Showa’s new Big Piston Fork

[cowpoos]

Showa’s new Big Piston Fork (BPF) design, the same design used on the GSX-R1000 that won the 2007 Suzuka 8 Hours endurance race.

Rather than placing a cartridge mechanism inside of each fork leg, Showa has simply lined the inner walls of the 43mm BPF fork tubes and fitted a larger-diameter (39.6mm) piston. This design eliminates parts, saves weight (720 grams), provides better feedback, has better compression damping qualities and with the springs located at the bottom of each fork leg instead of the top makes servicing the forks much easier. Rebound and compression damping adjusters are located on the fork cap of each leg, while preload is adjustable at the bottom of each leg.


Interesting...any of our regular guru's care to share some thoughs on this pricapal?? and anyone come across a schematic or diagram on the net feel free to post it

[McJim]

Generally the simpler a mechanism is the more efficient it is. Sounds like they've done something sensible by taking away the "Black magic" aspect of suspension.

[Quasievil]

I Started to read it but it got borng at the first sentence

[Pussy]

I'll be interested to see a schematic of how they work. I wonder if they will give a more "real time" damping characteristic?
Where did you find that info, Poos?

[Sensei]

Some stuff about them here
http://www.motorcycle-usa.com/Articl...ID=7108&Page=1

[Robert Taylor]

Showa’s new Big Piston Fork (BPF) design, the same design used on the GSX-R1000 that won the 2007 Suzuka 8 Hours endurance race.

Rather than placing a cartridge mechanism inside of each fork leg, Showa has simply lined the inner walls of the 43mm BPF fork tubes and fitted a larger-diameter (39.6mm) piston. This design eliminates parts, saves weight (720 grams), provides better feedback, has better compression damping qualities and with the springs located at the bottom of each fork leg instead of the top makes servicing the forks much easier. Rebound and compression damping adjusters are located on the fork cap of each leg, while preload is adjustable at the bottom of each leg.


Interesting...any of our regular guru's care to share some thoughs on this pricapal?? and anyone come across a schematic or diagram on the net feel free to post it

If it works as well as the usually highly inflated pr blurb I would be very very surprised. It will only be a shadow of the real race stuff that was used. Year in year out the pr guys overstate the reality and the sad thing is many people believe it without question.

[cowpoos]

I Started to read it but it got borng at the first sentence

Well that may figure...I didn't think you could read?

[cowpoos]

If it works as well as the usually highly inflated pr blurb I would be very very surprised. It will only be a shadow of the real race stuff that was used. Year in year out the pr guys overstate the reality and the sad thing is many people believe it without question.

Thats a fair remark...but what do you think about the principle, from a engineering point of view? and in practise with all that piston area would it have advantages?? or disadvantages?

Another thought I had...with fork flex and the piston presumably being round..would there be potintial sealing issuses with a system like this...given that a cartridge is seperate from the fork in cartrige forks.

[avgas]

Generally the simpler a mechanism is the more efficient it is. Sounds like they've done something sensible by taking away the "Black magic" aspect of suspension.

oh no heaven forbid - you mean to say suspension isn't a secret black art that i must never touch.
you saying that its just a simple principal that a drool could understand?
oh no, fiddle dee dee......but what will all the lowly "suspension gurus" do now?

pt

it still makes me laugh about the whole "black magic" thing - good on you for dragging that out of that other thread.
Also what is the deal with the forum named after you these days....i have been out of the loop.

[avgas]

Thats a fair remark...but what do you think about the principle, from a engineering point of view? and in practise with all that piston area would it have advantages?? or disadvantages?

Another thought I had...with fork flex and the piston presumably being round..would there be potintial sealing issuses with a system like this...given that a cartridge is seperate from the fork in cartrige forks.

Yep it sounds interesting - but at the end of the day will it really achieve such a major difference.
Making it all one unit removes a lot of the harmonics and removes alot of the dynamics of the system - but most of these are removed by feedback produced by the oil.
I doubt that there will be too major a difference - but it good to see showa trying to mix it will the big boys again.
A long song from the old Showa's you preloaded with 20 cent pieces and cut down springs (progressive lol).

[Robert Taylor]

oh no heaven forbid - you mean to say suspension isn't a secret black art that i must never touch.
you saying that its just a simple principal that a drool could understand?
oh no, fiddle dee dee......but what will all the lowly "suspension gurus" do now?

pt

it still makes me laugh about the whole "black magic" thing - good on you for dragging that out of that other thread.
Also what is the deal with the forum named after you these days....i have been out of the loop.

I empathise with your cynicism re ''black magic'' Perhaps such a phrase is coined by those who either havent taken the time or simply havent the time to begin to understand what is actually a very complex field, especially as you also have to relate it to the dynamics and interaction with the tyres.

[Robert Taylor]

Thats a fair remark...but what do you think about the principle, from a engineering point of view? and in practise with all that piston area would it have advantages?? or disadvantages?

Another thought I had...with fork flex and the piston presumably being round..would there be potintial sealing issuses with a system like this...given that a cartridge is seperate from the fork in cartrige forks.

To be honest I havent really sat down and studied it. But forks have for too long been no better than emulsion shock absorbers with all their attendant cavitation problems. The sooner they all internally are constructed like a gas charged shock absorbers the better. In reality that means gas charged cartridges, at least at present.
More attention to friction reduction would also be a bonus.

[no-coast-punk]

I see two potential problems with this:

1) A traditional double walled fork is exponentially more rigid. Maybe Showa used a much thicker wall... but for a weight savings of 720grams... that's A LOT of metal that is missing. I'm sure the damping characteristics are a bit better... but how spoungy is it?

2) Heat. The external surface area has remained unchanged. However piston diameter and oil volume have both increased. This means more friction and ability to generate heat. More capacity to hold heat. But the ability to bleed off heat has remained unchanged.

Companies like to get up front and wave around new technologies in Superbike/Supersport. Problem is that those areas are so heavily rider dominant that it's pretty damn hard to prove a single innovation made any rider go much faster.

<--- Still thinks Ohlins is way way out there ahead.

[Brian d marge]

I also haavent had much of a look at these , but after a lifetime of NEW concepts from japan ,,,TSCC ATAX , Mass centeralization Traction Improvement Radial Ergonomics Systems ,, 3/4 of a kilo is a lot to lose ..me also wondering from where ....
Also fluids , yes,,I use a programe called OPEN FOAM , free fliud sim software ,,quite powerful if a little tempermental.. ( Operator I think ) ...... It will kill my 2.8 Ghz 2meg ram ,,, linux desktop stone dead ... I must catch up with the tech in showa ,, sometime

Stephen

Ps ,,, My Enfield has suspension

[Robert Taylor]

I see two potential problems with this:

1) A traditional double walled fork is exponentially more rigid. Maybe Showa used a much thicker wall... but for a weight savings of 720grams... that's A LOT of metal that is missing. I'm sure the damping characteristics are a bit better... but how spoungy is it?

2) Heat. The external surface area has remained unchanged. However piston diameter and oil volume have both increased. This means more friction and ability to generate heat. More capacity to hold heat. But the ability to bleed off heat has remained unchanged.

Companies like to get up front and wave around new technologies in Superbike/Supersport. Problem is that those areas are so heavily rider dominant that it's pretty damn hard to prove a single innovation made any rider go much faster.

<--- Still thinks Ohlins is way way out there ahead.

Actually heat is not so much of a problem with front forks, there is so much metal mass and the forks are always in the cooling airstream. They run either at or vary little from ambient temperature.