Progressive Fork springs

[MPittma100]

I am in process of rebuilding both forks on a 1980G and am wondering if changing over to the progressive springs is a good idea. If you do change to the progressive springs, do you still need to add air pressure? Thoughts?

Thanks, Mike

[jetmechmarty]

Whether or not it's a good idea depends upon who you ask. If you're asking me, I say no! Put straight rate springs that are for your weight and riding style.

How far are you from Woodstock, Mike? Traxxion Dynamics is over there. I recommend you have a chat with them. Send a PM to JeffH. They did his forks over there.

FWIW, I believe my OEM springs in my Special were progressive wound. Nope, I don't like 'em!

[bikerphil]

They are an improvement over the worn out stock springs. If you are a spirited rider, then Marty's suggestion would be better. The progressives will give more of a plush feel than the straightwound.

[jetmechmarty]

The progressives will give more of a plush feel than the straightwound.

That's going to depend upon the rate you choose. I see progressive as more of a one size fits all.

[bikerphil]

I see progressive as more of a one size fits all.

Yes, I agree. IIRC, they only offer one version/stiffness for the XS11, the 11-1110.

PDF...

http://www.progressivesuspension.com/pdfs/7100-105.pdf

[Jerry]

I have Progressive springs in my XJ. There are two main philosophies to fork springs.

First, you have only a limited amount of fork travel. In my case I do a lot of super-slab riding and wanted the extra comfort that progressive springs provide. I found that progressive springs, standard weight oil, and recommended preload of 1.75 or 2 inch PVC tubing gave me the cruising ride I wanted. Bike still handles well in the twisites, by the way. I use no air pressure in the front forks.

The other approach is to use straight-wound (non-progressive) springs. This approach will give you a bit more precise handling and is probably more suited to a more aggressive riding style. It will generally yeild a bit more useable fork travel as well. The down side is a stiffer, less road-compliant ride.

In either case you can play with the pre-load to fine tune your ride. The recommended pre-load is about 1/3 of your fork travel. That is to say you should compress the forks about 1/3 of their travel when you get on the bike. After that the progressive spring take less force to cause the forks to move the first couple of inches than the straight springs.

FWIW, rear shock springs are progressive on the XJ. You can tell if your springs are progressive as the coils will be closer together on one end of the spring. I decided to keep both ends progressive when I replaced the fork springs and the combination works well for me. If you go straight springs you may want to take a look at your rear springs and maybe make a change there as well.

[jetmechmarty]

If you put straight springs on your bike, you may get them as stiff or as compliant as you like. Straight rate does not mean stiffer. I have Progressive shocks on my Special. I got fussy about setting my laden sag so that it matches the front. When my back tire goes over a dime, I can tell if it's heads or tails. I carve corners without dragging anything, but to get the performance I wanted from the Progressives on the back, I get a very harsh ride on the back. My laden sag is matched, front to back. The front forks soak up bumps better than my rear shocks.

For those of you who like the progressive technology, there's nothing wrong with it. I just don't like it. The same money gets me a precision ride. Straight rate does't mean stiffer and vice versa.

[madmax-im]

Marty I went with progressive springs up front with 15w fork oil and like Jerry said my harsh ride really smoothed out...since i only ride twwisties once or twice a year...I just couldn't justify the cost difference between Progressive and Traxxion Dynamics...at the time i did this i was trying to get my bike ready for the SE rally and my budget was limited... I have progressive rear shocks as well that Randy had installed...the changing of my rear tire eliminated all the wobbles and unstable riding in corners...Good tires are just as important as a good suspension...

[MPittma100]

Rear Springs

Who carries the rear springs for the XS11s? Do they interchange onto the OEM shocks?

Mike

If you put straight springs on your bike, you may get them as stiff or as compliant as you like. Straight rate does not mean stiffer. I have Progressive shocks on my Special. I got fussy about setting my laden sag so that it matches the front. When my back tire goes over a dime, I can tell if it's heads or tails. I carve corners without dragging anything, but to get the performance I wanted from the Progressives on the back, I get a very harsh ride on the back. My laden sag is matched, front to back. The front forks soak up bumps better than my rear shocks.

For those of you who like the progressive technology, there's nothing wrong with it. I just don't like it. The same money gets me a precision ride. Straight rate does't mean stiffer and vice versa.

[jetmechmarty]

Who carries the rear springs for the XS11s? Do they interchange onto the OEM shocks?

Mike

AFAIK, you can't replace the springs on the OEM shocks. There are some sane price point shocks you can buy with springs to order. Hagon, YSS, and Bitubo come to mind. I believe they can all be ordered with straight rate or progressive wound springs. Progressive Suspension is a decent product as well, but they only offer progressive wound springs.

Hagon Shocks USA

Y.S.S. USA Racing Suspension

Bitubo Race Suspension

Progressive Suspension

[Jerry]

Straight rate does not mean stiffer.

Well, just to clarify...

Staight-rate springs take the same force to compress the springs the first couple inches as they do to compress the spring the last few inches. Progressive springs takle less force to compress the springs the fist few inches than they do the last few inches. So, of you get progressive spring rates, of say, 90/140, then it means it takes 90 pounds of force to compress the spring the first couple inches (per inch) then 140 pounds to compress the spring (per inch) the rest of the way. A straight 140 spring requires 140 pounds to compress the spring any measurable distance. The straight 140 spring will be stiffer - require more force - to compress the first few inches than a progressive 90/140 spring.

So I agree, a straight-rate spring does not have to be stiffer, but if you compare a straight-rate to an equivilant progressive spring's final rate, 140 in this example, the straight-rate spring will always be stiffer for the first few inches of fork travel.

[Yahman]

Spring rates

The manual lists the spring rate for the XS1100 as follows:
0~4.055" 30.4 lbs/in
4.055"~6.89" 35.3 lbs/in
Free length 19.82"

The XJ1100 specs:
0~4.33" 26.7 lbs/in
4.33~6.89" 30.2 lbs/in
Free length 23.59"

Progressive lists the 10-1110 spring rate as 30/40 lbs/in.
Free length 20.5"

These are the spring specs as listed, without any air pressure and not including any spacers. The progressives are stiffer than stock, more so with the XJ than the XS. Progressive did not specify at what point in the travel the rate changes.

Ride safe,
Larry

[jetmechmarty]

So I agree, a straight-rate spring does not have to be stiffer, but if you compare a straight-rate to an equivilant progressive spring's final rate, 140 in this example, the straight-rate spring will always be stiffer for the first few inches of fork travel.

Yes, exactly! That's why I dislike progressive wound springs. If I get a smooth ride, I'm dragging hard parts in the turns. With the hard parts kept off the pavement, my spine is tortured. I just don't like the progressive set-up.

Progressive:

[MPittma100]

Progressive Springs

Yes, exactly! That's why I dislike progressive wound springs. If I get a smooth ride, I'm dragging hard parts in the turns. With the hard parts kept off the pavement, my spine is tortured. I just don't like the progressive set-up.

Progressive:

Marty,

I am beginning to think that you are not in favor of the progressive springs? LOL

[Jerry]

To each his own. I like the progressive set-up; combined with the Diamond custom seat I could put 500 - 600 miles a day on the XJ with no discomfort at all. (Have a similar set up on the '06 Concours but with a Russell Day-Long seat.) I also added a Tkat forkbrace and SS lines to the XJ. Along with the Vetter IV and lugage it made a good touring bike. XJ also has touring foot rests mounted on the 3-point engine guards and a throttle lock so I can give my right hand a rest from time to time. Stock foot pegs have been replaced by lowered mini-floorboards and a heel-and-toe shifter replaced the stanard shift lever..

So, there is no "best" set up; one has to consider your riding style and terrain as well as comfort. I had set out to build a long-distance cruiser and the progressive springs fit right in with that goal. The same philosophy is behind keeping, on both bikes, progressive rear shock springs. I know I can't keep up with some other bikes in the twisties, my lowered pegs drag sooner, but I can outlast a heck of a lot of riders on long-haul, multi-day rides. At 60+ years of age comfort starts to have more influence on my decisions than balls-to-the-walls performance.

And, after all, after the first few couple inches of fork travel the progressive springs act the same as straight-rate springs anyway. We are talking about the difference in the first few inches of travel. I prefer the smoother ride of the progressive springs which tend to absorb more tar strip, railroad track, and other road imperfections without sending all that jarring into the handlebars. Makes for more comfortable long rides.

Just depends on what you want out of your bike.