peyman

iTrader: (6)

I have tendonitis in both forearms, so i purchased a IS350 since they have easy steering and my hands can tolerate it

my previous cars ( gto , g37 ) were difficult to mod; changing tire size, lowering, rims would make my steering stiffer and wasnt good for my health problems

i want to make sure i do this right this time.

my plan: 19" Stance Concave SC-5 wheels, since wheels are heavy and might effect steering a bit, ive decided on throw on a skinny 215/35/19 tire up front so make up for that

what i need help with:

what tire brand is good, and smooth that wont grip the floor hard and stiffen up my ride?

also what coil overs should i use to lower the car? something that will feel exactly like the oem ride?

any help / suggestions would be appreciated

azndriver

well any more specs on the 19" wheels, are you running staggered?

and using a skinny tire up front and pending width of your wheels, could mean a stretch, stretch means a much more harsh ride....

so going find a tire for the proper width of your rim...

for comfort....and like i said pending specs of your rims (offset, and width and stagger setup or not)

stagger 19" Setup common tire size:
225/40/19 - Front
255/35/19 - Rear

On the topic of coilovers, now taking your health consideration into play...height and spring rate, even shock settings would take a big factor to your liking, so a lot of time would be need to get that right

I would just go with a simple shock and spring setup, as those combinations would be best and closest to an OEM like ride...

H&R Sports and a drop of 1.4 front / 1.3 Rear would be the nicest drop and not to aggressive plus stock shock friendly


You can also consider the steering Damper mod as well:
https://www.clublexus.com/forums/is-...-damper-2.html

peyman

iTrader: (6)

my wheel setup would be
19 x 8.5 +35 offset was planning 215/35/19
19x9.5 +35 offset was planning 255/35/19

i know 225 would be ideal for the front however i dont think 215 is much of a stretch and thought the 215 being skinnier would help with tight steering

i'm kind of set on coils because i want a nice drop / perfect drop
thanks for your tips.

Gville350

iTrader: (10)

Nah man, stick with the 225s up front. Increased air pressure will help with the ease of handling.

azndriver

215 would be way to skinny for the isx50...those things are rubber bands

225 is the minimum you would want to run with the isx50..

and remember the 35 series tires, more so for the front, would be very harsh when driving on the streets, so try to stick with 40 series at least...unless going wider then a 225 then 35 would be more suited for a 235 and wider tire

forgot to mention, if you looking for a comfortable tire...look up Barum Bravuris 2 (made by continental)

Coilovers ,tanabe sustec pro 5 coilovers, have a good spring rate for street / daily driving

SCWB

To keep within Factory Spec:
for 17" wheel: 225-45-17
for 18" wheel: 225-40-18
for 19" wheel: 225-35-19

So, every inch bigger of the wheel diameter, we compensate with 5% decrease of the tire aspect ratio. This may not be a universal fact, but it applies to our front wheel application very well.


Using 225-40-19 will result in one inch too tall for ISX50

It is either:

225-40-18 (Stock ISX50 Sport Version)

or

225-"35"-19 to retain the stock diameter.

For me, I happend to have the same wheel spec as yours.

I don't like strectched tire, so I went with 235-35-19 with 19X8.5+35 on the front. No problem at atll. Steering effort doesn't feel heavier at all. The ride is about 10-20% stiffer than my 17" stock wheels (seat of the pant tells me)

Jeff Lange

iTrader: (1)

Factory size in some areas (not the USA) for the base model IS250 is 205/55R16 all around. While they are somewhat small, they work fine. I run 205/50R17's for the winter.

That being said, you probably won't even notice much difference between the 215 and 225 as far as steering effort, provided they are both the same tire. I run 245/40R17 Dunlop Z1 Star Spec's up front in the summer and coming from the 205/50R17 winter tires to the 245/40R17 summer tires makes a huge difference in steering effort, but that is a much bigger jump and from a winter tire to a sticky summer tire, so it's somewhat expected.

I'd say go with the 225's and find a tire that has the grip you need but no more. Sticky tires will add to the effort.

Jeff