OS Giken Limited Slip Differential

so why choose a OS Giken LSD? well, lets take a look at the picture below first.


***Courtesy of OS Giken/OS Giken USA***

and here is a random LSD i found online. i had to crop the name off since i will be talking shmack about it… lol hahahha well, i will save the shmack talking for later. please take a look at the picture below.


***Courtesy of Google Image Finder*** …lol

now do you see the difference? yes the number of the clutch plates, also known as the friction plates. OS Giken has twice the number of the plates inside the differential. and its springs in the pressure ring is to pull the two rings together unlike the others where it tries to keep it open as much as possible. with all the patent received mechanism, OS Giken’s LSD for lock 100%. below is the simple steps of how the OS Giken LSD works.


1.) the spring inside the pressure ring will switch from free to lock in split second.

2.) the drive force thats been flown from the engine to transmission will revolve the differential case, and at the same time, spins the pressure ring simultaneously.

3.) the pinion gears and the cross shaft will push open the pressure ring.

4.) the stretched open pressure ring will push out the pressure plates to lock.

5.) the pressure plate locks perfectly to rotate the side gear which is hot forged.

6.) the drive force will be transmitted to the drive shaft upon the rotation of the side gear. 


1.) プレッシャーリング内のスプリングがオープンとロックの状態を瞬時に切り替えます。

2.) エンジンからミッションを通って来た駆動力がデフケースを公転させてプレッシャーリングを回転させます。

3.) ピニオンと十字軸がプレッシャーリングを押し広げます。

4.) 広げられたプレッシャーリングがプレッシャープレートを押し広げてロックします。

5.) 確実にロックされたプレッシャープレートがサイドギア(熱間精密鍛造加工済み)を回転させます。

6.) 回転したサイドギアがドライブシャフトに駆動力を送ります。

one of the LSD out in the market is the same type as the OS Giken LSD since they use the OS LSD as for OEM. i’m not sure if they still do OEMs. i believe some people do know which company i am talking about. but still, the mechanism within the LSD is different. there is this one company that tried to make it like the OS Giken. not mentioning who though.. and this guys is the one i would like to bash on lol. here is how the story goes. one of the engineers went to this lawn mower factory in Okayama Japan with all the blue prints memorized (not completely though since he was doing minor works) and made a mock up of the differential. but of course the product was a complete fail. just kept on breaking. and yes they been doing more and more research. then one of te engineers have took all the tech info and started his own company. to fill in gaps of the quality, they used carbon fibers for clutches and differentials. not gonna mention who though… hahha this was long time ago. i bet some people do know about this pretty famous john dory in the industry. well, copy is only a copy even though they added their originality. they cannot copy the mechanism of their STSG (Spline Through Side Gear) and the LTCS (Lock Timing Control System). the number of the pressure plate and the diameter size is one and only from OS Giken. that is the reason why i recommend OS Giken LSD.

OSのデフと近い構造の物がマーケット内にあります。今はどうかわかりませんけど、以前はOSさんがOEMで卸していたので。知ってる人も多分多いでしょうねそのメーカーがどこなのか。でもやっぱ本物のOSの機構は違いますね。誰とは言いませんが一社似せようとした奴等が居ますねぇ。そこまで言いませんけどね(笑。話はこんな感じです。開発陣の一人が設計図を丸暗記して(完璧に覚えれなかった様ですねぇ)岡山県にある某芝刈り機の専門工場に駆け込んだらしいです。そこで似せたデフを作り始めたそうです。まぁ当たり前ですけど、失敗に終りました。それでも開発などを続けて行くウチに独立したそうです。技術の足りない部分は素材で補おうって事でカーボンを使用し始めたそうで。誰とは言いませんがねぇ…笑。もぅかなり昔の話らしいですよ。知ってる人も意外と多いでしょうねこの業界内はかなり狭いので。まぁ、所詮コピーはコピーです。OSの機構は簡単には真似出来ないでしょう。STSG(Spline Through Side Gear)やLTCS(Lock Timing Contorl System)とか。プレッシャープレートの枚数や直径の大きさはOSが群を抜いています。それが僕がOS技研をお勧めする理由です。