Suspension sag height

[E30TECH]

I'm sending my ohlins out for rebuild and i forgot to take the sag heights (bike, bike+rider). He asked me for these so he can try to set them up as close as he can without being on the bike.

 

I suppose it is too late now as I am not putting the shocks back in.

 

Is there a spec of what the sag heights should be? I looked and can't find anything.

 

 

[ShovelStrokeEd]

Try about 10mm bike, 25-30mm bike+rider on the rear. About 5 more on the front. It should get you in the ball park.

[E30TECH]

You think that would be suitable for a 220lb rider? Thanks for the info.

[Selden]

ShovelStrokeEd's recommendations for static sag are an appropriate starting point for any size rider. However, a heavier rider may require stiffer springs; otherwise, even if you crank in enormous amounts of preload, you can still bottom out the suspension on a bump, because the spring rate is too low..

 

Measuring the front is easy: attach a zip tie to one of the fork tubes.

 

Rear is a little more difficult. I usually place a felt tip marker in line with the rear axle, then attach (rubber bands, duct tape, whatever) a yardstick to the seat, vertically, so that it is in contact with the marker.

 

Suspension is fully extended on the center stand; static load is when you are seated, with as little weight as possible on your toes.

[ShovelStrokeEd]

Yep! At 220 lbs, you are gonna need a 1.0 or 1.1 spring on the back of that thing. Set the hydraulic adjuster, if you have one, to about 20mm of preload. I tend to like a heavier spring with a bit less preload but that is a personal choice based on advise from Jim Lindemann.

[E30TECH]

"ShovelStrokeEd's recommendations for static sag are an appropriate starting point for any size rider."

 

Understood - which is what I was hoping to find.

 

 

"However, a heavier rider...."

Its mostly muscle

 

 

"10mm bike, 25-30mm bike+rider on the rear. About 5 more on the front."

Does the 5mm more for the front get added to both dimensions (15mm bike AND 30-35mm bike+rider) or just the 30-35mm for bike+rider.

 

Just want to make sure as these were rebuilt last year. unfortunately, by someone who didn't know what they were doing. The front one blew on me this weekend. I thought the bike caught fire and was getting ready to start ripping farkles off. Then I realized what it was.

 

Roger at onroad offroad cycles is going to do the rebuild. After speaking with him, I'm confident that he will do the job correctly.

 

 

 

 

 

[Selden]

Assuming the correct spring rate, my personal preference for the rear is to set enough preload on the spring to achieve desired static sag for solo rider, no luggage, with zero turns on the hydraulic adjuster. Not only does this give you the maximum range of adjustment for the hydraulic adjuster, but it makes it very easy to count turns for other load conditions, since the starting point is zero turns. With an Ohlins, I found that rider + luggage = 4 turns; rider + luggage and passenger = 10 turns.

 

I have no experience with other shocks, but the hydraulic adjuster knob on the Ohlins has no markings; I cut a thin sliver of aluminum tape and stuck it to one of the flat portions of the knob to mark my zero point. Paint would work equally well.

 

I just returned from a trip, and after writing the above, went out to the garage to back off the hydrualic adjuster to zero turns -- I was wondering why I was on tippy toes today.

[ShovelStrokeEd]

For the front, the 5mm more refers to the bike+rider although I tend to allow a little more static sag on the front due to more travel up there.

 

BTW, when I referred to the preload on the hydraulic adjuster, I meant at zero turns. That needs to be wound in by turning the entire assembly so you have 20mm of preload on the spring BEFORE you expand the hydraulic adjuster. Obviously, this needs to be done with the shock on the bench.

 

BTW, for compression and rebound, start with both adjustments at about 12 clicks out from full hard.

[kmac]

e30..did you take the spring off of the shock already, because that would be what he needs as the initial base setting...at the shop that is all he could do is set it back to what it was at...

 

i do not want to assume your suspension knowledge...so i am just gonna ask...have you set sag on a bike before?

do you know what static sag or bike sag is? full drop? rider sag?

 

it seems that stokeED is a suspension Guru, and has the best advice...i just wanted to make sure you have the basics before you start....if you do know all of this stuff, i apologize for asking...

[E30TECH]

I only removed the shocks - the springs are what they were set at from the last rebuilder.

 

I doubt that I have set the sag correctly as it seemed comfortable with the setting it was. When 2 up, I put the adjuster at max.

 

My suspension knowledge is extremely limited. I know what bike sag and rider sag is - I think (sag with just the bike, and sag with both - rider and bike).

 

Here is an example of my limited knowledge...

 

"BTW, for compression and rebound, start with both adjustments at about 12 clicks out from full hard."

 

Both adjustments...meaning the round dial 'thingy' () at the base of the shocks (and the rear remote adjuster)? I was not sure what that round adjuster is for - and I'm still not.

 

Also - How do I tell which spring is on the rear for my overweight self? I don't recall seeing a number, but I would bet it is the lighter spring.

 

BTW - I bought these from a member on here.

 

Since I'm asking questions - is it normal to have VERY light witness marks on the shaft which are even around the entire shaft (not on one part indicative of a bent shaft)?

 

The last rebuilder did these 4500 miles ago. The front started weeping at 450 miles. I sent it back and he replaced the seals (which he said he didn't do the first time as they 'never go bad'). After 4500 miles, the front failed catastrophically. I am sending both to http://www.ororcycle.com and having him do a correct rebuild on both shocks as the rear seemed a little damp. He is going to replace every seal and do that shock dyno test.

 

[ShovelStrokeEd]

You are correct on the sag idea.

 

You have two adjustments on the rear shock for damping. The rebound damping is set by a round knob just above the lower shock mount. CW is harder. The compression damping is set by a knob that is usually located on the end of the Nitrogen cylinder thingie. Again, CW is harder.

 

Ohlins springs should have a number stamped into the rubber covering on the spring, near the end of the spring. The first part of the number, ie, .95, is the rate of the spring. At your weight, you should have a 1.0 or 1.1 spring, talk to your shock guy.

 

As to the witness marks on the shaft, if you can see them but not feel them with your fingertip, you should be OK. If you can feel 'em with a finger nail, you'll need a new shaft.

[E30TECH]

Thanks for all the info everyone.

 

The marks cannot be felt, so i should be good there.

 

Is it worth doing that dyno testing?

[Antimatter]

It can't hurt to do the dyno testing on the shock. That basically checks whether the shim stack inside the shock is correctly set for the spring rate, meaning that the damping the shock can provide versus the rebound of the spring are balanced. It might a bit 'belt and suspenders' for a road bike (versus racing), but if it's not a huge expense, why not?

 

I admit, I'm curious that the shock guy wanted the sag measurement before you took the shocks off the bike (if I read that properly). If the shock set-up person already knows the weight and handling characteristics of the bike, shouldn't they just need the rider's weight to build the shock to put the bike and rider in the correct range of sag?

 

I'm not trying to agitate, just understand.

[E30TECH]

Antimatter -

He asked me since he said it would make it easier for him. I'm not sure if he has the specs on my bike, and he is in TX and I'm in NJ.

 

I checked the #'s on the spring before I packed it. They were:

01096-13 / 58 L214 I'm checking online to see if I can figure what these numbers mean.