Rear Shock Preload
Tourer
Joined: Jun 2014
Posts: 250
Likes: 7
From: Kentucky
Wow 170lbs and running at 2 plus. You should be at 1 or just above. The ride should be harsh at 2 for your weight. I have a 20 Fatboy that I have been toying with on the suspension myself and I'm 190 and have it set at just under 1 and it seems pretty good there. I used to ride at 2 then rode my buddies fatboy and his was set 2 full turns under 1 and he weighs 175 and felt like his rode much nicer then mine so I lowered mine to just under 1 and if feels good now.
Tourer
Joined: Jun 2014
Posts: 250
Likes: 7
From: Kentucky
Yes, I started at 2 allowing for kit and luggage (bag, tools and waterproofs, essential for the UK!). Increasing the preload changes the ride height, it doesn't make the spring any more or less harsh. I raised it because it was feeling like I was bottoming out on my local roads (hitting the stop, being fully compressed). Reducing preload can actually make the suspension harsher, because you are reducing the distance the suspension has to travel before it hits the stop. Someone more knowledgeable than me can explain the engineering. But, on my test route I didnt get the spine crushing thump, when the shock was seriously compressed, in places where I previously did. I didn't sense any topping out either, where your **** leaves the saddle or the revs start to rise, because the shock has run out of its extension limit. So I decided I could feel a difference and I'm thinking of going up a little more to increase ground clearance. That said, I don't think the shocks are that clever and the main effect of fiddling with it is in our heads, not on the road. But it's the only adjustment we've got and it's easy to fiddle with, so worth a try.
Banned
Joined: Sep 2015
Posts: 261
Likes: 186
If you had the Softail FatBob before, then unfortunately you have a shorter shock and much less ground clearance. I actually went from Sport Glide to FatBob because I was grinding pegs and exhaust way too much (well, and I needed better brakes). I have my FatBob cranked up to 4 at 200 lbs, and its much better, enough clearance not to notice until I get a bit aggressive. Getting a taller shock should help a bit.
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Road Master
Joined: Mar 2018
Posts: 978
Likes: 423
From: UK
Wow I am going to have to research that more. I have honestly never looked into what all the preload actually does. I know it adjusts ride height and the general consequences of doing it. But in my mind all this time I "assumed" that adding preload was compressing the spring and thus making the spring stiffer or harder to compress. And that would inherently make the ride harsher as the more compression you dialed on the harder it would be. So therefore every bump you hit would be harsher with more preload. And somehow I can't see how that would not be true just on that very limited interpretation. So I am going to have to look into that to educate myself. Although I just stick with what the manual recommends for me anyway so I feel like I am not messing it up
So, my bike came on 2. I read the manual and set it at 1. I was constantly bottoming out, which hurts and scraping the footboard. I set it to 4. Much more comfortable and on a spirited ride with mates around lots of twisties, only scraped once. Handling is good. One mate reported I was very close to touching exhausts down on right handers. Out of interest I increased preload to 6 and on a shorter ride on Thursday, it was comfortable, perhaps even better. At settings 4-6, I am no longer bottoming out the rear and as a bonus, less likely to scrape the footboard. I will leave it at 6 for now, knowing that if I need it, setting 4 works for me. Might be easier to get my lift under the bike too!
I definitely read things (performance upgrades usually) and think, 'no way you can tell, it's just in your head'. So, possibly it's in my head. But I honestly dont think so. Cost me nothing, nothing to prove!
Last edited by Mart; May 30, 2020 at 01:49 AM.
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Road Master
Joined: Mar 2018
Posts: 978
Likes: 423
From: UK
Correction, it originally came on setting 3 and I reduced to 2. This made it worse. Increased then to 4, best so far. Now 6. Will see how this goes. If doesn't give enough clearance I'll investigate the fatbob idea.
Banned
Joined: Jan 2019
Posts: 3,036
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From: Nunya.
The FXBB rear shock's handling of high speed compression damping is very poor OR the shock spring is way too soft for me.
The front is sprung a little soft but I've added 20mm(3/4 inch) of oil in each leg and about 12mm(1/2 inch ) of preload with spacers but it doesn't slam through the stroke like the back end. Out back if I hit a square edge bump it just blows through the damping and bottoms hard.It might need a stiffer spring.
Does anyone know the spring rates for these things ?
The front is sprung a little soft but I've added 20mm(3/4 inch) of oil in each leg and about 12mm(1/2 inch ) of preload with spacers but it doesn't slam through the stroke like the back end. Out back if I hit a square edge bump it just blows through the damping and bottoms hard.It might need a stiffer spring.
Does anyone know the spring rates for these things ?
Last edited by Agoober; May 30, 2020 at 08:53 PM.
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The Cheesehead
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Dec 29, 2012 07:32 AM
