Chains for Audi Q7 with 20" wheels

Discussion in 'Snow Talk' started by AndrewA, Jul 28, 2012.

  1. AndrewA

    AndrewA One of Us

    Joined:
    Jun 26, 2012
    Messages:
    666
    Likes Received:
    507
    I've done some searching about this, and found little.

    I'm after some chains for our car - wheel size 275/40/20. From what I've found, chains are difficult to find for this tyre size, and probably shouldn't be fitted anyway as " it will damage the tyres...".

    There must be has of Q7s, and other cars with the same tyre size who drive up to the snow each weekend in Victoria. What do you do about chains? Des anyone have any to sell, or know anyone who wants to offload some?

    We've recently upgraded our 1991 Nissan Patrol to a 2007 Q7. I'd like some chains for my use getting along the 4wd tracks to Mt Bogong, but Los need some for any resort entry in Victoria.

    Andrew A








    We have replaced our 1991 Nissan Patrol with a Q7,
     
  2. HockeyMonkey

    HockeyMonkey First Runs

    Joined:
    Jul 24, 2009
    Messages:
    96
    Likes Received:
    0
    #2 HockeyMonkey, Jul 28, 2012
    Last edited by a moderator: Dec 15, 2013
  3. gareth_oau

    gareth_oau Pool Room
    Ski Pass - Gold

    Joined:
    Dec 27, 2008
    Messages:
    43,602
    Likes Received:
    14,282
    #3 gareth_oau, Jul 29, 2012
    Last edited by a moderator: Dec 15, 2013
  4. gareth_oau

    gareth_oau Pool Room
    Ski Pass - Gold

    Joined:
    Dec 27, 2008
    Messages:
    43,602
    Likes Received:
    14,282
     
    #4 gareth_oau, Jul 29, 2012
    Last edited by a moderator: Dec 29, 2013
  5. snowtyres

    snowtyres Hard Yards
    Ski Pass - Gold

    Joined:
    Jun 8, 2006
    Messages:
    894
    Likes Received:
    104
    Suggest you check the Tyre Info plate in the door opening of your Q7.

    I am sure it will show the 20" tyre option to be 275/45R20 with a load rating of 110. You posted your tyres are 275/40R20 which are likely to have a load rating of 106 or even 102. 
    If this is so it is likely the previous owner has fitted incorrect tyres. 
    If tyres with an inadequate load rating are fitted to any vehicle they should be replaced as there insurance and roadworthy issues.

    You will also need to check the speed rating of the 20" Tyres you have as  high speed W or Y rated tyres were never designed to be driven in off road conditions. The ideal alternative is to have another set of 18" wheels as there is a much larger range of tyres available for use in off road (4WD tracks) or snow in sizes 255/55R18 or even 255/60R18

    There is no problem in supplying snow chains for either tyre size and no snow chains will not damage a tyre. Chains are fitted to the rear wheels of Audi Q7.

    You posted "I'd like some chains for my use getting along the 4wd tracks to Mt Bogong, but Los need some for any resort entry in Victoria."

    Thule/Konig would never suggest you use their K-Summit snow chain for the application you have detailed as they are not correct for this use.

    The correct chains for the application you have described are Konig Rallye, subject to tyres to inner guard, clearance check.
    http://www.roofcarriersystems.com.au/item/konig-rallye-snow-chain/

    The alternative, if you prepared to use this snow chain off road, would be Konig T2 Magic 16 mm clearance chain.
    http://www.roofcarriersystems.com.au/item/konig-t2-magic-snow-chains/
    Both these chain types are also correct for "resort entry in Victoria."

    As shown in the video in the previous post the Thule/Konig K-Summit snow chain is designed to further increase the performance of a winter tyre. (The Thule/Konig video  actually shows the K-Summit being fitted to a Nokian WR winter tyre)
    No snow chain will ever change a vehicle that is fitted with high performance rated summer tyres into a safe winter performer.
     
    #5 snowtyres, Jul 29, 2012
    Last edited by a moderator: Dec 15, 2013
  6. AndrewA

    AndrewA One of Us

    Joined:
    Jun 26, 2012
    Messages:
    666
    Likes Received:
    507
    Thanks for that. You are right - my tyres are 275/45/R20, and they are M&S Cooper Zeon XSTs.

    I presume they are fine to use with chains if needed.

    By the way, why do you fit the chains to the rear of a Q7?

    Andrew A
     
  7. snowtyres

    snowtyres Hard Yards
    Ski Pass - Gold

    Joined:
    Jun 8, 2006
    Messages:
    894
    Likes Received:
    104
    Fitting of chains on an AWD is determined by the transmission system of the vehicle make, some are on the front, (Volvo XC90, Captiva, Audi Q3, VW T5&Tiguan etc) some are on the rear. (Audi Q7&Q5, MB ML, BMW  X5, Prado, LC100 etc)
    Snow chains are required to improve the performance of a vehicle because of the gradient of the road NOT just the weather conditions. 
    Any vehicle maker would always assume that the vehicle would have winter tyres before snow chains are required. For them the idea of fitting snow chains to a summer tyre is illogical, "why would you bother" they may say.
    Somewhat of a contrast to the way snow chains are used in the alpine areas of Australia.
    Snow chains, on summer or all season tyres, on the back wheels will help you climb but will not help you stop, or steer, when you are driving down hill. When the vehicle is fitted with winter tyres, and you have snow chains on the rear wheels, you will still have the braking and steering control.
    This will help to explain why the majority of incidents on alpine roads here in Victoria and NSW occur when driving down hill, not uphill.

    In addition to this if you put your hand over the front tyre, at the twelve o'clock position, you will there is no clearance for snow chains on Q7 between the front wheels and the suspension.
     
    fletch likes this.
  8. AndrewA

    AndrewA One of Us

    Joined:
    Jun 26, 2012
    Messages:
    666
    Likes Received:
    507
    I'd didn't realize the Auds had a rear transmission, and, yes, there's little room at the front, as you say. The Auds is a v different voiture to my 1991 Nissan Patrol!! No issues with wheel clearance with the latter!

    I have plenty of experience with driving in the snow - just hadn't got my head around the requirements of the Audi, as it's a newish acquisition.

    A
     
  9. silverfox.mike

    silverfox.mike First Runs

    Joined:
    Nov 6, 2018
    Messages:
    4
    Likes Received:
    0
    The on-line manual for my Q7 also states that Snow Chains are to be fitted to the rear wheels. But that the tyres should be changed to 215/60/R18 on 18 inch rims. This makes the wheel much narrower (standard 20" tyres are 275mm wide and the winter tyres are therefore 60mm narrower).
    Consequently there is a noticeable gap behind the front wheel at the 12 o'clock position. Therefore I am surprised that chains are stipulated as rear fitment in the manual.
     
  10. snowtyres

    snowtyres Hard Yards
    Ski Pass - Gold

    Joined:
    Jun 8, 2006
    Messages:
    894
    Likes Received:
    104
    "The on-line manual for my Q7 also states that Snow Chains are to be fitted to the rear wheels."
    (this is correct for Audi Q7 2006-2015 series)

    "But that the tyres should be changed to 215/60/R18 "
    (this is incorrect, suggest you check again as it should read 235 60 R 18 not 215/60R18)
    "on 18 inch rims."

    AUDI Q7 2006-2015 AUDI Q7 (PL71) 4L 2006-2009, Q7 (PL71) 4L9 2009-2015
    Q7 - Audi approve the fitting of snow chains to 235 60 R 18, 255 55 R18 and 275 45 R 20 winter tyres & winter wheels
    Q7 - Audi only approve the fitting of snow chains to rear wheels

    AUDI Q7 2015- AUDI Q7 (Typ 4M) 2015-
    Q7 - Audi approve the fitting of snow chains to 255 55 R 19 tyres on winter tyres & winter wheels.
    Q7 - Audi only approve the fitting of snow chains to front wheels.
     
  11. silverfox.mike

    silverfox.mike First Runs

    Joined:
    Nov 6, 2018
    Messages:
    4
    Likes Received:
    0
    You're right of course, it was a mis-type on my part 235/60R18 is the stated size
    I just hope I get sufficient steerage when running on snowy terrain in the alps
     
  12. snowtyres

    snowtyres Hard Yards
    Ski Pass - Gold

    Joined:
    Jun 8, 2006
    Messages:
    894
    Likes Received:
    104
    Wheel chains fitted to 275 45 R 20 summer tyres on the rear wheels of Audi Q7 will increase traction for take off and driving but can not assist with steering or lateral stability. Because of inadequate grip on the front tyres the vehicle will not ‘turn in’, it will understeer and when braking the ABS system will be activated, further increasing the stopping distance. Again the problems are always worse when driving down hill than up hill.

    On summer tyres snow chains will grip compacted snow but the tyre can slip or spin on the chain even when they are tensioned to the tyre. The problem is compounded by the camber of the road, the weight and torque of the vehicle and the amount of tread on the tyre. The problem is worse when the vehicle has been parked at the resort because of the low ambient temperature makes the tyres harder and therefore has even less grip to the chain.

    Wheel chains rely on the tread of the tyre for grip to help prevent the tyre/wheel from spinning inside the chain.
    In order for wheel chains to work effectively they must penetrate into the compacted snow surface to penetrate to provide the maximum amount of traction. Traction may be lost, when the snow and/or ice begins to break up and melts to slush, and wheel spin is experienced. In certain situations the vehicle can slide on the wheel chains.
     
  13. Whatever really

    Whatever really Hard Yards

    Joined:
    Sep 21, 2017
    Messages:
    230
    Likes Received:
    190
    Audi have a service where you can call in and they will swap the summer road tyre 20” wheels for a 18” winter tyre option and chains,
    There is a fee and it has to be booked but if it is only an occasional trip in bad weather it’s not a bad option.
    I was told this when I bought my Q5 with 20” wheels.
     
  14. Boodwah

    Boodwah One of Us
    Ski Pass - Gold

    Joined:
    Jun 20, 2006
    Messages:
    3,732
    Likes Received:
    4,739
    I found a pair of cheap well fitting rear wheel diamond patterns online, can find the brand and size if peeps want. Just to avoid being fined.
    In fact they work really good, but we would have also been fine without them every time they made us put them on. Which these days at Gotham is any sign of a light frost.
     
    Hully likes this.
  15. Xwing

    Xwing One of Us

    Joined:
    Jun 22, 2016
    Messages:
    671
    Likes Received:
    786
    Don't you have a snow driving button? I just press the Hold button, the snowflake appears on the dash, and my Liberty is fine. Snow is never deep enough here to worry about anything though.
     
  16. Boodwah

    Boodwah One of Us
    Ski Pass - Gold

    Joined:
    Jun 20, 2006
    Messages:
    3,732
    Likes Received:
    4,739
    Haven’t found a snowflake button!
    Haven’t needed one.
    But do need some semblance of chains to avoid copping a fine when made to put them on.
     
    teckel likes this.
  17. teckel

    teckel Old n' Crusty
    Ski Pass - Gold

    Joined:
    Oct 16, 2004
    Messages:
    37,941
    Likes Received:
    5,644
    LOL Dunno where you drive then. Your little snowflake merely lowers the gear ratio.
     
  18. Charlie

    Charlie Still the most depraved poster here
    Ski Pass - Gold

    Joined:
    Jun 27, 2002
    Messages:
    23,065
    Likes Received:
    6,482
    Useless, unless it automatically fits chains
     
  19. snowtyres

    snowtyres Hard Yards
    Ski Pass - Gold

    Joined:
    Jun 8, 2006
    Messages:
    894
    Likes Received:
    104
    electronic driver aids, such as ABS, ESC, traction control and the “snow driving button” do not provide more traction. These electronic aids only prevent drivers from over braking or overpowering the available traction of their tyres. The only thing the driver can do to increase traction, to actually get more grip and safer control, is to install winter/snow tyres
     
  20. Boodwah

    Boodwah One of Us
    Ski Pass - Gold

    Joined:
    Jun 20, 2006
    Messages:
    3,732
    Likes Received:
    4,739
    Unless you ski Hotham in which case snow tyres are pointless
     
  21. teckel

    teckel Old n' Crusty
    Ski Pass - Gold

    Joined:
    Oct 16, 2004
    Messages:
    37,941
    Likes Received:
    5,644
    FIFY
     
  22. silverfox.mike

    silverfox.mike First Runs

    Joined:
    Nov 6, 2018
    Messages:
    4
    Likes Received:
    0
    I have a second set of 18" alloys with snow tyres fitted - I swap out my regular 20" rims each winter should bad snow be expected or if I am going to be driving to the Alps in France for a ski holiday. Last time I went the roads were clear enough to not need to fit the chains. Which was good because by default I would have installed them on the front wheels as per my old XC90 without recourse to the manual.
    Now I'm aware that they need to go on the rear. Question still stands though, an 18" wheel with snow tyres compared with a 20" wheel with summer tyres has:

    A total diameter that is 33.55mm (1.32") smaller
    A total radius that is 16.78mm (0.74") smaller
    A total width that is 40.0mm (1.57") narrower
    (Most of which seems to come from the inside edge of the wheel as the outer edge appears broadly the same as the 20" wheel)

    So my snow chains that are max 10-12mm in thickness should fit the front wheels with no risk of catching on any of the front suspension components.
     
  23. snowtyres

    snowtyres Hard Yards
    Ski Pass - Gold

    Joined:
    Jun 8, 2006
    Messages:
    894
    Likes Received:
    104


    Question still stands though, an 18" wheel with snow tyres compared with a 20" wheel with summer tyres has:

    Image of tyre details/tyre pressure sticker from Audi Q7 -2015 shows
    Summer tyres (Y XL) marking, that are approved for Audi Q7 -2015
    (Y speed rating is up to 300km/h)
    Winter tyres (M+S)* marking, that are approved for Audi Q7 -2015
    (H speed rating is up to 210km/h)
    (V speed rating is up to 240km/h)

    The difference in diameter/circumference of the 275 45 R 20 (Audi Q7 Summer tyre) and the 235 60 R 18 (Audi Q7 winter tyre) is around 2%.
    This is quite acceptable for Audi Q7, if it was not then Audi certainly not list this winter tyre size in the owners manual or on the tyre details/tyre pressure sticker.

    Refer Audi Q7 owners manual for further details of winter tyres and snow chains for your Audi Q7 -2015

    *In Germany the old rules have been tightened and the M+S logo no longer suffices. Only tyres with the Snowflake logo (3PMSF) comply with their new regulations. Motorists in Germany have a legal obligation to fit winter tyres on their vehicles.
    Any forthcoming regulation changes for Victoria are likely to include a requirement that snow chains comply with the European ON-V5117 standard and snow/winter tyres be identified with the 3PMSF symbol as per the ECE 117.02 snow test as tyres with M+S marking are not associated to any mandatory traction test and there is no performance guarantee associated with M+S marked tyres.
     
    #23 snowtyres, Nov 14, 2018 at 4:34 PM
    Last edited: Nov 15, 2018 at 11:25 AM
  24. silverfox.mike

    silverfox.mike First Runs

    Joined:
    Nov 6, 2018
    Messages:
    4
    Likes Received:
    0
    Unless I am completely misunderstanding what I have read up on, it is a mathematical impossibility for all those tyres to have the exact same diameter and circumference. You've only got to look at the maths to see why.



    The sidewall of the 20" tyre is 45% of the 275mm width = 124mm
    The sidewall of the 18" tyre is 60% of the 235mm width = 141mm
    A 20" alloy has a diameter of 508mm
    A 18" alloy has a diameter of 457mm

    If you add these respective numbers together you get the total wheel diameter for each wheel and they are definitely different which would make the circumference different too. Using Pi x diameter you get the circumferences as (20" tyre = 78 inches and 18" tyre is 74 inches [rounded to 0dp])
     
  25. snowtyres

    snowtyres Hard Yards
    Ski Pass - Gold

    Joined:
    Jun 8, 2006
    Messages:
    894
    Likes Received:
    104
    The difference in diameter/circumference of the 275 45 R 20 (Audi Q7 Summer tyre)
    and the 235 60 R 18 (Audi Q7 winter tyre) is around 2%.
    This is quite acceptable for Audi Q7, if it was not then Audi certainly not list this winter tyre size in the owners manual or on the tyre details/tyre pressure sticker.

    The https://tiresize.com/tyre-size-calculator/ takes the measurements of two tyres and compares the diameter, width, sidewall, circumference, and revolutions per mile.
    Then as a bonus it shows examples of your speedometer reading with the first tyre, and the actual speed you”re traveling if you were to install the second tyre.

    You can use this link to compare the other tyre sizes shown on the Audi Q7 tyre details/tyre pressure sticker