Is300h F sport - Bigger tyres

skyjaws · January 23

Heya,

I would like to put wider tyres up front for looks as i prefer the beefer look, also having a bigger sidewall would help with kerbs + comfort isn't a bad thing either

Like 235/40/18 instead of the standard 225. I have F-sport so the lower suspension i presume.

It looks like even a 45 profile would fit the massive arch gap it has too but haven't seen anyone else try this?

235/45 might be pushing it too much maybe?

I have searched throughout the web but not got a definite answer if they will rub or not

I have already put bigger tyres at the back for comfort, 255/40/18 instead of the 255/35/18 and they fit perfect.

In the past i have put bigger tyres on my CT i had also and that helped with comfort + looks. 225/50/17 instead of stock 215/45/17

FYI i know about speedo issues, insurance issues ect lol

If anyone has tried this i would love to know.

IS300FSPORT · January 24

Based on the number of responses its unlikely that anybody has done a tyre swap like that :shock:

It defies the purpose of having the F Sport model if your adding bigger tyres, I appreciate its not a performance car but out of the box it handles quite well very capable in standard form with the comfort level that doesn't knock your dentures out . You say to fill the bigger arch gap but its setup like that for a reason to allow for suspension travel when loaded with weight it will potentially bottom out, the thicker profile tyre may hit the wheel arch?

I'd leave it as it is insurance look for any excuse not to pay out in the event of a claim so no point voiding your insurance if not declared.

Unless of course you want to experiment let us know how you get on. Interested in seeing any pictures if already done.

J Henderson · January 24

17 hours ago, skyjaws said:

235/40/18 instead of the standard 225.

I did this on my previous 2nd-Gen IS250 F-Sport, which had the same front wheel & tyre specs as a 3rd-Gen.

Zero issues with rubbing whatsoever. The arch gap was really massive on that car for whatever reason, and I wanted to change the front tyres anyway as they were a different brand to the rears, so went with 235s to try and eliminate some of the unsightly gap.

Pros & Cons;

+ Was visually more appealing.

+ The wider tyres didn't skip or crab when steering sharply in the cold.

- 235s were about 10% more expensive.

PS. This car was written-off with those "wrong" 235/40R18 tyres on it. Insurance never said a word and paid out in full.

skyjaws · January 24

8 hours ago, IS300FSPORT said:

Unless of course you want to experiment let us know how you get on. Interested in seeing any pictures if already done.

I am on the lookout for some good part worns to put on the front for a test until i get my wheels refurbed + colour change this year, so will update when i have put the tyres on

5 hours ago, J Henderson said:

I did this on my previous 2nd-Gen IS250 F-Sport, which had the same front wheel & tyre specs as a 3rd-Gen.

Zero issues with rubbing whatsoever. The arch gap was really massive on that car for whatever reason, and I wanted to change the front tyres anyway as they were a different brand to the rears, so went with 235s to try and eliminate some of the unsightly gap.

Good to hear + when i had my IS 250 i put 19s on it from a Mazda so didn't experiment with the stock rims. Nice looking IS btw.

jannylance · March 11

It seems doubtful that anyone has performed a tire swap of that kind based on the volume of responses:startling:

I understand it's not a performance car, but right out of the box, it handles fairly well and is highly capable in regular form, with a comfort level that doesn't knock out your dentures. It defeats the purpose of having the F Sport model if you add wider tires. You advise filling the larger arch gap, however the suspension is set up that way to allow for movement; if the vehicle is overloaded, it may bottom out and the thicker tire may contact the wheel arch.
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