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Author Topic: Understanding rear shock setup  (Read 609 times)

mattsz

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Understanding rear shock setup
« on: April 30, 2014, 05:10:12 PM »
It's interesting how assumptions get made about what one understands and how one applies information.  As it turns out, when I replaced my OEM shocks with Hagons, I really didn't have a complete understanding of what I was doing and why - I knew that the ride was harsh and uncomfortable, and I followed advice to try to improve things.

After a bit of back and forth, Dave Quinn recommended 18kg springs.  I installed them, but I didn't really think the ride was that much improved.  This last month, I tried 16kg springs, and as much as I wished for it, I couldn't honestly say I'd improved things much.  Now, he's trying to help me get it sorted.

He suggested I slide what he calls the "over-stroke rubber bump stops" down to the tops of the damper bodies, to see how much travel I'm using.  I didn't even notice those things were there until I changed the springs!

Anyway, I have the 16's at the softest preload setting, and I slid the bump stops down, and I rode to work - mostly little rattly bumps which try to shake your fillings loose, but a couple proper frost heaves which made me, and my back, take real notice.  When I got to work, I found the stops hard up against the top of the shaft.  This means that the shocks are bottoming out... which is what I figure we don't want.

On my ride home, I pushed the stops back down, and rode just a quarter mile of the little rattly bumps, and I stopped to look at the shocks again, and found the stops less than an inch from the top.  So to me, it seems as if those 16 springs with soft preload aren't cutting it - I'm talking here about just me and a fairly lightweight backpack, no bags or other cargo.

So now I'm thinking about the 18's again - when I went through the motions of changing those springs, the stops were at the top of the travel, so I assumed that I didn't have a useful indicator there, but Dave says that when he builds shocks, he ships them with the bump stops pressed down against the shock body.  He also says, if the buffers were at the tops of the shocks when I removed the 18kg springs, it suggests I was bottoming with them as well.

So in theory, the cause of at least some of my discomfort could be that I've never had stiff enough rear springs.  Now I'm not a heavy guy - does it seem likely that at 170 pounds locked and loaded I should be bottoming out 18kg springs?

Anyway, I'm going to reinstall the 18's, drop the stops and ride a bit to see what happens.  I did take a couple of longer rides last year with some luggage, without changing preload settings, which could have made the difference and bottomed out the 18's.  It could be that they're perfect for me after all, travel-wise... but that means that I've still got a rough-and-tumble ride.  Only my sprung solo seat has made things bearable thus far.

The things we learn...

ace.cafe

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Re: Understanding rear shock setup
« Reply #1 on: April 30, 2014, 05:57:05 PM »
I think part of the issue is related to the limited suspension travel that is typical in these bikes. There isn't enough room to for the suspension to move up and down in a cushiony way. It has to do everything in just a few inches of travel. Not much spare room for  "floating" on a soft spring.
The purpose of the Hagons is for more suspension control and handling in sporting scenarios. They really are not for luxury car type riding, and I don't think it will be easy to find any Bullet shocks that will be like that. Not enough travel available..
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mattsz

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Re: Understanding rear shock setup
« Reply #2 on: April 30, 2014, 06:03:09 PM »
Ok, so my goal then is to sort out the springs so I get the correct travel.  I'll stick with my original plan and go back to the 18's, do some normal riding around and see where their travel is at...

ace.cafe

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Re: Understanding rear shock setup
« Reply #3 on: April 30, 2014, 09:55:50 PM »
Ok, so my goal then is to sort out the springs so I get the correct travel.  I'll stick with my original plan and go back to the 18's, do some normal riding around and see where their travel is at...

Your worst bumps should come just shy of bottoming the shock out, when set at your normally desired solo preload. For two-up riding, or with a lot of luggage, use the stiffer preload adjustments.
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mattsz

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Re: Understanding rear shock setup
« Reply #4 on: May 01, 2014, 12:15:14 AM »
I'm learning a lot which is probably very obvious to you experienced guys...

Dave Quinn has been very helpful with this.  Some of his input:

Quote
You are correct, bottoming out is bad for the longevity of the shocks.  Therefore, on the face of it, the springs are too soft- at least for the preload setting they are in at the time of your test. In order to get the best ride possible with progressive springs such as Hagon use, it is best not to have to preload the spring.  This effectively coil binds the softest windings, which take away the suppleness of the spring. If the same adjustment was made on a single rate spring it would effectively increase the entire springs load bearing ability. So ideally you would be best off with a spring you did not need to adjust at all until you add weight (passenger/luggage or both).

The ideal situation is to end up with the buffer at or near the top of the stroke but not flattened- ie using as much of the stroke of the shock as possible without bottoming.

mattsz

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Re: Understanding rear shock setup
« Reply #5 on: May 02, 2014, 07:16:36 PM »
So I put the 18's back on, and at the softest pre-load setting, the worst bumps did bottom the shock out... but they're pretty bad frost heaves.  The smaller washboard stuff pushes the bump stop to within about 1/2 an inch of bottoming out.  And it's still a pretty "shocking", uncomfortable ride... basically unacceptable without my sprung solo seat.  I'm riding the factory bench/log while I sort this out...

What are we talking about here as far as bottoming out goes - should it never happen?  Or are we in the ballpark if it happens once every few hundred miles when the roads are particularly bad?
« Last Edit: May 02, 2014, 07:24:29 PM by mattsz »

singhg5

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Re: Understanding rear shock setup
« Reply #6 on: May 02, 2014, 08:23:02 PM »
I personally do not like the idea of shocks bottoming out, unless it happens once in a several thousand miles. Good input from Dave since he knows what will be best suited for you.

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ace.cafe

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Re: Understanding rear shock setup
« Reply #7 on: May 02, 2014, 08:35:27 PM »
If it bottoms out the suspension, that is particularly jarring to the frame and to you. It would best be avoided, if possible.

What I do, and used to be common riding practice in the old days of short travel suspensions, was to just stand up on the pegs when we were able to see a big bump coming up. This evens out the weight load on front and rear, and keeps your butt out of the seat when the impact happens.
All the old bikes were like this in the good old days. We managed to survive it okay.
The bike isn't supposed to feel like riding on a cloud. You should feel feedback from the road and suspension.
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Arizoni

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Re: Understanding rear shock setup
« Reply #8 on: May 02, 2014, 10:46:46 PM »
mattsz

Have you adjusted the pre-load up to the "middle" setting and tried riding over the same bumps?
That should keep things from bottoming out on all but the biggest pothole.

As for the rough ride at that setting, I guess that's what happens when a middleweight motorcycle is ridden over bumpy roads.
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Mr.Mazza

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Re: Understanding rear shock setup
« Reply #9 on: May 03, 2014, 12:25:57 AM »
If it bottoms out the suspension, that is particularly jarring to the frame and to you. It would best be avoided, if possible.

What I do, and used to be common riding practice in the old days of short travel suspensions, was to just stand up on the pegs when we were able to see a big bump coming up. This evens out the weight load on front and rear, and keeps your butt out of the seat when the impact happens.
All the old bikes were like this in the good old days. We managed to survive it okay.
The bike isn't supposed to feel like riding on a cloud. You should feel feedback from the road and suspension.

That method is still taught here in Australia, even just a few inches of your seat helps stop you getting thrown up and potentianlly making a mistake.
Mind you our roads are a lot worse compaired to America, our A roads look like your B roads and our B roads and half offroad!
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lemming

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Re: Understanding rear shock setup
« Reply #10 on: June 24, 2014, 06:28:29 PM »
What about using longer rear shocks? I realize this would also make the front end steeper, which should quicken up the steering a bit, no?
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cafeman

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Re: Understanding rear shock setup
« Reply #11 on: July 13, 2014, 10:36:40 AM »
A simple thing you can do is lower the rear tire air pressure. Use common sense when setting it, not so low the tire deforms and squirms all over the road!. Used this on an old sportster with short travel stiff shocks and it improved the comfort a bit. Go down in small increments and test.

Mr.Mazza

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Re: Understanding rear shock setup
« Reply #12 on: July 14, 2014, 03:11:59 AM »
Ive also found a good way to avoid heavy front end shock when on a dirt road at 20mph and no way to avoid that pothole is to stand up and bounce down, then lift up on the bars as you hit it. So instead of slamming into it you sorta skip over it, the rear end still copes it but no front jarring.
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barenekd

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Re: Understanding rear shock setup
« Reply #13 on: July 31, 2014, 10:11:12 PM »
Going to suggest lowering the tire pressure. I dropped mine to 18F and 24R and the ride was greatly improved over the 24/28 I'd been running. It was even comfortable! I still get a bottoming smack now and then, but overall the ride was greatly improved.
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« Last Edit: July 31, 2014, 10:14:24 PM by barenekd »
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ruufman58

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Re: Understanding rear shock setup
« Reply #14 on: August 26, 2014, 12:13:08 AM »
I also installed hagons in an attempt to smooth the ride on my g5.With no spring seat I would get a lot of jarring sacks right up my spine.The most relief was found in dropping the rear tire to 24psi and the front tire to 18 psi.Anyone have a shock with a longer stroke?
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