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Hi, planning a big trip in my gt86 in a few months and just gave a question about using a spare wheel. I currently have 18s running 225/40, I’m going to try and get a spare wheel in 18” but if I can’t could I run the standard rim if I had a puncture? I think there is a 3% difference in tyre size would this work ok or will it throw off the abs sensors? 

Also do you know of anywhere I can buy single wheels from? Not fussed on the look

thanks

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I'd just use spacesaver, as by my experience it's sufficient to get by in case of emergency, eg. drive to tire repair shop, can be relied upon in all cases (unlike stock tire repair kit, after which usually tire repair shops refuse to repair tires filled with that gunk), and it also won't reduce already not that big boot volume of our cars. AUDM twins had also option of full size spare same as main four wheels, and boot liner with extrusion for that full-size wheel, but i don't like reduced boot clearance due that, and need to carry extra weight all the time for something needed rarely more then once per two years.

As for wheel size .. main bit should be tire's outer diameter, not wheel diameter, as similar outer diameter can be reached in multiple ways/sizes, eg. low profile tire + bigger wheel, or smaller weel and tire with high sidewall .. but again "precision" of that outer diameter matching doesn't matter regarding our cars, as, like manual says, spare wheel should be used only on front, not rear (due twins having limited slip differencial). On front wheels may differ by a lot, they are not driven. On rear diameter matching is very important due LSD, as even small differences will mean diff working all the time, even when driving straight, thus in turn overheating, which will quickly degrade oil in diff, as result LSD diff can quickly be killed, which will result in expensive, non under warranty, repair/replacement.

So if punctured front wheel, put spare wheel there, almost no matter size, as far as it clears front brake caliper & suspension bits, it should do. If punctured rear wheel, put (as same sized, luckily our cars have square wheel/tire setup as stock, which simplifies things like tire/wheel rotation) wheel from front to rear, and again - (any fitting/clearing) spare on front.

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I believe the driver assist systems will quit on you for running an undersize wheel across an axle. It should just throw a warning and leave you to it if it's anything like Mazda electronics, so you'd be able to drive but without VSC or perhaps even ABS still operating. Think kindly of your diff!

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That provision on wheel size in relation to LSD is there also for other cars equipped with it, but of course if it's eg. FWD one, then that is about wheels on front axle. It also can be attributed on 4WD vehicles regarding same size of wheels but now on all four ends, if there is eg. viscous diff between axles or transfer case, that can be overheated/damaged due different speeds due different wheel sizing.

So in general - if it's not undriven end or at least with open diff - wheel sizing on that axle matters a lot. Of course it's usually said in user manuals for all such cars, but more often then not people don't read manuals these days or miss that sentence in few hundred pages glanced through :) (btw, i was of such too, noticed mention of that elsewhere and almost by chance, and only then found out that it's not some generic advise/hint but actually gets noted in manuals (which i admit of not reading back then, baselessly overconfident that there was nothing new to me from past driving experience (always on open diff cars)). Heck, when choosing spacesaver spare for myself back then, i even checked fitment/clearance of it both for front & rear :D)

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I carry a Full Size Spare 17" Alloy Wheel with Tyre in the Boot and have the Boot Liner that fits over the top of the wheel.

Got the Liner from Toyota Australia

Certainly improves traction....lol

85115486832fbfbb316c5c7a1835ef8e.jpg

Sent from my ASUS_A001 using Tapatalk


I too carry a full size OEM wheel as spare. I did see the OZ boot liner which is also available with Toyota UK. They keep claiming it's for 2017+ models only but am pretty sure will fit older models. I use my original one with some insulation on sides of tyre. Makes the depth of boot smaller but hey ho my car is 50-50 perfect weight distribution not 53-47, as manufactured.

Sent from my SM-G970F using Tapatalk

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