Rear Shock Pressure

[Todd]

I am hoping the vast knowledge here will help me skip a little of the trial and error method on getting to the correct air pressure in the rear shocks.

I have ridden for a year with NO pressure in them and on occasion, though rare, will bottom out when riding two up or even scrap the V&H baggers (the nut/screw on the bottom) when pulling out of a parking lot too fast.

I am no light weight 270ish and ride 2 up a bunch with my wife who is 120ish.

So, what pressures have you folks found to be the best?? (with rear tire off the ground)

I don't find any pressure to be neccesary. I'm slightly over 200 my wife is about 150. It seems like #1 on the shock setting is still stiffer than #5 was on my shadow.

I'm confused on what the difference is between the settings and the additional air? Does the added air just supplement the 4 settings or does one affect compression stiffness and the other for rebound pressure?

Seems like too much hassel unless there is any easy way to get the tire off the ground. If you do it on its side stand wouldn't the pressures be off due to more weight leaning on the left side?

[Todd]

Yes, its a hassle...have to get wife or one of the kids to help steady the bike and had to rig a sort of jig like on a car frame machine to lift it..finally found it easier to just do on the ground and held upright by one of those volunteers mentioned earlier. Just read a few post on different sites that said it adds 3-5 lbs pressure from your pump reading.

My understanding is that the settings on the shocks are for rebound and the air pressure affects the compression..but I am asking the question here so I could definitely be wrong. Never really been able to tell a bunch of difference on mine playing with the settings on the shocks.

[blowndodge]

No air pressure is for a single rider at about 170lbs. Since you a big boy like some of us, I'm 225lbs, I run 15psi and the damper on the second click. It still is a soft ride but it doesn't bottom out.

You have to keep two things in mind when your talking about shocks. Air and/or springs determine how much resistance to your suspension movement is allowed "load" . The compression and/or rebound setting determines the speed of that movement "load".

Your bike would ride like a pogo stick without the dampning effect. Once the spring compresses in a bump in the road if allowed to expand back to its original shape without something to slow that expansion "damper" effect you would bounce down the highway.

Think of the compression and expansion damping as oil passing through a series of holes. Largers holes allow the oil to pass quicker than smaller holes for obvious reasons. Thus largers hole allow the spring to compress and rebound quicker than smaller holes. This is what the 4 position clicker on your shocks do. It changes the size of the holes in the shock to either slow down or speed up the movement of the "load"

Make sense???

So the air adds more resistance to the downward suspension movement and the 4 clicks change the speed of the rebound?

Mine seems to ride nice on #3 with no air single or 2-up

A chart would be nice to show ideal settings for any given weight.

Is it a comfort thing or safety? It seems like too much air for the load would make it more hardtail like possibly causing the rear tire to bounce off the ground if you hit a nasty bump?

[blowndodge]

You got WM! Ideally for a cruiser rider wanting the most compliant ride you would add enough air to the riding situation to just stop short of bottoming out. Bottoming out, by the way, is harder on your shocks that you realize. Seals that contain that air take a beating becaue your hitting the stop inside the shock and its beating the heck out of the inside of the air bladder.

Many have thought that stronger damping with softer spring/air is the key but that can be overdone and let me explain:

Air inside the shock acting like a spring is compressed, the air is compressed and the resistance starts to increase. Mathmatically if you compress the shock one inch, the second inch takes twice as much to compress and the third inch takes twice that. It's ever increasing exponentially.

This is because air is compressible, remember it's how we inflate our tires. The oil inside the shock however is not. Liquid doesn't compress at all. Thats why liquids blow up in your freezer and why glaciers rip mountains apart.

Reducing the oil flow through the holes in the damper (1 to 4 ) makes the "speed" slower and you can "over damp" the shock and set it at no air pressure but too much damper and it won't let the shock compress fast enough and the ride will feel like you have 40 pounds of pressure in them. The oil will only move a certain speed through the holes because liquid (oil) is not compressible.

[Todd]

I had been on II rebound and no air...a little "bouncy" on rough roads....put 20lbs in today..cause me and wife scare the H&LL outta 400 lbs..mostly me in case she reads this. Rode very nice..stayed on II for rebound. I tried to hit every dip and road patch I could find and it never approached a bottom out situation. Maybe just a tiny bit stiffer...I am going to back them down a couple pounds at a time and see how that works.

By the way...If anyone intends on doing this, make sure to use a suspension pump (about $40). I takes very little air to make 20lbs pressure..high pressure would damage the shocks and you could never get accurate pressure with a standard bicycle pump.

It gave you a scare? Elaborate if you could....

[dogdoc]

Ihave never checked my air in my shocks but run the setting on ll and it was fine even 2-up. Then I added V&H bagger pipes and when I pulled out of the drive with the wife, it made a scrapping noice(bottomed out), thought it was the baffle scres but they looked clean. Might have been the tire hitting inside of fender? I set number to lll and seems better for 325 lbs of riders. Thought you could use any low volume pump(I.E. bike pump)??

Doc

[trip]

I run mine the same as Wolfman....#3 and no air in the shocks. Never had any problems.

[Todd]

Sorry Nico...I should have been more clear....

I meant that the wife and I scare the h*ll outta 400lbs when we are both on the bike....no scares on the ride..just a little stiffer ride...I barely noticed and the wife said she thought it was the same.

I too have scraped the V&H baggers with 2 up and need to replace one of the bolts that holds the baffle in. I tend to lean the Nomad over to its limits sometimes though ;)

Ahh... Good to hear you didn't have a scare on the bike.... whew~~

[Todd]

Doc,

A bike pump will put air in the shocks fine..but you will lose some pressure when you take the connection off of the schrader valve..then when you check it with an air guage you will lose a little. It takes such a small amount of air that this can make a difference and you can have really different pressure on one side vs the other.

The suspension pumps do not allow any air to escape when you disconnect and you can be precise with each shock..or you can install the equalizing system I have seen on Gadgets page to make sure they are equal.

[lw]

I had mine bumped up druing break-in service since I'm not my mother's smallest child, and the fact that I didnt like bottoming out riding two-up. Shop told me they put about 50% of the max air charge in and I havent bottomed out again. I switch the damper to the 3rd setting for riding two-up.

[toxictavrn]

dang!!!! i run 50psi in my rear shocks with me and my girl and cargo, i figure 450lbs weight or so, i dont know how in the world you can run on no air pressure in the shocks! i d be dead!