Anyone re-sprung a DDC bike?

[rcannon409]

I like the thought behind this.

Heres what I can see happening.   

We hit  a bump that would compress the forks 1 inch, with stock springs. No problem, the computer offers its programmed rebound damping for a spring thats compressed 1 inch, in x time.

Now we use a stiffer spring.  Lets say it only compresses 1/2 in for the same bump, in the same time.

Our computer uses the rebound damping for the 1/2 in, which is probably lighter than a 1 in. I imagine compression damping to behave in a similar manner.

Id be very interested in what you really find, but my thought is you'll have  a pogo stick unless you stay very close to stock settings.

[SimonUK]

Originally Posted by rcannon409

I like the thought behind this.
Heres what I can see happening.   
We hit  a bump that would compress the forks 1 inch, with stock springs. No problem, the computer offers its programmed rebound damping for a spring thats compressed 1 inch, in x time.
Now we use a stiffer spring.  Lets say it only compresses 1/2 in for the same bump, in the same time.
Our computer uses the rebound damping for the 1/2 in, which is probably lighter than a 1 in. I imagine compression damping to behave in a similar manner.
Id be very interested in what you really find, but my thought is you'll have  a pogo stick unless you stay very close to stock settings.

I think this is exactly the issue that Lowrance encountered when he put stiffer springs in the DDC shock/fork. The OEM damping 'algorithm' is programmed for the OEM spring setup.

[hedonist222]

Originally Posted by SimonUK

I think this is exactly the issue that Lowrance encountered when he put stiffer springs in the DDC shock/fork. The OEM damping 'algorithm' is programmed for the OEM spring setup.

Would you kindly elaborate. At your convenience of course.

How does the  electronic damping work?

Does it assesses how much or how fast the spring was compressed?

[Noggie]

it is entirely possible that too stiff a spring will upset the system.
But on the flip side, the system is not working well with a heavy rider either.

I seem to remember Lowrance installing a 1,1kg/mm spring (custom made), and had issues.
Stock spring is 0,85kg/mm.
The stiffest Wilbers spring is 0,91kg/mm.
This may be enough not to upset the system too much with too stiff a spring, and still allow the system to work better with a heavier rider.
I dont think I will get my sag within BMW spec (6-10mm) with the Wilbers spring, but I will probably be much closer.
My front sag is 15mm now, but if that spring gets me to 12mm that should hopefully help a lot.

Hedonist222.
This video explains the system operation.

[hedonist222]

thanks Noggie

[SimonS1KR]

This old thread suggests JohnnyBMWGood changed the springs in his DDC system...

https://www.s1000r.co.uk/index.php/topic,1893.20.html

It would be interesting to get more info about that

[jucam]

I'll be interested to see the reference of the springs that works for our bike.

[Blade.RRunner]

Originally Posted by Noggie

...
I dont think I will get my sag within BMW spec (6-10mm) with the Wilbers spring, but I will probably be much closer.
My front sag is 15mm now, but if that spring gets me to 12mm that should hopefully help a lot.

Other than not being able to achieve BMW-spec front sag, do you experience any adverse effects (bottoming out, etc.)?

[Noggie]

Originally Posted by Blade.RRunner

Other than not being able to achieve BMW-spec front sag, do you experience any adverse effects (bottoming out, etc.)?

I can't physically feel that it is bottoming out, but I have had my go pro mounted so that I could see the compression, and it is not far off, I have a "mark" roughly 20mm from the bottom.
I have some brake dive, compared to an RR I rode (non DDC) it dives a fair bit more.

The rear end is also very soft so there is a lot of movement when pushing through corners.
All in all this causes some cornering instability and it makes me hesitant through corners.

[Blade.RRunner]

Originally Posted by Noggie

I can't physically feel that it is bottoming out, but I have had my go pro mounted so that I could see the compression, and it is not far off, I have a "mark" roughly 20mm from the bottom.
I have some brake dive, compared to an RR I rode (non DDC) it dives a fair bit more.

The rear end is also very soft so there is a lot of movement when pushing through corners.
All in all this causes some cornering instability and it makes me hesitant through corners.

Can't argue with the rear end wallowing a bit when accelerating out of a corner on less than perfect roads.

In the front, however, 20 mm seems just perfect if that's what's left after really hard braking. 
I don't know too much about this bike yet, but the first thing I did was put a zip tie on the fork tube. Testing whether the ABS would kick in in different modes riding two-up (so a couple of nice, progressive, but hard braking), the zip tie was fully down spare maybe 2-3 mm at the end of that ride. So this bike does, indeed, use (almost) all of that chrome tube travel (some bikes don't).
I recommend using a zip tie as poor man's telemetry to gauge how much fork travel you actually use.