10-31-2014, 11:59 AM | #1 |
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Winter wheel/Tyre Change - Will this require any change to set up of car?
Hi Guys,
I'm looking to get some winter wheels/tyres, wanted to check if I can change between wheel/tyre sets without having to make any technical changes to the set-up of the car. Apologies if this is a really dumb question. I currently run the standard factory fit rear 245/35-R18, front 225/40-R18 tyres. I'm thinking of buy a set of bmw 16inch alloys with 205/55-R16 conti winter tyres. Both these tyres will have different diameters and circumferences sizes so I’m concerned my speedo will give me incorrect readings and it may have other effects to the set-up of the car, like fuel economy or handling etc? bmw actually sell this wheel/tyre combination and say its compatible with my car, so I want to know if it is a case of simply swop the them over and your good to go? or if you need to change some setting or something to factor in the change in tyre/wheel size? Thanks in advance |
10-31-2014, 01:51 PM | #2 |
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You vill have to recalibrate the tyre diameter in the iDrive in the vehicle status screen. The car does this by itself, but you have to initialize the process.
The handling of the car will change slightly, as the winter tyres behave more sluggishly. Somewhat less stability at high speed, slower steering response, and more forgiving at the limit. |
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10-31-2014, 05:56 PM | #3 |
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Thanks for the reply.
Im guessing it's the tyre pressure fuction your referring to? I had a play with this function while driving home today. it didn't do anything of course because the wheels haven't changed yet but I'm glad it's a simple thing to set up. Thanks |
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11-01-2014, 02:34 AM | #4 |
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You can initialize the tyre pressure feature (which is really supervising the tyre diameter) anytime you want, as long as the ignition is on, and the car is standing still.
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11-01-2014, 04:10 AM | #5 | |
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Stick with the BMW Recommendations
Quote:
Hi there, As long as you stick with BMW's recommended tyre sizes you will be fine. While the rim diameter reduces from 18' to 16', you'll notice that the aspect ratio (height/width) is bigger, meaning that your tyres have deeper sidewalls.....in other words, while the inside diameter is smaller, the outside diameter and therefore circumference are the same. All you'll need to do is re-initialize your tyre monitor as ovekvam mentioned and you're good to go. Just to note that using non-standard tyre sizes with different diameter and circumference will screw up your speedo readings and change your final gearing slightly. Good winter tyres like Continentals offer a slightly plusher ride (more sidewall compliance), less sharp steering and ultimately less dry weather grip, all of which you'll hardly notice due to the poorer road conditions that generally prevail during winter. In the poorer road surface conditions they'll offer improvements in both grip and braking, which is exactly the point of winter tyres. |
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11-01-2014, 06:20 AM | #6 |
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You will notice the ride is softer with the taller sidewalls, even if the winters are runflats. I run the 16" steel wheel and use the BMW store and fit service, the steels also feel noticeably heavier than my 18" alloy set.
May still be a few weeks before I consider booking in to swap as it was 20c here yesterday.
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11-02-2014, 03:59 AM | #7 |
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Nice one, thanks for the responses guys.
I will most likely buy wheel tyre set. Now in a weird way i'll be hoping the weather turns nasty to see what the tyres can do! Final question.. do you guys run your winter tyres at the same pressures as summer tyres? Thanks |
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11-02-2014, 04:50 AM | #8 |
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