I've been on a bit of a "journey" on the subject this winter and thought I'd try to centralise and impart some of the knowledge that I picked up.
I hope its insightful and comes in useful in future!
Having some relaxing personal time on my hands, it nice to be able to give back to the community in this way. If you spot any errors or augmentations, drop a reply and I'll update!
I've had a decent amount of driving experience with winter and summer tyres in winter conditions so I've a good feel for the difference between the two on varying vehicles.
Over the years, I've been in some dangerously precarious situations with wide summer tyres in winter conditions which I don't ever want to repeat.
<b>P's and C's</b>
Here is the main winter wheel/tyre P&C list, please feel free to augment/correct this!
Pro's
- Improved water evacuation
- Improved wet traction
- Reduced aquaplaning tendency
- Improved snow/slush evacuation
- Improved snow traction
- Improved ice grip
- Lower operating temperature
- Potentially improved comfort due to tyre wall height
- Potentially increase lifetime of summer tyres
- Reduced dry traction
- Potentially worse economy, more rolling resistance? Urban myth?
- Potentially increased body roll due to tyre wall height
- Limited top speed
- Tyre Bible @ Car Bible
- Tyre sidewalls explained @ Black Circles
- Tirerack - great for reading up user input and comparing tyres analytically
- Tyre Test - as the name suggests
In DE, No doubt you can add additional options legally (e.g. 20") however I'd wager new rims and tyres would have to equal the same rolling radii as the OEM specs.
As far as we've researched, there is no specific law in Germany that enforce the use of winter tyres. However there are some counties that can be funny about it and can slap heavy fines on motorists that are endangering other road users/pedestrians with inappropriate tyres for the conditions. Not to mention that it can totally invalidate your insurance. If you have a bump and investigation deems it could of avoided with more appropriate tyres, your insurance can refuse to support you.
Generally motorists in DE keep a set of summer rims and a set of commonly steel rims with winter rubber that get fitted when the temps start to drop.
For the E60 B5 there are limited rim options because of the truck sized discs and calipers from the B7 and 760Li.
19" and 18" rims are our current options, with the following rim/tyre combos. Of course I wouldn't want to fit steal rims, even if I could!
I've built this info up with help from my Father, my owners book, Alpina DE and UK clarifications, extensive web research incl. this forum and speaking with others.
<b>19" Winter option</b>
4x 19" x 8.5J rims with 245/40 R19 98V+ XL rubber
Note that the summer staggered setup isn't permissible here, I've confirmed this with Alpina DE.
I'm guessing the main reason is because its near impossible the get winter rubber at 275/35 100Y XL.
<b>18" Winter option</b>
4x 18" x 8J rims with 245/45 R18 100V+ XL rubber
As mentioned anything outside these specs with our DE registration and insurance would give us major issues.
This makes tyre choice a little tricky.
<b>19" Complications</b>
First we'd need to find/buy two 19" 8.5J rims. New, prices seem to start around 1,350 EUR / 1,200 GBP for a pair.
Finding <i>cost effective</i> winter rubber at 245/40 is near impossible.
As clarified by Alpina DE, The only worthwhile 19" consideration is the Dunlop SP WinterSport M3 New, prices seem to start around 1,100 EUR / 1,000 GBP for a set of 4.
The next issue is trying to find stock of the Dunlop SP WinterSport M3... As of writing officially this size isn't stocked/shipped to UK/IE. If your outside the mainland EU, shipping is the only option. This brings in the "Who will fit them" complication.
I have found other 19" tyre options to spec but cost and stock availability make it prohibitive.
We looked at Vredestein Wintrac Extreme, very promising but don't have the spec we need. Nearly bought a set of 19's for the summer staggered set up when we realised that they were not legally permissible.
So for new Alpina recommended kit, minimum spend around 2,450 EUR / 2,200 GBP
<b>18" Simplifications</b>
The 18" option does make things considerably simpler.
In comparison to the 19" option, there is a massive range of to spec winter tyres available.
So, first you need to find some 18" rims, if you asked Alpina to supply you with a complete winter wheel and tyre package you'd be looking at cool 3,485 EUR / 3,150 GBP.
If you went to an after market supplier for 4 authentic Alpina rims, new, start around 1,800 EUR / 1,600 GBP.
Alpina recommended tyres for 18's, new, start around 900 EUR / 800 GBP.
Other performance options, new, start around 800 EUR / 700 GBP.
So for new Alpina recommended kit, minimum spend around 2,700 EUR / 2,400 GBP.
<b>B5 specific conclusions</b>
If you only have staggered 19" rims and want to use 19" and follow Alpina's recommendations, you'd need to procure 2x 8.5J rims and 4x 245/40 tyres. New, this starts around 2,450 EUR / 2,200 GBP.
Trying to find 19" staggered to spec winter tyres is like looking for hens teeth up the backside of a rocking horse! If you did find something, you'd be starting around 1,100 EUR / 1,000 GBP.
19" tyre replacement cost is always going to be higher due to the size.
18" are the way to go imho, the narrowest you can get. Tyre choice and price range is wide and replacement cost is less than 19".
<b>General conclusions</b>
As a general rule, the narrower tyre contact surface, the more cutting traction it will achieve in snow/ice conditions.
As a rule winter tyres enter there optimal performance temperature quicker, well suited for winter temps.
In theory the investment of a winter wheel set should extend the lifetime of summer tyres, long term cost saving.
The Pro's list above really shows that if the conditions deem it and if you can, running winters makes a lot of sense for year round optimal traction.
<b>Personal Choice</b>
Given that our B5 does a fair bit of Pan-European cruising year round and we often spend XMAS with German family. Winter tyres wheels and tyres make a lot of sense for us.
I went hunting for a second hand set of 18" Classics and with the help of Alpina DE and bit of luck I found some going for decent money in DE.
