Front Shock Question

[Drew]

When I sit on the bike there is no deflection in the shock. After hitting some bumps it compresses approx 1 inch and remains there as long as I remain seated. I can feel that there is still a bit of travel left once it is compressed. I get off the bike and it rises back up. I run 140psi in the shock and weigh 180lbs.

The fork just started behaving this way yesterday after the first 400 KM of riding. I noticed it because my knees started hitting the bar after riding 15 minutes. I returned home and verified there was 140psi in the shock.

Is this normal operation for the Kind shock? I would like to try a lower pressure but I'm converned it will start to bottom out. Should I be looking to have a small compression when I sit on the bike?

 

[Mark B]

I'd almost bet money you're not putting enough air in the shock first of all and when you release the pump, you let what little air there is out. So, you're riding your front shock deflated. For the sake of argument, run it up to 190, then take the pump off and see if that makes a difference.

Mark

 

[Drew]

Mark
I will give your suggestion a try but I am confident I am getting the pressure set correctly. As confirmation I used a digital gauge to confirm the pump gauge was accurate. That gauge drains the air but U only used it one to confirm the pump and valve were working properly.

The odd thing is I get zero sag when sitting on the bike rocking back and forth. The assembly notes states I should see 8mm of sag. It appears to me that there is too much friction between the shock seal and the piston.

 

[defjack]

It looks like I have been pumping my shock wrong also. Go to the Cruzbike website.products >Silvio then look for air shock pumping follow this and you cant go wrong.I did it this morning and bingo. The instructions on the Kind box didnt do it for me. Jack

 

[Gromit]

defjack wrote: It looks like I have been pumping my shock wrong also. Go to the Cruzbike website.products >Silvio then look for air shock pumping follow this and you cant go wrong.I did it this morning and bingo. The instructions on the Kind box didnt do it for me. Jack

Direct link

 

[Drew]

The replies are all appreciated.

I just rechecked the bike and the the shock is set at 140psi. A digital gauge also verified the psi. Getting air into the shock is not the problem. For the first 400 Km I had no problem getting the shock to function well. But now I cannot get the shock to sag the recommended amount by rocking the bike.

The problem appears to be binding on the piston which makes it hard to move and it does not rebound after hitting bumps. I may have contamination in the seals that is causing excess friction. I definitely know it is not caused by low pressure.

 

[Flasharry]

I have had this problem with my Softrider and Silvio.
Turn the bike upsidedown and put a small amont of oil all around the shock slider, this should cure it.

Stuart.

 

[Drew]

Thanks Stuart,
I tried oiling the shock piston but not while it was inverted. I'll give your technique a try.

 

[Lief]

I have also noticed this "problem". I originally ran at 150PSI but changed to 130PSI after I figured out how to use the pump (at about 300 miles). I checked and rechecked and rechecked the inflation of the shock. I am now almost at 1K miles and have started to worry about the problem less (used to it?)
I will try the oil suggested.

I also wonder about what is happening when I do (which I almost always do at least once) bottom out the shock on a ride.
Am I slamming parts together that shouldn't be slammed?
I would like to know what results you have seen Drew?

Lief

 

[Drew]

Lief
Let me first state that Jim & Doug have been very supportive and quickly responded to my queries. I beleive they want to know what the problem is as much as I do. We may not know exactly what the problem is until a shock is returned for disassembly. Stuart says he rectified the problem so when it stops raining I will try again using his technique.

The following report was sent to Jim & Doug this week that more clearly explains what I began to experience after the first 400 km (250 miles) with no problems at all. I used a digital pressure guage to verify the pump guage was accurate and that I was operating it correctly.


"I applied 3 in 1 and cycled the piston up and down thru its full range six times. With no air in the shock it was very hard to move.

I pumped the shock to 150psi. There was 3-4mm sag rocking fore/aft. I went for a ride and after a few bumps the shocked was compressed approx 25-30mm . The shock compresses a bit with each bump and does not rebound. No improvement.

Pressure was then increased to 180psi. There was no sag rocking fore/aft. I took the same bumpy road but the front wheel was lifting and the vibration was very bad. It felt like it was bottomed out. There was no movement of the shock at all.

Pressure was decreased to 120psi. The shock sagged approx 10 mm rocking fore and aft. At the bottom of my driveway the shocked compressed a lot and I could see the boot folded in half. It almost bottomed out and remained there.

I checked the torque on the BB clamp to ensure it was not slipping and binding but it was good. The carboyoke was straight but I loosened the BB clamps and QR before re torquing them again. I repeated the above tests with no change. "

 

[WhiteSilvio]

Drew wrote: "I applied 3 in 1 and cycled the piston up and down thru its full range six times. With no air in the shock it was very hard to move.

Hi Drew,
Just a quick question. Is "3 in 1" some kind of penetrating oil, maybe from an aerosol can?
Thanks,
John R.

 

[trapdoor2]

http://www.3inone.com/products/multi-purpose/

Not aerosol, drip can/bottle.

 

[Dave Killen]

Exactly how does one "lube" the shock with 3 and 1 oil?

I understand the inverting of the Silvio. What I am unclear about is the displacement of the rubber sheath that covers the piston. Does one simply pull it out and move it up (down) the housing? Should the air pressure be 0 when one does this?

I'd appreciate an explanation before I attempt this.

Thanks,

Dave Killen

 

[John Zabriskie]

I tried lubing the shock with the bike upside down and found no difference; the shock was still binding. I would expect this is due to the lower wiper seal on the fork shaft.

However, I did come up with a possible solution (it worked for me) which I'll post in the "Air Shock Problems" thread.