PEP Rear ZPS question

[sleestack68]

I have front and rear PEP ZPS that I bought used. The rear I kept as is because it was in perfect shape and set to my weight. The front I go back a few weeks ago from derisi for revalving.

The front is great but my question is this.

I took my R for a ride, I lowered the rear ZPS as low as it would go. It corners and comes off jumps great but if I'm going fast down a trail or gravel road with dips the rear end rides hard.

I was wondering is this because the shock is all the way down or because the compression damping is too high or the rebound is too high causing the rear shock not to extend quick enough.

I haven't taken it out since I felt this last weekend so I am looking for info so I know what to tinker with when I go out this weekend.

[sleestack68]

anyone?

[turnandburn]

sounds like the shock is stacking meaning every time it hits a bump it compresses and doesnt rebound before it compresses more, i cant remember which adjustment takes care of this. Try doing a search on shock set up.

[NacsMXer]

You definitely have symptoms of shock packing. Its a quick fix, you just need to turn up the rebound, its the little screw on the bottom of the shock. Test it out by compressing the rear end a few times to make sure youre not turning the rebound down. Turning the rebound up will make the rear end feel more springy when you push down on the grab bar. Also, it helps if your ZPS isnt set at the lowest setting. Ideally, you want to have about 7-8 inches of clearance when measuring from the frame by the footpegs straight down to the ground.

[sleestack68]

I think that might be it, I raised it one inch and checked the rebound damping. It was turned almost all the way (slow).

I moved it to the middle and the back tires seem to kick out quicker now. Let's see if this does it.

[wilkin250r]

"The rear end rides hard" is pretty vague. What do you mean rides hard?

If the shock was packing up, the rear end would be sitting really low while it was happening because the shock is not extending, and I think you wouldn't mistake why it was happening because your back end would be dragging on the ground.

If the rebound is not damping enough, then the rear shock will act as a pogo stick. You would hit a bump, the shock would compress and soak up the bump, but then it would immediatly extend again with full energy (because there is little or no rebound damping) and give that bump right back to you. THIS could be the cause of the rough ride.

Is it set up for MX or XC. MX setup usually uses a much stiffer spring than XC to soak up bigger landings. Perhaps your spring is too stiff for the type of riding that you are doing. If you're riding XC on a MX-type shock, then yes, you will have a rough ride.

[sleestack68]

By rough I mean that I can't hit these dips sitting down at med-high speed.

I had the rear at set as low as possible. In fact I think I was riding off the rubber stopper.

I think it is a combination of having the rear end set to low and having too much rebound damping.

[boogiechile]

If you are so low that you are riding on the rubber bumper or so close that a normal bump would cuase it to bottom on the bumper then yes it will be very rough. It should only get into the bumper on hard hits like landings.

If the shock only has a zps and a main spring with no tender spring then the spring could be stiff enough to give a rough ride. The zps is normally collapsed and provides nothing while you are riding along so you are on the main spring only. If it is a stiff MX setup you will ride rough.

[Bruno]

Turn the rebound adjustment to the left about 4-7 turns. This is if you are standing directly behinde your quad. I had the same problem with my pep zps shock when i got them from my buddy. You will notice right away the back will quit packing and follow the contour of the ground better.

[sleestack68]

Thanks guy, I took a spin on it, I think that fixed it.