progressive springs

[AOD]

TTT - this is a great thread everyone should read!

I've got maybe 200 miles on my new front suspension set and it's magnificent! It probably cost ~$80 total to do the fork springs and oil, money well spent!

~Adam

[Billyboy]

This IS a great thread! I learned a LOT.

Sandy, Where did you order the springs for your GS1000 from? Gotta get me some. My GS1000 has only 2 inches of travel before bottoming out.

[yogib]

Just put progressives in my 1150,very very noticeable difference.Pretty much rebuilt the front end(new seals and oil 15wt)glad I did too the old oil was naaaasty.

[Billyboy]

Did mine a few weeks ago. I screwed up one new seal. Dammit.
I'm going to have to take 'em apart again and redo that seal. But it can wait untill winter.

[Hayseed]

Spring part number

Anyone have the progressive part number for an 82 GS1100GK? Would the 111107 for the GS1000 be right?

[Sandy]

Anyone have the progressive part number for an 82 GS1100GK? Would the 111107 for the GS1000 be right?

Try this reference page here http://www.partscanada.ca/catalogue/.../en/index.html in the center top box go to page 1116.

[Hayseed]

Thanks Sandy

Got springs ordered yesterday

[garyS-NJ]

fork oil should be measured with springs in and legs extended

There may be two ways of measuring fork oil but I think Progressive Suspensions says to install springs and measure the oil level. This being because different springs may well have different thickness coils (dimensions/volume) and thusly displace different amounts of oil. The volume of air is important (but tunable as a progressive spring itself). I myself have a hard time believing that you cant fill with below method, then drop the spring in and be within an undecernable difference.. Hell, when I was a kid we just drained the forks on dirt bikes and added a specific volume of oil...

Even though Dennis Kirk isnt the cheapest place to buy, I went ahead and ordered Progressive springs from them because I have delt with them for years and they have good customer service and will take care of any problem that may arise. They also ship promptly. :-)

Anyway, I received the springs and installed them in the 1150 today. I went for a 50 mile twisty test ride to see how much improvement they made. There was a VERY noticible increase in stability and precise tracking through the curves with the suspension loaded. I think I picked up about 10-15 mph through a curve with no increase in rider effort. I came up on a few posted 25-30 mph curves and entering the curve at 60 mph and adding a little throttle made it a sit back and relax proposition. The bike tracks calm and smooth through the curve with the front wheel planted in an arc about 12 inches from the edge of the pavement.

For installation, I followed the prep and proceedure suggested by Progressive. Put the bike on the centerstand and a block under the engine so the front tire is hanging in the air. Remove the fork caps. Remove the springs, washers and spacer if you have one. Drain the fork oil from both tubes. After draining the forks, I compressed them a couple of times to push out any residual oil in them. Put drain screws back in. With the forks
fully COMPRESSED (put a block and wedge under the front tire to hold the forks completely compressed while filling the fork tubes with oil) Put an amount of oil in each tube that will bring the oil level in the tube to a height of 5 1/2" below the top of the fork tube. (this will likely be different than the amount specified in your manual) To measure this height, I put a large finish nail through a 1/4" dowel I had. From the finish nail, measure down 5 1/2" and mark a pencil line. Now you will be able to hang the dowel into the fork tube and the nail will rest on top/across the tube. Fill the tube with oil until its on your mark on the dowel. When the oil level is correct in each tube, remove the block and wedge under the tire, allowing the fork to go to full extension. If you have an anti dive unit or Posi Damper as I have, its a good idea to compress the forks a couple of times and recheck the oil level before continuing with the installation as the anti dive may not fill completely without the forks being pushed through their travel a couple of times. With the forks once again fully extended, drop in the new springs, then a washer, then the PVC spacer and finally another washer. For the 1150, the progressive chart specifies a 2" PVC spacer. The required spacer length is 3" for 1980 through 1983 1100E and also 3" for 82-83 1100L. I used 20 weight oil.

Earl

[derwood]

how do you find threads this old to reply to?

[Rich82GS750TZ]

He is the Neromancer. Bringing up a lot of dead threads lately. This one may have been dead the longest. 13 years!

[garyS-NJ]

IDK what a Neromancer is and I thought we were supposed to work within old threads via search rather then create new.. and I thought I was helping to correct a technical reference but later in the thread I did see the correct method.. sorry for the trouble,

He is the Neromancer. Bringing up a lot of dead threads lately. This one may have been dead the longest. 13 years!

[Rich82GS750TZ]

Necromancy (/ˈnɛkrəmænsi/) is a practice of magic involving communication with the dead – either by summoning their spirit as an apparition or raising them bodily

Gary, no offense intended. My weak attempt at a joke. Just commenting on derwood's comment about replying to really old, seemingly dead threads. You are right to search for answers in this vast knowledge base. I wish more people would do the same. Peace.

[bwringer]

I posted a lot in this thread 13-14 years ago, and it's important to note that a LOT of this information is now outdated!

For example, most of us have upgraded to straight-rate springs (mostly from Sonic Springs) in more appropriate spring rates. These were not easily available back then, or maybe we just didn't know about them or where to find them.

Anyway, Progressive brand springs are sort of a "universal" solution with very soft spring rates heavily biased toward comfort for small riders. If that describes you, great. If not, you need a different spring. They are a rising-rate spring, so I and others were partially patching around this problem of inadequate spring rates with large amounts of preload to at least get sag into the right ballpark.

Still, the spring rates were still not nearly stiff enough. I was running 15W fork oil thickened with "motor honey" to get enough control via overly stiff damping (which leads to an imbalance in compression vs. rebound damper rod forks). We were doing the best we could, and this all still worked far better than the limp stock springs, but now things can be a LOT better still.

Nowadays, my GS850 (and all my bikes, for that matter) are wearing Sonic straight-rate springs in appropriate spring rates. On my GS850, I was able to move back to 10W fork oil, which can now offer plenty of damping and much better compliance and balance now that the spring rate is correct. The springs also only need a "normal" amount of preload (about 19mm) to achieve proper sag.

Good suspension is crucial for safety, even if you're not a hard-charging red-eyed slobbering curve fanatic. One of the biggest daily benefits in normal riding with traffic is much better braking; there's far less brake dive and much better compliance under braking when sag, spring rate, and damping are all closer to ideal.

[garyS-NJ]

haha, I don't think much of the 15year old post is outdated. I read somewhere that the my '79 GS 1000 OEM springs were progressively wound and that was new technology for the damping rod forks and the design engineers were smart back then as they are now.. If you think about it the fork oil weight is a compromise heavy weight to get good rebound damping so anything you can do to let them dive easier on compression against the weight of the oil is good. the progressively wound springs give that and then right before cartridges they came out with antidive units to minimize extreme dive and front end shifts under braking but everyone knows getting the front down weight shifted forward onto the front braking wheel is better to stop. Ive installed a bunch of progressive springs in old jap bikes and Harleys and was always happy with them. This shift to linear springs so far isn't working for me but I trust adding the emulators will make it nice nice.