Which way up to install progressive springs?

[SANGER_A2]

Right then, this is the deal, I've ordered (and installed) new progressive replacement lowering springs for my FZ6 from Hyperpro. According to the manual that came with the springs (here and here), the progressive part of the spring (where the coils are closer together) should USUALLY be mounted upwards. According to my Haynes manual, the fork springs go with the progressive part at the bottom (as were my stock springs when I took them out).

The question is: does it really matter which way round they go??? And if so, which way is that?

At the moment, my rear shock has the progressive part at the top (as that's the way Hyperpro said to mount it) and the fork springs are the other way round as that's the way Yamaha did it originally!

 

[Cali rider]

In my opinion, it does not make any difference at all which way they are installed. They are in a sealed chamber, the center of gravity is irrelevant, and the soft (tight wind) section will compress until the tension equals the rate of the stiff (coarse wind) section.

As long as the outer diameter of each end is the same it will operate the same either way.

 

[SANGER_A2]

In my opinion, it does not make any difference at all which way they are installed. They are in a sealed chamber, the center of gravity is irrelevant, and the soft (tight wind) section will compress until the tension equals the rate of the stiff (coarse wind) section.

As long as the outer diameter of each end is the same it will operate the same either way.

Ooh. I like that answer. It would mean I don't need to tinker with stuff. I hope it's the right one though. I asked on my other forum and had people saying top, bottom and doesn't matter!

One annoying thing though is that it feels too bouncy. I used to have the stock rear preload on 4 and that was perfect. I weight about 11 stone with gear. I was told that you need to take two off the preload you had at stock with the progressive, but that's too bouncy for me. I'm going to try knocking it up to 3 later. I was wondering if that may be caused by the spring being a different way up to how it should be.

 

[Wildcard]

hyperpro tells you to have the tighter section at the top in their book. Why would you not do what they tell you to do with their own setup?

 

[bugsterkiton]

Hi Sanger,

I am of agreement with the answer of Cali rider and Wildcard. The most important thing is to place both spring in the same way. Mine are placed the progressive part upwards (as described in the manual).

Hello of belgium.

 

[Fred]

Short answer: It doesn't matter, but do them both the same.

Long answer: If you measure your fork oil by height, putting one spring in upside down will change the perceived level of fork oil, since one spring will have more windings under the oil, raising the level higher.

The springs work the same each way.

Hyperpro probably just specified orientation in the manual so that people would stop calling them asking which way to put the springs in.

Although there may be a slight advantage to putting the tight coils at the top. They bind up first, and so the looser coils will then be working harder and getting hotter. By putting them at the bottom, you're placing more of them in the oil, which may help cool the springs.

I doubt it's a major factor, but it can't hurt.

Fred

 

[SANGER_A2]

For future reference if anyone else has this issue: I rang the Hyperpro distributors in the UK and they told me to follow the Hyperpro instructions - not Yamaha/Haynes and install them both with the tight part of the spring at the top (so I need to change my fork springs round).

I also need to top up my fork oil from 20cm air at the top to 12cm.