Harley Davidson Softail Suspension Diagram
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Discussion Starter · #1 · (Edited)
Softails's come from the factory with the lightest setting for the rear shocks (for <180lbs solo rider). However, they can handle well over 400lbs with no problems with a simple preload adjustment.
The service manual is a bit vague on how to set the preload. The procedure I use is fairly simple. Its based on the procedure from fatbillscustoms.com, but their website is gone now. It was fairly detained. I've made some tweaks to it for simplicity... Enjoy...
1) Jack the bike up so the rear tire is off the ground. The more clearance you have the easier it is. Don't forget to strap the bike down. You don't want it falling on you while your wrenching underneath it.
2) Loosen the jam nut all the way out. Its a 1-11/16" nut. If it doesn't want to loosen easily (which is often the case), soak it in some penetrating lube.
3) With a spanner wrench (HD p/n 94448-82B) turn the adjuster plate counter-clockwise (so the shock housing moves towards the front of the bike) until its up against the jam nut.
4) Then take a light colored paint pen, or a piece of duck tape, and mark the 6 o'clock position on the adjuster plate to use as a reference point when doing your adjustment. Don't worry if they're not in exactly the same position on both shocks. Thats normal.
Now your ready to adjust the shocks to your weight/load.
5) With the spanner wrench, turn the adjuster plate clockwise no more then 4 complete turns by counting how many times the mark from step 4 crosses the 6 o'clock position. 0 turns is the stiffest setting, and 4 turns is the softest setting.
6) While holding the adjuster plate in place with the spanner wrench, tighten the jam nut up against the adjuster plate by turning the nut clockwise.
6) Now repeat the exact same process on the other shock. The key is to adjust both shocks equally.
The general rule of thumb I use is:
4 turns for load <= 180 lbs
3 turns for 180lbs < load <= 235lbs
2 turns for 235lbs < load <= 300lbs
1 turn for 300lbs < load <= 375lbs
0 turns for 375 < load
Examples:
235lbs solo rider: 3 full turns
235lbs solo rider + 32lbs pack: 2.5 turns
235lbs rider + 150lbs passenger + 32lbs pack: 0.5 turns
I like a slightly stiffer ride when running solo (3 turns for my 235lbs fat booty), but run a softer ride when my girlies on the back (1 turn). Adjust your shock to taste by 1/4 turn increments till you get it dialed in for you and your riding style.
Note: you may be tempted to skip step 1 and not jack the bike up. Resist the urge. A stock ride height with the bike on its kick-stand, you may be able to use a crowsfoot or similar to get the jam nut loose, but you will have little to no room to use the spanner wrench. So take the time to do it right and jack the bike up. It only takes a minute (including strapping the bike down).
Enjoy...
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Your right, the Service Manual does not even give you a clue as to how much to adjust. Thanks for the info!
Now if I only had the spanner wrench :-(
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Trying to learn something here as I would like to lower my Deuce.
Will changing the preload alter the height of the frame?
Seen some mention of adding washers to increase the length of the bolts. Anybody like to chime in here?
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Don't know about adding washers, but changing the preload will change the bike's ground clearance (more so when laoded or sitting on the bike). The shocks are what supports a Softail, the "softer" or "lighter" they are adjusted the lower the bike will be.
Again, note that the lowering effect is more as the weight on the bike increases. For example it will sit much lower with two people that weigh a total of 400 lbs as opposed to a single rider that only weighs 170 (if the preload is the same for both cases that is).
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Rather than "....Jack the bike up so the rear tire is off the ground.." you could roll both wheels up onto say 4 x 1 " wooden planks. Place a similar piece of wood under the sidestand if the bike looks to be unstable.
This leaves the underside of the frame clear so that you can more easily see the rear suspension and insert the adjustment tool. (over 60, overweight, bad back, bad eyes, I need all the help I can get)
It is necessary to somehow raise the bike since (on my softail at least ) the genuine tool HD p/n 94448-82B is frustratingly 1/2" too long to rotate before it hits the ground. You could cut an inch off the tool but don't cut off too much since you will need all the leverage to turn the spring adjuster screws.
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Thanks for this post. I bought a 98 FLSTS and the shocks were so soft that my 235lb frame would make it bottom out on a good rut. Jacked it up and adjusted to 1 1/4 turns (they were cranked in all the way to the softest possible setting). Rides perfect with the wife on the back and firm when I'm, solo. Changed the whole fell of the bike.
Thanks for sharing the info. Appreciate it!
Pete
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That's some good information petrock..
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That is good info. The service manual isn't too helpful when it comes to this. I adjusted mine because the girlfriend and I would bottom out on occasion when a good bump came up. Something to keep an eye on.....while I was adjusting one of the shocks, I noticed that althought I made the same rotation adjustment, the shock housings were not lined up. I found that the main rod (name of it anyone??) that runs through the shock was also turning with the housing and I didnt know it. When you are adjusting the plate with the spanner wrench, keep yur eye on that stud to make sure its doesnt spin as well..
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Thanks for this post. I bought a 98 FLSTS and the shocks were so soft that my 235lb frame would make it bottom out on a good rut. Jacked it up and adjusted to 1 1/4 turns (they were cranked in all the way to the softest possible setting). Rides perfect with the wife on the back and firm when I'm, solo. Changed the whole fell of the bike.
Thanks for sharing the info. Appreciate it!
Pete
+1 on the 1&1/4 turns
Al
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Spanner wrench dimensions?
Put the extenders in recently and unintentionally set the preload all the way in (?) and bottom out very easily. (Weigh 225 lbs) Attempting today to adjust the preload to my weight as desribed above but will try it with a strap wrench as was suggested somewhere else.
But if anyone knows the dimensions of the tool, I can, a; borrow one here at work or, b; make one here as well.
Thanks in advance!
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Discussion Starter · #12 ·
Put the extenders in recently and unintentionally set the preload all the way in (?) and bottom out very easily. (Weigh 225 lbs) Attempting today to adjust the preload to my weight as desribed above but will try it with a strap wrench as was suggested somewhere else.
A strap wrench around the outer shell of the shock (the 'can') works sometimes. Its kind of hit or miss. More often then not all you'll achieve with the strap wrench is spinning the can instead of turning the adjuster plate. If you turn the can with a strap wrench and the adjuster plate moves too, then cool. If not, then you'll need the spanner wrench. Its the adjuster plate that controls the adjustment. Hence it's name. 
So count the turns of the adjuster plate, not the turns of the can.
But if anyone knows the dimensions of the tool, I can, a; borrow one here at work or, b; make one here as well.
Why bother making one? The tool only costs $10.95 at your local dealer. An hour of my time is worth way more then $10.95 (to me at least).
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A strap wrench around the outer shell of the shock (the 'can') works sometimes. Its kind of hit or miss. More often then not all you'll achieve with the strap wrench is spinning the can instead of turning the adjuster plate. If you turn the can with a strap wrench and the adjuster plate moves too, then cool. If not, then you'll need the spanner wrench. Its the adjuster plate that controls the adjustment. Hence it's name.
Why bother making one? The tool only costs $10.95 at your local dealer. An hour of my time is worth way more then $10.95 (to me at least).
I just recently had the shocks apart so I believe they will turn. If not I can borrow one in a jiffy, but prefer not to if possible. The borrowed one is closer than dealer and it's free. I limit my dealer dollars very carefully.
I did find some information about the spanner wrench. Seems it's 1-1/16". Got a couple here in work that are 1-3/8".
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Nudder' problem solved today!
Turns out the nut is 1-1/16" and the spanner is 1-3/8", same size as the one I brought home!
Thanks petrock for your detailed instructions.
Note to self: Build a couple 12" high wood stands to support bike during projects!
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Thanks for the shock tip Petrock. I ride alot with the GF on board and I had to be careful crossing speedbumps and RR tracks. I adjusted my shocks today but rain hasn't allowed me to test drive yet, need a rear tire too. I noticed my spanner nut was backed off 5 turns originally, I wonder why so much? To make it lower? Seems to sit just about the same, I backed off 3 turns, may need more, but I'll try that first. I parked my bike on three 16x16x2 patio blocks, 2 for wheels, one for kickstand, worked perfecty, took about 15 minutes.
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The 2011 Manual is a little different. It states in turns out (counterclockwise) from minumum preload.
FLSTC, FLSTF, FLST
Less than 165 = 0
165 - 220 = 1
220 - 275 = 2
275 - 335 = 3
335 - 395 = 4
Greater than 395 = 5
FLSTFB, FLSTSB, FLSTN
Less than 185 = 0
185 - 235 = 1
235 - 285 = 2
285 - 340 = 3
Greater than 340 = 4
FXCWC
Less than 150 = 0
150 - 195 = 1
195 - 240 = 2
240 - 290 = 3
290 - 340 = 4
Greater than 340 = 5
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Petrock is the MFMAN!
signed: shock daddy
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Discussion Starter · #18 ·
Petrock is the MFMAN!
signed: shock daddy
Thanks… Its based on your formula. :cheers:
Sticky?
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Petrock....you are da man!
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I have an '08 Fatboy that I've been thinking of changing the preload on for when my ol' lady rides with me, and this helps alot. My question is, does changing the preload significantly affect the handling or control of the bike?
Posted by: deldelkearsee0277837.blogspot.com
Source: https://www.v-twinforum.com/threads/how-to-adjust-softail-rear-shock-preload.168539/
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