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It's me again, just trying to learn. Read a bunch of threads...just need to know how these air shocks work. When reading I found discrepancy, some say when you add air the ride gets softer, others say vise versa. Please don't flame me for not calling Howard...ain't got the dough right now. Thanks guys!
The stock Harley ones have lightweight steel springs in them, plus a damper. The air is additional to the springs, in other words it adds extra springing. Add more air (increase pressure) to compensate for additional weight on the bike, such as a passenger or luggage.
How do they work?! Reasonably well solo, less so when 2-up, or if the rider is heavy. They have poor damping, so IMHO ride quality is marginal. Unfortunately H-D fits cheap shocks across the entire range and you will find tons of suspension threads all around HDF. Hence there is an enormous market in aftermarket stuff, to improve the ride!
Thanks guys. Well, appreciate the non biased approach Howard! Hopefully I am not out of line by asking... Is there something you can recommend more in my price range...I was thinking blocks, then started looking at bitchin baggers and was like ooftah.. A little out of my budget, then saw progressives for a few hundred bucks and thought...maybe just maybe. So to give you a frame of reference budget is low for the next year or so. I have a 2011 flhrc, want to lower rear an inch. I know grbrown's advice, which I took a while back and glad I did..Already have low seat and big boots and I know I want to lower suspension. First Harley and I ride solo. Weigh about 165. Thanks everyone. Thanks grbrown I have read a ton of your posts and they have helped me quite a lot.
Last edited by SnoRider; Dec 20, 2015 at 07:03 PM.
Yes lots of shock threads, I have been researching and the Progressive 944 would seem like an ideal mid range choice with a 13" shock that sags to a 12" profile. I.E. on my Street Glide it will look like stock ride height but have that extra inch of travel. Or lower an ultra or RK one inch.
But... I'm having a hard time trying to wrap my head around this mounting them upside down thing!
It seems they don't fit with detatchable tour pak or passengers backrest.? They get mostly good reviews but not much mention about mounting them this way. I called and they said it makes no difference. Maybe it's just me but I'm also looking a bit higer up the price scale, Pro-Action and then Olhins at the top.
The stock Showa shock uses coil springs as the primary load carrier, with air over that to provide adjustable increased spring rate. The air is a booster spring if you will.
This image might help. While it is a standard automotive shock, it works well enough for illustrative purposes:
Under that green outer cap is where the metal coil springs live. All well and good.
Now, put an air tight seal around that green outer cap at the bottom. As the shock goes up, the space gets smaller and the air gets squished, creating pressure. That's how the stock air over Showa shock works without any added air.
Now put a fitting on the top of that green outer cap so we can run an air line and pump up pressure. With it pumped up, there is increased air pressure at the fully extended position, as well increased pressure when the shock is compressed.
Because the metal coil springs take the load, the air is just supplementing the load capacity, which is why the pressures are quite small.
Unlike the use of say the Monroe air shock where the metal coil springs are removed and the air is the sole thing carrying the load. In that case, the air pressure has to be quite a bit higher in order to hold the motorcycle up.
Thanks guys. Well, appreciate the non biased approach Howard! Hopefully I am not out of line by asking... Is there something you can recommend more in my price range...I was thinking blocks, then started looking at bitchin baggers and was like ooftah.. A little out of my budget, then saw progressives for a few hundred bucks and thought...maybe just maybe. So to give you a frame of reference budget is low for the next year or so. I have a 2011 flhrc, want to lower rear an inch. I know grbrown's advice, which I took a while back and glad I did..Already have low seat and big boots and I know I want to lower suspension. First Harley and I ride solo. Weigh about 165. Thanks everyone. Thanks grbrown I have read a ton of your posts and they have helped me quite a lot.
If you want budget, pick up a set of SGS take-offs, they will lower you one inch in the back and handle pretty good. But the fact that they are always coming up for sale should be a hint that there are much better options out there. But they are more then satisfactory for the majority of people i would think.
I changed my SGS shocks cause they were to stiff for my weight (140lbs) but i thought the bike handled great. I've read the Progressive's have the same issue with being stiff for lightweight riders, which is why i chose to go with something that is sprung specifically for the riders weight.
One would think with that many parts in a cheapo shock..it would be cheaper to put a well balanced spring shock less all that air hardware...I just don't get it... HD would make so many new friends.
The stock Showa shock uses coil springs as the primary load carrier, with air over that to provide adjustable increased spring rate. The air is a booster spring if you will.
This image might help. While it is a standard automotive shock, it works well enough for illustrative purposes:
Under that green outer cap is where the metal coil springs live. All well and good.
Now, put an air tight seal around that green outer cap at the bottom. As the shock goes up, the space gets smaller and the air gets squished, creating pressure. That's how the stock air over Showa shock works without any added air.
Now put a fitting on the top of that green outer cap so we can run an air line and pump up pressure. With it pumped up, there is increased air pressure at the fully extended position, as well increased pressure when the shock is compressed.
Because the metal coil springs take the load, the air is just supplementing the load capacity, which is why the pressures are quite small.
Unlike the use of say the Monroe air shock where the metal coil springs are removed and the air is the sole thing carrying the load. In that case, the air pressure has to be quite a bit higher in order to hold the motorcycle up.
If this is so, could you please tell me how the oil is pressurized as everything is than equalized and how the white cup is pushed down and sealed on the outside & inside so the spring could be compressed? I am confused with this explanation, please clear it up.
If the whole shock is pressurized (around 0~50# PSI) how would spring pre-load work or the only function of air pressure would be to compress the spring (spring pre-load)?
There are many things that make a great shock work.
Reduced stiction (friction) so the shock can move relatively easy & reduced rubbing so the shock can actually work. More money is spent on developing a shaft, (seal head with seals & bushing), and piston ring along with seperator piston ring. Let us not forget oil. All oils are not the same as far as reduced friction.
Design of the shock, materials, and piston design.
Correct valving for the rider.
A spring on a great shock is only chosen to hold the bike up and equalize the gravitational pull of the earth making the bike, passenger, and load equal zero. The shock controls bike and not the spring. There is no light, medium, or heavy duty spring. There is only one spring & that spring is the exact spring that can be adjusted to fit your application range. Riders preference also plays on how his bike should feel to the rider.
Ability to control the bike and riders sag which means that the bike must have a rebound stroke to go down into the hole without moving the frame. More friction, more the frame will be dragged down through stiction.
Unfortunately, you only know what you have experienced. Sometimes it pays to ask questions from someone who actually knows how something works and not someone giving an uneducated opinion in a field they are unqualified to give.
It is not cost effective purchasing a product only to have to re-purchase it again from another manufacture. Do real research and nor rely on opinions.
A little out of my budget, then saw progressives for a few hundred bucks and thought...maybe just maybe. So to give you a frame of reference budget is low for the next year or so.
I know budgets are a big consideration and was in the same situation. I considered other shocks and alternatives as well, but in the end I justified it by doing it once and doing it right, and couldn't be happier.
I bought a set of Ohlins 2-2(A) from Howard and I know now I made the right choice. With the HDF member discount that Howard provides, the shocks weren't that much more than the nicer Progressives. And the Ohlins were built for my specs and riding style.
The decision is ultimately yours, but just pointing this out.
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How do air shocks work
