Pre- load vs Shock Adjustment.

TearlessTom · Apr 5, 2008

I am a little confused on the whole preload adjustment thing.

Does less preload mean more rebound bounce or does it mean less rebound bounce.

Which is a smoother ride for the passenger?

I ask because the better half and I have a weekend outing planned for the last week of this month going up to the races at the Barber museum.

I think about 5 couples are going, only two couples will be two-up. I think the other couple that is going two up is also on an ST, the rest are cruisers so we will not be going fast. Just a 250 mile lazy ride up and back and some small mountains while we are there.

Combined weight of me, her, bestem box, an luggage should be a bit under 400lbs. probable close to about 350lbs.

What would be my best settings for comfort on the ride up and back and also for a little more spirited riding in the twisties while up there?

Thanks,
Tom

Killtimer · Apr 5, 2008

Tom

Spring preload is the adjustment to get the correct "sag". Sag is simply the amount of wheel travel that happens when the bike is loaded but stationary. For the ST that should be 1.25 to 1.5 inches for 2 up riding. The rebound damping controls how fast the spring is allowed to return the suspension to it's pre-bump position. More damping creates a slower return and a harsher ride. Too much damping creates a situation where the suspension may not recover fast enough and allow bottoming out on a subsequent bump. It also is a factor in how planted and secure the bike feels. It's a balance based on a lot of personal factors.

I'd suggest you start with the preload at about 3/4, maybe the second last mark on the adjuster, and the rebound set at full hard. If the ride is a bit harsh, back the rebound damping out a bit, usually 1/4 turn at a time, and test again. If the bike bottoms out on any road surfaces, crank in more preload. HTH

Raven · Apr 5, 2008

Actually for that weight, given that the ST tends to be undersprung, you'll want your PRELOAD dialed in at almost full hard maybe one line showing - otherwise you'll be bottoming out on every bump.

The DAMPING is NOT weight sensitive. I've adjusted over 25 ST's over the past two years teaching the Total Control Advanced Riding Clinic and, without fail, proper rebound damping has been at ~1 & 3/4 full turns to 2 full turns out from full hard on a stock shock. Any harder than that and the rebound is too slow (bounce on the rear with it set at full hard and you'll see how slow the bike rebounds - looks almost like it's sticking).

So to set your damping, set it to full hard and bounce it. It will look like the suspension is sticking. Now set it to full soft and bounce it. It will pogo so fast that it actually pulls the wheel off the ground and oscillate. Now, turn it back to full hard and dial it out 2 full turns. Bounce it and it will come up and settle without oscillating. If it oscillates, turn it a 1/4 turn towards hard and bounce it again. This will be darn close to "just right." Play around in 1/4 turns to get it dialed in perfectly - it should come up and settle without looking like it's sticking.

myhrdly · Apr 5, 2008

Raven said:
(bounce on the rear with it set at full hard and you'll see how slow the bike rebounds - looks almost like it's sticking).

When you say bounce on it, just how do you mean? Do I sit on the bike and hold the handle bars like I am going to ride it and jump up and back down seating my butt firmly on the seat? Can you explain how to "bounce" the rear?? I'm a blond and a female, so I have go to things working against me already!!!

: :crackup

Thanks for the help!!!
Kim

Killtimer · Apr 5, 2008

The best way is to have a couple of strong friends hold the front, one on each side holding the bars, bike balanced upright, while you, standing behind the bike, push straight down on the rear rack and release.

myhrdly · Apr 5, 2008

Killtimer said:
The best way is to have a couple of strong friends hold the front, one on each side holding the bars, bike balanced upright, while you, standing behind the bike, push straight down on the rear rack and release.

Ok, that means it is not a do it "by" yourself job!! LOL Next time I corner hubby and his friend, I will get them to hold the bars!!! Oh, Can this be done while the bike is on a m/c lift? I have one of those lifts that you pull the bike up on it and put the front wheel into a "vise" type thingy! If it can be, that means the next time I do it's service, I can play with suspension!!!!

Thanks!!!!
Kim

Killtimer · Apr 5, 2008

myhrdly said:
Oh, Can this be done while the bike is on a m/c lift? I have one of those lifts that you pull the bike up on it and put the front wheel into a "vise" type thingy! If it can be, that means the next time I do it's service, I can play with suspension!!!! Thanks!!!!
Kim

As long as the front wheel is all that's held it should work. I use a wheel chock from my MC trailer in exactly that way to set the rear sag. Just be very careful that the front is held securely and by the wheel only.

dduelin · Apr 5, 2008

Raven said:
Actually for that weight, given that the ST tends to be undersprung, you'll want your PRELOAD dialed in at almost full hard maybe one line showing - otherwise you'll be bottoming out on every bump.

The DAMPING is NOT weight sensitive. I've adjusted over 25 ST's over the past two years teaching the Total Control Advanced Riding Clinic and, without fail, proper rebound damping has been at ~1 & 3/4 full turns to 2 full turns out from full hard on a stock shock. Any harder than that and the rebound is too slow (bounce on the rear with it set at full hard and you'll see how slow the bike rebounds - looks almost like it's sticking).

So to set your damping, set it to full hard and bounce it. It will look like the suspension is sticking. Now set it to full soft and bounce it. It will pogo so fast that it actually pulls the wheel off the ground and oscillate. Now, turn it back to full hard and dial it out 2 full turns. Bounce it and it will come up and settle without oscillating. If it oscillates, turn it a 1/4 turn towards hard and bounce it again. This will be darn close to "just right." Play around in 1/4 turns to get it dialed in perfectly - it should come up and settle without looking like it's sticking.

Raven,

I believe in your experience but on my stock shock I rode many thousands of miles with the rebound damping 3/4 turn out from full hard and that was the sweet spot for that shock and my bike.

Raven · Apr 5, 2008

If you bounce the rear with that setting, you'll see that it is a bit slow rebounding. You want it to rebound and just settle (not oscillate). I used to have mine set extremely hard (1/2 to 3/4 turn from hard) but, despite feeling pretty good by the seat of the pants, you actually have a negative effect on your traction b/c the spring can't rebound fast enough. The first bump isn't too bad but it's the next one, then the next one and the one after that. The suspension hasn't fully rebounded so it gets packed in and now you're knocking the wheel off the ground.

Finewest · Apr 5, 2008

dduelin said:
Raven,

I believe in your experience but on my stock shock I rode many thousands of miles with the rebound damping 3/4 turn out from full hard and that was the sweet spot for that shock and my bike.

Ditto.

TearlessTom · Apr 5, 2008

Killtimer said:
Tom

Spring preload is the adjustment to get the correct "sag". Sag is simply the amount of wheel travel that happens when the bike is loaded but stationary. For the ST that should be 1.25 to 1.5 inches for 2 up riding.

Okay , At what point are you measuring? At vertical to the axel nut, at the rear of the bike, or in front of the rear tire?

The futher back you measure the more travel there will be, so what is the sweet spot to measure from.

(Finally I have a reason to try out my remote control on the camera so I can set on the bike and photograph the measurement at different settings.)
Tom

shutupnride · Apr 6, 2008

Quoth the Raven:

Raven said:
...proper rebound damping has been at ~1 & 3/4 full turns to 2 full turns out from full hard on a stock shock. Any harder than that and the rebound is too slow...

Thanks for the tip, Raven. I have read postings on this forum about the rear shock/spring being 'soft', so I cranked up both the preload and rebound settings near the top end. I'm about 175lbs and ride one-up mostly, and I've never felt truly 'dialed in'. My major complaint has been the kidney punch impact during a series of bumps, very much like you describe.

While the ST's stock suspension may be soft for riding 2-up with gear, it's less of a concern for a skinny guy riding solo (I was gonna say naked). I think I've had the rebound damping dialed way too hard, which doesn't allow the suspension to recover for subsequent bumps. It begins to actually make sense to me now. I'll try backing it off as you suggest.

I value your wisdom and input on this and other postings. Thank you for your efforts to make all of us safer and smarter. I hope to take one of your seminars one day soon, too!

Killtimer · Apr 6, 2008

TearlessTom said:
Okay , At what point are you measuring? At vertical to the axel nut, at the rear of the bike, or in front of the rear tire?

The futher back you measure the more travel there will be, so what is the sweet spot to measure from.

(Finally I have a reason to try out my remote control on the camera so I can set on the bike and photograph the measurement at different settings.)
Tom

The preferred point is from the axle to a point on the bike directly above it, or from the floor vertically through the axle to the same point. A bit of a pain if you're trying to measure with the bags on. I used a wheel chock to hold the bike, some sandbags for weight and measured from a few different points. I determined that the difference between the preferred point and a floor to rear rack measurement (more convenient to measure) is 8/10. I multiply the rear rack to floor measure by .8 and it seems to work out. I've now got 3 settings for pre-load, single rider, single rider with pillion or full luggage, and 2 up fully loaded. The main reason I went to an after market shock (Penske) was not being able to get the fully loaded sag where it should have been which resulted in cornering clearance issues more than suspension bottoming ones.

TearlessTom · Apr 6, 2008

Killtimer said:
The preferred point is from the axle to a point on the bike directly above it, or from the floor vertically through the axle to the same point. A bit of a pain if you're trying to measure with the bags on. I used a wheel chock to hold the bike, some sandbags for weight and measured from a few different points. I determined that the difference between the preferred point and a floor to rear rack measurement (more convenient to measure) is 8/10. I multiply the rear rack to floor measure by .8 and it seems to work out.

Thanks for all the info guys. I will work on this today as well as finishing up my 24000 mile maintaince.

Tom

hojo in sc · Apr 6, 2008

Kim: Look at this link and scroll down to see the adjustment for your bike.

http://motorcycleinfo.calsci.com/Suspension1.html#AdjustRearSuspension

Raven · Apr 6, 2008

Yep, calsci is good but the damping adjustment recommended there is too hard (making the rebound too slow).

If you really want to allow for friction in the system you'll need three measurements as outlined in THIS THREAD.

timeagain · Apr 6, 2008

I found that Preload of about 10 turns (from full out) and Damping set to 1 and 1/2 turns from full hard is great for me. Will tweak Preload sometimes for 2 up riding.

dduelin · Apr 6, 2008

Raven said:
If you bounce the rear with that setting, you'll see that it is a bit slow rebounding. You want it to rebound and just settle (not oscillate). I used to have mine set extremely hard (1/2 to 3/4 turn from hard) but, despite feeling pretty good by the seat of the pants, you actually have a negative effect on your traction b/c the spring can't rebound fast enough. The first bump isn't too bad but it's the next one, then the next one and the one after that. The suspension hasn't fully rebounded so it gets packed in and now you're knocking the wheel off the ground.

Oh, I rode over a few bumps in 42,000 miles before replacing the shock and know what suspension settings worked for the way I tend to ride on the roads I like to ride. 3/4 out did not cause the rear wheel to hop from packing in bumpy turns. Toward the end of the OEM shock's life it was rebounding fast enough to top out the spring.

myhrdly · Apr 6, 2008

Ok, let's make this a whole lot simpler! Insted of me having to figure out all these math equasions! How about somebody here that weighs around 200 pounds, let me know how you have yours set up?!!!

: :mrgreen:

To tell you the truth, I don't even know where my (little screw) adjuster is now. I messed with it one time and it made the ride real hard. I turned it back (don't remember how many turns) and now the ride feels fine to me! I think I have the big knob about in the middle. The ride feels good to me! I was just currious on what exactly it should be at for my weight so I can try it at that position to see if the ride may be even better????

THanks!
Kim

AZ711 · Apr 22, 2008

Raven said:
If you bounce the rear with that setting, you'll see that it is a bit slow rebounding. You want it to rebound and just settle (not oscillate). I used to have mine set extremely hard (1/2 to 3/4 turn from hard) but, despite feeling pretty good by the seat of the pants, you actually have a negative effect on your traction b/c the spring can't rebound fast enough. The first bump isn't too bad but it's the next one, then the next one and the one after that. The suspension hasn't fully rebounded so it gets packed in and now you're knocking the wheel off the ground.

I can second this motion. While on a ride this past weekend I went over some "wash board" bumps in a right hand corner. The bumps "walked" the bike over to the left and I crossed the double yellow. I checked my dampening and it was 1/2 out from full hard. I've now set it to 1-1/2 turns out and it seems much better. I have to reason that the hard setting did not allow for the suspension to react to the bumps, so the tire just basically skipped over them.

Pre- load vs Shock Adjustment.

TearlessTom

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Killtimer

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Raven

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myhrdly

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Killtimer

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myhrdly

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Killtimer

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dduelin

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Raven

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TearlessTom

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shutupnride

Killtimer

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TearlessTom

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hojo in sc

Raven

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timeagain

dduelin

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AZ711