Looking to start shopping around for my next rims/tires (likely for winter use).

What bolt pattern, rim, tire size should I be looking for?

 

I think the smallest you can go to clear callipers would be 17x8 rim. Bolt pattern is 5x112, not sure about stock offset but it looks like +45mm based on TireRack, correct me if I am wrong.

I have 20" AMG rims on it but for winter will be searching for 18 with meaty tires, as in 235/60/18.

 

1. Look in the trunk for the spare donut tire. measure the diameter of the wheel. That is the smallest rim you can fit.

2. Look in the OM in the Specs section in the rear. It should give you both wheel and tire specs for winter tires.

For winter (put on when the temp. are below 45 degrees F consistently), on our 2013 GLK350 4 matic we use a TUV 17" German wheels with Pirelli Fire and Ice tires (they in fact are subtly recommended by MB if you read between the lines.) We got the package from Tire Rack. Wife loves the combo in all kinds of winter conditions here in the snowy icy Northeast. Our 3 season stock MB wheels with "all seasons" are 19" because we have potholes.

NB - the brake system on the 2015 comprises different part numbers that the 2013.

 

The 250 does not have a spare - that's where the AdBlue tank sits.


Smallest wheel / tire combo is 17x8, ET around 40-45 mm, 5x112 bolt pattern, 66.6 mm center bore, 235-60R17 tire.

 

By the way, collapsible (spare) tire is $600 at the dealership if you feel like the "Fill the tire" canister is not enough.

 

The canister is only the sealant - there is an air compressor that you connect to the canister, and in turn the cannister gets connected to the valve stem. Pretty ingenius - and seeing as there are no TPMS sensors to foul, I figure I'll take my chances (plus I've only had two flats in over 25 years of driving). Thanks for the info though - that's good to know. Biggest problem is there's no room on the 250 to store a spare, so if anything, I'd carry another can of sealant and test the air compressor before a long road trip.

Re OP's post - with a 20" rim where the sidewalls don't bulge out like balloons, an ET 35 offset with a 8.5" rim is still very nice loooking and flush with the fenders (but not bulging out) with a 235-45/20. On a 17" rim with a 235-60/17, I'd probably stay at 40mm or above.

 

What would be a good OEM fit rim for a 17? (What other MB has a 17" rim that looks good and fits well on my 2015 GLK 250?

40mm or above? that is for the centre of the rim?

 

Here is the data from the OM on winter tires with a 17" rim:

Winter tires R17

Tires
Alloy wheels
BA: 235/60 R17 102 H M+S plus iceflake symbol
BA: 7.5 J x 17 H2
Wheel offset: 1.87 in (47.5 mm)

The ice flake symbol on winter tires is very important. As you know you cannot drive in the winter in certain Provinces (and States) without tires with that symbol. Call your MB dealer for wheel recommendations. Either the Sales or Parts Dept. Have Wheel catalog. Otherwise, for Canada we use 1010tires.com. You want a TUV rated wheel if you can't find an MB to match or is too pricey. Don't monkey around with sizes or offsets or wheels without the TUV rating/symbol. This could void your warranty.

 

Just answered this in the other forum as well. 40 mm is the offset. I am using RTX Kassel - it's an AMG style rim made only for MB (17x8, ET 40, hub-centric 66.6 mm, 5x112 bolt pattern). Takes the OEM center cap. Proper size and fitment for the GLK, the finish is excellent and I'm told fairly tough, and it's a Canadian company to boot. It's a lot better stance-wise than the OEM MB 17s at about a third of the price. If you're in the GTA, SimplyTire is an authorized reseller.

http://www.rtxwheels.com/en/wheels/r...l-hyper-silver

 

Since my wife is from Toronto I am glad you are recommending a Canadian company. However they are probably just the importer.

"Just answered this in the other forum as well. 40 mm is the offset." No, the factory offset is 47.5mm.

I've tried "universal MB fit" wheels on my AMG (for winter tires) and they were a nightmare. In my case the offset was 40mm rather than 48mm recommended. They screwed up the suspension, the alignment and went back immediately.

The real problem is the RTX specs are way off from the factory specs. Just having the right bolt pattern means you can screw it into the hub. But, this wheel has the wrong offset and it is too wide. As you know the rule is a narrow tire for snow conditions. If it was my car, and we did this for my wife's GLK, I would search for a TUV certified (the minimal testing procedure MB uses) wheel that fits the factory specs. Being "told are fairly tough" is nice and but actually passing TUV proves they are tough. Punkt. The brand we used was RIAL, made in Germany and TUV certified. <50% of the price of the MB wheel. (I have no interest in the RIAL company financially.) It fits the width and offset of the factory specs precisely. Frankly, this stance business if fine in LA but why do you want to screw around with your life under winter conditions, and possibly void your warranty?

Consider going to school on my experience with the AMG....

 

Er... seeing as I own two AMGs and two other MBs, have three Porsches and partially own an indie Porsche shop, and furthermore as I have about 20 years of track and ice racing expereince, I like to think I know what I am doing, but of course you can do whatever you'd like with your car. Thank you for your advice, but I didn't ask for any - I was giving an answer to your question.

Thsi may sound somewhat conceited, but I am afraid that there are two things that you absolutely can't teach me anythign about unless you have more INSIDE and PROPRIETARY information than I do. One is wheels, and the second is motor oils.

Now, if want me to tell you why what you wrote above is wrong, ask and ye shall receive, but only if you promise that you're not going to waste my time with whatever you've read in some of my earlier posts and elsewhere on the Internet.

 

Woo hoo! Found this table in the Manual today. Hope it helps someone. And a mandatory thumb picture too

 

I think that this picture above, as well as the specs I compiled from the on-line OM, confirm what I posted above as to the proper dimensions and tire selections for winter driving, viz:
Here is the data from the Mercedes Benz OM on winter tires with a 17" rim:

Winter tires R17

Tires: 235/60 R17 102 H M+S plus iceflake symbol
Alloy wheels: 7.5 J x 17 H2
Wheel offset: 1.87 in (47.5 mm)

Note that, in the picture above, NO wheel spec for any season is less than 45mm offset.

If other people want to cite their opinions, that is what they they are, and no more. They are not the factory recommendations. Why are the factory specs wrong?

 

First of all, the OEM MB 20" wheels on the 2015 GLK 250 with the AMG package are 20x8 ET42. I am not looking at the manual - I am looking at the casting markings on the back of the wheels themselves. I'll leave it up to you to decide which one is correct.

Second, that small difference in the offset is there in order for the wheel to be able to accomodate snow chains seeing as they are still widely used in Europe (in fact, carrying a set in the vehicle is still madatory in most of Europe during the winter months), and in order to eliminate the possiblitly that the thick metal chains will scratch your fenders, the wheels are made to sit further in. I am not sure what the laws in the US are and whether they vary state-to-state, but in Canada snow chains are illegal everywhere (and in more than half of the cities in the country where they salt in the winter even studded tires are illegal). In other words, you have a 20 mm gap between the fender edge and the tire edge that at least in this country is is compltely useless, and furthermore, seeing as a vehice with a wider track is more stable than one with a narrower one, you are actually sarcrificing some small degree of lateral stability by having your wheels sit further inward than they need to.

When it comes to the wheel width, every tire size has somethign called an "approved rim width" range. In the case of the 235/45-20 Pirellis, the approved rim width is 7.5-9". In other words, those are the rim widths that that particular tire can be safely mounted on. The section width on that particular 235/45-20 Pirelli tire is 9.3" (the widest area of the tire). Now, I would again like to draw your attention to the "lateral stability" issue. The narrower the rim, the more of the tire sidewall extends past the rim and flexes under lateral loads. Why does MB use narrower rims, then? Because with a 8" rim and a 9.3" section width tire, you have 0.5x1.3" or about 16.5 mm of tire that sticks out past the edge of the rim, which is what stands between the rim and the curb when your wife needs to parallel park and scrapes the curb. In other words, thay are again making a small sacrifice in lateral stability in order to give your wife a slighty better chance of not curbing the rim. With an 8.5" rim, you now only have 10 mm; with a 9" rim, you're down to below 4 mm between the rim and curb when you get too close to it, and seeing as tires are made of rubber and flexible, you are now pretty much guaranteed to curb it.

When you look at the GLKs fenders, a 235 section tire on an 8.5" wide ET35 rim still sits well inside the wheel well. In fact, on that wheel there's certainly more than enough room for you to run 245/45-20s if you wanted to, and they would both sit properly centered in the wheel wells and would not rub either on the fender or the suspension components.

Going back to the 17" snows, the section width on a 235/60-17 snow tire (like the Michelin Latitude X-Ice Xi2 that I use on my GLK) is 9.5" - they are wider in the middle as they "ballooon" more than the lower profile 20s. The approved rim width is 6.5-8.5" so they not only fit perfecty on a 8" wide rim, but the sidewall also flexes less than it would mounted on a 7" wide rim, which btw is lot more noticeable on a 235/60 than a 235/45 tire due to the much larger sidewall height. Furthermore, with an ET40 offset, they again fit exactly where they should to give you maximum stability but certainly without poking outside of the wheel wells.

And, the rims I mentioned are hub-centric to Mercedes - in other words, the hub bore is 66.6 mm so they are perfectly centered on the hub, unlike your RIALs that are made to fit a variety of vehicles and need to use centering rings and are still likely to vibrate at speed unlike a proper hub-centric wheel.

TÜV certification is the German safety standard, so if you buy German aftermarket wheels that's the certification you'll have to get - seeing as it's the TÜV that performs annual vehicle safety inspections in Germany (which are IMHO sorely lacking in North America - the number of unsafe clunkers on the roads here is outright astounding). In other words, it is essentially a vehicle certificiation inspection like the safety test you have to get here before you can get a set of plates for a used car. The RTXs I mentioned on the other hand are JWL and VIA certified (and they ARE Canandian - RTX is headquarrtered in Quebec), just like the OEM Mercedes AMG 20s - which are the industry standards SPECIFICALLY FOR WHEELS. The OEM MB 20" wheels are made by Ronal (IIRC my particular set was made in Spain), and interestingly enough, they are JWL and VIA certified but I don't see a TÜV marking anywhere on the back.

So - that's the "Wheels 101" primer. In the second level course we can talk about different casting processes, flow forming, forging, etc. Third level would be how to disassemble, repalce centers and rim halves, reassemble and reseal modular three-piece wheels for track use, and finally in the fourth level course we can talk about stress propagation, metal fatigue and fractures in aluminum alloys. The graduate level courses would be about the incestuous nature of wheel manufacturers and who makes what for whom in what plant or foundry, but I am afraid that you'd need special clearance for that course as there are some trade secrets that the wheel manufacturing companies are not too keen to share with the general public.


P.S. Another thing that most people ignore when buying aftermarket rims is the weight of the vehicle and the load rating of the WHEELS THEMSELVES. I have a set of gorgeous forged BBS RS-GTs that are a perfect fit for the GLK, but each rim is rated for a maximum of 695 kg (or 1532 lbs), which is definitley pushing it on a vehicle with a 4500 lb curb weight and GVWR of 5500+ lbs keeping in mind that the weight distribution front-to-rear is not going to be 50/50. Both of the aftermarket wheel sets that I use on the GLK have a load rating of 1925 lbs per wheel. Again, unless you have that info for the RIALs, I'd be careful.
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Snow chains are not widely used in Europe. Having said that, to proceed onto to some mountain passes in winter you must carry snow chains in your vehicle, for possible use.

Definitely agree that the U.S needs something at least remotely similar to a TUEV inspection. Better and more serious driver training would be a good thing too.

 

By "widely used" I meant exactly the same thing as you - as in "every vehicle must carry a set in the trunk so that they can be put on if/when needed", not that people living in urban areas actually drive on them all the time. If you live anywhere near a mountian - which basically means most of western Europe - by law you have to have them in the car and be able to put them on if/when needed, hence the wheel to fender clearance requirements.

Also completely agree on the second point.

 

I checked, again, and the RIALs we have are hub-centric for the GLK. They needed no centering rings when installed. They can also handle the weight of the car at each corner.

I agree that car inspections in some States are a joke. For example, in MA and CT I see many cars with terminal rust and p/u trucks with the rear gates, bumpers and so on being held on with bungee cords. You can't make this stuff up. Talking to some of the local rescue folks they say they get many calls to rescue "drivers" who run off the road due to equipment failure. I see bald tires in mall parking lots or people driving on a set of donut spares all the time. If one of those things hit us would we have recourse because they were mechanically unsound to travel the roads?

Thanks for sharing your knowledge!

 

Glad to hear that about the RIALs. They make decent wheels (they're one of the better brands in an industry that's increasingly full of garbage) where most after-market wheels made by most after-market manufacturers are made to fit a variety of vehicles. If they're hub-centric for the Benz, they were obviously made for a MB (and possibly Audi) application ONLY and so by definition of a higher quality than a "universal" wheel that fits every car with more than two letters in its name.

Always glad to share knowledge and learn from others. That's why we're all here - to learn from each other!