Wheels - change down?

[Hugh R]

I'm thinking of buying an IS250-L and viewing it tomorrow.  It has these wheels:  225/40 Front  -  255/40 Rear.  I'm totally non-technical and I'd really like to know if I can, and would be better-off, fitting 17" - in terms of insurance - comfort - cost - but with the hassle and cost of doing this?  Am I being stupid?!  Thanks for any help.

[Mr Vlad]

What size wheels are on it? 17's are a great compromise between grip and comfort. 

[Hugh R]

Sorry - I should have said they are 18 wheels.  

[Mr Vlad]

So it's got 18's theat is a standard size so shouldn't have any insurance implications. You can change to 17's 225/45/17 front and 245/45/17 rear. However there's the expense of getting 4 wheels and tyres. However you could Google around and try and find a swap. 

[LenT]

I too have 18” wheels on my IS250 which was about 2 years old when I bought it.  They too require different sizes.  Given the choice I would have gone for the 17” wheels, which are the same size fore and aft on my model.

The bigger wheels are supposed to give better handling at speed because the lower profile tyres have less sidewall to flex when cornering.  The compromise is that the general ride is firmer.

 But, like Vladimir, I concluded that the cost of changing both the wheels AND the tyres did not justify any marginal gains.  Instead I changed the tyres, when due, to Goodyear Asymmetric 5 which greatly improved the handling, especially in the wet, reduced the noise levels and improved the ride quality.  (Other tyres are available).

I don’t think you mention whether this is a private sale or from a dealer.  If from a Lexus dealer, I suppose you could always suggest a wheel swap to clinch the deal.

PS Remember to check the spare.  Is it missing or a Space Saver in good condition.

 

 

[Linas.P]

If I understood correctly OP is looking at IS250 SE-L? 

SE-L came with 17" as standard, 18" were optional and not many had them. As long as they Lexus OEM wheels makes no difference for insurance... and generally whole mods notification to insurance topic is little bit overblown. Back in the day (maybe 20 years ago) when alloy wheels were rare and expensive option, and when wheels used to be stolen insurance wanted to know if you have them. Nowadays - as long as the wheels are roughly same size (not 30" spinners) insurance just doesn't care, nor could prove anything. If even an issue one can say they bought the car that way and it is no longer modification.

As for whenever to have 17" or 18"... 17" will be little bit more comfortable, quite good compromise actually, 18" will be better for handling. But difference really isn't massive to justify removing set which is on the car and replace it with something else. 

[65mike]

Hi all.

Sorry Linas in 2009 SE-L came with 18" as standard mine are what you see in the picture they also mention what model had what size wheels and tyres.

Page 17 tells you wheel and tyre sizes for different models.

65mike.

Lexus IS-Series-(5mar09)_tcm-3066-452060.pdf

[Linas.P]

Not 2007 car thought... 

[Hugh R]

This is a 2007  IS250-L  - I think it would have been supplied with these 18's as it was a new demonstrator for a few months, then bought by present owner.  Seems to me after above advice (many thanks) it's more sensible to go with what's there and hopefully tyres will be ok, but if not then change for something like those mentioned and at least it will still be cheaper than going down to 17's.  My main concern is really about ride comfort and noise, which doesn't seem to worry you people too much.  

[scudney]

Since its a 2007 car chances are they were fitted with 17's rather than 18' or had them as optional extras I have a facelift model  250 f sport with staggered 18 inch wheels and don't find the ride too hard 🙂

[Linas.P]

10 hours ago, Hugh R said:

This is a 2007  IS250-L  - I think it would have been supplied with these 18's as it was a new demonstrator for a few months, then bought by present owner.  Seems to me after above advice (many thanks) it's more sensible to go with what's there and hopefully tyres will be ok, but if not then change for something like those mentioned and at least it will still be cheaper than going down to 17's.  My main concern is really about ride comfort and noise, which doesn't seem to worry you people too much.  

It depends how much time you want to spend on it and how much comfort you need e.g. if 18" alloys themselves are in decent shape, then it may be worth selling them. You can certainly find 17" OEM set for less and still have change towards the tyres (heck... I have 2x 17" sets myself). But obviously they will require time to find buyer, time to find another used set etc. So it is not impossible, but I don't see it as worthy time investment for what will be marginal difference.

Noise is not going to be an issue with premium tyres like Goodyear Asymmetric 5s, Dunlop Sportmaxx rt2 or Continental Premium/Sport Contacts, even Michelin PS4 (although they ride little bit harder), Pirelli P-Zeros are as well quote comfortable, but lacks little bit in grip. Ride comfort is decent on 18", but it depends what you comparing it with - it won't be as comfortable as Merc S-Class for sure.  

[2ddesign]

Hi on another forum site SC430, a discussion on comfort by increasing the stock 245/40/R18s to 245/45/R18s. Found their was an increase in comfort over rough roads, but a small difference in speedometer by a few mies an hour! Might be worth keeping the R18's and having 45 tyres?

https://tiresize.com/speedometer-calibration/?fbclid=IwAR2hljNDMPBed7mpvAyMck5kxSBkmlL9MVsEi1d0WGl6Nd0MOuys4qUliOs

[Linas.P]

Just to note - the stock tyres on 18" are not 245, they are 255... that becomes important if you want to calculate speed difference. Obviously, there is and alternative of fitting 245/45 instead of 255/40 - resulting in similar OD and minimal speed change, theoretically better fuel consumption and perhaps more comfort. Although, again - the difference would be so small it becomes subjective. 

[rich1068]

16 hours ago, Hugh R said:

I'm thinking of buying an IS250-L and viewing it tomorrow.  It has these wheels:  225/40 Front  -  255/40 Rear.  I'm totally non-technical and I'd really like to know if I can, and would be better-off, fitting 17" - in terms of insurance - comfort - cost - but with the hassle and cost of doing this?  Am I being stupid?!  Thanks for any help.

No stupid about it. As a couple of others have suggested I'd definitely be looking at fitting the same size 17s all round. 18s and staggered 18s at that, are all about looks. I value comfort more.

[Linas.P]

....not only about looks, but about handling as well. Having square set-up does not improve comfort either, nor staggered set-up reduces it. Car being RWD it does make sense to have staggered set-up, not only to increase the grip in the rear, but as well to make wear on both axles more similar.

Besides difference between 17" and 18" in terms of comfort are not as dramatic as you make it sound. If you really want to float in the clouds, then get 16" and put something like 205/65 and just float on the road... without any feel of what the wheels are doing, but in great comfort.

I do agree however than Lexus 18" 225/255 are a bit silly and makes car way too much front biased, meaning that despite being RWD car will understeer first (people consider FWD like handling "safe"). More suitable sizes would be 235/245 for IS350 and 225/235 for IS250. This would provide more neutral balance (with just touch of Rear bias) and would make wear more even across the axles.

[rich1068]

Yep. Because it's all about the handling on an IS250 SE-L.

[Linas.P]

Lexus calls it "the sports sedan" - so I guess yes...

But again - it is not like on 18" is suddenly uncomfortable and moving down to 17" makes all the difference. Yes even I said that "17s are the best compromise for this model", but that is only because it just marginally improves comfort, by just marginally impacting handling.

Let's put it this way - if somebody would come and say that they have 17" and they considering 18" to improve handling, I would say it is not worth it. Simply put more aggressive/sporty tyres, maybe pump 2-3more PSI, like wise if we talking about downsizing - not worth it... just put more comfort oriented tyres. 

[LenT]

So how did the viewing go, Hugh?  I think we’re all agog to know.

In the great scheme of things I wouldn’t let your purchase decision rest on the wheel size.  As I think many of us have said, tyre choice may be a more significant factor than wheel size - and the easiest to change.

Meanwhile, as I’m sure you’re well aware, there are plenty of other possible problem areas to worry about!

Good luck.  They’re great cars!

 

 

 

[steve2006]

7 hours ago, Linas.P said:

It depends how much time you want to spend on it and how much comfort you need e.g. if 18" alloys themselves are in decent shape, then it may be worth selling them. You can certainly find 17" OEM set for less and still have change towards the tyres (heck... I have 2x 17" sets myself). But obviously they will require time to find buyer, time to find another used set etc. So it is not impossible, but I don't see it as worthy time investment for what will be marginal difference.

Noise is not going to be an issue with premium tyres like Goodyear Asymmetric 5s, Dunlop Sportmaxx rt2 or Continental Premium/Sport Contacts, even Michelin PS4 (although they ride little bit harder), Pirelli P-Zeros are as well quote comfortable, but lacks little bit in grip. Ride comfort is decent on 18", but it depends what you comparing it with - it won't be as comfortable as Merc S-Class for sure.  

Pirelli P- Zeros are so noisy though! I put a full set on mine recently ( 245/45/18-100Y) 

[Linas.P]

There are certainly P-Zero 245/45/18-95Y rated 67dB, which is as good as it gets for noise, yours (100Y) I guess rated are 70dB... which isn't bad, but sort of average. 

What I would say as well - noise is personal thing, different people are annoyed by different frequencies and sometimes lower DB level rated tyres noise can be perceived as more "noisy" or simply their noise more annoying. Besides most tyres are more noisy when new until the sharp edges and little rubber bits wears off (say ~1000miles). As you fitted them recently maybe they still needs to "wear-in"?

Overall, in my experience I would consider P-Zero to be more comfort oriented tyre, when compared to say more performance oriented PS4s (or even PS4), Conti Sport Contact, more universal tyres like Conti Premium contact 6, GY Asymmetric 5 or Dunlop RT2s. I generally do not recommend Pirelli as I am not that interested in "comfort" and in all other aspects they are much more expensive without delivering much more (sometimes less), but tyres are difficult and subjective topic.

[ALTSpitfire]

My is250 has the 17 inch alloys and would be looking at swapping to the 18 inch alloys in the near future 

 

[H3XME]

On 3/15/2021 at 2:38 PM, ALTSpitfire said:

My is250 has the 17 inch alloys and would be looking at swapping to the 18 inch alloys in the near future 

 

Do it! Here's mine 😉 

Before

After

I just realised I haven't got any pictures from the same angle as the first pic 😄 

[Hugh R]

Sorry not to have updated everyone sooner but I have been busy with other things.  Then, very soon after posting my original question the car was sold.  But your answers were really helpful and I'm grateful to all of you for your explanations to a non-technical guy like me - and all is not lost, as I have just found another one that is a year older, a 2006 IS250L, under 50k and FSH, but because of lockdown I've not been able to view.  But again wheels are 18’s fitted with Kumho tyres:  front are 225/40 (ZR18 92Y)  Rear are: 255/35 (ZR18 94Y) all in good condition apparently.

So the question remains - if I want a quiet comfortable ride should I change down to 17’s all same size or keep existing 18 wheels but change tyres for different size and/or brand?   Reading all these answers seems to suggest that with 18's I'll always need different size tyres front and rear, but with 17's I can fit same size front and rear??  Am I wrong? I’m no expert and may be chasing a wild goose around a pond here. Or should I just leave well alone?! 

[Mr Vlad]

Hi Hugh. My 2007 SE-L is on 17's. 225/4517 front and 245/45/17 on rear. Leave your 18's on and research a softer walled tyre. But basically let me tell you about a Ford Mondeo I had. It ran on 19's. The car was the titanium sport x. So yes it had ki d of harder suspension etc. However that car rode the road sublimely. Very comfortable and compliant. Just food for thought. 

Oh going back to a softer walked tyre. No. Typically what I've found is the cheaper the tyre the harsher the ride.

And well done on your latest purchase 👍

[Hugh R]

3 minutes ago, Mr Vlad said:

Hi Hugh. My 2007 SE-L is on 17's. 225/4517 front and 245/45/17 on rear. Leave your 18's on and research a softer walled tyre. But basically let me tell you about a Ford Mondeo I had. It ran on 19's. The car was the titanium sport x. So yes it had ki d of harder suspension etc. However that car rode the road sublimely. Very comfortable and compliant. Just food for thought. 

Oh going back to a softer walked tyre. No. Typically what I've found is the cheaper the tyre the harsher the ride.

And well done on your latest purchase 👍

Thanks, but not actually bought it yet, but don't think wheels would hold me back from doing so.  So if I kept the 18's what tyre configuration (F+R)do you people suggest for comfort and quietness?