Fork midvalve - shim stack or check plate?

[Shaun]

On our side of the world it is Ohlin's that is the main shock here, with the best support anywhere in the world!

What has inspired you to start posting on a New Zealand bike web site?

[Yankee Doodle Dandy]

A post with a lot of info came up in a google search.

It seems like people over here are more interested in talking about stuff that matters regarding suspension work.

If you were to ask this same question on a US forum it would go like this - first people would tell you that they know nothing about suspension so you should just send the forks out to either X, Y, or Z. Then the rest of it turns into a 35 page argument about how X & Z suck and that Y is the greatest thing since sliced bread.

[SARGE]

welcome to the site YDD.. glad to have another Yank on board

A post with a lot of info came up in a google search.

It seems like people over here are more interested in talking about stuff that matters regarding suspension work.

If you were to ask this same question on a US forum it would go like this - first people would tell you that they know nothing about suspension so you should just send the forks out to either X, Y, or Z. Then the rest of it turns into a 35 page argument about how X & Z suck and that Y is the greatest thing since sliced bread.

same here.. stick around

[Shaun]

A post with a lot of info came up in a google search.

It seems like people over here are more interested in talking about stuff that matters regarding suspension work.

If you were to ask this same question on a US forum it would go like this - first people would tell you that they know nothing about suspension so you should just send the forks out to either X, Y, or Z. Then the rest of it turns into a 35 page argument about how X & Z suck and that Y is the greatest thing since sliced bread.

Fair enough indeed! Robert is very good with what he does, as he really loves the game, to me, he is like a racer, wanting to find out how to be better quicker and safer, he helped me to win many many races

[Yankee Doodle Dandy]

I see Ohlins uses the older check plate configuration on their now 30mm R1 pistons.

[Pussy]

I see Ohlins uses the older check plate configuration on their now 30mm R1 pistons.

Don't forget that one leg does compression and one rebound in the '09 R1

[Yankee Doodle Dandy]

Don't forget that one leg does compression and one rebound in the '09 R1

Yep and they both have check plates.

[Robert Taylor]

Yep and they both have check plates.

Yes but there is damping only in one direction for each piston so there is no longer a midvalve in the accepted sense.

[Yankee Doodle Dandy]

Wouldn't you still want a mid valve stack to control initial dive?

[FROSTY:Me]

Hmm so no Ohlins independant person in the whole of the USA ??
I wonder how RT would sound with an american accent?

[Robert Taylor]

Wouldn't you still want a mid valve stack to control initial dive?

No, because the compression stack is right where the midvalve used to be.

[Yankee Doodle Dandy]

Hmm so no Ohlins independant person in the whole of the USA ??
I wonder how RT would sound with an american accent?

There are only a few that I know of.

I could count them on one hand and still have plenty of fingers left to pick my nose.

[Yankee Doodle Dandy]

No, because the compression stack is right where the midvalve used to be.

So maybe I have things wrong.

The way I understand it is that the compression stack requires x amount of pressure for the shims to start to bend.

The mid valve would require much less than x amount of pressure for its shims to start to bend. This provides damping at low shaft speeds to prevent any harsh feel and provide control.

I am not trying to argue, just understand. When you look at the individual stack/valve/parts combination they look like a traditional arrangement pre-mid valve. If the mid valve assembly works great in a traditional fork what is the dynamic that changes when things are set up separately?

[Pussy]

There is NO base piston in the '09 R1 forks
So the piston/shim stack on the rod of the compression side is ONLY looking after compression... and does it right away

[Yankee Doodle Dandy]

I thought about it some and think I understand now.

Since you have removed the rebound circuit from that fork leg the pressure builds up faster as there is no low speed rebound circuit for it to bleed off through which allows the compression stack to react faster therefore eliminating the need for the mid valve.

Taking it one step further, the elimination of the other circuits (ie - mid valve and low speed rebound) is why they say the BPF tend to ride higher in the stroke.