Mismatched shock absorbers
#1
11-01-2013, 04:23 AM
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Mismatched shock absorbers
Here's a question for the suspension gurus:
What negative effect (if any) can result from mismatched shock absorbers?
Background - I have Ikon shocks on my bike (original owner replaced the standard shocks) which are adjustable for preload and dampening. Standard length of 13 inches.
I also have a set of Ricor shocks on my Sportster, 13 inches long. Collapsed length of this shock is 9.5 inches whereas the touring shocks have a collapsed length of 10 inches. Therefore (spring and dampening rates aside), the Sportster shocks cannot be used as a pair because the tire will rub the guard.
Therefore, I removed only one Ikon shock with the Ricor sportster shock (therefore preventing the Ricor shock from bottoming out) and adjusted the preload on the Ricor shock for correct rider sag (1 inch). The preload on the Ikon is already on the highest setting.
The ride is much improved. The single Ricor has almost eliminated the bouncing effect and settles almost instantly after bumps, the ride is more plush and handling is great through the corners. In fact, you'd swear that I had the pair of Ricors on there. This was only intended to be a test until such time as I purchase the touring shocks, but results are so good, I'm not inclined to muck up a good thing. Additionally, the Ikon shock gives me the ability to adjust dampening (something that does work well on this shock) which a pair of Ricors don't.
From my experience and considering the swingarm and rear axle prevent the wheel from doing anything other than traveling up and down, I see the difference in spring rates and dampening to have an overall negligable effect (if any). I have a mate though that can't get his head around the fact that it would have to induce wallowing or some other negative side effect. Also consider that the Switchback uses a mismatched system in its front forks. Technically, you should be able to run one shock only, but being so off centre, the swingarm may flex in this condition and it would possibly stress out the swingarm bearings faster.
What do you guys think?
What negative effect (if any) can result from mismatched shock absorbers?
Background - I have Ikon shocks on my bike (original owner replaced the standard shocks) which are adjustable for preload and dampening. Standard length of 13 inches.
I also have a set of Ricor shocks on my Sportster, 13 inches long. Collapsed length of this shock is 9.5 inches whereas the touring shocks have a collapsed length of 10 inches. Therefore (spring and dampening rates aside), the Sportster shocks cannot be used as a pair because the tire will rub the guard.
Therefore, I removed only one Ikon shock with the Ricor sportster shock (therefore preventing the Ricor shock from bottoming out) and adjusted the preload on the Ricor shock for correct rider sag (1 inch). The preload on the Ikon is already on the highest setting.
The ride is much improved. The single Ricor has almost eliminated the bouncing effect and settles almost instantly after bumps, the ride is more plush and handling is great through the corners. In fact, you'd swear that I had the pair of Ricors on there. This was only intended to be a test until such time as I purchase the touring shocks, but results are so good, I'm not inclined to muck up a good thing. Additionally, the Ikon shock gives me the ability to adjust dampening (something that does work well on this shock) which a pair of Ricors don't.
From my experience and considering the swingarm and rear axle prevent the wheel from doing anything other than traveling up and down, I see the difference in spring rates and dampening to have an overall negligable effect (if any). I have a mate though that can't get his head around the fact that it would have to induce wallowing or some other negative side effect. Also consider that the Switchback uses a mismatched system in its front forks. Technically, you should be able to run one shock only, but being so off centre, the swingarm may flex in this condition and it would possibly stress out the swingarm bearings faster.
What do you guys think?
#3
11-01-2013, 07:00 AM
Club Member
What do I think? Being upside down obviously has a bad affect on you chaps in Oz!
Harley and other brands use different set-ups in front forks, with apparently great success. One trick they use is to have damping in one direction in one fork leg, the other direction in the other leg. There are technically sound reasons for doing that, especially if the trees/yokes and front axle/spindle are sturdy enough. That is a proven way of doing things.
So let us consider your set-up. The swingarm is a large U fabrication, which frankly is not very stiff in torsion (left versus right sides). In addition the entire engine/trans/suspension is rubber mounted in the frame. Any differential performance in the shocks, unless well tuned and balanced, is likely to have some strange affects on what the rear wheel does.
If a mismatched pair of shocks can be developed to give good results, what are the chances you cracked it without any development and in your backyard? Has any reputable shock brand ever offered us such a set-up? Well yes, they have, but not many brands as yet. Harley don't currently make a swingarm that is sturdy enough IMHO. You're meddling with the dark arts!
You're also deluding yourself old chap. Go buy yourself a nice new shiny set of decent quality matched shocks and compare the ride. And get out of the sun......
Harley and other brands use different set-ups in front forks, with apparently great success. One trick they use is to have damping in one direction in one fork leg, the other direction in the other leg. There are technically sound reasons for doing that, especially if the trees/yokes and front axle/spindle are sturdy enough. That is a proven way of doing things.
So let us consider your set-up. The swingarm is a large U fabrication, which frankly is not very stiff in torsion (left versus right sides). In addition the entire engine/trans/suspension is rubber mounted in the frame. Any differential performance in the shocks, unless well tuned and balanced, is likely to have some strange affects on what the rear wheel does.
If a mismatched pair of shocks can be developed to give good results, what are the chances you cracked it without any development and in your backyard? Has any reputable shock brand ever offered us such a set-up? Well yes, they have, but not many brands as yet. Harley don't currently make a swingarm that is sturdy enough IMHO. You're meddling with the dark arts!
You're also deluding yourself old chap. Go buy yourself a nice new shiny set of decent quality matched shocks and compare the ride. And get out of the sun......
#4
11-03-2013, 06:54 AM
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Convincor - interesting fact that. Something that grbrown seems to have overlooked in his reply.
Although I appreciate your input, which is exactly what I asked for, I can't see that it's very well informed. For one, I think you'll find that the rubber mounting will only allow for horizontal movement, not lateral. And the upgraded, more solid swingarm of the 09 model might have some torsional effect if placed under great strain from one side, but there is also an axle solidly mounted between the two. With wheel bearing in good condition, your U fork becomes a box. Remember too, that we're not going to be talking huge differences in spring and dampening rates. You're going to see far more torsional effect just by leaning the bike during a turn, and if this was addressed through the frame and swingarm upgrade, these small shocker differences becomes even less of an issue.
No strange effect has been observed. I've now tested them over all sorts of road conditions including some hard riding up my favourite mountain range and with two up and a load of shopping. The pair of Ricors that I'll eventually purchase will no doubt be as good (I'd like to say better, but the ride is so good now that this is hard to believe) but I don't see a need to rush into buying a set.
This also isn't about developing mismatched shocks to give a superior ride over a well matched pair, but simply my observations because I happened to have one better shock on hand that I could use as a test (couldn't use the pair because of the collapsed length issue). If I've cracked a good ride in my backyard without adverse effect, then I guess I'm the lucky one. As for dark arts, Ricor have some pretty good technology, but I know you are also running a pair of intiminators modified by fabric8r as he worked out the patent and how to make them work even better, so this, combined with some pretty simple spring and fluid dampening is hardly 'dark arts'.
For now I'm happy to stay deluded (and in the sun
Although I appreciate your input, which is exactly what I asked for, I can't see that it's very well informed. For one, I think you'll find that the rubber mounting will only allow for horizontal movement, not lateral. And the upgraded, more solid swingarm of the 09 model might have some torsional effect if placed under great strain from one side, but there is also an axle solidly mounted between the two. With wheel bearing in good condition, your U fork becomes a box. Remember too, that we're not going to be talking huge differences in spring and dampening rates. You're going to see far more torsional effect just by leaning the bike during a turn, and if this was addressed through the frame and swingarm upgrade, these small shocker differences becomes even less of an issue.
No strange effect has been observed. I've now tested them over all sorts of road conditions including some hard riding up my favourite mountain range and with two up and a load of shopping. The pair of Ricors that I'll eventually purchase will no doubt be as good (I'd like to say better, but the ride is so good now that this is hard to believe) but I don't see a need to rush into buying a set.
This also isn't about developing mismatched shocks to give a superior ride over a well matched pair, but simply my observations because I happened to have one better shock on hand that I could use as a test (couldn't use the pair because of the collapsed length issue). If I've cracked a good ride in my backyard without adverse effect, then I guess I'm the lucky one. As for dark arts, Ricor have some pretty good technology, but I know you are also running a pair of intiminators modified by fabric8r as he worked out the patent and how to make them work even better, so this, combined with some pretty simple spring and fluid dampening is hardly 'dark arts'.
For now I'm happy to stay deluded (and in the sun
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