IS350 GSE21


Code No. 80230-AT003


Awesome control and comfort ride on the street for a sporty drive. The new Max IV sporty suspension.



▲The model in the photo is GRS191.




Engine 2GR-FSE
Model Year 05/09 - 13/04


Damping force adjustment 30 steps 30 steps
Base valve - -
Height adjustable lower bracket
Upper mount Rubber Rubber
Inverted/Normal type Normal Normal
Damper/Spring layout Coilover Coilover
Spring rate change at factory Possible Possible
Damping force adjustment with wire -
Helper spring
(Spring rate N/mm)
○ ( 19.8 ) ○ ( 19.8 )
Ride Height mm
  Factory *2 Test data Adjustable range
High - Low *3
Drivable range
High - Low *4
FRONT Ride height *1 648 675 ~ 618 675 ~ 618
Against stock -27 0 ~ -57 0 ~ -57
REAR Ride height *1 648 676 ~ 550 ※5 676 ~ 582
Against stock -28 0 ~ -126 ※5 0 ~ -94

*1. Height from road surface to fender arch.
*2. Height at factory is the data tested at HKS with the setting of Full Kit. (HKS' recommended setting.)
*3. Adjustable range (However, the lowest value may not be road legal.
Even within the adjustable range, car body, arm etc. may contact. In such case, it will be hard to drive.
Damper oil leakage or any other problems caused by low ride height setting from the factory setting will void the warranty of the product.)
*4. Drivable range that there is no contact of car body or arms etc. (However, change of tire/wheel size may cause a problem.)
Caution). Actual data depends on each vehicle.

Kit information

Spring of Full Kit

  F R
Spring rate N/mm(kgf/mm) 69 ( 7 ) 59 ( 6 )
Free height (mm) 200 250
Spring type Straight Straight
Recommended range to change spring rate N/mm(kgf/mm) ±20 ( 2 ) ±20 ( 2 )

Specification of damper

  F R
Damping force (Rebound/Damping)N* 853 / 226 745 / 196
Default position of dial 15 15
Remaining damper stroke (Rebound/Damping)mm 70 / 45 72 / 83

* The value of the damping force is at piston speed of 0.1m/sec.

Setting data

  F R
Default Test Drivable limit
High *
Drivable limit
Low *
Default Test Drivable limit
High *
Drivable limit
Low *
Length of
case (mm)
410 428 405 380 399 368
Set length(mm)
225 225 240 277 277 309
Length to ride hight
adjuster (mm)
87 105 67 44 63 0
Lever ratio 1.49 1.51

* Refer to the above explanation *3 of ride height information for drivable high and low limitations.

Test vehicle information

  F R
Vehicle weight kg 856 (840) 738 (770)
Tire size (Air pressure) kPa 225 / 40 - 18 ( 240 ) 255 / 40 - 18 ( 260 )
Wheel size 8 JJ × 18 off 45 8.5 JJ × 18 off 50
Test data 0 mm / -1°15' in 3 mm / -2°00'
Standard value - -

* Test data at HKS.

Parts List  * It may be changed without prior notice.



MAX IV production concept was aimed at "Comfort & Fun of steering". In normal driving, such as streets and highways, has the exquisite taste of fine and comfortable ride with HKS large bore single-cylinder piston. The stock's a little stiffness is reduced and at the bump, MAX IV gives smooth and mild response. Also the steering can be set in detail for your needs by rate up for the damping. MAX IV is all length adjustable type, so that the height can be set to your needs and wants for your style. The standard dial is both front and back at the step 15, and for smoother ride, set the step at 20 to 30. For European style suspension, set it at dial of 3 to 5 step.
and this new design makes even under 10 step dial, it will not be stiff.
※We have confirmed MAX IV with HKS GT Supercharger Kit, we have checked with the power-up IS350, too.
and this new design makes even under 10 step dial, it will not be stiff.
HKS has developed the MAX IV according to thorough data analysis of many cars in the market and tested them all. We didn't only rate of damping but also analyzed balance and stroke, which made this product more safe and fun to drive. We also redesigned the inner parts and developed new parts for MAX IV. MAX IV has new design of needle which gives more stable damping and steering characteristic at a low to mid speed range. We also revised dial adjustment by oil path and this new design makes even under 10 step dial, it will not be stiff.
※5 require to change bump rubber L=10
● Process for installation
Required to make an hole for rear damping adjustment cable(rear interior)
When the spring interferes, you might need to cut the rear inner fender.