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Ohlins Compression

3K views 10 replies 5 participants last post by  Momo1970 
#1 ·
I had my Daytona Ohlins in my 2015 Strx for few months now, an I couldn't get the set up work for me. The compression load is very progressive and none linear for street riding.
The bike is very smooth on low speed suspension movement but when I hit big bumps (high speed suspension movement) the compression load rate is too high and the bike simply bounce up.
I tried low compression set up with high rebound, yet all I got is smoother low speed and harsh high speed suspension.
My suspension guy suggest re-valve of the Ohlins shock to modify the compression rate increase and increase rebound.
I'm considering but just about to try the original OEM shock again.
Could you please remind me how the OEM shock handle big bumps?
Is it worth trying to modify the Ohlins internals?
 
#3 ·
While the progressive links on the bike are not the best, they are like most things a compromise. If you've checked to make sure you have the right spring rate for your weight first, then more than likely you will need to revalve the shock. The Ohlins is likely valved to work at higher speeds on track, so won't be as good on street out of the box.

In most shocks and forks, the high speed compression circuits are handled by the shim stacks, which are not adjustable. The low speed compression is by fluid movement through an orifice, and this you adjust by turning the compression knob.

Check your springs first, set sag properly, put the shock to it's default settings, then if you are still having issues, you might need to revalve.
 
#4 ·
I should have mentioned in my initial thread that:
1) The Ohlins spring rate matches my weight and I get proper sag (I tried variable rider sag level from 30MM to 40MM)
2) Indeed the bike preforms great on the track (I only rode Laguna, but the suspension was amazing)
3) I work with suspension guy (same guy that I worked with for the last 10 years, very reliable). The guy recommended the re-valve as reducing the low speed compression will sacrifice handling and increasing re-bound (to slow the compression kick) will sacrifice ride quality. This is why I consider using the stock shock for street riding as it might have less progressive high speed. I simply don't remember how the stock shock behaves.
 
#6 · (Edited)
[...]The bike is very smooth on low speed suspension movement but when I hit big bumps (high speed suspension movement) the compression load rate is too high and the bike simply bounce up.[...]
What do you mean when you say "big bumps"? Tall or sharp?

If they are tall but not sharp then it's probably not a high-speed compression issue. It's the progressive linkage. It produces a harsh bottoming sensation, but only when you get the shock deep into its travel. The Ohlins shock should have good compression stiffness to minimize this, certainly better than the stock shock. I wouldn't recommend downgrading back to stock.

But if these troubling bumps are short but sharp, then yes, you'd need to modify the compression valving for more high-speed compliance. But it's a compromise. You'll probably lose some low/medium-speed control.

I have a Matris shock which is of the more traditional design---in which there is significant cross-talk between the rebound and damping circuits. It's quite stiff but I've found sufficient ride comfort by backing off both the Rebound and Compression adjusters about 20%. Your TTX shouldn't have as much cross-talk but you might try backing off both adjusters an equal amount.
 
#7 ·
I'm talking about sharp bumps (especially the nasty ones mid corner...). I found that reducing the compression and increasing the rebound didn't provide the control I'm looking for. My current set up (40 MM sag, compression 20 clicks from full in, rebound 6 clicks from full in).I think I should try this: increase pre-load (just a bit perhaps a turn or two), increase compression (my track set up is 14 clicks from full in I will try 12-14 clicks from full in) , keep rebound tight at 6-8 clicks from full in (perhaps even more). What do you think?
 
#8 ·
Seems as my solution is counter intuitive. In order to avoid reaching the compression "wall" towards the end of the shock movement I need to add more compression (more pre load will help to some degree).
The result will compromise some of the low speed comfort I currently have with the softer compression.
 
#9 · (Edited)


Even though the TTX does have good isolation between rebound and compression, I wouldn't suggest setting the two clickers so far apart. If the shock isn't allowed to rebound as fast as it compresses it will "jack down" and you'll lose free travel. I don't have any direct experience with the TTX but I've found it's important to keep the two phases in balance for optimum handling and ride quality.

Increasing preload will definitely help keep you out of the harshly progressive region of the stock linkage, though. See if you can get about 35 mm of rider sag. And try the Standard or Comfort settings above. (Does the image show up on your end?)

If it's still too harsh then you'll have to spend some money.

EDIT: Yeah, you're on the right track. The compression adjuster itself won't do much to take the edge off those sharp bumps. But if you can keep the spring in its happy place with additional preload and more compression damping (to match the rebound damping, at least) the shock will react better to them.
 
#11 ·
2 more pre-load turns made things much better. I'm at the spring soft spot which helps a lot (and ride quality in general is better too). Still the compression wall comes to play but much less than before. I can surely try to restrain the back with a bit more rebound. But, for sure i keep my Ohlins on.
 
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