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So, my friends is350 is kinda soft in the rear, and I started researching stuff here and there. So is250 and is350 have same suspension. But didn't find much info if is350 and isf have same one. On figsshop some items are marked as 2is, 3GS, which to my understanding are same for all 2 gen IS Lexus. I also found out that is350 is wider in the back... can anyone elaborate ? Thanks.
The suspension points between the IS250, IS350 and IS F are the same. There are some differences between models, years and components. This post will not be 100% comprehensive, but I will aim for technical accuracy regarding the components I discuss. I will ignore AWD models, and compare only 2IS RWD models. At a high level, the suspension between the IS250, IS350 and IS F is very similar or the same with the exception of coil spring rate, shock valving and sway bar spring rate.
For the front suspension, the subframe, control arms and knuckles are the same for all models, for all years. The lower control arm rear bushing is stiffer on the IS F, however all other bushings are the same. The shocks are the same between the IS250 and IS350, however the IS F has different shocks; supplier and valving for each varied by year and options (Tokico for all ISx50, Tokico for 08-11 IS F, Sachs/ZF for 12-14 IS F). Factory springs are different for all models, again they vary based on year and options; the IS250 and IS350 offered a factory 'Sport Suspension' option for all years which included stiffer shocks and springs, the IS F used the same shocks and springs for all option packages but varied through the years. For 2006-2008, all IS250 and IS350 models used the same sway bar, on 2009-2013 IS250 and IS350 models changed the shape of the sway bar and the sway bar was stiffer for sport package models. The IS F used the same sway bar for all years, which is larger than any of the ISx50 models, but shares its shape and end links with the 2006-2008 ISx50. The hubs on the IS F stick out 5mm further than the IS250 and IS350, which share the same hubs.
For the rear suspension, the IS350 and IS F share the same subframe while the IS250 subframe is different due to the smaller differential mounting. In general, the 2008-2010 IS F shared the same control arms and knuckles as the 2006-2010 ISx50 as well as the 2011-2013 ISx50 without Sport Suspension while the 2011-2014 IS F shared the same components with the 2011-2013 ISx50 with Sport Suspension (notably the F-Sport models). Two notable exceptions for the earlier cars are the toe link and upper control arms, which the IS F had stiffer bushings installed. 2011+ ISx50 Sport Suspension models shared the same components with the IS F (excluding the lateral upper link which changed for 2013+ IS F models and the lower control arm which changed for 2011-2012 models and then changed back to the older design for 2013). The 2011 IS F updates to the rear suspension were mainly slight geometry tweaks, though there may have been some bushing material changes as well. For the shocks and springs, the story is the same as for the front with the exception that the IS250 and IS350 share the same springs. For the sway bar, the story is again the same as for the front with the exception that the end links stayed the same through the years and that on 2009-2013 ISx50 models without the sport package, the rear bushings are bonded to the bar and not available separately (also necessitating different brackets and bolt length). The rear hubs are the same for the IS250, IS350, and IS F.
The front track difference is due to the hub difference. The rear track difference is due to the wheel width and offset. The length difference is due to differences in the front radiator support (approx. 35 mm further forward) and bumper.
The is 350 is not wider in the back. It just has wheels with different offsets. The isf's suspension is not the same as the is350s. Some bushings might be the same size.
The is 350 is not wider in the back. It just has wheels with different offsets. The isf's suspension is not the same as the is350s. Some bushings might be the same size.
okay. Mind telling me the differences? Of course if u know for sure I'm tempted to text my friend with js350 and measure everything with measuring tape. But it's holiday season.
From my understanding there's nothing different other than spring rates.
thank you Patton, that's what I think so too... cuz I don't see anything anywhere stating that it's in any way different... so technically we have same suspension as on is250 and so on....
thank you Patton, that's what I think so too... cuz I don't see anything anywhere stating that it's in any way different... so technically we have same suspension as on is250 and so on....
Different spring rates usually means different valving. You can check part numbers and see that they're different. The isf is a heavier vehicle. It's also longer and wider at the front. Same width at the rear but different track width because of the different offset wheels.
Different spring rates usually means different valving. You can check part numbers and see that they're different. The isf is a heavier vehicle. It's also longer and wider at the front. Same width at the rear but different track width because of the different offset wheels.
Yea, front is wider because of the hub bearings. Rear is same hubs, sway bar, swaybar links, rear track links...
is250 and is350 have identical suspension but just different part numbers for the hack of it, sadly part numbers are not always the sign of difference. Would be nice to set it once and for all, if there are or there aren't any difference... come on Lexus guru u can start typing now
P.S btw all bushings are same, and control arm at shopfigs is to all 2is.
Last edited by xaker777; Dec 20, 2018 at 02:46 PM.
The struts and springs are definately different on all three. All three have different ride heights don’t they? My IS350 sits and rides nothing like my F. IS250s sit higher than my 350, I see them all the time around time.
There are no struts in any ISF or ISX50 - There are shock absorbers however. As far as sway bars go, A few years ago I crawled under a few new 2IS vehicles on a dealer's lot. They thought I was crazy, but I did some measuring:
And, BTW, Bushings are definitely not the same between the ISF and ISX50.
Lou
Last edited by flowrider; Dec 20, 2018 at 05:55 PM.
The suspension points between the IS250, IS350 and IS F are the same. There are some differences between models, years and components. This post will not be 100% comprehensive, but I will aim for technical accuracy regarding the components I discuss. I will ignore AWD models, and compare only 2IS RWD models. At a high level, the suspension between the IS250, IS350 and IS F is very similar or the same with the exception of coil spring rate, shock valving and sway bar spring rate.
For the front suspension, the subframe, control arms and knuckles are the same for all models, for all years. The lower control arm rear bushing is stiffer on the IS F, however all other bushings are the same. The shocks are the same between the IS250 and IS350, however the IS F has different shocks; supplier and valving for each varied by year and options (Tokico for all ISx50, Tokico for 08-11 IS F, Sachs/ZF for 12-14 IS F). Factory springs are different for all models, again they vary based on year and options; the IS250 and IS350 offered a factory 'Sport Suspension' option for all years which included stiffer shocks and springs, the IS F used the same shocks and springs for all option packages but varied through the years. For 2006-2008, all IS250 and IS350 models used the same sway bar, on 2009-2013 IS250 and IS350 models changed the shape of the sway bar and the sway bar was stiffer for sport package models. The IS F used the same sway bar for all years, which is larger than any of the ISx50 models, but shares its shape and end links with the 2006-2008 ISx50. The hubs on the IS F stick out 5mm further than the IS250 and IS350, which share the same hubs.
For the rear suspension, the IS350 and IS F share the same subframe while the IS250 subframe is different due to the smaller differential mounting. In general, the 2008-2010 IS F shared the same control arms and knuckles as the 2006-2010 ISx50 as well as the 2011-2013 ISx50 without Sport Suspension while the 2011-2014 IS F shared the same components with the 2011-2013 ISx50 with Sport Suspension (notably the F-Sport models). Two notable exceptions for the earlier cars are the toe link and upper control arms, which the IS F had stiffer bushings installed. 2011+ ISx50 Sport Suspension models shared the same components with the IS F (excluding the lateral upper link which changed for 2013+ IS F models and the lower control arm which changed for 2011-2012 models and then changed back to the older design for 2013). The 2011 IS F updates to the rear suspension were mainly slight geometry tweaks, though there may have been some bushing material changes as well. For the shocks and springs, the story is the same as for the front with the exception that the IS250 and IS350 share the same springs. For the sway bar, the story is again the same as for the front with the exception that the end links stayed the same through the years and that on 2009-2013 ISx50 models without the sport package, the rear bushings are bonded to the bar and not available separately (also necessitating different brackets and bolt length). The rear hubs are the same for the IS250, IS350, and IS F.
The front track difference is due to the hub difference. The rear track difference is due to the wheel width and offset. The length difference is due to differences in the front radiator support (approx. 35 mm further forward) and bumper.
Jeff
Last edited by Jeff Lange; Oct 13, 2025 at 10:18 PM.
Jeff this is finally some good info. Thank you!! If u were a girl I'd kiss you! It needs to be tagged so anybody looking for this info can find it with ease.
The suspension points between the IS250, IS350 and IS F are the same. There are some differences between models, years and components. This post will not be 100% comprehensive, but I will aim for technical accuracy regarding the components I discuss. I will ignore AWD models, and compare only 2IS RWD models. At a high level, the suspension between the IS250, IS350 and IS F is very similar or the same with the exception of coil spring rate, shock valving and sway bar spring rate.
For the front suspension, the subframe, control arms and knuckles are the same for all models, for all years. The lower control arm rear bushing is stiffer on the IS F, however all other bushings are the same. The shocks are the same between the IS250 and IS350, however the IS F has different shocks; supplier and valving for each varied by year and options (Tokico for all ISx50, Tokico for 08-11 IS F, Sachs/ZF for 12-14 IS F). Factory springs are different for all models, again they vary based on year and options; the IS250 and IS350 offered a factory 'Sport Suspension' option for all years which included stiffer shocks and springs, the IS F used the same shocks and springs for all option packages but varied through the years. For 2006-2008, all IS250 and IS350 models used the same sway bar, on 2009-2013 IS250 and IS350 models changed the shape of the sway bar and the sway bar was stiffer for sport package models. The IS F used the same sway bar for all years, which is larger than any of the ISx50 models, but shares its shape and end links with the 2006-2008 ISx50. The hubs on the IS F stick out 5mm further than the IS250 and IS350, which share the same hubs.
For the rear suspension, the IS350 and IS F share the same subframe while the IS250 subframe is different due to the smaller differential mounting. In general, the 2008-2010 IS F shared the same control arms and knuckles as the 2006-2010 ISx50 as well as the 2011-2013 ISx50 without Sport Suspension while the 2011-2014 IS F shared the same components with the 2011-2013 ISx50 with Sport Suspension (notably the F-Sport models). Two notable exceptions for the earlier cars are the toe link and upper control arms, which the IS F had stiffer bushings installed. 2011+ ISx50 Sport Suspension models shared the same components with the IS F (excluding the lateral upper link which changed for 2013+ IS F models and the lower control arm which changed for 2011-2012 models and then changed back to the older design for 2013). The 2011 IS F updates to the rear suspension were mainly slight geometry tweaks, though there may have been some bushing material changes as well. For the shocks and springs, the story is the same as for the front with the exception that the IS250 and IS350 share the same springs. For the sway bar, the story is again the same as for the front with the exception that the end links stayed the same through the years and that on 2009-2013 ISx50 models without the sport package, the rear bushings are bonded to the bar and not available separately (also necessitating different brackets and bolt length). The rear hubs are the same for the IS250, IS350, and IS F.
The front track difference is due to the hub difference. The rear track difference is due to the wheel width and offset. The length difference is due to differences in the front bumper.
Jeff
So technically, i could swap out the front hubs on an IS250 to the ones from an ISF, hypothetically, if say, i want to run the same track and width as an ISF, by using stock ISF wheels/tires?
Last edited by SamuraiBlues; May 23, 2025 at 11:18 AM.
Reason: clarity
So technically, i could swap out the front hubs on an IS250 to the ones on an ISF, hypothetically, if say, i want to run the same track and width as an ISF, by using stock ISF wheels/tires?
Yes, but you would also need the IS F brake calipers to make this work.
Isf suspension vs is350
I'm tempted to text my friend with js350 and measure everything with measuring tape. But it's holiday season. 
