235/40R18 & 255/40R18 possible in 2IS?

[Neurus]

My car came with these wheels from factory:

 

Front: 18x8 and 225/40R18

Rear: 18x8.5 and 255/40R18

 

I wanted to increase just the front tyres going to 235/40R18 keep stock height and stock rims, no spacers, no other change. The change would represent a 1.2% increase in the front diameter and 10 mm in width.

The guys from the tyre shop insisted I kept the factory settings to avoid trouble. They think this change could upset sensors as the front wheel would be rotating at a 1.2% slower than the system expects.

 

Does anybody have 235/40R18 and 255/40R18 in a 2IS with stock rims and stock height?

Does this cause any issue with sensors, abs system, any rubbing, or any trouble at all?

How does the car feel with these slightly bigger front tyres?

What wheels provide the input for the speedometer? Front or rear?

 

Let me know please.

Many thanks, Ruben

[bazzle]

From reading the US Lexus forums "0" issues other than looking a bit  fatter and "maybe" having to warm up the plastic splash guard at the rear of the wheel well to prevent any rubbing on lock.

I will be going that route on my next change just to try to protect the front rims. I will also see if I can go up one on the rear also.

 

[istatic]

I put 235x40x18 's on my front wheels (350X) instead of the standard 225's (got them a little cheaper) and i've had no issues with them whatsoever.

No discernible difference in steering feel or ride.No rubbing on guards.

[Neurus]

19 hours ago, istatic said:

I put 235x40x18 's on my front wheels (350X) instead of the standard 225's (got them a little cheaper) and i've had no issues with them whatsoever.

No discernible difference in steering feel or ride.No rubbing on guards.

Hi, can I ask what brand tyres were those 235x40x18?

I have an IS350X too; I wanted that little increase to protect the rims a bit more. I am interested in Michelin Pilot Sport 4.

Information on the internet is contradicting... 

[istatic]

Hi Ruben, I have Michelin Pilot Sport 4's all round.

I would have to say the slightly bigger front tyres (235's) only give very minimal extra rim protection for the lightest of kerb grazes though .

I don't know if you're into the aesthetics of your car ,but unless you are thinking about wider rims, then in my opinion the wider tyres don't look as good on the standard 8" rims...a little bit 'balooney" as opposed to the slightly stretched look of the original width tyres.But not ugly or a deal breaker.

 

 

 

 

 

[Neurus]

I believe the 235 in the front will make it closer to the rear look. I don't mind it.

Also, my car just touches the bottom of the front bumper on my driveway... I was hopping the extra milimetres will help avoid this.

I had decided to change them but the guys from the shop insisted on keeping the 225 to avoid problems.

They told me I would likely get ABS problems due to front sensor reporting different speed compared to the rear.

It is good you didn't get any issues with the change. Did you have to make any setting change or reset any sensors or anything like it?

[ilv1004s]

if grip is reason why u want to go wide

then get some grippy tyres or semis with oem sizing

[Neurus]

I ended up buying 4 Michelin Pilot Sport 4 factory size, I am happy with them.

The convincing argument to keep factory size was that even though I wouldn't get any warnings on the dash, the margins for the ABS would be modified if I changes sizes.

[bazzle]

You will be happy with the choice.

I keep mine at 40psi all around from my guage.

[2bling]

I would not go back to that tyre shop, different tyre ratios will not affect the ABS one bit.

[Neurus]

On 10/23/2019 at 1:10 PM, 2bling said:

I would not go back to that tyre shop, different tyre ratios will not affect the ABS one bit.

I read an explanation elsewhere and made my own decision, the tyre shop where I ended up buying the tyres had nothing to do with it.

What I understood (maybe incorrectly) is that if I increase the ratio on the front tyres only then the front sensors will be reporting less revolutions than the rears....

Anyway, I am happy with my new tyres.