stark.

Starting to think? Rogdeb's was gone @ 28K...but they ride 2-up 98% of the time. I'd try adjusting the ride height as mentioned above, at least split the difference.

Part of the joy of this farkle is the "learning curve" and adjustments.

 

[dcarver]

TWN, It really is THAT different. I'm starting to think that my stocker with 45k was simply gone, kapoot, making all these difference very stark.

Starting to think? Rogdeb's was gone @ 28K...but they ride 2-up 98% of the time. I'd try adjusting the ride height as mentioned above, at least split the difference.

Part of the joy of this farkle is the "learning curve" and adjustments.

But my svelte low mass body should have enabled at least 60k worth of shock life!

 

[kaitsdad]

But my svelte low mass body should have enabled at least 60k worth of shock life!

On what, your pickup truck?

My stock was gone at 14K - replaced with a 642 Wilburs. Big difference.

 

[ahchiu]

A custom seat with more rearward sloop and raised front will keep your passenger from sliding forward, my wife would always had to adjust her sitting position until I got a custom seat for her. if you material on the seat is slick it will cause slippage, you can also try a nonslip cover over the rear seat.

 

[Fairlaner]

6 years......is that a record???????

wake up Marcus...

R

 

[ahchiu]

I thought my reply was for a passenger sliding forward, I don't know how it got here.

MCRIDER007 had a post right before mine now it's gone.

 

[Fairlaner]

hehe.....SURE...

R