Info on OS Giken STR1C, STR2C and TR2C Clutches
 

There doesn't seem to be a concentrated place for OS Giken clutches on here, so I figured I would ask info for several of their clutches all in one thread.

Evasive, CounterSpace Garage and FR-Sport seem to be the main retailers of these clutches in the american 86/brz scene so any first hand info would be beneficial for both the community and yourselves.

Anyone else with first hand experience should chime in too

So lets this fill in blank session started.

STR1C:
Single Plate
Found in the $1400 range (+/- $100)
What is the max tq rating of this clutch?
- I have only found one site that mentioned a max tq rating at 500tq
- It had the warning that it is recommended to not exceed 60% of this max tq rating. Is this statement (True or False)?

The STR1C and the GTR1C are in the same price range so what exactly sets these two clutches apart? If the do not exceed 60% of max tq from OS Giken is true than the STR1 and the GTR1C would not really have to much of a difference between them (True or False)?

STR2C:
Twin Plate
Found in the $1900 range (+/- $100) *sometimes less*
What is the max tq rating of this clutch?
- The same one site that claimed the STR1C was rated at 500tq also rated the STR2C at 500tq. But claimed that OS Giken recommended this clutch should not go past 80% of the max tq, which would be in the 400tq ball park. Is this max tq and recommended don't exceed 80% of the max tq statement (True or False)?

TR2C:
Twin Plate
Found in the $1900 range (+/- $100) *sometimes less*
What is the max tq rating of this clutch?
- The same site as above along with a couple of others made claims that this clutch is rated around the 500-600tq range. answers seem to vary.

It seems at though the TR2C needs a separately purchasable throw out bearing, but does the STR2C also require that same throw out bearing? or will it come with one?

Comparisons:
I have had gone through 3 Exedy twin plate clutches between my evo 8 and 9. So my questions will be coming from a place where I felt that the Exedy twin plate on a 490tq/520hp was very easy to use. I enjoyed the clutch pedal feel, the on/off style engagement point was only annoying when I drove while being super sleepy or while breaking in new shoes, the chatter was there and fine for the most part only noticeable and annoying when trying to leave a shady neighborhood at night or when showing up to a meet your new friend off of tinder at 1am and then trying to silently leave that tinder friends place at 3am....or worst the tinder friend is in a shady neighborhood and it is 1am :bellyroll:

So for those with twin plate experience please chime in as you get where I'm coming from. Even better if it is twin plate experience in an evo/sti... I'm looking at you Evasive!!!

How does the pedal feel on the STR2C and TR2C compared to the exedy twin or anything similar?

How does the chatter on the STR2C and TR2C compare to the exedy twin plate?

How do the on/off engagement points on the STR2C and TR2C compared to the exedy? More smooth? Less smooth? as in do you have more or less pedal range to slip the clutch into engagement?

OS Giken USA office has people you can just call and get all of this info from.

I can help.

HTR1C: TY421-AR6
Hard Cover - Single Plate – Solid Hub – Includes Reinforced Fork Kit Conversion (OS Clutch Exclusive) and Release Sleeve Assembly (Fork Kit Exclusive).
MSRP: $1450.00
NEW MSRP: TBD
What is the max tq rating of this clutch?
400ft lbs maximum, stay within 80% for best longevity.
GT1CD is no longer available.

STR2C: TY421-BJ5
Soft Cover - Twin Plate – Solid Hub - Includes Reinforced Fork Kit Conversion (OS Clutch Exclusive) and Release Sleeve Assembly (Fork Kit Exclusive).
MSRP: $1980.00
NEW MSRP: TBD
Max torque would be 570 ft lbs. Stay under 80% for max longevity.

TR2C: TY421-BF5
Standard Cover - Twin Plate – Solid Hub – Includes Reinforced Fork Kit Conversion (OS Clutch Exclusive) and Release Sleeve Assembly (Fork Kit Exclusive).
OLD MSRP: $2050.00
NEW MSRP: TBD
What is the max tq rating of this clutch?
680 ft lbs is max for this clutch. Stay under 80% for best longevity.
The TR clutch will now include the fork kit conversion as well. New pricing should be updated shortly.

How does the pedal feel on the STR2C and TR2C compared to the exedy twin or anything similar?
The HTR and TR will be similar in feel to the Exedy if not a bit lighter. The STR2C will be much lighter than the Exedy.

How does the chatter on the STR2C and TR2C compare to the exedy twin plate?
Both STR2C and TR2C have little to no chatter. This is due to the use of full face metallic clutch discs and the unique floating pressure plate leverage design using the 360-degree housing. The housing provides additional reinforcement to the flywheel to prevent warpage and flex under heavy use. The bearing is tapered to provide a smooth leverage point to aid in pedal feel.

How do the on/off engagement points on the STR2C and TR2C compared to the exedy? More smooth? Less smooth? as in do you have more or less pedal range to slip the clutch into engagement?
The engagement point would immediate, so there would be a learning curve between the two. The OS provides a much easier pedal to find that modulation point. They tend to get better as it wears. OS actually recommends tracking the clutch or beating on it early to get some heat and pad transfer between the mating surfaces of the clutch and flywheel. Similar to breaking in brake pads and getting pad transfer. It gets better with use.

I saw they had a number and office in LA somewhere or I'm assuming LA since the area code was 310. But due to the 2nd half of my questions I wanted feedback from seller/users that not only have knowledge of the product but also have had first hand experience using the clutches and relating that experience with a similar product that we may both be familiar with (the Exedy twin plate) to give me a better persepective. Plus if you look on any other car forum that talks about this companies clutches, you will find it impossible to come up with one negative review on any of their clutches. So I figured it would be beneficial to the North American 86 community to have some good concrete info on these clutches in one nice thread.

Mike thank you for taking the the time to answer my questions thoroughly. From all the positive reviews I've found on GTR, Supra, Lambo forums to Evo, Mini and Silvia forums it seriously blows my mind that these clutches don't have a bigger market presence outside of organized racing circles.

These are the last grey area questions I have after reading your response.

1) Most retailers that sell these clutches have wording in their item descriptions to the extent of "Release bearing included". You have now explicitly stated that all clutches sold through CounterSpace will have the full Throw out bearing, Clutch fork kit included with each purchase. Is the TOB/Clutch fork kit inclusion something that only you guys do or is this something each clutch gets bundled with automatically from the manufacture no matter the retailer?

2) As you guys know the Velox/Verus Clutch forks and Pivot are quite a popular item. For those that already own this piece, would the Verus Clutch and Pivot be compatible with the full line up of OS Giken Clutches or do the exclusively work with the clutch fork provided in the OS Giken TOB/Clutch fork kit?

3) Will other aftermarket throw out bearings work with the full line up of OS Giken clutches or do they exclusively work with the provided OS Giken throw out bearing?

4) I know these clutches are rebuildable but are these clutches also upgradable? As in can a STR2C be rebuilt into a TR2C ro HTR1C onto a STR2C?

1. All of the clutches above have the TOB/Fork, regardless of retailer. I'd hope you support someone who can actually answer your questions and provide technical support though!

2. No

3. No

4. Yes, although depending on what exactly you want to upgrade, it may not be cheap. OSG clutches are modular, and can even be customized beyond the OTS versions.


You don't see them because most people look for cheapest that works, not best. Same reason you see a lot of cheap coilovers, and not many expensive ones. Or why you see a lot of $7000 engine builds, rather than $20k CSG engines. Or $300 ebay headers, instead of $1635 Ace headers, etc. You get the idea. Anyone buying a OSG clutch knows exactly what they're getting.

Thank you for you time and effort on this topic. As I stated in my first post, bringing all this info together in one place would be beneficial to both the community and the shop/retailer that helped out with the info.

;-)

Just got mine from CSG, beautiful! The centering tool came wrapped in Japanese newspaper!

How do you like the clutch?