Winter tyre size confusion

[mjbarnard]

Apologies new thread - but want to enquire about what size winter tyre - rather than discussion on pros and cons as discussed extensively elsewhere.

I have W211 E320CDI saloon. It is sports version with front 245/40 18 and rear 265/35 18. The wheels are slightly different widths. According to the owners manual the front is 8.5J x 18 and the rear 9J x 18.

I would like to fit winter tyres, but the manual is confusing. It lists my tyre and wheel sizes for my model, and then under winter tyres says for both front and rear 245/40 18. However just below this it says wheels should be 8.5J x 18. The offset on existing wheels are 38 and 39. It is further confusing in that it says for winter tyres refer to page 369, but there is nothing related to the sports model on that page.

My questions are :
I would prefer not to buy new wheels. Obviously I can buy winter tyres in the identical size to existing ones, but if I prefer to buy 245/40 18 for all four (as advised by handbook) - can I fit 245/40 18 to existing rear wheel (9J). Or will I need to change rear wheel to 8.5J?

I rang Mercedes (Park Royal) for advice. Unbelievably they told me
1) Winter tyres do not come in 18 inch size (not true!).
2) I would have to change to 17 inch "rims" if I wanted winter tyres (not true)
3) In any case winter tyres were "not recommended" for this country. I should only use them if I go to "countries like Germany where there is a lot of snow" !! They asked if perhaps I wanted snow chains instead?!

I then went to my regular tyre dealer who is usually very reliable. He said he didnt know the answer. He suggested the safest was to use existing sizes - however he can only source a budget tyre for the 265/35 size. He is ringing around though.

So now I am thoroughly confused - can I fit 245/40 18 onto my 9J x 18 existing rear wheels which currently have 265/35 18. If I need to change the wheel - do I simply buy a 8.5J x 18 ET38 and it can be safely fitted in place of the current wheel?

 

[312 Sprinter]

I'd be inclined to buy another set of wheels. Generally a slightly narrower winter tyre will work better than the summer equivalent with a big footprint

 

[GordonTarling]

I bought a set of 17" wheels for my S211 Sport, to use in the winter. Rims are 17" x 8" and I'm having 225/45/17 Falken tyres fitted. Check the online tyre size calculators to see what size tyres you can fit on your existing rims. This one's quite useful - Tyre Calculator - Alloy Wheels, Rochford Tyres - Specialist supplier of alloy wheels and tyres packages, Fast Delivery, Buy Online.

 

[grober]

The first thing to say is the the doofus you talked to at MB Park Royal knows nothing about fitting winter tyres! In Germany people often have a complete alternative set of winter wheels and tyres fitted to their cars in the winter months. The general rule is narrower tyres/ wheels are better and the higher the profile the tyre [ taller sidewall if you like] the better. However for each individual model there are specific rules e.g. going down to a smaller diameter wheel say 16" or 17" might be a good idea in order to fit higher profile tyres-----but a smaller diameter wheel might start to foul the brake calipers!! Best practice is to follow the size recommendation in the car's handbook and usually that involves reducing the rear wheel size to the same as the front so the tyre size is the same all round. Because the the tyre manufacturers keep an eye on what tyre sizes sell you will find certain "favoured" sizes like 245/40 R 18 offer a wider choice of tyres simply because there's a bigger market for them. Altho best practice is to fit 4 winter tyres you will see a considerable improvement in handling and traction by fitting 2 winter tyres on the rear. If you are worried you can check the suitability of fit/offset of the smaller wheel on the rear by test fitting one of your front wheels/tyres on the rear to check for clearances.

 

[clk270]

There is no issue putting a 245mm wide trye on a 9J rim, other thant he fact you will have 10mm less wider each side of the rime, sio less protection of the rim against any obstacle, road debris or kerbstone.

The biggest online selection of winter rubber is tyres online @ mytyres.co.uk: tyre dealer for cheap passenger, summer, winter tyres or Cheap Tyres Discount Tyres Buy Tyres Online & Japanese Import Car Parts Spares Tuning Performance Servicing Accessories :: - will give you a good idea of the choice in your sizes, and availability.

Nokian WR G2 is available in 245/40/18 in V speed rating (up to 149mph), 97 load index, although they are the saem price as Pirelli Sottozero (£184 each fitted via mytyres). If you are happy to drop to H speed rating, which is more than adequate for UK and continental driving unless you want to max the car on an autobahn, then Nankang SV-1 are £500 a set fitted, and Falken HS439 £575 a set.

Whilst having 2 sets of wheels can be a pain, you need to consider them against the £50 cost to fit winter tyres to your current rims, and then another £50 in spring to put the summer tyres back on - you effectivley have £100/year fitting costs by using one set of rims.

 

[mykulmerc]

Hi mj,

I am in a very similar position - I have would like to fit winter tyres on my existing rims and get some better rims in thed spring for summer tyres. The manual says that I should have the smaller rims all round. One of the wheel suppliers has sent me a MB document which apparently says I can put winter rubber on the rear. I have phone MB UK, who basically only repeat what the manual says. I have now emailed Daimler in Stuttgart to get an answer and will let you know if I do.

The idea of having 2 sets of rims certainly does make sense - my present ones are not in great nick which is why I want to keep them for winter use and get some better ones for the summer.

Just for the record I have used Toyo Snowprox 952 before which were at least as good as Michelin Alpins I had previously.

 

[Horrgakx]

Similar thread;
http://www.mbclub.co.uk/forums/wheels-tyres/97454-vredstein-quatrac.html

 

[Stratman]

Get a set of steel wheels and put winter tyres on them. As clk270 says, you'll save the cost of two fittings per year which will pay for the steel wheels, and you'll also be protecting your alloys from winter salt.

Mytyres will supply winter tyres already fitted to steel wheels.

 

[grober]

There is nothing preventing you putting winter tyres on your wider rear wheels provided you can find tyres to fit. [ and in this I would only fit European/cold-weather-country developed tyres] Their performance/traction won't be quite as good as using the slightly narrower rims recommended by MB but will still be a huge improvement on the summer tyres fitted at the moment.

ps:- as has been said a complete set of dedicated winter tyres and rims is the best choice

 

[mjbarnard]

Many thanks for all your informative answers. I am much clearer now.

I appreciate that getting narrower tyres confers benefit in winter, which is why I was keen to do so for the rear - not just following the handbook.

I am now looking at getting a second set of wheels for the winter tyres as you suggest. I shall probably go for the recommended size of 18 inch, and 245/40 in the manual.

Bizarrely when I put my exact model into the mytyre steel wheel calculator it only lists 16 inch wheels and 225 tyres. Also it doesnt seem to provide a way of choosing steel wheels (as opposed to tyres) by size rather than make. Understand the size and number of holes are probably why. Still, will give them a call perhaps.

Thanks again
Matthew

 

[grober]

One thing to look out for with steel wheels is they normally have a thinner cross section which means they require a shorter wheel bolt compared to alloys to prevent fouling the internal handbrake mechanism.

 

[clk270]

Many thanks for all your informative answers. I am much clearer now.

I appreciate that getting narrower tyres confers benefit in winter, which is why I was keen to do so for the rear - not just following the handbook.

I am now looking at getting a second set of wheels for the winter tyres as you suggest. I shall probably go for the recommended size of 18 inch, and 245/40 in the manual.

Bizarrely when I put my exact model into the mytyre steel wheel calculator it only lists 16 inch wheels and 225 tyres. Also it doesnt seem to provide a way of choosing steel wheels (as opposed to tyres) by size rather than make. Understand the size and number of holes are probably why. Still, will give them a call perhaps.

Thanks again
Matthew

I think the best option on their site is the E280 CDI Sport packet option from the model dropdown. Need to be wary of brake clearances though if your E320 has bigger brakes !

 

[mjbarnard]

Mytyres are widely recommended, and I can easily order tyres of the appropriate size from them. However they say they are unable to provide steel wheels in the size recommended by MB.

I put every possible model into their search engine (cant find 280 cdi sportpaket, but tried all the other sportpakets including 280 sportpaket), but am unable to get any 18 inch wheels. For the reasons clk mentions, a bit wary of going outside the manufacturers recommendations.

Phoned mytyres and they were very helpful, but said that they were unable to provide any sizes other than those calculated by the search engine. They said check with the dealer in case 16 inch would fit. So I did - and they were a bit uncertain, but basically said go by what is in the manual.

So any other recommendations for wheel/rim purchases? Looking at all the alloy websites, but it looks a bit of a minefield!

 

[clk270]

So I did - and they were a bit uncertain, but basically said go by what is in the manual.

I'm not surprised by this response - when i queried the use of 15" steel wheels on my Golf (which as std comes with 16" alloys) with Volkswagen they wouldn't be drawn , even though there is a lower spec version of my car/engine combo with 15" steel wheels !!



I doubt very much anyone , anywhere make 18" steel wheels - just no market. It might be worth looking on a German website what they are using. German ebay is full of steel wheel/tyre packages (not checked but could be the german parent of mytyres !), and you may find some listings specifying what version 16" will fit.

If you have 18" rims on now, you should be able to see whether there's an inch clearance between the inner edge of the rim and the brake caliper. Another thought, what is the spare ?, try this if its a 16" steelie ??

 

[mjbarnard]

Thanks very sensible advice. Will check the brake calipers and spare.

I'm now looking at 18 inch alloys. Plenty on ebay. They seem to cost around 350 ukp. I understand it's a bit of a waste, but in the absence of steels would be happy to keep these as winter wheels.

Two simple questions -

First are these sorts of replicas in general safe/reliable?

Second (forgive the naivety) I assume that the savings referred to by keeping extra wheels compared to "fitting" a tyre to a wheel twice a year reflects that changing wheels plus tyres costs less than changing tyres only? (I cant do it myself). Since others quote 50 ukp for fitting 4 tyres, would swapping wheels be very much cheaper?

Thanks again
matthew

 

[grober]

The sport edition versions of MB models usually run larger diameter front discs and callipers which does restrict how far any owner can downsize the wheels. I would be surprised if the OP could safely reduce to anything below 17" wheels due to clearance issues

 

[Smiley]

If you are buying new rims i would suggest getting the smaller 17 inch wheels - more and cheaper choice of winter tyres and narrower tyre as well.

 

[mjbarnard]

Indeed.

It turns out the spare is 17 inches, so that must mean I could replace all 4 with the same?

 

[Smiley]

Correct.
I think that you will find a 245/45/17 should give you approx the same rolling diameter as a 245/40/18 - the winter tyre would be better as a 225/50/17 if the tyre is wide enough for the rim.
Best to ask an expert though.

 

[raymont]

Correct.
I think that you will find a 245/45/17 should give you approx the same rolling diameter as a 245/40/18 - the winter tyre would be better as a 225/50/17 if the tyre is wide enough for the rim.
Best to ask an expert though.

245 45 17 should go on 8 to 9.5 inch wide wheels.

225 50 17 should go on 6 to 7.5 inch wide wheels.

The rolling radius of the 225 50 17 will be close enough, less than 1% difference.

As suggested check with tyre manufacturer though to be sure of fit.