Tyre size for upgrade

[DT_Racing]

54 minutes ago, emjay82 said:

@DT_Racing Interested to know if you find the USRS's make the ride any harder during daily driving? @Peter P18 reported the difference was minimal with a huge improvement in the feel, what are your thoughts? Seriously considering these! Thanks..

@emjay82Do it you won't regret it, steering feel especially around centre is drastically improved with immediate weighting on steering input and an added tactility and feedback for the remainder of the stroke. The only perceptible change I have found in additional cabin noise is on very high frequency suspension inputs like on concrete motorways. I will caveat that by saying I 'think' it's a little louder so that should give you an idea that it's barely noticeable. Pro's greatly out way the 'maybe if I strain and listen' cons. 

[DT_Racing]

1 hour ago, Cargav said:

Decision made for me too .... Just need to pull the trigger on Camskill now.

One last question - my car is a 2009, presume the 245/35 and 275/30 sizes will fit just fine on standard alloys ?

Cheers,

 

Gavan

Gavan

As far as I know there were never any changes for 2008 to 2014 on rim size on the ISF so these sizes will do you just fine.  Standard rims on mine and appears a very common upgrade.

[dandydons]

I am needing two front tyres and am thinking going for the upgraded size but just wondering if OK to leave stock size on the rears until they need replaced - any views ? 

[emjay82]

7 minutes ago, dandydons said:

I am needing two front tyres and am thinking going for the upgraded size but just wondering if OK to leave stock size on the rears until they need replaced - any views ? 

I might be wrong and might need a more technically minded member to confirm  but it could cause a 'slight' inaccuracy on your speedo reading. Also the cautious of us would declare the larger tyre sizes to the insurance company. 

[FTBBCVoodoo]

1 hour ago, emjay82 said:

I might be wrong and might need a more technically minded member to confirm  but it could cause a 'slight' inaccuracy on your speedo reading. Also the cautious of us would declare the larger tyre sizes to the insurance company. 

The increased tyre size for the Lexus ISF (as I am running) makes your speedo show a reading that is 0.7% too fast.  So if your Speedo is showing 100mph then you are in fact doing 99.3mph based on standard speedo calibration.  Worked this out on a website when I put the increased tyre size on mine.  Fairly sure you could live with that :-)

Also informed insurance company who didn't bat an eyelid (although I do work for them).

Wrt larger front size and standard rear size....  I know of someone with an ISF who has been running a square setup of Toyo R888's with the standard rear tyre size on both the front and rear axles so would think you should be fine.

[Flytvr]

I’d be very careful changing tyres sizes. I’d go as far as saying, don’t do it!

 

[Rusty Crobar]

Quite a few American owners run the square set up for the track so you should be fine as long as you don't take libertys in the wet without the traction control on 😉

 

[dandydons]

Thanks for the comments guys . Think will go for it and worst case is I need to get two rears up sized Sooner that I was budgeting for .