For the first time in the GLK's 10 year history after running over a terrible pot hole, I was about to use the collapsible spare donut for the first time and boy was it a life lesson... so hoping my experience can help others.

After spending hell of a time getting the car jacked and removing blown factory wheel off (each lug bolt is torqued at 138ft lbs!) on a heavy rainstorm, I was dismayed when I found out that my new (but 10 year old) collapsible spare would not properly inflate!! instead, it would inflate unevenly across the outside barrel of the wheel. As a result, part of the radius was not even able to seal to the rim; causing a leak and making the tire useless in an emergency.

After getting towed home, I decided to see if there were any tire shops that could help fix spare .... NOPE NOPE! no tire shop (incd. Mercedes dealer) would touch a 10 year old tire even if it looks brand new, let alone servicing a "collapsible tire version which they don't typically have the mounting tools for. No other alternative tire spec opted up for my car.

Sourcing a new replacement spare wheel is a pain that isn't worth it. The spare wheel/tire size was unique as in NO Other tire manufacturer makes it in the spare tire in that spec (185/75/17). The OEM supplier of the tire Vredestein also won't sell direct to consumer either. You would only be able to acquire the tire/wheel from Mercedes dealer only probably at $500+.

Somehow I manage to convince an independent tire shop to take a look at it. And within minutes he noticed the original lube that came in the with the spare wheel have drived up. After that, he filled it slowly and watched how the spare tire would expand evenly; all the way till each side of the rim and creating a proper seal. Success! saved another spare tire!.

So key lessons:

• keep spare 1/2" breaker bar w/ star socket for Mercedes specific lug nuts (so you don't strip them using the emergency 17mm hex wrench)
• annually apply some tire/bead lube on any exposed outer wheel barrel of the donut (important for proper inflation and sealing in the next step
• annually (or the sooner before a trip) pump up your spare tire up to 41PSI SLOWLY using either using the inflator from the trunk or a handheld one you have laying around. Do not pump it up laying it flat! instead pump it upright. Avoid using high pressure one such as gas station or compressed air because these steps are important for the staggered inflation of the tire on each side of the wheel.
• check for cracks/dry rot. Otherwise, apply some 303 aerospace protectant on the tire to preserve the rubber
• should all else fail, make sure your towing company can bring a flat bed to haul the car

 

That’s not a pleasant thing to have happen or worry about. I keep usually a few air pumps and a cheap tire repair kit in the Glk . I always have tire pressure showing on dashboard to know when the tires are having a problem. I find mechanics always just slam on lug nuts with an air tool , even when I demand they use a torque wrench , they refuse. I’m sure mine are over torqued .

 

Your tire changing experience seems typical -- always happens under the worst circumstances. You forgot one bullet point. Do a trial tire change in your driveway so that you know the tools, how they operate and where to place them. Make sure you're up to the task of lifting the tire's weight, stowing it and mounting the spare. And carry the needed accessories -- wheel chock, light, knee cushion and wheel hanger pins.

As an aside, I am always amused by folks who inquire about tire chains for winter driving. Once you've tried installing a set of chains under the worst possible conditions, you'll decide staying home is the better choice.

 

If they refuse I guess the only option is to do it yourself.

 

Perhaps try something called modern spare I heard circling around mbworld to replace the oem one?

 

Modernspare.com

 

ez-sparewheel.com is a slightly less expensive option

 

Maybe it’s because we have a lot of cars and light trucks, but where our tires are serviced, a torque wrench for final tightening is used. It’s usually me, but could also be the driver, who witnesses it.

 

Thanks for sharing, good to have options.

 

Will those options fit in our "less than standard size" spare tire wells? It's really not nearly big enough for anything other than a collapsible spare like the OEM one...

 

tried inquiring with modern spare as well as ez spare. The former doesn’t have an option and the latter’ only has a 20” spare that requires spacers and their own tool kit. Not something convenient to lug around with the already small trunk size of a glk. Plus at that price point you might as well order a new replacement collapsible spare from mercedes.

And to anyone that says carry mobile tire repair kit or the sealant kits, that does not apply to blow outs which is why I always have a spare in all my cars even if they do not come with it.

 

it will not. I looked into it already. Plus it requires spacers and their own lug nuts to clear the rotors and calipers. At that price point, spend $100 more and get a brand new collapsible spare from mercedes

 

I see. Oh well : (

 

No options for the GLK though...

 

The only thing I see listed from MBUSA is A 204 400 98 00 — 6B x 17H2 wheel with 185/75-17 98P tire. There’s not enough info to really tell if that’s the collapsible spare. The temporary spare for the W204 C-Class has T125/90-16 98M tire, same load rating, very different size.

 

Discount Tire sells replacement donut spares in a variety of brands. Nothing is exactly your 185/75R17 size, but Continental and Yokohama have tires in 165/80R17 which is close enough for a spare tire, and should fit in your spare cavity.. Prices are ~$125.

 

also looked into that and couple of issues:

A 165 tire is 20mm narrower and will not bead properly against the rim of the specific glk spare wheel. That wheel has a uniquely tapered barrel on both ends of the wheel and a high profile rim that was design for the collapsable tire inflating and deflating. (You will see what I mean when you try to pump up the spare it and notice that the tire does not inflate uniformly)

The spare wheel well in the trunk diameter is 22-24 inches which is slightly larger than the spare tire when collapsed. Even a fully deflated 165/80/17 is 26 inches in diameter at best

Spare tire diameter when fully collapsed is 22 inches in diameter

 

Tire specs say it's compatible with 4"-6" wheel widths, but if the diameter is a fit problem then an OE replacement is likely the only solution. I have only 1 car with a donut spare and it stows fully inflated. Didn't realize some need to be pumped before use.

 

I should had checked before posting, sorry about that : (

 

Perhaps that site only have models of which never came with a spare tire in the first place? I understand that is not exactly helpful. Perhaps asking customer support on that site and see if they have a recommendation?

 

My EPC says that is the correct part number for a GLK350 or GLK350 4Matic $226

 

That same part in Canada is listed for $494.69 CAD.

 

Ouch! With today's exchange rate, it should be 327 CAD... Probably pretty easy to sneak across the boarder.

 

Our weak dollar and um tariffs already in effect?

 

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Perhaps use mail forwarding over as well I guess?