I've changed the rear shock to a Hyperpro type 041. It feels great to have a new shock, which also is fully adjustable. When I opened the fork to put in Hyperpro progressive fork springs, I was surprised to find springs that are 200 mm longer than stock springs! There was no spacer of course. The springs are marked WP30 (or 36 or 38), so I guess they are Wilbers springs. Any one having expedience in this type of mod and can say if it’s a good or bad?. The springs are either progressive or 2-step. One third of the springs have much tighter wounds.

I have not encountered any problems with the front and am not sure if I should put in the shorter Hyperpro springs at all. Any comments are appreciated, especially from you who have knowledge in 200 mm's longer fork springs.

The bike in quiestion is my Blackbird, but I belive this is a generic question and I know Trips and Dad and more of you have a lot of chassie knowledge.

 

Do you have the rate of the new springs? That might help a little to have some idea. Did they recommend a fork oil level other than stock?

My experience with spring changes is limited to linear springs using the fork oil level for the progressivity. Typically the fork oil level recommended with new linear springs is higher so they're telling you that they're adding progressivity to the linear spring, just don't know how much or how to compare that with what you've got.

 

No I don’t have the rate for the new progressive Hyperpro springs. Even if I did that would probably be an unlinear value. Hyperpro recommended almost the same fork oil level as stock and 7,5 weight oil, which came with the new springs. I guess that means that the progressitivety would increase a lot compared to stock due to the same air pocket plus very progressive springs.

I found that the strange long springs now in the fork are WP suspension springs. The have that type of long springs which eliminates the spacer. The theory is to use the longest spring the fork can take. They are progressives though. I'll measure the free sag and rider sag and see if they match me. I think they do since the front always felt fine and the trouble was from the rear shock with zero damping. The bike has not been tested on track yet so I don’t know how it will handle during maximum braking before curves and hard acceleration on exits.

Edit: I got the chance to ride a couple of hours today and test the new installed Hyperpro shock. I'm very happy, the nervous rear is not there any more and it eats bumps very effectively. The old stock shock was out so I can't say how it compares to a new stock shock, but the Hyperpro is fully adjustable which is an advantage and it is a far more advanced solution. I will definitely recommend it to anyone.

I also was to replace the fork springs to Hyperpro progressives I have, but didn't do that since there was already extra long WP-suspension progressives in the fork. I just cleaned the fork and put new 7,5W oil into it. I don’t mind the extra stroke that the longer springs provides

I also shimmed the rear shock 6 mm's and found the steering to be much more responsive as many others has reported.

Total impression is great, now I hope for warm and dry roads since the Bird really asks to be driven hard.

 

updated above