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tomw
Active Member
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Posted: Fri Nov 14th, 2008 09:41 pm | 1st Post |
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This is on an '83 Aspencade with the air shocks on the rear.I got the system mounted and seems to be working but I also have a set of spring shocks from another bike rated to 450lbs.They are 12 3/4 eye to eye which seems a bit long but I think they'd fit.What do you all think if I run the springs? and remove the air shocks and the pump from the machine?
Last edited on Fri Nov 14th, 2008 09:42 pm by tomw
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Relax,we all have a little Gomer Pyle in us.
Two things extinct in America in the 21st Century,customer service and management.
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wda-83wing
Senior Guru
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Posted: Fri Nov 14th, 2008 10:06 pm | 2nd Post |
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| adjustment of the preload of the springs are a real bear to do if you go to the nonair shocks .
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1979 gl1000 dressed --back to naked
1980 gl1100 interstate --side lined
1983 gl1100 interstate the fastest color--RED
retiered trucker---going to see it again ----on 2 wheels---love it--love it--- love it
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Feetup
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Posted: Fri Nov 14th, 2008 10:15 pm | 3rd Post |
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| There is another current thread on this regarding a 1200. I have both for my 1200, and also my 1000. Springs work well, and both air assisted and spring units work as well as the dampers within them. I also have a set of air only units on my GL1000 at the moment. They seem very good, if you have no air leaks. All in all I prefer the spring only units if there is not too much weight change from one day to the next. On a dressed bike I found considerable difficulty adjusting the preload, which is probably the reason that Honda used air assist in the first place. The one other advantage I can see for air is that compressed air has very little resonance so unlike a spring it does not require much damping. Most spring units allow the pre-load to be adjusted but not the damping so as you tighten up on the pre-load you will in effect have the equivalent to a softer damper. Both OEM Honda and Progressive air assist units allow you to change the fluid in the damper so that as it ages it can be refreshed, or replaced with a different weight of fluid thus changing the damping characteristics harder or softer within the design curve of the damper. Of all the units I have tried I like the air only units the best for handling and ride, but I am always nervous that a punctured diaphragm will render them useless.
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Tim Johnson
'84 GL1200I
'75 GL1000
'02 GASGAS Trials
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tomw
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Posted: Fri Nov 14th, 2008 11:01 pm | 4th Post |
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ah-hah...I see.Fluid in the damper,huh? Gotta get the manual out and see what thats all about.Feetup you say air has little resonance and does not require much damping.Would you tell me about resonance and damping? I have not had this bike out for anything more than a half mile ride so far.Got it registered today but the rain is keeping me from riding.
What should I be looking for with the air shocks? This is the first air shock bike I have ridden.Feels a bit different than springs.
I guess my main idea was to loose the compressor for the air shocks.One less "thing" to ask the bike to do.I kinda like mechanical things.Not much of a gadget guy but I could learn to like it I guess.
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Relax,we all have a little Gomer Pyle in us.
Two things extinct in America in the 21st Century,customer service and management.
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Feetup
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Posted: Fri Nov 14th, 2008 11:30 pm | 5th Post |
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Tomw;
The whole idea behind a damper, (usually wrongly called a shock absorber) is to slow down the movement of the suspension. Metal springs, whether coil, leaf or torsion bars have a tendency to absorb energy (from a bump) and return it with almost as much energy. Without some form of damping the spring would rebound past the original rest point and return again and again until friction in the system absorbed the energy imparted by the original bump. A sprung vehicle with no dampers can be forced down and released quickly and it will continue to bounce up and down till it comes to rest. When the wheel strikes a bump it will bounce off the bump into the air till the energy in the spring forces it back down again where it will bounce back up again. Having the tire off the ground, bouncing isn't going to help us at all so we have dampers installed. Inside the damper is a cylinder full of oil and a piston connected to a rod. There are a series of small passageways through the piston that will allow it to move up and down but the oil from one side must flow through the passageways to get to the other side. Oil will not compress so for the piston to move it must displace the oil. This is easy to do if it is done slowly, but to do it quickly takes more effort the faster it is done.
So, when the wheel hits that bump, the spring absorbs the energy, but when it rebounds back to it's normal state the damper tries to slow it down, and prevent it from bouncing around like a pogo stick. The compression damping (First impact) is often designed to be less than the rebound damping to give a smoother ride.
Air, in a compressed state has energy, and bounce (a basket ball) but it does not develop a resonance the same way as a metal spring so will bounce much less each time it bounces. Compare the way a basketball bounces with the way a ruler held over the edge of a desk and flicked vibrates. Not a perfect analogy since a basketball bounces more from the stretch in the rubber and a ruler is of course hardwood, (at least when I went to school) but the idea is there. If you have ever dropped a valve spring on end onto a hard floor you know exactly what I mean, This is the reason over the road trucks are beginning to opt for air ride suspension.
Last edited on Sat Nov 15th, 2008 01:01 am by Feetup
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Tim Johnson
'84 GL1200I
'75 GL1000
'02 GASGAS Trials
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Feetup
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Posted: Sat Nov 15th, 2008 01:25 am | 6th Post |
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Got rushed to finish that last posting.
Simply put, the question of air shock vs. spring shock is a tough one to advise on since there are so many variables. Both work well if they are in good condition and neither works well if they are badly worn. If you ride both light and heavy, off and on, the air shock is very convenient to adjust and quite comfortable if you get the adjustment right. It takes a while to learn how much air for how much weight, but it is quite quick to adjust again if you feel you need more or less. Some folks pump a certain amount of air for the load and leave it at that, and some will stop and add a few pounds of air just because the 'S' turns are nice and tight and the rear end seems less tight than they like. Spring shocks tend to be set and forget, and if you ride with the same load all the time than they work just as well.
One advantage as I said before is that it is possible to replace the fluid in the air shocks when it breaks down, or to adjust the viscosity to account for wear in the damper or to add or remove stiffness from the rear end. We can do that with our front forks as well but very few spring shocks are not permanently factory sealed. There is a superb article in the tech section about rebuilding the air shocks, in this case upgrading to the progressive springs.
On the other hand the air shocks have seals and hoses and a compressor and a valving arrangement and an air drier and a gauge, etc., etc. It all is well designed and works well and doesn't require much maintenance other than the air drier, but springs are simpler.
Perhaps put a season on the air shocks and make a decision then.
____________________
Tim Johnson
'84 GL1200I
'75 GL1000
'02 GASGAS Trials
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