Progressive Springs question.

[climber_dhl]

Hey I am installing some progressive springs in my 1980 GS850G and my springs didn't come with the chart about how big to make the spacer. Could someone just tell me how big the pvc should be. I believe an inch and a half but I just wanted to make sure. Thanks

[chef1366]

Depends on your weight, if you ride two up and riding style. I'm a big guy and cut the PCV pipe so it stuck out of the end of the fork about an 1 3/4 inch.

[climber_dhl]

Thanks

I weigh about 150 and I often ride with my girlfriend. Right now I am using 1.5in pvc spacers. Should that be enough for my girlfriend and I, while also allowing me to have some fun on my own?

[twr1776]

Here is a link to the instructions in case you do not have them. It shows the spacer even with the top of the fork tube as standard. As Chef said you can make the spacer length above the tube to customize for your weight & riding style. I went with the even with the top of the tube spacer on mine and it worked fine but I primarily ride one up. Maybe start about 3/4" to 1" up from the tube and see how you like it. You can always cut it down if it seems too firm or lengthen it if too soft. It will take extra pressure to push the cap in the more spacer length above the tube you go so be careful when threading the cap back in.

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

[chef1366]

The overall length doesn't mean anything to me because the spacers are different in all the models. You need to concentrate on the amount of PVC that sticks out of the top of the fork. Make sure they are the exact same size and also your cuts on the pipe are even or you will have a bear of a time getting the caps to thread with uneven cuts.

[salty_monk]

Bill's right as usual... on my 1000G I think 70mm brought them level to the topr of forks so that's 1" preload (or basically the amount of thread on the cap (or was it 42mm) on my Skunk I had them stand about 1/2" proud as I wanted to stiffen them up a little.

Both ride well, the G is definitely noticeably softer but not much (& it has more miles on them, they do "bed in" a bit.

I'm 165. STock 15w oil 140mm level below the top of fork.

Dan

[Steve]

These guys will get you close, but what really matters is how much the suspension "sags" when you put your weight on it. The general rule of thumb is that you don't want to use up more than about 25% of your travel just getting on the bike. Most forks have about 6 inches of travel, so you want to see the forks compress no more than 1.5 inches when you are on the bike, ready to ride. Depending on the fork spring rate, accessories on the bike and your weight, it is possible that the forks will not compress at all until you get on. That's OK. If they compress more than 1.5 inch, use a longer spacer for more preload. You may have to make a few spacers before you get it right. I don't think that carrying a passenger will affect fork compression very much until you hit the brakes.

Same 25% rule applies to rear suspension. Most shocks have about 4 inches of travel, so adjust "sag" to be about 1 inch. Check it with your passenger, too, so you know how much to adjust for her. If you use Progressive (brand) shocks and springs on the rear, be aware that they have several different spring rates, so you can customize them to your needs.

.

[KEITH KRAUSE]

These guys will get you close, but what really matters is how much the suspension "sags" when you put your weight on it. The general rule of thumb is that you don't want to use up more than about 25% of your travel just getting on the bike. Most forks have about 6 inches of travel, so you want to see the forks compress no more than 1.5 inches when you are on the bike, ready to ride. Depending on the fork spring rate, accessories on the bike and your weight, it is possible that the forks will not compress at all until you get on. That's OK. If they compress more than 1.5 inch, use a longer spacer for more preload. You may have to make a few spacers before you get it right. I don't think that carrying a passenger will affect fork compression very much until you hit the brakes.

Same 25% rule applies to rear suspension. Most shocks have about 4 inches of travel, so adjust "sag" to be about 1 inch. Check it with your passenger, too, so you know how much to adjust for her. If you use Progressive (brand) shocks and springs on the rear, be aware that they have several different spring rates, so you can customize them to your needs.

.

+1. Generally, if you sit on the bike and the forks compress approx' 1 to 1 1/2", you're good.

[gshub]

I weigh about 150 and I often ride with my girlfriend. Right now I am using 1.5in pvc spacers. Should that be enough for my girlfriend and I, while also allowing me to have some fun on my own?

Fitted a set progressive fork springs to my Gs1000s but could never get them to
work properly so went back to a 15wt oil and 12psi in each leg.
my question is about using PVc for the spaces,what if one broke on you?.
me and wife way about 30stone between us.

[Steve]

my question is about using PVc for the spaces,what if one broke on you?.
me and wife way about 30stone between us.

Since you are measuring your graviational attraction in "stones", I'm guessing that your location is Norwich, UK, not Norwich, CT.

Not sure what your standards are for PVC piping, but over here we have a standard grade called Schedule 40 and a thicker grade called Schedule 80. The thicker pipe should have no problem with the compression loads of the forks. The thinner stuff will probably work, too, but your best bet is to select the largest diameter that will fit into the fork tubes, and use a flat washer between the PVC and the spring.

.

[hampshirehog]

my question is about using PVc for the spaces,what if one broke on you?.
me and wife way about 30stone between us.

The stuff to get is what they lay underground for water mains. Trouble is you can only buy it in something like 50 metre rolls and you only need a few inches! You need to be ready with a hacksaw next time you see the road dug up

[twr1776]

This is what the Progressives ship with. I have used the pipe and washers setup without any problems. I kept the stock spacer and washer and stacked the PVC and new washer on top of them for the preload. I have not heard of anyone that has had a problem with the PVC spacer set up. As long as your spacers are even lengths and cut square I think you should be fine.

[bwringer]

Here's an extreme example of the amount of preload I need -- I'm roughly (cough) 19 stone with gear, and I ride like a bat outta you-know-where.

Don't try this at home -- most normal people will never need this much preload, but after several rounds of experimentation, that's what it takes for me. I used aluminum pipe here, since that's what I had lying around, but PVC works fine:

It takes a LOT of bad words to mash this down and get the caps to thread in:


Bingo -- about 25mm sag:


The happy result:

[Griffin]

Here's an extreme example of the amount of preload I need -- I'm roughly (cough) 19 stone with gear, and I ride like a bat outta you-know-where.....

There was an AC/DC groupie named Rosie who weighed that much. Bon Scott immortalized her in song.....

The Progressive spring kit for the '80-'82 GS750E doesn't have any spacers with it. When installed, the springs stick out above the top of the tubes about 1 1/4". It is a royal PITA to get those caps on.

Ride is firm but not harsh at all. Sag is about .875" for my (cough) 14 stone 7 lb weight.

[chef1366]

Dang Brian, that's more preload than I use.