Ohlins DU440

[greenmonster]

Whatever happend to
"Set the damping according to the manual and it feels great. Very poised and composed but reasonably supple." ??

Sooo easy to get lost in suspension fiddling....
And what spring do you have?

[koko64]

I can't get lost if I know the oem settings.
But it is very easy to get lost, albeit suspension or engine tuning if you dont document your changes. I have eliminated the compression damping and focused on the interaction between the rebound damping and spring.
Since I have the oem settings (which are good minus 4 clicks on rebound), I can experiment and learn. I write down my impressions and get a feel for what the shock is doing by setting at extremes and also making 2 click adjustments at a time.  I can say that the adjusters still work on an old shock. As I stated earlier, the spring code has long since worn off so the spring rate is a mystery until the shock is serviced when the spring can be removed and tested.

Another thing I found was in relation to adjustments on the fly, I always hated the look of the compression gas cannister up near the tank (mine is near the shock), but I now appreciate the ability to make changes on the fly. The County I ride in has some roads that are in great condition (down here that means bumpy but not dangerous) and then roads that may cause a sedan to crash, so I found that there is not one single correct setting (that seems obvious), but everyone seems to be looking for that magic bullet when two or three settings for different roads/riding is more realistic. The gum tree roots can lift the road between rides or a pot hole form overnight so the road conditions are dynamic.
Active suspension would be an advantage around here. On the bad roads the sport bikes get smashed by the adventure bikes and motards and on the good roads the sport bike guys are waiting on top of the mountain with their helmets off..

For me  it's about learning and documenting. I have some note books laying around.. I take my hat off to suspension guys. I have found suspension fine tuning relatively easy when working with race track suspension set up by a pro, because you start with an excellent base line, but what can be very difficult is finding a reliable base line when dealing with street suspension and vastly different road conditions. I don't know about you guys but I have a much easier time setting up forks than shocks.

[koko64]

Similarly, 14 out on rebound is roughly seven up from minimum, out of 21. So about a third of the possible rebound adjustment range.

My suggestion was to back it off a further 8 - that is, in total 22 out. Well, the adjuster will probably freewheel after 21, so you will then be at minimum rebound.

The point of going there is just so that you can see if the shock feels freer and more supple. I think Ohlins sometimes specs more rebound than we want on rough Aussie roads. The result is a rear end that feels a bit rough or fatiguing on the bumpy bits, although it is really nicely tied down on the smooth bits.

Certainly the case with mine. I think I am three or four rebound clicks softer than Ohlins spec, on what is a standard Ohlins rebound stack. Fairly recently I decided I wanted a bit more control, and deducted just one of those clicks - i.e. went a single click back towards full hard from where I had been. The difference on bumpy bits from just that single click was profound.

So I reversed that change pretty soon. If I were racing, I might wind on more rebound. But for the road, a setting right on the edge of too bouncy works best for me.

The only reason I suggested winding off the full extra 8 (or 7, probably) was so you could see what she felt like at minimum rebound. As an alternative, just wind off four.

The change, when the shock stops packing down and instead recovers fully from each bump is quite noticeable. It feels almost as though the rear brake had been dragging and suddenly it's released.

Hope that helps some. It may well be that on that shock, Ohlins spec is spot-on.

OTOH it might also be that the rebound stack is identical to what they use on my DU333, for which they also recommended 14-out. I think I've settled on 17 out, but could be a click either way.

 

Thanks mate. Testing this out.
Cheers.

[ducpainter]

...and in the end, you'll set the rebound at the factory setting...+ or - a click...

set the compression at factory, and adjust as necessary.

Have fun.

[koko64]

Probably.

I also tested at minimum damping all round and it still handled very well. Not bad. Good to have options.

[koko64]

MHPD, Speeddig and Moronic, I'm following your advice and running minimal damping all round with a click here and there. Very happy.

[Moronic]

Well, happy is good. 

Great way to get a feel for your options.

[koko64]

Cheers.

[koko64]

Setting of 21 out of 24 clicks from the recommended 12 for compression. Had it all the way out for comfort but felt the shock compress and fall into it's stroke too quickly. Rebound is 18 clicks out from recommended 14.

Edit: Was able to compensate for adding those few clicks of compression damping to stop the shock falling through its stroke too quickly by backing off the rebound from 15-16 to the 18 and this removed any harshness and slight "packing". Interesting interface between the damping circuits.
Thanks for the feedback you blokes.

[Moronic]

Interesting Tony, that is within a click or two of where I have ended up for general cruising. (Different shock as you know, although as I have said above I suspect the rebound stacks are identical.)

Yes, with a bit of extra compression you can get away with less rebound. Strangely, an Ohlins tech I was talking to at an Australian GP in the 90s offered me that as an example of advice he might give to a rider. He said the rider might ask for more rebound to control oscillation at some point on the track, and he might suggest instead a bit more compression, which would reduce shock deflection and thus give the rebound a bit less to do.

Are you really happy now? 

[koko64]

Yeah, I am less aware of the shock working and more aware of tyre feedback. The sense of feel has given me a lot more confidence.

[koko64]

Out of interest, I checked the range of settings on the damping adjusters. Compression had 25 clicks then a dead stop with no more movement so that was nice and clear. Rebound on the other hand went to 60 clicks out before freewheeling  . I think minimum rebound damping may be around the 25-30 click zone. Anyone able to clarify this?
Cheers.