Anyone Tracked 17" vs 18" wheel/odometer differences?
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From: Albany, NY
My Ride: '04 545iS 6 spd, bought new via eBay, 11/05; Blk/Gry, Cold, L7, PDC, BMW Rear seatcover for pets.
First "Bumwa" was a new 1971 2002. High performance 5s since 1987. Beamer motorcycles too, currently on an 07 BMW K1200 GT; also a Moto Guzzi 1000 SP III.
Has anyone seen reports, or done any testing, of the veracity of our odometers/speedometers when switching from 18 to 17 inch wheels and tires? I'm not really worried, but since my 17" snows are on 5 months, some added difference could accrue.
I'm sure with all the "plus-sizing" that goes on, someone has studied this and I'd appreciate a reference.
Cheers,
Ray Hull
I'm sure with all the "plus-sizing" that goes on, someone has studied this and I'd appreciate a reference.
Cheers,
Ray Hull
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From: FLA - East Coast, USA
My Ride: (USA) 645Ci, Silver Gray, Chateau, Cold Weather PKG, Premium Sound PKG, Sport PKG, Step, NAV [Std Equip in 645], HUD, Satellite (SIRIUS) Radio, Aux Input, Bluetooth enabled using iPhone 3GS w/ adapter cradle - Build date - 01/05, Baby delivered 2/24/05
It is the total diameter that counts. So for instance if you go down an inch in wheel diameter but go up in aspect ratio (say from an 235/35/18 to a 235/40/17) you may find you lost no total diameter, or very little. BMW recommends you stay within 3%. Go to tirerack.com for comparisons and discussion. Now you should know that BMW odo/speed reads high as is (indicated speed of 60 mph may really be 58 mph for example). So, if you were to get a total diameter that is less than current then you would be even further off. If you went down the full 3% then at indicated 60 you might be at real speed of ~ 56. Odo follows in same manner. If on the other hand you went larger in total diameter you would end up getting real speed and odo closer to the indicated on gauges.
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My Ride: 545iSMGSilver GrayAuburn Dakota LeatherLogic 7 Premium SoundSports Package
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The new VW Passat has a menu item in the on-board-computer where you can choose your tire size (e.g. when changing between winter and summer rubber). It re-calibrates speedo, odometer, and the OBC average fuel consumption calculations etc. Kind of cool feature.
BMW, are you listening? Maybe CIP 21...
BMW, are you listening? Maybe CIP 21...
Thread Starter
Senior Members
Joined: Nov 2005
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From: Albany, NY
My Ride: '04 545iS 6 spd, bought new via eBay, 11/05; Blk/Gry, Cold, L7, PDC, BMW Rear seatcover for pets.
First "Bumwa" was a new 1971 2002. High performance 5s since 1987. Beamer motorcycles too, currently on an 07 BMW K1200 GT; also a Moto Guzzi 1000 SP III.
Originally Posted by Heikki' post='213090' date='Dec 19 2005, 03:46 AM
The new VW Passat has a menu item in the on-board-computer where you can choose your tire size (e.g. when changing between winter and summer rubber). It re-calibrates speedo, odometer, and the OBC average fuel consumption calculations etc. Kind of cool feature.
BMW, are you listening? Maybe CIP 21...
BMW, are you listening? Maybe CIP 21...
Thx,
Ray Hull
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From: Espoo, Finland
Enclosed picture of the Passat settings menu. The item "Winter tires" allows you to specify different tire size for your winter tires. And then the computer figures out how to adjust speedo/odometer accordingly.
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From: FLA - East Coast, USA
My Ride: (USA) 645Ci, Silver Gray, Chateau, Cold Weather PKG, Premium Sound PKG, Sport PKG, Step, NAV [Std Equip in 645], HUD, Satellite (SIRIUS) Radio, Aux Input, Bluetooth enabled using iPhone 3GS w/ adapter cradle - Build date - 01/05, Baby delivered 2/24/05
The new VW Passat has a menu item in the on-board-computer where you can choose your tire size (e.g. when changing between winter and summer rubber). It re-calibrates speedo, odometer, and the OBC average fuel consumption calculations etc. Kind of cool feature.
BMW, are you listening? Maybe CIP 21...
BMW, are you listening? Maybe CIP 21...
Thx,
Ray Hull
[/quote]
No. Unfortunately it is only an FTM, and no tie in with speedo/odo. But that does remind me that that would have to be reset when new tires/wheels mounted.
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My Ride: #1: 2004 545i; 6-speed manual; Sport Package; Mystic Blue with a gray leather interior and Anthracite wood; CWP; Logic 7.
#2: 2010 535xi Touring; Automatic.
Originally Posted by Heikki' post='213090' date='Dec 19 2005, 03:46 AM
The new VW Passat has a menu item in the on-board-computer where you can choose your tire size (e.g. when changing between winter and summer rubber). It re-calibrates speedo, odometer, and the OBC average fuel consumption calculations etc. Kind of cool feature.
BMW, are you listening? Maybe CIP 21...
BMW, are you listening? Maybe CIP 21...
Thx,
Ray Hull
[/quote]
I go from 18" summer standard wheels and low-profile sport package tires to 17" winter wheels (225/50s) but higher profile, so the outside diameter should be the same. On this last swap, a month ago, I wondered whether the car would care, and the FTM never went off.
Question: Would the FTM notice a different outside diameter, or would it only notice if the four were not the same?
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From: So Cal, USA
My Ride: 545iSMGSilver GrayAuburn Dakota LeatherLogic 7 Premium SoundSports Package
Originally Posted by Heikki' post='213106' date='Dec 19 2005, 03:43 AM
Enclosed picture of the Passat settings menu. The item "Winter tires" allows you to specify different tire size for your winter tires. And then the computer figures out how to adjust speedo/odometer accordingly.
Attachment 13579
Attachment 13579
Wow now thats pertty cool! BUT I can see people screwing with it and make it read lower milage and so they can sell the car for more money.
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From: FLA - East Coast, USA
My Ride: (USA) 645Ci, Silver Gray, Chateau, Cold Weather PKG, Premium Sound PKG, Sport PKG, Step, NAV [Std Equip in 645], HUD, Satellite (SIRIUS) Radio, Aux Input, Bluetooth enabled using iPhone 3GS w/ adapter cradle - Build date - 01/05, Baby delivered 2/24/05
Originally Posted by Ray Hull' post='213101' date='Dec 19 2005, 06:04 AM
[quote name='Heikki' post='213090' date='Dec 19 2005, 03:46 AM']
The new VW Passat has a menu item in the on-board-computer where you can choose your tire size (e.g. when changing between winter and summer rubber). It re-calibrates speedo, odometer, and the OBC average fuel consumption calculations etc. Kind of cool feature.
BMW, are you listening? Maybe CIP 21...
The new VW Passat has a menu item in the on-board-computer where you can choose your tire size (e.g. when changing between winter and summer rubber). It re-calibrates speedo, odometer, and the OBC average fuel consumption calculations etc. Kind of cool feature.
BMW, are you listening? Maybe CIP 21...
Thx,
Ray Hull
[/quote]
I go from 18" summer standard wheels and low-profile sport package tires to 17" winter wheels (225/50s) but higher profile, so the outside diameter should be the same. On this last swap, a month ago, I wondered whether the car would care, and the FTM never went off.
Question: Would the FTM notice a different outside diameter, or would it only notice if the four were not the same?
[/quote]
Your, probably right, that it would not go off since all four were the same and close to original diameter. I personally do not know for sure if you did have a significant difference in diameter but all were the same "difference" if the FTM would care or not.
Maybe some other snowman could tell us