rear shock quandary

[Trikesyke]

I am hoping there are some engineers/HD mechanics on here to answer my post. How does Trike and maybe all bike, rear suspension operate? I have been trying to adjust the rear shocks on my TG but fail to reach that 'sweet spot'. I am familiar with autos having bad shocks to the point if they are blown out, the car will 'bounce' up and down like an amusement ride, after hitting a bump. I have been trying to find that lower limit on the shocks as a starting point to a softer ride. If I calculate the recommended pressure based on my weight for everyday riding and set the rear suspension for that weight, the ride still seems very stiff as well as when I adjust the pressure up/down, even when I lower it to 5 pounds. But, when I have a passenger, it seems to smooth out at a higher pressure setting, say 40 pounds. What gives? My ride is still under warranty so right now, replacing the stock shocks is not an option. And I do realize I will never get a Cadillac ride. I just want to find a softer setting.....

[geezerglide11441]

I am hoping there are some engineers/HD mechanics on here to answer my post. How does Trike and maybe all bike, rear suspension operate? I have been trying to adjust the rear shocks on my TG but fail to reach that 'sweet spot'. I am familiar with autos having bad shocks to the point if they are blown out, the car will 'bounce' up and down like an amusement ride, after hitting a bump. I have been trying to find that lower limit on the shocks as a starting point to a softer ride. If I calculate the recommended pressure based on my weight for everyday riding and set the rear suspension for that weight, the ride still seems very stiff as well as when I adjust the pressure up/down, even when I lower it to 5 pounds. But, when I have a passenger, it seems to smooth out at a higher pressure setting, say 40 pounds. What gives? My ride is still under warranty so right now, replacing the stock shocks is not an option. And I do realize I will never get a Cadillac ride. I just want to find a softer setting.....

Tikesyke, you may not want to hear it, but you will NEVER get the ride you are searching for with the OEM air shocks as all you can do is experiment with the "Pre-Load" and there is not way to set the re-bound with the OEM air shocks. I understand the Warranty issue, but never gave it a thought with respect to improving the ride. I changed the front to a mono-tube unit and the rears to the Pro-Action Shocks and both my self and the wife love the ride.

Good luck with the OEM air ride if that what you choose to stay with!!

Ride safe;

Roger

[rhino 2]

Kevin, I have never found that sweet spot people are taking about... With my [ex]11 Tri-Glide In 45 thousand miles, I ride only solo. With too much air it road rough!, With too little air it would when i hit a bump bottom out with a hard rap!!... Now on a smooth highway, I would keep it at 35 pounds...And it would be just fine, But out on local roads NJ/NY Metro area with all the pot holes and sunken man hole covers, And all the construction cuts in the streets . There wasn't any sweet spot...

[Lee H. Mann]

I am hoping there are some engineers/HD mechanics on here to answer my post. How does Trike and maybe all bike, rear suspension operate? I have been trying to adjust the rear shocks on my TG but fail to reach that 'sweet spot'. I am familiar with autos having bad shocks to the point if they are blown out, the car will 'bounce' up and down like an amusement ride, after hitting a bump. I have been trying to find that lower limit on the shocks as a starting point to a softer ride. If I calculate the recommended pressure based on my weight for everyday riding and set the rear suspension for that weight, the ride still seems very stiff as well as when I adjust the pressure up/down, even when I lower it to 5 pounds. But, when I have a passenger, it seems to smooth out at a higher pressure setting, say 40 pounds. What gives? My ride is still under warranty so right now, replacing the stock shocks is not an option. And I do realize I will never get a Cadillac ride. I just want to find a softer setting.....

Part of your suspension system is the tires. Harley-Davidson recommends 26psi in the rear tires. That is toooo much. Try 20-22PSI and 15psi in the shocks as a starting point.

[HDB0B]

^^^^^ What he said! Tire pressure 20-22 psi in the rear. Shock aftermarket lower "lift" brackets with lay back position also helps. Changing out the factory shock oil for a different brand/weight can make a big difference. We are assuming you are using a zero loss air pump for your shocks??

Personally I like 22 psi in tires and 38 psi in shocks. I'm using a newly designed shock lift bracket in the lay back position on my 2014 TG.

Lots of options now for replacing your shocks .... but frankly if the road surface sucks ... the ride sucks regardless of shock type.

Bob

[Trikesyke]

Tikesyke, you may not want to hear it, but you will NEVER get the ride you are searching for with the OEM air shocks as all you can do is experiment with the "Pre-Load" and there is not way to set the re-bound with the OEM air shocks. I understand the Warranty issue, but never gave it a thought with respect to improving the ride. I changed the front to a mono-tube unit and the rears to the Pro-Action Shocks and both my self and the wife love the ride.

Good luck with the OEM air ride if that what you choose to stay with!!

Ride safe;

Roger

Thanks Roger. I have some decisions to make.

[Trikesyke]

Kevin, I have never found that sweet spot people are taking about... With my [ex]11 Tri-Glide In 45 thousand miles, I ride only solo. With too much air it road rough!, With too little air it would when i hit a bump bottom out with a hard rap!!... Now on a smooth highway, I would keep it at 35 pounds...And it would be just fine, But out on local roads NJ/NY Metro area with all the pot holes and sunken man hole covers, And all the construction cuts in the streets . There wasn't any sweet spot...

Bob, We have terrible roads too. As in Rogers implied response, I may be searching for 'the spot' for ever.....

[Trikesyke]

Part of your suspension system is the tires. Harley-Davidson recommends 26psi in the rear tires. That is toooo much. Try 20-22PSI and 15psi in the shocks as a starting point.

Jim, Thanks for the starting point. It will be a worthy beginning.

[Trikesyke]

^^^^^ What he said! Tire pressure 20-22 psi in the rear. Shock aftermarket lower "lift" brackets with lay back position also helps. Changing out the factory shock oil for a different brand/weight can make a big difference. We are assuming you are using a zero loss air pump for your shocks??

Personally I like 22 psi in tires and 38 psi in shocks. I'm using a newly designed shock lift bracket in the lay back position on my 2014 TG.

Lots of options now for replacing your shocks .... but frankly if the road surface sucks ... the ride sucks regardless of shock type.

Bob

Thanks Bob. Many have suggested less tp. The 38 sp may be too high for me but it's worth considering. I didnt know about oil change...hmmm. I am using the HD zero loss hand pump. Well, if I add an additional pound before I unscrew it, that is. And I do have a lift kit, but I will look into shock relocation points on it.

[DK Custom Products]

Here is a very useful report on Rear Suspension. REPORT LINK

Kevin

[vito]

Here is a very useful report on Rear Suspension. REPORT LINK

Kevin

This is to all but maybe Kevin has some ideas. The problem with Trikes (and cages) is lean. If we make the springs/shocks soft we get too much lean in corners. Make them hard enough to minimize lean and, as we know, it rides hard.

Cages use sway bars to fight lean and permit softer rides. I'm not sure how/if this would work on a trike. Maybe somebody (hint, hint) does or could do some experimenting (I'm too old and frail) and offer a suspension package. For the non-technical, sway bars are simply torsion bars attached to frame and wheels that twist when cage leans.

Also, I am trying out a H-D "Hammock" seat. It does a good job of isolating both rider and passenger behinds and spines from the hard jolts that are still felt through the floor boards and bars.

Ride on!!

[rhino 2]

This is to all but maybe Kevin has some ideas. The problem with Trikes (and cages) is lean. If we make the springs/shocks soft we get too much lean in corners. Make them hard enough to minimize lean and, as we know, it rides hard.

Cages use sway bars to fight lean and permit softer rides. I'm not sure how/if this would work on a trike. Maybe somebody (hint, hint) does or could do some experimenting (I'm too old and frail) and offer a suspension package. For the non-technical, sway bars are simply torsion bars attached to frame and wheels that twist when cage leans.

Also, I am trying out a H-D "Hammock" seat. It does a good job of isolating both rider and passenger behinds and spines from the hard jolts that are still felt through the floor boards and bars.

Ride on!!

Sway bars are used on Spyder's.....But they are reverse Trikes....

[Trikesyke]

Here is a very useful report on Rear Suspension. REPORT LINK

Kevin

Kev,

Great article! Thanks!

[Jack Klarich]

^^^^^ What he said! Tire pressure 20-22 psi in the rear. Shock aftermarket lower "lift" brackets with lay back position also helps. Changing out the factory shock oil for a different brand/weight can make a big difference. We are assuming you are using a zero loss air pump for your shocks??

Personally I like 22 psi in tires and 38 psi in shocks. I'm using a newly designed shock lift bracket in the lay back position on my 2014 TG.

Lots of options now for replacing your shocks .... but frankly if the road surface sucks ... the ride sucks regardless of shock type.

Bob

This is the best so far

The HD air shocks SUCK unless u r willing to change the oil IMO

U can use a MityVac to suck out the old oil and put in some heavier oil

If u r real handy and careful, U can take apart the Showa rear shocks { Be Careful and use the right tools and safety} U can change the valves and use a heavier oil also

Be careful and try an old shock first

[DK Custom Products]

I am hoping there are some engineers/HD mechanics on here to answer my post. How does Trike and maybe all bike, rear suspension operate? I have been trying to adjust the rear shocks on my TG but fail to reach that 'sweet spot'. I am familiar with autos having bad shocks to the point if they are blown out, the car will 'bounce' up and down like an amusement ride, after hitting a bump. I have been trying to find that lower limit on the shocks as a starting point to a softer ride. If I calculate the recommended pressure based on my weight for everyday riding and set the rear suspension for that weight, the ride still seems very stiff as well as when I adjust the pressure up/down, even when I lower it to 5 pounds. But, when I have a passenger, it seems to smooth out at a higher pressure setting, say 40 pounds. What gives? My ride is still under warranty so right now, replacing the stock shocks is not an option. And I do realize I will never get a Cadillac ride. I just want to find a softer setting.....

Kevin, I have never found that sweet spot people are taking about... With my [ex]11 Tri-Glide In 45 thousand miles, I ride only solo. With too much air it road rough!, With too little air it would when i hit a bump bottom out with a hard rap!!... Now on a smooth highway, I would keep it at 35 pounds...And it would be just fine, But out on local roads NJ/NY Metro area with all the pot holes and sunken man hole covers, And all the construction cuts in the streets . There wasn't any sweet spot...

Regarding getting the best ride possible out of the OEM air shocks. We worked on that for many years. There are a few things to know-

1. As little as 2 PSI difference in the shocks will make a noticeable difference in the ride quality. So we always tested different PSI settings, changing them in 2 PSI increments, ON THE SAME BUMPS at the same speed, until we found the most comfortable PSI.

2. What may be a great PSI setting for a certain load and road will not be for a different road. ie. there is no one sweet spot for all different road surfaces and speeds.

3. Not matter what PSI setting you use, combining any shocks (including the factory air shocks) with a Comfort Lift Kit™ will give a plusher ride.

That is when we came up with the MacAir. It gives you fingertip control to change the PSI, while you're riding. Combined with a Comfort Lift Kit™, this is the best possible way to always get the best ride quality with the OEM air shocks, regardless of road conditions, speed or load.

^^^^^ What he said! Tire pressure 20-22 psi in the rear. Shock aftermarket lower "lift" brackets with lay back position also helps. Changing out the factory shock oil for a different brand/weight can make a big difference. We are assuming you are using a zero loss air pump for your shocks??

Personally I like 22 psi in tires and 38 psi in shocks. I'm using a newly designed shock lift bracket in the lay back position on my 2014 TG.

Lots of options now for replacing your shocks .... but frankly if the road surface sucks ... the ride sucks regardless of shock type.

Bob

This used to be the case. After riding over 60k miles with variations to the OEM shocks, we discovered the 13" Twin Adjustable and the Pro-Action shocks. As Roger noted above, the ride quality improvement is quite amazing...even on road surfaces that would otherwise jar your fillings loose.

I've had folks ride my TG with my 13" Twin Adjustable shocks and they thought the ride quality approached that of an IRS System.

Then, about 6 months ago Devin and I had the idea of building a 14" shock, designed from the ground up, specifically for Harley Trikes. We partnered with Pro-Action Suspension on the project, and kept working and tweaking them until the ride was as good as the ride on my Softail.

The 14" Trike Series Shocks™ have compression and rebound damping, combined with the extra travel of 14" instead of 13" that is specifically set up for the Trikes. The result is they have the ability to eat up the small and large bumps, not just one or the other.

This is to all but maybe Kevin has some ideas. The problem with Trikes (and cages) is lean. If we make the springs/shocks soft we get too much lean in corners. Make them hard enough to minimize lean and, as we know, it rides hard.

Cages use sway bars to fight lean and permit softer rides. I'm not sure how/if this would work on a trike. Maybe somebody (hint, hint) does or could do some experimenting (I'm too old and frail) and offer a suspension package. For the non-technical, sway bars are simply torsion bars attached to frame and wheels that twist when cage leans.

Also, I am trying out a H-D "Hammock" seat. It does a good job of isolating both rider and passenger behinds and spines from the hard jolts that are still felt through the floor boards and bars.

Ride on!!

The HD Trikes have a panhard rod...not the same as an anti-way bar, but it does significantly help handling. The body roll that most experience on their HD Trikes is from the poor rear shocks.

The compression and rebound damping is not conducive to keeping the Trike "Flat" in the curves.

With the 13" Twin-Adjustable or Pro-Action, & especially with the 14" Trike Series Shocks™, the trike will stay very Flat going thru a curve (absence of body roll).

We have been on a 1 year Suspension testing marathon, that we only recently took a break from. We have several "test circuits" that we have ridden thousands of times. Mostly myself and Devin. But quite a bit with Mary as a passenger also.

In one of the circuits is a 90* turn. Speed limit goes from 55 mph to 15 mph in the curve, then back up to 55 mph.

When testing the TSS shocks, Marys' comment when going thru curves, including the one above, was that the trike stayed "level" when going thru the curves, where before it sometimes gave her a feeling it was going to tip over.

On the one particular curve above, we can easily go thru it at 45-50 mph, completely stable (flat). Whereas with the OEM shocks, even at 30 mph I could feel the inside tire starting to lift because of the body roll. It was not a confidence inspiring feeling, and Mary really did not like it at all.

All that to say...HD had a mantra of "slip, not flip" when looking at making trikes again in the 2000's. In stock condition they are extremely stable at posted speeds, although ride quality is not so great.

With improved shocks they can have great ride quality, and be MUCH MORE stable AND stable feeling, as they will ride "flatter" thru the curves, at greater speeds.

In our Report on Rear Suspension (Link HERE) we specifically address the subject of body roll. You may find the info in the report to be helpful/interesting.

Kevin