Ohlins front fork Springs

[FreakyFreak]

Got ohlins fork spring .90 kg/mm installed and now I feel that the front has raised a few centimeters and the front feels lighter. Is this normal?


FreakyFreak

 

[colinlinz]

I haven't used the Ohlins stuff. With RaceTech, they give you a tube that you cut to the right length to retain your ride height. Perhaps a similar process needs to be applied with Ohlins?

 

[flipper]

Don't cut the spacers. Decrease preload. You need different spacers with racetech because they don't supply springs the same length as stock.

The bike will ride higher as the spring is stiffer and therefore compresses less for the same load............. you have decreased the sag.

Now you need to fit a decent rear shock that has some compression damping and doesn't squat to the bumpstop when you apply the throttle.

You could raise the forks in the yokes a few mm to pitch the bike forward more.

 

[flipper]

OP - what do you weigh? Are the Ohlins springs too stiff for your weight??

 

[Locksmith]

As Flipper said, probably got to decrease the preload on the forks.
When I had my ohlins springs fitted I had to wind the preload from a long way in to a long way out to get the sag right!

 

[l34chy]

Don't cut the spacers. Decrease preload. You need different spacers with racetech because they don't supply springs the same length as stock.

The bike will ride higher as the spring is stiffer and therefore compresses less for the same load............. you have decreased the sag.

Now you need to fit a decent rear shock that has some compression damping and doesn't squat to the bumpstop when you apply the throttle.

You could raise the forks in the yokes a few mm to pitch the bike forward more.

Yeah like Flipper says I fitted race tech internals in an r1 I had and springs are longer you need to sort the rear out the complete suspension is pants it will probably be worse than before with the bike sitting higher on the front

 

[FreakyFreak]

OP - what do you weigh? Are the Ohlins springs too stiff for your weight??

Fully equipped I weight between 90-95kg. The spring rate was indicated for my weight.


FreakyFreak

 

[colinlinz]

If you can't get the correct ride sag together with the correct static sag, then the spring rate might need revising. Changing hieght at one end of the bike or the other will change the way the bike steers High front will increase the trail of the front wheel. Low from will decrease the trail. The rear hight also effects the front trail, and further effects the moment of pull on the chain and sprocket (squat, ant-squat). This can change the way the rear end grips under acceleration.

 

[flipper]

What is your front preload set to? I weigh about the same as you, have 0.9 springs with the preload set to 7 lines - pretty much minimum. It feels ok.

The .9 is close enough for your weight for it not to need changing. It is the only rate Ohlins offer, so you would need to shop around to find a different rate. Sonic Springs in the US offer a good range of springs the right length.

As Colin says, the geometry has changed due to the front compressing less for a given weight (you). The suspension works as a system, so changing one thing will have an effect elsewhere, but you will end up in a world of pain chasing specific sag figures.

You either need to get used to the new shape of the bike or alter it by lowering the front or raising the back some. Installing a decent shock will help no end. You will be amazed at how much better the bike is doing just this.

What were you trying to fix?

 

[FreakyFreak]

What is your front preload set to? I weigh about the same as you, have 0.9 springs with the preload set to 7 lines - pretty much minimum. It feels ok.

The .9 is close enough for your weight for it not to need changing. It is the only rate Ohlins offer, so you would need to shop around to find a different rate. Sonic Springs in the US offer a good range of springs the right length.

As Colin says, the geometry has changed due to the front compressing less for a given weight (you). The suspension works as a system, so changing one thing will have an effect elsewhere, but you will end up in a world of pain chasing specific sag figures.

You either need to get used to the new shape of the bike or alter it by lowering the front or raising the back some. Installing a decent shock will help no end. You will be amazed at how much better the bike is doing just this.

What were you trying to fix?

The preload is set to what I had before with the stock fork Springs. 4 rings showing. If you have 7 rings showing won't the sag increase? The sag is supposed to be between 30-35mm. With 7 rings showing won't that increase the sag? I have a Nitron track shock on the back, with rebound and compression.

I was trying to fix the brake dive when braking.


FreakyFreak

 

[flipper]

Yes, less preload means more sag. But you have less than before because of the stiffer springs.

Like I said, don't go chasing specific sag numbers. Put the tape measure away, set preload to minimum and test ride the bike. Adjust preload to suit your taste or feel.

You will not reduce or eliminate brake dive by changing springs. You have just found the effect they have. To do what you want you really need to revalve as the forks have too little compression damping but you could use a heavier oil. What is in there now? You could also try a higher oil level. Beware that heavier oil will also increase the high speed compression which will make the forks kick off bumps and the rebound so you would need to back this off some as well. Try different combinations and work out what you prefer.

Good choice on the shock.

 

[FreakyFreak]

Yes, less preload means more sag. But you have less than before because of the stiffer springs.

Like I said, don't go chasing specific sag numbers. Put the tape measure away, set preload to minimum and test ride the bike. Adjust preload to suit your taste or feel.

You will not reduce or eliminate brake dive by changing springs. You have just found the effect they have. To do what you want you really need to revalve as the forks have too little compression damping but you could use a heavier oil. What is in there now? You could also try a higher oil level. Beware that heavier oil will also increase the high speed compression which will make the forks kick off bumps and the rebound so you would need to back this off some as well. Try different combinations and work out what you prefer.

Good choice on the shock.

Thanks flipper. Will try backing out the preload to minimum and try and play with the settings. The only thing that have noticed is the height being a little higher and the front feeling a lot lighter than before.
The springs where installed at a Yamaha dealer so I suppose the oil weight must be 7.5 which is the stock weight oil.


FreakyFreak

 

[flipper]

It would be worth asking the dealer what oil they put in.

Ohlins spec a thicker than stock oil with those springs............ if your dealer used the original Yamaha stuff then it won't help you.

Silkolene 5W fork oil is a little heavier than the Ohlins stuff, much cheaper and easier to get hold of.

Without modified valving the Silkolene 10W would firm up the damping quite a bit.

 

[flipper]

also worth noting............. Sonic Springs suggest an oil height of 120mm.

 

[FreakyFreak]

also worth noting............. Sonic Springs suggest an oil height of 120mm.

You have ohlins springs right? What oil height did you put in? I presume the dealer put in the recommended oil height in mine, which is I think 148mm. In the ohlins site they recommend 145mm for the springs with original cartridge and for the ohlins FGK 230 cartridge kit 160mm.


FreakyFreak

 

[flipper]

I have sonic springs, but that is irrelevant. The springs don't know who made them.

Last time I checked ohlins suggested 145mm for their 0.9 springs. If you are still feeling too much dive then you could raise the oil level. Sonic suggest 120mm for their 0.9 springs which will improve fork dive.

I have revalved forks and gp suspension suggest 130mm which is where mine is now.

Prior to revalving I had just the 0.9 springs and oil at 145mm. There was still a lot of dive. If I were in that position now I would be raising the oil level. You can do this by adding a known cc or ml of oil. You don't have to do it by removing the springs. Pretty sure marthy reckoned that 27cc was equivalent to 20mm in height.

 

[Baz69]

Fork revalve

I have sonic springs, but that is irrelevant. The springs don't know who made them.

Last time I checked ohlins suggested 145mm for their 0.9 springs. If you are still feeling too much dive then you could raise the oil level. Sonic suggest 120mm for their 0.9 springs which will improve fork dive.

I have revalved forks and gp suspension suggest 130mm which is where mine is now.

Prior to revalving I had just the 0.9 springs and oil at 145mm. There was still a lot of dive. If I were in that position now I would be raising the oil level. You can do this by adding a known cc or ml of oil. You don't have to do it by removing the springs. Pretty sure marthy reckoned that 27cc was equivalent to 20mm in height.

Hey flipper,where did you get the revalve kit from I spoke to Nick in stoltec he doesn't do them anymore if that's where you got them he is referring me to Penske ,

 

[flipper]

Baz I bought the kit from gp suspension in the states. They're very helpful. Only thing to bear in mind is customs duty.

The kit does not include springs or oil.

 

[Baz69]

Thanks ,do you mind me asking how much the revalve kit was as they don't state any prices on website,I understand there may be import duty to be paid and I can organise springs and oil from sonic or local to me is an ohlins dealer
Thanks

 

[flipper]

From memory it was about 150 US dollars plus postage. Sonic springs were 85 USD plus post. Any half decent suspension tuner will have the tools to fit the kit. Local place here wanted £70 so I spent the money on tools and did it myself.