Lindagail

Will be traveling long distance this summer, want to carry a real spare. Currently have Michelin Pilot Sport all season 255 40zr 20 tires. Searching Tire Rack for similar, but don’t know which rim to choose. Advice appreciated. I’ll order the same tire.

Serhan

I bought the spare tire from modern spare, but I have not used it. In the shop it was fitting to the rear, but the brakes are bigger in the front.
https://modernspare.com/product/2019...e-kit-options/

You can select GLB35 in tirerack and go with the cheaper option as it will be staying not used most of the time. Here is the official specs:
https://www.wheel-size.com/size/merc...lass-amg/2021/

I have 8.5Jx20 ET42 Mandrus Estate wheels (made for MB) for winters and they fit with no problem. I bought them from ebay and installed it at the local shop. I also have another set 8.5Jx19 ET42 for AS from same manufacturer with different brand name, and the wheels didn't clear the brakes. Luckily I had 10mm spacers at home as initially I bought them for the winters, so they installed the spacers with 19" AS's. Try to stay with ET49-53 range with the wheel.

Lindagail

I'm going to order a SportEd A20, at their recommendation, for the rim. Smaller width, 8.5", according to the specs, but Gus said that would be okay. My current tires have a 9" width, according to the website. If I want to put the same tire, the Michelin Pilot Sport, on my MB rims, I can. hoping I don't have a flat that requires that kind of change during the t

EQBFan

I have been considering getting a compact spare for my EQB rather than a full size spare. I would like to mount it vertically on the side of the boot rather than laying it flat on the boot floor - I think that will likely allow for better space utilization. Something like this:
Donut compact spare

Still have not been able to find a perfect match for my 18" wheels yet. I am running 235/55 spec tires.

Odd Piggy

Have you tried Modern Spare? They don’t list EQB, but they do list GLB. Your 235/55R18 is also a standard tire size for the GLB.

EQBFan

I did consider modern spare but I was looking for something even more compact which got me interested in the Vredestein Spacemaster donuts - trying to figure out what size I should get. So far, their 155/90 R18 comes closest but is 5% over. So my search continues.

Serhan

You can try a donut from GLK350. GLK tire size is same as GLB and even the ET is very close:
https://www.wheel-size.com/size/merc...lk-class/2015/

Only problem is tire age eg newest tire will be 9-10 years old unless you find a newly manufactured one...

Odd Piggy

145/85 R 18 is only 1.6% larger than 235/50 R 18 which is within the 2% allowable difference in tires sizes. That size has a 103 load range which should be sufficient for an EQB. I don't know how available that size is.

EQBFan

While the wheel sizes are the same, the donut for the GLK is 185/75R17. I am just concerned whether the 17 inch rims will foul with the calipers or some other assembly, so that is why was looking for an 18" donut. Otherwise, the size is just perfect with only a 1% difference.
And yes, there is the age. I was hoping to get a relatively unused one on ebay with the hope that I may never have to use it. I am fairly adept at plugging punctures - the spare would only be used in case of a sidewall cut.

Lindagail

Is there a comparable donut for my 20” rims?

EQBFan

I do not think the 20" rims would make a difference. GLBs come with rim sizes from 17" - 20". So a 17" spare should likely fit (unless your specific model has larger brake calipers in which case they may foul). My EQB (basically a GLB with battery instead of gas), only ships with 18" rims or bigger. I was considering getting the 17" spare wheel meant for the GLK - checked my car and noticed that the front calipers only have around a 3/4" gap between the calipers and the 18" rim. So the 17 inchers are a bit iffy for me. And then there is the age of tires and the load rating to consider too.

The 17" spare from the GLK may work out for you. See this thread - folks have been able to mount it on the 2017 GLC which also used to ship with rim sizes between 17-20".
GLC Spare Wheel

Odd Piggy

I’m just about certain that the 17” GLK spare will not work on the GLB35. The GLB35 comes standard with 19” wheels. I had a GLB35 loaner a few weeks ago and it had silver AMG calipers that almost filled the 20” wheels. The calipers on my GLB250 don’t come close to filling my 19” wheels.

EQBFan

Likely why I will also be dropping the GLK spare as a possibility. The front calipers are way bigger than the rear ones and there is only a 0.75" gap between the rim and the front caliper. So, I will likely need to consider an 18" space saver. The 18" compact spare from MB comes in at 195/75 R18 which is 4.5% over, so not a great fit.