Author Topic: 18ins Wheels  (Read 492 times)

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Offline 3spav

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18ins Wheels
« on: November 18, 2018, 02:47:25 PM »
Apologies to bring up the 18ins wheel and tyre saga again, I'm new to Mazda and the fronts on my 2018 2.2D Auto Sport Nav will need replacing soon. Has anyone come up with an economical replacement ? 
Having read members comments it seems that the 18ins wheel's only attribute is that it looks good! Poor ride, noise, wear and cost of replacement make me consider changing to smaller wheels. 
I think that the standard 16ins wheel will fit and it seems economical to buy replacement wheels and tyres at this stage and benefit from then on. Does anyone know of any problems as a result of changing? 
Alternatively, is it possible to change to 17ins wheels as this might have less impact on looks ??  I do see adverts for Maz3 17ins alloys.
I'd much appreciate any guidance.
Thanks

Offline Engineer Andy

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Re: 18ins Wheels
« Reply #1 on: November 21, 2018, 01:37:42 PM »
To be honest, I'm not sure if you can change down on the Sport/larger engined models.  Not sure whether you gen-3 owners are provided with an owner's handbook, but in mine (gen-1) it states what allowable tyre and wheel combos are 'officially' allowed; there should also be a copy of that table on a plaque on the inside of the drivers' side door/frame.  Essentially what can technically be fitted will depend on:
  • The size of the brake discs - they 'may' be same as on the non-Sport/1.5 models, but they might not.  They weren't on the gen-1 cars, limiting 2.0 models to 16in+ alloys;
  • Some alloy wheels are offset and may not fit over the brakes or legally inside the wheel well, though most probably do unless you go for boy-racer type ones;
  • Have a look on a website like https://www.oponeo.co.uk/advice-and-tips/tyre-size-calculator and enter your tyres' details to see what's possible generally, subject to the previous and following criteria.  The law states that the rolling circumfrence must not be more than 2% more or less than the OEM fitment, to ensure that the speedo and odometer read correctly - preferably the lower difference, the better.  That being said, some 'alternate' size combos are far more common than others, and the tyres in particular are FAR cheaper with lots more choice and newer, high quality models on offer;
  • Mazda may only allow certain size (and speed rating) combos, which 'should' match those on the plaque and in the handbook.  Similarly, most insurers will follow these rules, normally charging more for going up a size, but (if allowable) less likely if you downsize.  You WILL need to inform your insurer of the change - check before you order anything to see what the implications are for your premium, bearing in mind many charge (e.g. £25) just to CHANGE a policy mid-year (mine didn't because I spoke to them when I was near the annual change date and I am a long-term customer) - get a new quote a month beforehand and at the time of the change.  I try and changeover, if you can, when your premium is due for renewal to avoid any fee.  Note also that some insurers may charge for the fitment of non OEM alloy wheels, even if they are an allowable size from Mazda, whether the same size, larger or smaller - check first;
  • If you can downsize, it 'may' (depending on how good your local dealership is) be better to get both the tyres and wheels changed over at the main dealership rather than a tyre fitter - mine only charged £10 for fitting for each tyre and wheel (£40 total), whereas a fitter may charge for the fitting wheel and tyres separately (more) and may not warrant the wheel's fitting if they are sourced separately.  I bought my tyres via Blackcircles on mail order and took them to the dealership, and they ordered the OEM alloy replacements;
  • Prices for both the wheels and tyres obviously vary (offers on tyres come and go), so it may be beneficial, once you've worked out whether you can change and want to as regards the costs, to purchase the tyres a bit early - IF you can find somewhere suitable to store them.  Check tyre fitter websites for what is suitable for periods more than a day or two (NOT stacking).  I saved about £30 by waiting until and offer came about, even though it meant I had to store them at home for 2-3 weeks.  They can mark floors BTW.
I downsized from 205/55 R16 to 195/65 R15, 0.4% different and a common, standard size that Mazda and my insurer allowed (I actually got a reduction in my insurance of £14/5% - that won't always be the case).  The new tyres are between 15 and 30% cheaper; the alloys vary quite a bit, but the OEMs (check Mazda's website) were ~£155 (16in) vs ~£85 (15in).

Hopefully you can downsize, though the gen-3 standard 16in and 18in tyre size combos are unusual, though they do 'match' as regards the 'compatibility' in that Oponeo table.  The 16in ones aren't that much cheaper, though being 60 profile, they do provide a more cushioning and quieter ride than the 45 profile (?) 18in equivalents, and are a bit narrower so will be better on mpg (not THAT much, maybe 1-2) and, in theory, better in snowy conditions (though the actual type and model of tyre makes just as much, if not more of a difference in those conditions).  Obviously the dry grip in average to warmer conditions won't be quite as good, but in my experience this is minimal.

The most common tyre sizes (and thus, for the matching alloy size, have the most choice, availability and lowest cost) are:
  • 16in - 205/55 R16V (H rated [up to 130mph, not 149] can be a bit cheaper, but may not be allowable on your car for insurance purposes - not sure what the top speeds of the gen-3 are for the petrol and diesel - they could well be over 130 - my 1.6p gen-1 was under 120 so it was ok [and on the plaque]);
  • 17in - 225/45 R17W or Y
Both the above may not be allowable on your car or physically possible - best to check, and other forum members here (especially gen-3 owners) may know what is possible/not.  The gen-1 17in version actually comes with (not sure if all the time - I just looked it up on cars for sale on Mazda's website) 205/50 R17W tyres, which are about 10-15% more expensive than the most common size combo of 17in tyre.  The gen-3's 205/60 R16V is a LOT more expensive (rarer) than the very similar 205/55 R16 which were the OEMs on my gen-1 car.

Best of luck.

PS. Make use of the Tyre Reviews website as well as this forum to source the best tyres suited to your car, circumstances, wallet and driving style.
« Last Edit: November 21, 2018, 02:17:57 PM by Engineer Andy »

Offline 3spav

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Re: 18ins Wheels
« Reply #2 on: December 23, 2018, 12:53:27 PM »
Thank you Andy for such comprehensive advice, we're away dodging the winter but will get on the case in the spring and I'll let you know what I come up with.
David

Mazda 3 Forums UK

Re: 18ins Wheels
« Reply #2 on: December 23, 2018, 12:53:27 PM »