Ride quality with 225/45-17 all around vs 225/45-17 front & 245/40-17 rear combo? (07 IS250)

KamD · May 10, 2022

51 minutes ago, H3XME said:

I will be, I'm not understeering my way into a ditch on 225/265 combo 😂

My friend, before I start writing lengthy and heavy posts on this subject, let me apologise in advance... You keep going like this, and I'll have to fire up the laptop and begin a lecture... phone typing isn't my forté. But my work day is over and I'll be home soon... Still would try to refrain from actually doing it, but you about to start pushing the envelope.

I don't know you, you don't know me, so on so forth, right? Let me just clear that out for you, alright? I'm not from UK and although you don't have these in here, my education after 8th grade (14 years old) school was a Professional Academy for Transport, primary discipline - Exploatation and maintenance of motor vehicles and agricultural aggregates. One of the discipline's main chapters for 5 years was DRIVING. By the age of 18 (a year before school was over the only licence I didn't have was HGV hazardous goods, due to age restriction and experience, and a tank... for entirely different set of reasons.

Please stop educating me on tyres, traction and how to break it, ride whatever tyres you like on your car, but please be safe! The only reason you're struggling to break traction on 2IS is that you probably don't know how (I'm wildly guessing here).

I would really try not to get upset with you and turn this into a very lengthy and heavy read.

Still not salty, just mildly offended by the dismissive tone you and Linas are using, implying you're all-knowing and all-wise... and there can be no other opinion but yours - there is!

The only real and meaningful sentence (after clarification) you wrote (or was Linas) is that you use skinny tyres for traction (in certain circumstances) on wet (meh!) - deep mud, deep water and snow! And wide tyres for dry grip AND well drained roads (99% of UK) Very small but distinctive difference, isn't it?

Take care!

KamD · May 11, 2022

17 hours ago, H3XME said:

🤣 🤣

But why? You're killing the car. The characteristics, the feel, mpgs, tiring the engine too as it needs to work harder to spin those fat tyres.. and for what? Tyres can only do so much, and if you over-tyre your car, it will perform worse. I have no doubt your car will be understeer-y when pushed now because of such a big tyre difference on your car.

I'll let you figure that one for yourself... Trip to work, consisting of 75 miles of B and A roads of various description. And again... You were saying!?

Just because the car is automatic it doesn't mean that your driving has no input on it's performance and economy. Learn how to coast, feather both throttle and brakes and most importantly - use whatever limited control you've got over the gearing and make the engine work for you, not only accelerating! Most powerful a d reliable brake you've got at your disposal is the engine.

Remember, I'm killing my car on 18' 225 front 265 rear 🤭🤭😏

Linas.P · May 11, 2022

I think we probably need another thread for this as the original answer was already answered. 225 all round will fit, will not impact ride quality, will improve fuel consumption and Lexus uses this set-up on AWD IS250 from the factory, so OP really cannot go wrong by going this way.

@KamD - cannot really see how the MPG proves anything here, 38MPG is fairly normal and not impressive for A/B roads provided they are quiet, 44MPG on motorway @90MPH, but if driving on quiet A road and sticking to 60MPH the best I got was actually 48MPG. Other thing I don't understand - is what is the point of always driving without TC? What does that actually achieve. I understand that if you want to go to track then having TC kicking in would be annoying, but on public I can't see any reason to do it. Likewise 265 is clearly overkill, Lexus fitted 265s on IS-F so I just can't see how fitting them to IS250 can be justified and what benefit that could bring. As well I didn't say that you can't loose grip on IS250, I said you can if you trying to do it deliberately, but with standard set-up you will always lose grip in front before you lose it at the rear ... and understeering is never good. So again it seems what you saying is contradictory in itself.

KamD · May 11, 2022

34 minutes ago, Linas.P said:

Other thing I don't understand - is what is the point of always driving without TC? What does that actually achieve.

One word - fun! Controllable and predictable fun... If you know, you know! And 265 is just about right comfort / control

You don't need 1000hp to go sideways... if and when you want 🤷‍♂️

Whatever... Again - as long as you're safe you can put ice skates on the car if you desire... Back home I keep an old Lada with "fog tyres" just to be silly when I feel like it. Completely stock... carburetor engine, still goes sideways 😏

H3XME · May 11, 2022

9 minutes ago, KamD said:

One word - fun! Controllable and predictable fun... If you know, you know! And 265 is just about right comfort / control

You don't need 1000hp to go sideways... if and when you want 🤷‍♂️

Whatever... Again - as long as you're safe you can put ice skates on the car if you desire... Back home I keep an old Lada with "fog tyres" just to be silly when I feel like it. Completely stock... carburetor engine, still goes sideways 😏

I'm sorry, but if you need 265 just to stay in control of a 200hp IS250 then that's all I need to know... Drive how you want. All we were saying is that your car would drive way better on 225s all round, because we tried this, but you won't have any of it because you think wider is better - It's not.

Linas.P · May 11, 2022

15 minutes ago, KamD said:

One word - fun! Controllable and predictable fun... If you know, you know! And 265 is just about right comfort / control

You don't need 1000hp to go sideways... if and when you want 🤷‍♂️

Whatever... Again - as long as you're safe you can put ice skates on the car if you desire... Back home I keep an old Lada with "fog tyres" just to be silly when I feel like it. Completely stock... carburetor engine, still goes sideways 😏

I am confused... are you saying you "drifting" all the way to your work every day, hence you put 265s and keep TC off all the time? Sorry, but it still doesn't make sense.

I guess if I give you benefit of doubt, then I would assume what you are trying to say is that you don't want "software safety" in TC and instead you want mechanical grip which is provided by tyre width? Still does not make sense, because that is why there is TC button in the car - when you just want to drive safely form A to B you keep it on, and when you want "fun" you run it off... and if you can have fun on 265s, then you will have even more fun with 225s and won't need to deal with unpredictable front end which is just eager to understeer due to having much narrower tyres and less grip. All in all I would say you solution is contradictory to your own goals... unless I still don't understand what they are...

KamD · May 11, 2022

33 minutes ago, Linas.P said:

I am confused... are you saying you "drifting" all the way to your work every day, hence you put 265s and keep TC off all the time? Sorry, but it still doesn't make sense.

I guess if I give you benefit of doubt, then I would assume what you are trying to say is that you don't want "software safety" in TC and instead you want mechanical grip which is provided by tyre width? Still does not make sense, because that is why there is TC button in the car - when you just want to drive safely form A to B you keep it on, and when you want "fun" you run it off... and if you can have fun on 265s, then you will have even more fun with 225s and won't need to deal with unpredictable front end which is just eager to understeer due to having much narrower tyres and less grip. All in all I would say you solution is contradictory to your own goals... unless I still don't understand what they are...

I'm not saying that at all... There's comfort mentioned as well... Not in the slightest. The only way to have TC off in an IS250 is to be in P and hold the button for few seconds. I assume you know better than me on this as well, right? Otherwise you get interrupted. Car behaves and works better with VSC off, fact. Or you have something against just driving without help?

@H3XME 2IS doesn't drive better on 225 in the rear - 'nuff said!

Seriously, guys, neither of you both has even given a thought for one little bit 265 maybe a much more comfortable and just overall better choice than either of the OEM specs or hints to alternative sizes? (I've been through all of those and the best suited to me setup is 225 - 265 )

Peace!

KamD · May 11, 2022

@Linas.P please do not give that advice nilly willy AWD and RWD act and behave very very differently! Hence - tyre combination suited for AWD is probably not the best idea on a RWD.

Linas.P · May 11, 2022

I think Lucas already summarised on this point - all people will have different views on what tyres works for them.

57 minutes ago, KamD said:

There's comfort mentioned as well...

Not in the slightest. The only way to have TC off in an IS250 is to be in P and hold the button for few seconds.

Otherwise you get interrupted. Car behaves and works better with VSC off, fact.

Or you have something against just driving without help?

If you really want comfort then R17 on 225s will be more comfortable than R18 on any tyre.

Yes you have to be stopped to turn off TC fully.

The claim that car behaves better without TC (VSC)... well it depends. Under normal driving - no... if you want to drift, then yes... but that is not normal driving. So it being a "fact" is kind of dependents - for most people and driving I would say that is incorrect.

I don't have anything against driving without TC, except the fact there is no benefit of doing it in normal driving conditions i.e. where you not deliberately trying to lose grip.

The reason AWD uses square set-up has nothing to do with the grip, the reason for it is differential - it can't handle different size tyres as that would damage it. As for the reasons Lexus has staggered set-up on RWD - part of it is just looks, second part is trying to make tyre wear rate similar between driving and driven axels, finally it is this "safe" handling characteristic - which Lexus decided is desirable (probably makes sense when majority of their customers are pensioners). There is belief that for inexperienced driver is safer if the car understeers first and this is what staggered set-up achieves on IS250, you will always lose grip in the front first. That being said I do not consider this safer (probably because I am not inexperienced) and actually it annoys me, because it makes car unbalanced and twitchy. What this means is that you can't reach the actual limit of your car, because anytime you try to push it car will understeer before it can come even close to it... Whole benefit of having RWD is that you can modulate car angle mid-corner with throttle, hence RWD is considered "better handling", but if you have less grip in the front and if car understeers before the limit, this just removes this single benefit. So in my opinion standard staggered set-up gives you less control and it is less "fun", nevermind with 265s in the rear.

KamD · May 11, 2022

13 minutes ago, Linas.P said:

I think Lucas already summarised on this point - all people will have different views on what tyres works for them.

If you really want comfort than R17 on 225s will be more comfortable than R18 on any tyre.

Yes you have to be stopped to turn off TC fully.

The claim that car behaves better without TC (VSC)... well it depends. Under normal driving - no... if you want to drift, then yes... but that is not normal driving. So it being a "fact" is kind of dependents - for most people and driving I would say that is incorrect.

I don't have anything against driving without TC, except the fact there is no benefit of doing it in normal driving conditions i.e. where you not deliberately trying to lose grip.

The reason AWD uses square set-up has nothing to do with the grip, the reason for it is differential - it can't handle different size tyres as that would damage it. As for the reasons Lexus has staggered set-up on RWD - part of it is just looks, second part is trying to make tyre wear rate similar between driving and driven axels, finally it is this "safe" handling characteristic - which Lexus decided is desirable (probably makes sense when majority of their customers are pensioners). There is belief that for inexperienced driver is safer if the car understeers first and this is what staggered set-up achieves on IS250, you will always lose grip in the front first. That being said I do not consider this safer (probably because I am not inexperienced) and actually it annoys me, because it makes car unbalanced and twitchy. What this means is that you can't reach the actual limit of your car, because anytime you try to push it car will understeer before it can come even close to it... Whole benefit of having RWD is that you can modulate car angle mid-corner with throttle, hence RWD is considered "better handling", but if you have less grip in the front and if car understeers before the limit, this just removes this single benefit. So in my opinion standard staggered set-up gives you less control and it is less "fun", nevermind with 265s in the rear.

I didn't even finished reading the whole post... Will go back to it.

The reason why AWD uses 4 identical tyres is that it drives all 4 wheel, at the same time. It's sluggish and slow and nothing like the RWD. It's even on Lexuses official papers .4 seconds slow to 60 than RWD, incorrect... AWD is a grosser getter in UK It's not needed. I'd much rather we had the 350

I've been in touch with all limits of my car and Lexus haven't even stated correct max. speed... anyway.

H3XME · May 11, 2022

34 minutes ago, KamD said:

@H3XME 2IS doesn't drive better on 225 in the rear - 'nuff said!

Seriously, guys, neither of you both has even given a thought for one little bit 265 maybe a much more comfortable and just overall better choice than either of the OEM specs or hints to alternative sizes?

It does. And if you actually knew anything about how sports cars are setup, you wouldn't argue about this. Sure, IS250 is not a sports car, but it doesn't mean it can't be improved with some mods.
You started all this by hinting at sporty driving, and for spirited driving you don't want 225 front and 265 rears on this car..

Linas.P · May 11, 2022

IS250 AWD is like 65-80% of power to the rear, but yes it is sluggish, understeers a lot and uses a lot of fuel (I had one for 40k miles, so I am familiar with it's issues). Still got stuck in winter and that was the only reason why I wanted to move from RWD to AWD - pointless model. Yes we all would like IS350 or RC350 here.

LenT · May 11, 2022

25 minutes ago, KamD said:

I've been in touch with all limits of my car…

May I just reassure my neighbours and fellow villagers who see me set off in my IS250 that I am, by choice, a stranger to the limits of my car. 😊

KamD · May 11, 2022

25 minutes ago, H3XME said:

It does. And if you actually knew anything about how sports cars are setup, you wouldn't argue about this. Sure, IS250 is not a sports car, but it doesn't mean it can't be improved with some mods.
You started all this by hinting at sporty driving, and for spirited driving you don't want 225 front and 265 rears on this car..

I really like what you've done to yours... modificationwise... I wouldn't put 225 on my RWD, not the way i drive and what I'm asking from the car to do occasionally. I find the ride choppy on 225s in the back. Soon on a cross Europe trip and honestly I prefer to be on 265s on the Autobahn. Call me crazy... 😉

What we're talking about here is really +5% or -10% so, nothing drastic really.

KamD · May 11, 2022

15 minutes ago, LenT said:

May I just reassure my neighbours and fellow villagers who see me set off in my IS250 that I am, by choice, a stranger to the limits of my car. 😊

You should try to touch them, even if it feels awkward at first. Between 4.5 and 5.5k rpm is where you'll find them most enjoyable. (I do realise it's a humorous post and reply the same way)

Bit of a shame that 140mph doesn't feel any differently than 90-95, only try that where legal (race tracks or Germany), actually it becomes slightly heavier past 130...

J Henderson · May 11, 2022

My tuppence worth...

I'm not a fan of the OEM 225f/255r combo for 18" wheels. Too much understeer like has been touched on.

On my previous (and first) IS250 I felt compelled to do something about it almost right away. Having come from a much sweeter-handling XE10 IS200, the balance of my new car just felt so wrong by comparison. The fact I now had electric PAS instead of hydraulic didn't help matters, but I digress.

So, I bought a new pair of front tyres within a matter of weeks despite the existing ones being nearly new.

I upsized the fronts to 235/40 and that eliminated a good deal of understeer and moved the balance of the car to a more neutral position. One that I'm more happy with.

I've adopted this policy with every set of new tyres ever since. Only now I downsize the rear tyres instead of upsizing the fronts - 245/40 instead of 255. The net result is the same - a more neutral balance, but with the additional benefit of the 225/245 sizes being considerably more popular, cheaper, and with a bigger range to choose from.

Bugster_MR2 · May 11, 2022

I replaced my rear worn out Michelin Pilot Sport 245/40-17 yesterday with the brand new Nokian Hakka Blue 3 in 225/45-17.

My two cents:

-It doesn't suffer in the looks department.

-It made a night and day difference in terms of noise. I will have to replace the fronts now too, even though they aren't completely worn out yet.

Haven't driven it hard in the twisties yet, so yet to conclude about their sportiness. But regarding noise? Absolutely brilliant.

H3XME · May 11, 2022

5 minutes ago, Bugster_MR2 said:

I replaced my rear worn out Michelin Pilot Sport 245/40-17 yesterday with the brand new Nokian Hakka Blue 3 in 225/45-17.

My two cents:

-It doesn't suffer in the looks department.

-It made a night and day difference in terms of noise. I will have to replace the fronts now too, even though they aren't completely worn out yet.

Haven't driven it hard in the twisties yet, so yet to conclude about their sportiness. But regarding noise? Absolutely brilliant.

Depends how old the Michelins were, and which spec exactly, but I think your new tyres will work better in wet whereas the Michelins would be a bit better in dry. All in all, you should give your new tyres at least 200 miles running in time before coming to a conclusion. They will work better once "bedded" in.