progressive springs

[earlfor]

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

[AOD]

Thanks for the report Earl...I'm looking forward to doing the same.

~Adam

[Joe Nardy]

Thanks Earl. You now have me totally confused (not really that hard to do).

The Progressive instructions I have read "Fork oil level/volume should be checked according to the steps outlined in your authorized shop manual. Measurement of your fork oil by level is the preferred method. However, some manuals only specify a volume measurement. Due to the design of a progressive wound fork spring it will displace more fork oil thus requiring a maximum oil level of 5.5" (140mm). Caution: This is not a recommendation, it is only a precautionary statement. If your manual specifies an oil level higher than 5.5" (140mm) set the oil level at 5.5" (140mm)".

I think the 1150 forks are similar to those on my '83 1100E. The Service Manual for the '83 model specifies a fork oil level of 7.7" (195mm). Since this is NOT higher than the 5.5" specified in the instructions, shouldn't the factory amount be used?

Also, the instructions I have (the same ones currently available on the Progressive website) don't have an application chart and I've been unable to find one. But the instructions do cover pre-load adjustment. The instructions state "Most motorcycles need between 3/4" and 1" of pre-load. As a rough rule of thumb the fork spring or fork spring and spacer should be at least flush (or above) the top of the fork tube with the forks fully extended. This is true for most motorcycles because their fork caps are between 3/4" and 1" long meaning that they will screw into the fork tubes the same distance. For fork caps longer than 1" you must calculate the pre-load length so the fork spring/spacer combination will be below the edge of the fork tube. if your fork caps have adjustable pre-load settings orare recessed below the edge of the fork tube (circlip type), they are usually much longer than the 3/4" to 1" caps and must be measured accordingly. I'm not absolutely sure but I think the springs were below the tops of my fork tubes but the built-in pre-load adjusters easily covered the length necessary. Does the 1150 have pre-load adjusters built into the caps? I thought the forks were similar to those on the '83.

Like I said, I'm confused because my forks work very well. The fork sag is correct and the front end is very controlled without being too harsh or soft. I would think adding 3" of preload and 2.2" of fork oil would make for a pretty harsh ride. Please help me!

Thanks,
Joe

[earlfor]

Joe, I dont think youre wrong. The way I interpret the Progressive instruction is that you may use any fork oil level as long as it is not greater than the 5.5 measurement. Yes, the more oil, the stiffer the action will be. My 1150 info does not (that I have found) specify a height measurement for the fork oil level, only a volume measure. I prefer fork action on the stiff side.

Your 83 with a spec'd oil level of 7.7 will be stiffer than normal with the new springs since the progressive springs are thicker and displace more oil than stock springs. On the fork caps, the 1150 caps are not like the 1100 caps. The 1150 caps have a 3 step, indent locking preload adjuster built into the tops, but my 83 1100E does not. Also, my 1150 fork tubes are about 2 incles longer than my 1100 tubes. The dimensions progressive suggests, with recommended spacer leaves a 2" space between the top of the spacer and the top of the fork tube. Installing the caps is merely a twist'em down with your fingers as there is no contact between the fork cap and the spacer until the last 1/8" of threads on the cap. Preload is set completely by indent position on the cap adjuster. I set about 3/4" of preload and I have about 1/2" of sag. The ride is fine on average pavement, but was a little harsh on a washboarded dirt/gravel road. I dont plan on spending much time on washboard forest trails though. :-)

It appears we merely have different preferences in handling. :-)
Yeah, I could have set it up softer. eh eh

Earl

Thanks Earl. You now have me totally confused (not really that hard to do).

The Progressive instructions I have read "Fork oil level/volume should be checked according to the steps outlined in your authorized shop manual. Measurement of your fork oil by level is the preferred method. However, some manuals only specify a volume measurement. Due to the design of a progressive wound fork spring it will displace more fork oil thus requiring a maximum oil level of 5.5" (140mm). Caution: This is not a recommendation, it is only a precautionary statement. If your manual specifies an oil level higher than 5.5" (140mm) set the oil level at 5.5" (140mm)".

I think the 1150 forks are similar to those on my '83 1100E. The Service Manual for the '83 model specifies a fork oil level of 7.7" (195mm). Since this is NOT higher than the 5.5" specified in the instructions, shouldn't the factory amount be used?

Also, the instructions I have (the same ones currently available on the Progressive website) don't have an application chart and I've been unable to find one. But the instructions do cover pre-load adjustment. The instructions state "Most motorcycles need between 3/4" and 1" of pre-load. As a rough rule of thumb the fork spring or fork spring and spacer should be at least flush (or above) the top of the fork tube with the forks fully extended. This is true for most motorcycles because their fork caps are between 3/4" and 1" long meaning that they will screw into the fork tubes the same distance. For fork caps longer than 1" you must calculate the pre-load length so the fork spring/spacer combination will be below the edge of the fork tube. if your fork caps have adjustable pre-load settings orare recessed below the edge of the fork tube (circlip type), they are usually much longer than the 3/4" to 1" caps and must be measured accordingly. I'm not absolutely sure but I think the springs were below the tops of my fork tubes but the built-in pre-load adjusters easily covered the length necessary. Does the 1150 have pre-load adjusters built into the caps? I thought the forks were similar to those on the '83.

Like I said, I'm confused because my forks work very well. The fork sag is correct and the front end is very controlled without being too harsh or soft. I would think adding 3" of preload and 2.2" of fork oil would make for a pretty harsh ride. Please help me!

Thanks,
Joe

[AOD]

So Joe, help me out here, you have preload adjustment on your 83 1100E, but Earl does not? What preload spacer height did you end up using? What is your oil level set to? What oil weight did you use?

That is all.

~Adam

[Joe Nardy]

So Joe, help me out here, you have preload adjustment on your 83 1100E, but Earl does not? What preload spacer height did you end up using? What is your oil level set to? What oil weight did you use?

That is all.

~Adam

That's what it sounds like. My '83 1100E has preload adjusters built into the caps. I'm not sure of the length but I remember that they were more than enough to meet Progressive's recommended preload. I set my oil level to the level specified in the Service Manual, 221mm or 7.7". I used 15W fork oil which is also recommended by Progressive for most bikes. Here's a link to the Progressive Installation Guide:

http://www.progressivesuspension.com/pdf/3055.pdf

Thanks,
Joe

[AOD]

Thanks for the details. I thought you mentioned (back in the days of your garage) something about using PVC tube spacers, but that might have been 'words of wisdom' for Ryan.

Do you have your anti-dive units hooked up on the bike still Joe? My next question would be how to remove that, but I didn't search the forum yet to see if someone already did a 'how to'.

~Adam

[Joe Nardy]

Thanks for the details. I thought you mentioned (back in the days of your garage) something about using PVC tube spacers, but that might have been 'words of wisdom' for Ryan.

Do you have your anti-dive units hooked up on the bike still Joe? My next question would be how to remove that, but I didn't search the forum yet to see if someone already did a 'how to'.

~Adam

Yes, we used PVC spacers on Ryan's 550. I think he used his stock springs but flushed the forks thoroughly and changed the fork oil. He was pleased with the results. I disabled the anti-dive units on my bike years ago. It is very simple to do:

1) Remove the brake line from the brake caliper to the anti-dive unit.

2) Use the single banjo bolt from the anti-dive unit to replace the double banjo bolt on the brake caliper.

3) Use a standard bolt and crush washer to plug the hole on the anti-dive unit.

While you're at it add some stainless steel brake lines. I was surprised at how much difference they made. I had to adjust the front brake light switch because the brake lever no longer traveled far enough to make the switch. Plus they look very cool!

Thanks,
Joe

[AOD]

Thanks, that's an easy way to remove the anti-dive. Just out of curiousity, why is it better to remove that system then leave it alone? Just curious.

I just confirmed with the owner of the 83 1100 I'm buying, his has preload adjusters on it that require a screwdriver to adjust.

With this setup, you didn't need spacers Joe?

Brian W., I take it your 850 didn't have preload adjustment on the front?

~Adam

[Joe Nardy]

Thanks, that's an easy way to remove the anti-dive. Just out of curiousity, why is it better to remove that system then leave it alone? Just curious.

According to the magazine reviews of the day the anti-dive didn't work all that well and the extra plumbing made for a less firm lever. The real issue is that forks back then were under sprung and compressed too much under braking. A properly sorted out fork (Progressive springs, correct pre-load, right fork oil) doesn't need the anti-dive for proper fork action. Ths is why there haven't been any anti-dive mechanisms on bikes for years. Only a few bikes ever had them and most of them were not effective enough to justify the extra hardware and expense. The extra plumbing adds cost if you want to buy stainless lines and makes bleeding more complicated.

I just confirmed with the owner of the 83 1100 I'm buying, his has preload adjusters on it that require a screwdriver to adjust.

With this setup, you didn't need spacers Joe?

That is correct. According to the Progressive Installation Manual the adjustable fork caps provide plenty of pre-load. I'm not even at the maximum position.

Thanks,
Joe

[AOD]

According to the Progressive Installation Manual the adjustable fork caps provide plenty of pre-load. I'm not even at the maximum position.

Cool.

[bucketsofgs1000]

Now the question after reading all this is: are progressive springs a better bargain than installing a used GSXR front end? Or is the GSXR front end going to make ANOTHER world of difference over the progressive springs. Just a thought...I have no idea either way on this one.

[mcycle-nut]

I found that putting Progressive springs in the forks, and Progressive shocks and springs on the rear of my 750 made a night and day difference. Because of that, I put fork springs in my EZ. It firmed up the front end substaintialy. I didn't use any air. Can't remember the oil viscosity.

[bwringer]

Now the question after reading all this is: are progressive springs a better bargain than installing a used GSXR front end? Or is the GSXR front end going to make ANOTHER world of difference over the progressive springs. Just a thought...I have no idea either way on this one.

I would hazard a guess that a GS is a heckuva lot heavier than a GSXR, so you would need to dig up a heavier spring rate and fine-tune preload with spacers. Just guessing, though. I think the GSXR forks would be somewhat shorter, too, so that could create a lot of problems.

I do know some folks have had success with transplanting forks from a Bandit, which is a bike closer in weight and mission to a GS. However, later/larger model GSXR forks would have the yummy adjustability features, and some models even have the coveted upside-down forks.

Looking at it purely from a time/trouble/money standpoint, I would have to say that you're best off to optimize the existing suspension (don't forget good shocks on the rear) and spend your money and time on interesting roads learning to be a better rider.

Even with zooty modern forks in place, remember that the frame is still a relic from the '80s. With good springs in place and some attention to fine-tuning preload and fork oil, the fork is definitely not the weak point in GS handling.

On a GS, frame and swingarm flex tends to define the outer edge of handling more than any other factor, and it's the most difficult to do anything about. You're stuck with either bracing the frame (messy, difficult, and heavy) or reducing weight (difficult to do beyond a certain point). It's probably easier to eat nothing but lettuce and ice cubes for six months and reduce the load the bike has to haul around... :roll: :roll:

[Joe Nardy]

I agree with bwringer here to a point. But the fact remains that the GSXR forks are newer and probably cartridge-type rather than damper rod types. This is a huge step forward. You can't even compare the two. Of course, you'd have to tune the GSXR forks properly but once set up you'd have a better front suspension than you'd ever get from damper rod forks.

Thanks,
Joe