Join Date: May 2016
Location: Victoria, Australia
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Space savers/Inflators kits
Having recently been in a position to buy spare alloy rims (at an excellent price) for my CX-3 I'm going to dump my temporary spare wheel. It prompted me to look deeper into the increasing practice of car manufactures to supply inflator kits or space saver wheels.
Note: All prices are in a$. I did at least use the "tire" spelling and not the correct "tyre" spelling (no nasty replies now).
In an effort not to be "too long winded" in what I write I've left out many important facts. I hope this article will inspire you to take a closer look yourselves.
Temporary spare wheels are only intended as an emergency replacement to get the vehicle to a place of repair, and the maximum allowable speed of the vehicle when one is fitted is limited to 80 km/h.
This speed limit is not because it’s necessarily the maximum allowable speed the temporary use tire will tolerate, (though in some cases it may be) but because with a mismatched wheel fitted to the vehicle, its handling and dynamics will be compromised, especially at higher speeds.
This can be an issue in outback or country areas where the vehicle may have to be driven several hundred kilometres, at reduced speed, before a suitable repair facility can be found.
While a temporary spare wheel may have practical limitations, it is still a better option than so called inflator or mobility kits. These single use kits are becoming more popular with vehicle manufacturers looking to completely dispense with spare wheels.
Here in Australia we get a temporary spare. If, when I purchased my CX-3 they only provided an inflator kit I would have insisted on a "full spare" or I wouldn't have bought the car.
The inflator kits are generally only capable of temporarily sealing small punctures. In cases where the puncture is large or the wheel or tire is damaged, they offer no assistance and the vehicle will most likely have to be towed to a place of repair. Ultimately though, it may not be possible to determine if the kit will reinflate the tire without actually trying it.
In some cases the tire will have to be replaced after sealant is used, regardless of whether it would ordinarily have been repairable. Replacement kits can be in the order of several hundred dollars and the sealants used often have a shelf life and need to be replaced after a certain period, regardless of whether or not they have been used.
Braking and Handling
In a series of comparative tests (by one of our motoring organisations) on four vehicles fitted with the standard wheel/tire combination and then again when fitted with three standard wheels and one space-saver on the driving axle, the following was observed.
The tests show that braking and handling can be adversely affected by using these different forms of temporary spare tyres."
In the emergency brake test in which the car was braked suddenly from a travelling speed of 80kmh -- the maximum recommended for driving with a space-saver -- the stopping distance increased for all four vehicles.
You can take the following with a grain of salt.
Mazda's public relations manager here in Australia says, the use of space-savers is to provide greater benefits for the customer.
"We fit space-saver spare tires because they give you the benefit of a larger boot and cargo area and that is the reason they are on most of our smaller vehicles. It is nothing to do with saving money," the manager said.
"There is also a safety benefit in using space-saver tire as it does help with rear-end crash protection".
"A space-saver is physically smaller and is therefore a much better proposition than having a full-size spare tire being pushed into the passenger cell."
The manager says Mazda has not been advised of any marked difference in braking performance with space-savers fitted.
"We are quite confident that our cars would perform well but, having said that, a space-saver spare tire is only for temporary use, is only allowed to be driven up to 80 km/h and should be changed as soon as possible."
Apart from the potential reductions in braking and handling performance another other issue is the fact that space-saver tires do not last as long as full-size spares and can be difficult and expensive to find, with prices ranging between $135 and $260.
One tire tested lasted just 450km before it needed to be replaced, which could place someone in a difficult situation if they were to have a flat on a country trip.
A standard tire rolls about 800 times per mile while a spare tire rolls about 850 times per mile (a difference of 50 tire revolutions per mile or about a 6% increase). Driving at higher than recommended speeds or for prolonged periods of time can result in excessive heat leading to driveline noise, wear or failure.
For this reason, many vehicle manufacturers recommend using Temporary/Compact Spare tires only in non-driven-wheel positions.
Please note: When Mazda show you how to put on the space saver either in the owners manual or on a video they ONLY SHOW changing the back wheel. That's because they don't want to tell you that if you get a flat on the front it means TWO wheel changes. That's because the space saver has to be put on the back.
Personally I think it's criminal to have to use a temporary spare. Let me know if you disagree AND WHY.
You only have the right of way if the other driver gives it to you
Last edited by Levi3xt; 12-19-2016 at 08:41 AM.