Don’t get me wrong the Progressive shock company makes one of the best quality products out there, no question.
And this is not to bash them.

But; like I said this could save your life.

I see a lot of chat & recommendations about progressive shocks but I wonder if every body knows what progressive wound shocks are all about? And how they react in BUMPY corners.

Anybody know what Progressive & Linear means when we talk about shocks?


And I know that almost every High performance part has the warning that they are for “track use only” or may not be legal in some states, blah blah blah.

But does any body know how “progressive” wound springs react over bumps in corners or in a skid or god forbid all 3?

You should before you spend big bucks on shocks.

It seems a lot of people buy Progressive shocks without knowing, that the name implies the type of winding & what different shock windings do.
Or at least my friends do.

You must take into consideration spring diameter, tolerances & windings when setting up a new suspension. Also keep in mind the difference the compressed shock under weight or the “bound”, and the shocks ability to extend or “rebound”.
Also important to most of us in the 1st place is ride height.


Linear springs are stock in most HDs and have a constant shape to the winding.
They are mostly comfy & cushy if long enough & balanced. The key word is “long enough” or as we see it ride height. This is why Electra glides ride so soft.

Progressive spring windings are wide on one end and close together on the other.
They are by nature a lot stiffer if not long enough (for us at least because most HD progressive shocks are shorter to lower our bikes & that’s the problem)

Shorter & progressive wound means a lot stiffer.
Not a problem if you are heavy or ride 2up a lot.
But for light weight riders it can make your bike feel like a hard tail.

If you lower your bike you will need a heavier spring /bound weight to avoid bottoming out.

Since HDs have a limited range of travel, sometimes after lowering a bike you can simply adjust the shock with a spanner wrench to increase the bound weight & reduce the un-sprung mass
(On Softail’s this will also ride stiffer but will maintain even spring rate & bike control.

In short;

Linear springs are constant. The weight travels from front to back & side to side and most important shock to shock smoothly & consistently.

It is easier for a rider to predict the rate of linear springs & there fore handle bumpy cornering emergencies a lot easier. I said bumpy!!!

Progressive wound springs increase rate as they compress or “bind”.

“Progressive” wound springs transfer force a lot more un-evenly from shock to shock in a bumpy corner than linear springs. Witch requires a lot more skill to maneuver & get used to in an emergency.

But who has time to get use to uneven spring rate in a bumpy corner in an emergency?

That is why progressive wound springs belong MOSTLY on the track. Where there are no bumps.

Progressive wound springs will also give you the most traction vs. power transfer loss in acceleration.


Just an example
Look at the current dirt bikes they have no ride height issues, they now have one huge (long)
Progressive shock, if they had 2 they would be all over the place.

Before you bash me to much you progressive lovers, take note of how many times I said “mostly” to c.m.a

Of course this will not pertain to all but “most” ha ha ha…

Just wanted every one to know because

Most dealers/suppliers will sell us anything without pointing out the dangers or benefits.

So I will go as far as to say if you never plan on encountering a bumpy corner or never going to have to react in an emergency in one, go ahead and put progressive wound springs on.

Like I said I am worried about ya all and wanted you to know.

 

Interesting...

 

Don't know about the rest of you,But I love my Progressive 422's.they feel more natural,and smoother for my driving style, than the stealers version.

 

Interesting info, thanks for sharing.

 

Agree, but very interesting is also your avatar picture Thats your fridge?

 

Excellent Post was aware of this but a good read anyway .. Hope some that may be considering Progressive shocks give this a go .. Love my progressives on the Sporty only shocks might switch to on the FLHT is Arnott Air Pump on the fly .. but thats gonna take more cash that I got handy right now..

 

Thanks for the interesting read 5speedblu. Now I'm really confused on what shocks to buy for lowering my Fatboy, because I'm not a big guy, & my back won't handle a "hard tail" ride. You might've saved me some money here, or cost me some money if I end up going with an air ride system.

 

interesting reading...but i love my 422's and everyone i know likes their's too

 

Interesting, there is an acticle in American Iron this month about lowering your ride. That too was very interesting.

 

Only 2 riders that I know of use a progressively wound spring either up front or in the rear @ the track. When you are riding at 200 mph the last thing you need is a surprise, that is why we never use them. The two riders, however, will argue and that is what makes racing. There are several shocks with the same list price that are a much better shock than Progressive but they do not advertise near as much. Look at Ohlins for either models. They list out at $600 range the same as a 440 but not even close in quality and ride.