Anybody with Ohlins experience?

JTT

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#1
I've recently adopted a set of Ohlins forks for my GasGas. The springs are a little light for me (.41s) (me at nearly 200lbs :ugg: ).

Surprisingly my sag numbers are very close. I would have expected it to be very soft for my weight but...

80mm of race sag
40mm of static sag

I've only had one short ride on them and they are definitely softer than my precious setup, but not bad at all really. I was going to add some spring preload, as there apparently is none from the factory.

The manual shows changing the "spring tower" (more like an inverted cup) for a longer one, but would this not effect the rubber bumper located inside this tower??. The fit in nice and snug in stock form, with no preload or slop in the rubber bumper.

In addition, the parts list does not show optional towers, but does show preload washers "to spec" :think:

The parts breakdown shows a preload washer between the spring and this tower, but mine has none. This seems to be the more obvious place (let alone easiest) place to add preload to the spring.

Any suggestions??
 
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#2
I'm unfamiliar with what you describe as the "spring tower". It sounds like a similar arrangement to the current Yamaha forks. Wherever you place the Preload washers it is important that they are held central to the fork tube and cannot shift from side to side. Particularly if they are placed at the top of the spring. If the they are at the top of the spring and are not held central. they could shift to the side allowing the chrome tube to contact them when the forks are fully compressed causing unwanted damage. Make sure the washers are no larger than the spring diameter.
Terry
 

JTT

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#4
Thanks Mike. That's what I figured. If you do use a longer cup, do you also use a longer rubber bumper? ...or at least a shim under the bumper?

Sorry for the vague description Terry. Thanks for the advise.
 
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#5
JTT
If you put a spacer between the spring and that cup you will cause quite a bit of damage. That is the same as the YZs. There is nothing to keep the spacer centralised. It will shift to one side, be impacted by the chrome tube damaging the cup and the spring guide. This will also send particles through the fork creating further damage elsewhere. With this style of fork if you wish to add preload, pull the spring out and place the preload washer underneath the spring.
Terry
 
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#6
Jtt, on ohlins site they have pdf manual downloads which tell you everything.
They do put the spacers between the cup and spring, but i will also advice that you put them down under the spring due moving at the top.
 

JTT

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#7
Thanks once again guys! :thumb:

Terry, I had thought about the problem with maintaining it centralized, but figured if I dimensioned the ID of it to avoid sideways motion that it would be OK, however your advise makes good sense. It's probably better at the bottom anyways, where there is no way to cause problems.