Tyre balancing - how specific to vehicle spec is it?

November 12, 2016 4:33 AM

When balancing tyres, does the difference between e.g. 2 distinct engine types on an otherwise identical chassis need to be taken into account? My snow-tyre-flake inside...

I've recently ordered some winter tyres online for my new-ish Skoda Yeti. Shipment notification arrived last night, so they're on the way to me and it would be a reasonable hassle to send them back.

I ordered tyres plus rims, mounted, balanced and ready to go, intent being to change them over myself (I live in the mountains, so this is a twice a year every year swap job that I'm happy to save paying a garage to do). I've ordered tyres on rims from this company before and been perfectly happy with this service.

The potential issue is... on ordering mounted tyres, they ask for specific model and sub-type of vehicle; I've just noticed on the shipment email that I've made a minor slip-up and selected a slightly different model Skoda Yeti to mine.

Mine has a 1.2 tsi petrol engine, 103hp, weighs 1265kg unloaded.

The one I selected was a 2.0 tdi diesel engine, 107 hp, weighs 1377kg unloaded.

Vehicle type is otherwise identical in every respect, same chassis, both 2wd.

The specs seem close enough that this shouldn't be something I should need to worry about, but I'd appreciate opinions from people in the know on the specifics of tyres as to whether I should get them re-balanced.

I'll be driving on Alpine roads at 1000 - 1500m, potentially in very snowy conditions from time to time. The tyres I went for are relatively high-end - Goodyear Ultra-Grip Performance Gen-1.

posted by protorp to Travel & Transportation (10 answers total)

Best answer: Tires are balanced to themselves. The weights are added because the tires are not perfectly even and oscillate at high speeds if you don't balance them. I'm not sure how much the specific car matters. I can't think of how or why it would.
posted by humboldt32 at 4:38 AM on November 12, 2016 [1 favorite]

Best answer: It would only matter if the other model had a different pattern of bolts on the wheel, which is spectacularly unlikely in this case. Alternatively if you were to put tyres of the wrong speed grade on your vehicle you might invalidate your insurance in some places. But a 2.0TDI is probably more powerful than your 1.2TSI so I doubt that will be a problem.

As humbolt32 says, the balancing is to make sure that the wheels spin on their axle without wobbling due to the weight of the tyre being slightly off-centre & has nothing to do with what vehicle the wheel is attached to.
posted by pharm at 4:42 AM on November 12, 2016 [1 favorite]

Best answer: Yes, the reason they ask for specific model is to make sure the wheels will fit on the car: not just bolt pattern, but in some cases, clearance for the brakes, fitting for inflation monitoring devices, etc. Nothing to do with the balancing.
posted by mr vino at 4:48 AM on November 12, 2016 [4 favorites]

Their requirement as to "specific type" etc. has only to do with the way the wheels are mounted, which may be different between cars, and possible design differences of the wheel area etc. As you say they're identical, there won't be any problems.
And as others said. Balancing has nothing to do with all that. If the wheels are bought "as balanced" they will be balanced. Have fun driving in the snow!
-- on preview, yeah right.
posted by Namlit at 4:51 AM on November 12, 2016 [1 favorite]

They sell cars in different trim levels. With a bigger engine, you get fancier electronic stuff, and often you get bigger/fancier wheels.

They ask for your trim level so they can know what size tires to sell you. It's less important if they're also selling you the wheels, since they know their tires will fit on their wheels. But if it's different from your current wheel/tire combination, things like speedometer calibration may be out of whack.
posted by Huffy Puffy at 7:38 AM on November 12, 2016

Best answer: There are many things that can vary between trim levels of cars when it comes to wheels. This includes rim size; caliper size and wheel shape; backspacing/offset; and bolt pattern. As others have said this is why the companies want to know your specific model. It's not unusual for the base model to have smaller brakes than others (my Caravan is like this; the base model of my year has smaller brakes than all the other models).

I ran into a weird situation once where the second time I went to put my winters on my Caravan they interfered with the caliper even though they'd been fine the previous year (the tires and rims were from a previous model Caravan). Investigation revealed a slight backspacing difference (like 3mm) and the brand new pads I installed at the same time as the winter tires pushed the outer surface of the caliper out enough to interfere with the wheel.

I'd email/contact their customer service and verify they have sent you equipment that will work on your car. But it is a fitment problem not a balancing problem.
posted by Mitheral at 8:26 AM on November 12, 2016

Response by poster: Thanks all, going to do some more digging on the 2 type specs re. brakes etc. as a result of this helpful rundown. Fairly hopeful that the tyres will thus be fine as ordered, we shall see next week.
posted by protorp at 8:51 AM on November 12, 2016

In your case the considerations would be gross weight rating and speed rating. You're fine.
posted by fixedgear at 9:45 AM on November 12, 2016

Check the tyre pressures, the different vehicles may have different specifications (good to do anyway).
posted by cosmac at 11:47 AM on November 12, 2016

Go to your supplier's website and spec out a package for the diesel engine version. If the result is the same as you ordered you are golden.
posted by leaper at 4:05 PM on November 13, 2016