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Problem with Progressive Mono Tube Springs

3287 Views 5 Replies 5 Participants Last post by  Wild Turkey
I have a 2010 Honda GoldWing GL1800 - Audio/Comfort - Base Model. I have 60,500 miles on the bike. I replaced the old factory springs with (I believe the 1st Gen) Mono tubes on 04/02/13 with 37,592 miles on the clock. I have rebuilt the forks once, since the replacement of the mono tubes only due to my negligence of messing up the left side seal when I installed the mono tubes. The seal lasted for 2 years. The rebuild was at 02/15/15 with 50,720 miles.*
My problem is that I have excessive bouncing on any road surface specifically on smooth roads. As far as I can tell, the forks are not compressing when hitting the smaller bumps causing the excessive bounce. Larger bumps, the forks are compressing or absorbing the bump like they are supposed to. This bouncing has started in the last 3 weeks. Prior to this problem, the mono tubes worked perfectly fine.**

Speeds when noticeable: 30-45mph does not matter if I am the only rider or 2 up.*

What I have done to try to diagnose the problem.
1. Lower tire pressure to 38 in the front and 42 in the rear.
2. Loosen up the fork caps to release air in tubes.
3. Disable Anti Dive Valve.
4. Adjust rear shock preload from 0-25. I rode the bike on every setting and the bounce is still there.

A little more info.
1. My weight is 170 lbs with my riding gear; full face helmet, summer jacket with body armor, gloves and textile riding pants over jeans.
2. I used one shim on each tube, I prefer a stiffer ride.
3. I used Honda Fork Oil SS8 10w.*
4. Added the necessary quantity per instructions for each fork leg.
5. Front Tire is 2 years and 2 months old with 14,987 miles, tread depth 3/32” D.O.M. 4113
6. Rear Tire is 3 years and 5 months old with 28,375 miles, tread depth 3/32" D.O.M. 1012

This all started last month.


An update on my 2010 Honda Goldwing GL1800 with Audio and Comfort (Base Model), I finally had time to replace the front and rear tires with Dunlop Elite 3’s, the steering head bearings with All Balls, and wheel bearings and seals with Honda OEM. My test ride home was about 36 miles from the shop I had the repair done at. My second test ride was to a work meeting approximately 38 miles. This gave me more time in the saddle to realize that the problem was still there. The bounce can be described as a springy type bouncing.

On 05/20/16, after my meeting and on my way home, I decided to go ahead and disassemble the front forks and inspect the Progressive Mono Tubes (PMT) and rebuild them by replacing the PMT’s, oil, seals, and bushings. Three hours later, I had the all the parts in hand and started disassembling the right fork.

Once the right fork was disassembled, I inspected the PMT and noticed nothing out of the ordinary. I tried compressing the spring by pushing down from above (standing position with the bottom of the tube on the floor and the mono tube and spring closest to my hand) and found it very difficult. I did this with the one shim installed and removed. The Honda SS8 fluid was still red and the bushings looked like they were still new. No metal shavings or plastic chunks when I drained the fluid.

The left PMT, with the anti dive valve, I found the spring to be bulging to one side with or without the shim. I also noticed that at the end of the mono tube (gas side), the plastic spacer was misaligned and it looked like the larger spacer is missing. Again, trying to compress it from above, it was very hard to compress with the shim installed and removed. The Honda SS8 fluid was still red and the bushings looked like they were still new. No metal shavings or plastic chunks when I drained the fluid.

Now comparing my old PMT’s to the new ones, I noticed that the spring thickness was a lot thinner than the older ones and the coil spacing was less from the top and bottom (or tighter wound). When I purchased the PMT’s in early 2013, I believe these were the first generation on PMT’s(??). What generation are the ones I have now? I decided to not put the one shim in per what the instructions said and I finished the job and took the bike bike off the center stand and noticed a dramatic drop in ride height, once all the weight was on 2 wheels. It was dark and late in the evening so I only had a chance to ride it up and down the street twice, I noticed a very dramatic difference when i rode up and down the street. I have 211 miles on the new tires and they are getting better by the mile. Tire pressures are; Front 38.5 and Rear 43.5 Psi +/- 2Psi. Date of Manufacture are; Front 3915 and Rear 0515. I have 112 miles on the new PMT’s with no more spring type bouncing at the speeds I listed in my emails. As a matter of fact, the ride is 110% better with the problem being solved.
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Friend had same issue rite after put them in. No luck with dealer so drove to traxion in ga. And got full monty = happy!!! Good luck
From your description I am going to guess that at least one of the gas-charged shocks failed, lost their gas and most likely ingested some oil. From other's descriptions, at that point it seems that they are all but locked up.

My 1st Gen PMTs failed from a major impact, one that destroyed both wheels and both tires. A week after that pot hole tried to eat me, my wife and my bike, the PMTs went super soft, real bouncy. It was actually a "progressive" thing. First day was fine, each day after was softer and softer until I was just riding the springs. With a little fun use of clutch and brake I could act like one of those bouncy low-riders. The wife only had to pop me up the backside of the head once for me to quit!

They have a Lifetime warranty from Progressive. Mine were about 3 years old and replaced without issue for the one-way cost of shipping.

Since it sounds like you already bought new, I would suggest that you Call and get a return authorization number, send them in and get another new set. Either save the new ones on shelf or put up for sale here to recoup most of your cost.

And, real good write up. Thanks for sharing.

Sent from my iPad using Tapatalk
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If you are also having trouble with driveway approaches, PMTs went bad.
UPDATE #2.... Its been a little over a month and I have had some saddle time to "re-evalutate" the "NEW PMT's". I have 935 miles on the PMT's and they are smooth as a baby's butt. My GW is so smooth now, I can't feel her under my butt when I am on her.
I took some measurements with the bike on two wheels and loaded with all the junk I carry to work (minus me on the bike). I measured from the bottom of the triple tree to the top edge of the fork, just below the dust seal and it was 4". With it being so dusty here in Arizona and where I work, I measured from the top of the fork to the edge of where the cleanness stops. This measured at 3". I noticed as I am riding down the rode I can see the forks absorbing the smallest to the largest bumps in the road. I get some jarring on some of the big bumps but not like the old Factory springs or PMT's. When coming to a stop I notice that the forks compress some and when I accelerate the forks pop up from being slightly compressed.
Handling is rock on steady. When driving straight on any road surface the ride is smooth and making L/R turns scraping the engine and saddle bag bars (and sometimes the center stand) she holds the line perfectly.
I know I have 62K plus miles on the rear shock and spring, but I am trying to match it up with the front PMT's. I am starting at 0 and will continue raising the number setting one increment a week and evaluating the ride to compare it to the front. I am on setting #2 this week and I will evaluate how it handles, rides, and comfort factor.
Before I started the thread here, I was in contact with 2 people at Progressive Suspension and getting advice as to what might be wrong. I could not afford to have my bike down for a month as my bike is my sole transportation. I had to buy another set to get by for the time being. It took 18 days until I received my new replacement PMT's on Tuesday 21 June 2016.
I have attached some pictures of my old PMT's next to the new ones. The new PMT's are clean and have much smaller springs. I hope this thread helps out others who are having problems and I am noticing that these don't last much longer than 3 years. I take that as 3 years of riding without being down for fixing a leak or replacing the PMT's.


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I also bought the new ones and did not put a spacer in. I noticed it is lower but the ride is much smoother. Had mine on for about 60,000 miles now without a problem. I think Generation 3 is whats on the market now.
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