I want to specify the tyre brand

[Mojo1010]

SPS - you know you needs best so go for it. I don't do many miles, takes about 4 years to change the front tyres. So spending £1k on new wheels and tyres isn't wise for me, as well no where to store the wheels. 

One day when I move to another region where it's colder then I would want to try all season tyres. 

 

 

 

 

[RobertR]

56 minutes ago, SinglePointSafety said:

RobertR, 215/55 is indeed an approved tyre size, for the 17-inch wheels. If you deviate from the so-called 'approved' tyre size, that's totally fine, as long as the diameter is within certain change limit, recommended < +- 3% and - of course - you notify your insurance company. There are many web sites which do the comparison for you, such as https://www.willtheyfit.com/ but the bottom line is: don't deviate too much from the 'standard' size, so that it's fine to go from 205/65 to 215/65 or 215/60 but not more extreme changes

TonyHSD, thanks: the above should answer some of your points regarding tyre size changes: my various posts above already answers the others as to why I might do this wheel size change

I forgot to mention 215/55 for R18...they recommended 215/50R18 but the offer is limited, not all manufacturers do this size, 215/55R18 is the more common size, but not sure what this does with the car.
The only reason why I thinking about this is more comfort on R18 wheels.

[SinglePointSafety]

RobertR, changing from 215/50 R18 to 215/55 wouldn't be recommended: you'd get a 3.1% increase in the rolling radius and it's the 'wrong way' - the speedo might underestimate your speed (unlikely given that speedos normally over-estimate) but it's still (just) outside the limit of change. The nearest size would be 205/55R18, but good luck finding all-season (or indeed any) tyres in that size

Others have mentioned cost, so trying to compare like-with-like... and this comparison is based on current prices of Michelin CrossClimate2 on BlackCircles site, not taking into account any offers on tyres (these come and go and vary with retailer)

16-inch 215/65 R16 are ~£127 each, can get decent set of alloys for ~£400 (or even less if you opt for steel wheels) total ~£900. 18-inch 215/50 are ~£186 each, total £744, so ~£150 difference and then get some money back when I finally sell the after-market wheels and tyres

If you don't need/want all-season or winter-capable tyres....of course, totally agree, the cheapest option is to simply do nothing!

Yes, wrecking a wheel is overall 'unlikely', but the local tyre fitters can tell you how many terminally-damaged tyres and wheels they see in a week, and round here, it's a **lot** (indeed, one tyre company owner has a relative who started up a wheel refurb/repair/replace business, and trade is, er, "very good", guess where he gets a lot of referrals from?)

[Yugguy1970]

https://www.miata.net/garage/tirecalc.html

 

[anchorman]

I’ve not read up in much detail on the Toyota systems but on other brands, wheel speed is linked in to the safety systems and having the wrong rolling radius could cause errors in them.  Just a thought.  

[SinglePointSafety]

Anchorman, I think you're referring to passive TPMS, which is linked to ABS and detects deflation by the change in the rolling radius by the ABS sensor. Toyotas use active TPMS, which relays tyre pressure to the car using a transmitter in the tyre/wheel valve

Rolling radius will actually change anyway as the tyres wear - a potential decrease of nearly 7 mm. And car tyres are never totally precise in their dimensions anyway (several articles on the web about this)

[flash22]

57 minutes ago, SinglePointSafety said:

I think you're referring to passive TPMS, which is linked to ABS and detects deflation by the change in the rolling radius by the ABS sensor. Toyotas use active TPMS,

Some mid 2000-2012 Toyota's and the Aygo up to 2021 use the passive system, the Mk3 and 4 Yaris uses the active system with temperature and pressure sensors in each wheel

TSS is not affected by wheel size neither is the ABS as long as they are the same size all around, ABS, TC and TSS are calculated by difference in the wheel speed of each wheel, the yaw sensor and SAS (steering angle sensor) turning left or right means the inner tire of the turn rotates slower than the outer, the algorithm in the ABS ecu compensates for this

Edit. If you're changing tire and rims, don't forget to factor in tpms sensors and reprogramming costs

[SinglePointSafety]

Thanks flash22, good info about the TPMS and the various 'traction control' sensors. And regarding the TPMS valves, when I buy the tyres, my local tyre shop is quite happy to move the valves to the new wheels FoC, and will even (they claim) take care to match the wheel location, so no need to budget for new valves nor reprogramme (which you can do yourself anyway, according to the user manual)

[Cyker]

The Mk4 doesn't actually need reprogramming unless you change the sensors - The car works out which wheel each sensor is on every time you start the car by the looks of it!

 

[Mojo1010]

If @Cyker likes to collect MK4 17" wheels memorabilia then I could use the cash to get 16" wheels & tyres 🤣

[TonyHSD]

55 minutes ago, Mojo1010 said:

If @Cyker likes to collect MK4 17" wheels memorabilia then I could use the cash to get 16" wheels & tyres 🤣

He has a brand new set of 17” 🛞 already as I understood. 👍

Tbh I always wanted to change the wheels and tyres on my Auris since day one to a more suitable size however the car was not in proper use as of now and I thought just a new tyres will do it and bought better tyres fitted to the oem wheels. All was good for around 4 years then started to use the car more and I needed again a new set of tyres, I bought a winter set as it was cold around this time of the year. Then in March I bought summer tyres and was swapping them on the same wheels for two seasons when I see the oem wheels are starting to peeling off paint, corrosion started to forum around the rims which leads to pressure loss etc, clearly I needed a new set of wheels or money spent on refurbishment. I decided to go for new set of smaller wheels and tyres and the car has noticeably transformed to a better drive. However just before the change I run quality tyres on the oem wheels and the difference between two sizes with same brand tyres wasn’t as big, therefore the tyres are everything, even more important than the wheels sizes. Yaris Cross that comes with 18” wheels and Goodyear tyres are perfect combination and highly recommended to anyone to keep this set as is because these are one of the best tyres on the market, plus the sizes are not so low profile at 50 👍

[Mojo1010]

I know, that's the reason I said if he likes to collect memorabilia haha. 

I read you and many other praise the Goodyear EGP2 over the internet reviews. I have a pair of the EGP1 on the back of the car currently. They have been in the shed for 4 years before it went on. Been 3 years now, still looks in very good nick, though I do low mileage. 

Can't comment on performance as my MK3 Yaris is more a city car, doesn't cope well with higher speed suburban/country roads, though it's on narrow 185mm tyres. The new MK4 comes with Bridgestone, which isn't rated that great, so once that is done I will be looking to replace with EGP2. Perhaps going to 215/45/17. 

 

[anchorman]

On 12/2/2022 at 5:24 PM, SinglePointSafety said:

Anchorman, I think you're referring to passive TPMS, which is linked to ABS and detects deflation by the change in the rolling radius

No and I’m aware the rr changes with tyre wear.  

[SinglePointSafety]

Anchorman, you're very welcome - I was genuinely trying to be helpful for others who may be trying to decipher the alphabet soup regarding the different manufacturers' ways of detecting tyre deflation and the various ways that the car monitors traction and other safety-related data etc. No patronising intended....sorry if I misinterpreted your post

Surely the takeaway message is the importance of having the same rolling radius - within a specified tolerance which allows for tyre wear and dimensional manufacturing variation - to best enable the car's safety systems to work optimally. It's perfectly acceptable to change tyre/wheel size provided that it happens on all 4 wheels and remains within the recommended +- 3% rolling radius cf the original size. And before anyone says "duh, yeah" my local tyre fitter has plenty of tales of people turning up with massively mis-matched tyre sizes, and getting indignant when they're told it's not legal and will fail the MoT

As an aside: Weirdly, the same tyre fitter tells me that the car's speedo is not part of the MoT! So provided your 4 wheels/tyres are the same size etc, MoT-wise you're OK. Insurance-wise.....dunno. Legal...?