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When consumers are shopping for winter tire packages, they are often asked if they want universal fit or hub-centric wheels, especially when buying steel wheels. If you aren’t being asked this, then you should inquire as to what product you are getting. Here’s the Lou-down on this subject.

The energy from road hazards, bumps and potholes needs to be transferred from the wheels and tires into the suspension, where the shocks and struts can do their jobs and absorb this energy. This transfer of energy is supposed to occur through the hub, a mating point located where the centre of the wheel mounts onto the vehicle. All auto manufacturers design their original factory wheels to directly mount in this fashion.

If there is no contact between these two points, all that energy will be transferred though the wheel fasteners. It’s a task they are not designed for. The job of the fasteners, also known as a wheel nut and stud, is to simply fasten the wheel to the vehicle. While it doesn’t happen often, a wheel separation may occur due to all the studs breaking simultaneously when extreme road forces have been applied to the fasteners and not the hub.

When you are sourcing alternative wheels, as is typical for winter applications, the economy wheels will be labelled as universal, meaning the wheel centre and hub do not mate. Alternatively, hub-centric products are labelled as such and are designed so that the two mating surfaces do their job as the manufacturer intended.

Rim-to-hub adapters can be bought to do this job, but calculating and sourcing them will be tedious.

While it’s not the end of the world if you don’t have hub-centric products, I do believe that for the minor bump in cost, the upgrade is worth it.

Your automotive questions, answered

Dear Lou, our Sante Fe and Mazdaspeed 6 are six- and four-cylinder engines, both 2006. 200,000 and 70,000 kilometers, respectively. Well-maintained and driven gently. We buy for the long term. At highway speeds, to stay with traffic flow, engines are running at about 3000 rpm. Should I consider an eight-cylinder for my next vehicle, so it turns over at lower rpm? Is that easier on an engine, and does it help it last longer? As well, our experience has been that other systems and components wear out before the drivetrain, anyways. Are their bigger longevity factors to consider? Your opinion please.

Paul C, Woodstock, Ont.

The number of cylinders an engine has has no bearing on highway rpm, only gearing dictates rpm.

There once was a legitimate argument to support the notion that V8s lasted longer, but that was quite some time ago. The first four-cylinder engines to gain popularity in the 1970s were indeed less robust and problematic. At that time, manufacturers hadn’t quite figured out how to produce long-lasting small-displacement engines. Fuel was cheap, and the vehicles were, shall we say, somewhat larger and heavier than contemporary counterparts. There was little need to fix something that wasn’t broken at that time.

But then the laws regarding emissions and fuel economy changed, forcing manufacturers to invest extensive resources in developing and producing fuel-efficient vehicles. They had no choice but to work out the kinks of their smaller-displacement engines. The only segments where V8s are still necessary are pickup trucks, work vehicles and performance-oriented vehicles.

Hello Lou.

I recently bought a 2016 BMW X3. The tires on it are 275/40/R19 on the back and 245/45R19 on the front. For winter tires, I have a set of rims from an old BMW, 17-inchers that clear the calipers on the newer vehicle. I’ve calculated that 225/65 R17 will work well for winter tires. Is it too much of a jump to drop the rim radius to 17? I have read that that is okay, but my local mechanic is not sure. Thanks for your help.

David S

The change from 19- to 17-inch wheels is not critical to any essential functions of the vehicle. The must-know information is brake-caliper clearance, wheel-center-to-vehicle-hub mating and overall tire diameter.

When testing out potential used donor wheels, ensure that brake-caliper clearance is generous; a minimum of 10 millimetres is necessary, especially in the front. On multiple occasions, vehicles have come in for brake servicing, and after the installation of a new set of brake pads, their winter wheels no longer fit. When we tried to bolt them back on, they now made contact with the calipers. This is because most brake calipers are floating and move inwards, making up for the shrinking/wearing brake pads. If the used winter tires you just bought were fitted at a moment when the brake pads were close to worn, a tight-fitting set of wheels may be problematic later on.

The wheel’s center bore should mount directly onto the hub. This is the way the manufacturer designed it. See below for further information on this.

Finally, overall diameter difference has to be within 3 per cent in order to assure accurate speedometer readings. I have also double-checked the calculations for you, David, and the results are 3.1 per cent. While slightly outside of acceptable range, I’m sure you will be fine.

Lou Trottier is owner-operator of All About Imports in Mississauga. Have a question about maintenance and repair? E-mail, placing “Lou’s Garage” in the subject line.

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