Another Emulator Thread?

Hey,

I'm trying to mod my front suspension with progressive springs and these harley-racetech-clones-emulators.

I set my sag right, shortened the spacer by about the height of the emulators and set the air chamber to 130mm, as advised by the spring manufacturer (well, they advised to use 140mm..)
The springs are progressive, mady by Wilbers (German brand), they should be at 80 or 85 Nm per mm

The holes in the rod are drilled up to 10mm, no additional holes (first had two 8mm holes extra, closed them again)

The emulator currently has about 4,5mm of thread showing out of the bolt at the end. This is 4,5 rotations from the standard settings towards more preload.

I tried different settings, the last one is 4,5 turns closed and an air chamber of approx. 100mm. Felt a bit to harsh after a long day of working on the garage floor on normal ride mode on bad roads. Worst thing is, when braking hard my data recording cable tie (?) (can't remember the englisch expression) is almost hitting the lower fork clamp.
So I need a bit less rebound on the first half and some more at the end of second half.
I'm thinking of reducing the preload of the emulator and decreasing the air chamber?

Any helpful hints on this ?

[mikerj]

What viscosity oil are you using?

SAE 15, as recommend by the spring manufacturer
I don`t know whether this is the same as your 15 wt


Changed the air chamber to 90 mm and reduced the emu-preload to 3,5 mm
Felt better
I guess I'm gonna try 80mm air chamber and 2,5mm preload

Btw the manufacturer recommends 100mm for race

[Bibio]

from what i know (and it aint much) emulators only slow down the compression they wont stop the forks going to full compression and they don't work on rebound. reducing air gap will cause a harsh ride.

what do you weigh fully kitted?

[mikerj]

Originally Posted by Herrmann

SAE 15, as recommend by the spring manufacturer

That was the oil recommended by the spring manufacturer in conjunction with standard damper rods. I believe that Racetech specify 20W oil for their Gold Valve emulators, though I used Castrol 15W with good results. The oil viscosity controls the rebound damping, the spring preload on the emulator controls high speed compression and the little hole in the emulator coupled with oil weight controls low speed compression.

I would be wary of closing the air gap up too much, it will put a lot of strain on the oil seals.

Is the spring rate suitable for your weight?

Originally Posted by Bibio

from what i know (and it aint much) emulators only slow down the compression they wont stop the forks going to full compression and they don't work on rebound. reducing air gap will cause a harsh ride.

what do you weigh fully kitted?

that ain't much you know is right
this emulator isn't much more than a small washer with a preload spring for compression and a bigger one with a very soft spring that allows the oil to flow back

i want a more progressive damping, so reducing the air gap will give me that. for not being to harsh, i want to reduce the emu-spring's reload

i don't know about my weight fully kitted. without gear etc its around 79kgs at the moment. so with leather, helmet etc it should be around 85+ kgs

i checked race-tech they recommend something
around 85 N/mm, as my springs are progressive they are 6,5 to 9 N/mm.
according to what i read on the german sv-board, these springs are suitable for my weight

it would be nice to know when "high speed compression" starts

less emu preload and a smaller air chamber felt more comfortable, than the other way round, as the fork was able to absorb the bumps less harsh

i talked to an Öhlins dealer in my town, but he said he can't help me as he has no experience with this simple type of forks and installs racetech emulators maybe once in 3 years

[yorkie_chris]

With 6.5N/mm initial there is no wonder you are blowing through all travel, add some preload to get into workable range of spring rate or get some linear springs.

With smaller air gap you are making spring more progressive, not changing damping at all.

With adding preload to emu you are giving more digressive nature to damping but spft springs make sure you blow through all travel in no time which is what causes your harshness issue. More oil won't cure this.

What bike and rider sag did you have?

[Bibio]

cue the man that can right on time lol

Y_C should sort you out

i was going to say get linear springs.

i was also going to say that 90% of riding is low speed compression as high speed only comes into force on sudden bumps like rumble strips.

Originally Posted by yorkie_chris

With 6.5N/mm initial there is no wonder you are blowing through all travel, add some preload to get into workable range of spring rate or get some linear springs.

With smaller air gap you are making spring more progressive, not changing damping at all.

With adding preload to emu you are giving more digressive nature to damping but spft springs make sure you blow through all travel in no time which is what causes your harshness issue. More oil won't cure this.

What bike and rider sag did you have?

I wouldn't call it "blowing through all travel", since I use approx half of the travel on bad roads, when aiming for all bumps, manhole covers, etc without hard braking

I know a smaller air gap is making the spring more progressive not the damping, I tend to choose the wrong words on this subject. Even in german...

what do you mean by "digressive"? I looked it up in the dictionary, but that proposal doesn't seem to fit in this case

Bike sag without me is about 2cm, with me about 4 cm, so I think this should be alright
I shortened the stock spacers by approx 18-20mm, which is about the height of the emulators
When the bike is lifted so the front wheel doesn't touch the ground and the fork caps are off, the spacers are on one level with the fork tubes.
I still got the smaller parts I cut off, so I could put them in and have a try

Thanks for your help so far, any advice?

[yorkie_chris]

Digressive, strong initial damping which tails off when the pressure exceeds preload and the washer "pops" open.

4cm, you have what 120mm of travel, so you are using half of this. That is only 20mm you have there, air gap (lack of) is stopping suspension from absorbing bumps so it feels harsh.