GLC300 Spare Tire Options
I have a 2017 GLC300 whose original run-flats are now worn at 18000 miles (US based, so no spare is available). Been reading these forums to solve my "spare problem" for the past year and was about to go purchase the donut as recommended by others above. Definitely do not want run-flats again !!
However, in a Google search yesterday, I came across a company called Modern Spare (modernspare.com), located in Colorado who have designed donut spares for many run-flat type vehicles. I got in touch with them and they stated that they have a spare for the GLC300, as well. One can configure a spare for the GLC300 on their website. The wheel is designed to handle large brakes also. Approx. $350 + $45 shipping includes wheel/tire, nuts, jack, wrench, cover etc.
Have any of you bought this spare ? Or heard of this company (are they legit) ? Thank you.
Last edited by shsabh6; Aug 5, 2020 at 01:34 PM.




They shipped pretty quickly, I had a couple questions via email for customer service and they responded quickly. Its a nice looking unit overall, i am very happy with the purchase, now i just have to figure out what non RFT tires to buy.
with that with the MB rim.... Good luck in your non RF tire section. I'll be doing the same research....




tire installed on 2017 US GLC300
Fuse box that sits underneath modernspare tire




The Best of Mercedes & AMG
Do I need different lug bolts than the ones currently holding the wheels on the car?
I thought I saw somewhere about shorter lug bolts for the spare wheel... Is this for convenience, or required?
Thanks!
Do I need different lug bolts than the ones currently holding the wheels on the car?
I thought I saw somewhere about shorter lug bolts for the spare wheel... Is this for convenience, or required?
Thanks!
you're going to need the shorter lug bolts for your spare rim the the STEEL version... if it's a regular mag wheel the same as your other 4 then you can use the factory lug bolts.. If the factory lugs use on steel rim they are too long and will bottom out against the rotors
the shorter lug bolts should be available on Ebay
Good Luck welcome to the Non Run flats club..




you're going to need the shorter lug bolts for your spare rim the the STEEL version... if it's a regular mag wheel the same as your other 4 then you can use the factory lug bolts.. If the factory lugs use on steel rim they are too long and will bottom out against the rotors
the shorter lug bolts should be available on Ebay
Good Luck welcome to the Non Run flats club..
Suggestion: Anyone going this route needs to do a trial run with their new equipment. Correct spare tire pressure (60psi) in my case, use jack (make sure it is correct for application), install lug bolts, use lug wrench . Move car and make sure there are no obstructions or lug bolts hitting rotor. On the side of the road at the worst time is no time to find out you missed something or have an issue.
I have put in an offer on a set of the short lug bolts on eBay... the non-run-flats are not yet installed, so I have a little time.
I like the idea of doing a trial wheel change in the comfort of my garage... rather than on the side of the highway...! Makes me think of Leon Russell, "Sitting on the highway in a broken van/Thinking of you again..."
They shipped pretty quickly, I had a couple questions via email for customer service and they responded quickly. Its a nice looking unit overall, i am very happy with the purchase, now i just have to figure out what non RFT tires to buy.




Check the date of manuf of your spare tyre, usually 4 numbers, like 4412. Translates into week 44 of 2012.
Tyres should be replaced after 7 years - they do degrade and can delaminate. Makes no real difference that they are in a cool, dark hole in the trunk !!!!
Good luck.
Also if buying new tires, spare the throttle for the first 500km as they have a silicon release agent on the outside to assist extraction from the manuf press - 500km allows silicon type coating to be scrubbed off tyre and then they are good to perform. No point suffering extended stopping or loosing control through tires ‘letting go’ on road surface when turning.



Thank you all who provide feedback, because of all of you, I was able to get all and its does look good, so now is my turn to provide the feedback.
It does fit under the lid with other junk no issues.
Here is my setup,
Spare tire
Attachment 425716
MB Vehicle Tool Kit
Part #1665806900
GSPSCN Portable Air Compressor Pump Dual Cylinder Heavy Duty Tire Inflator with LED Light,150 PSI 12V Air Pump with Tire Repair Kit and Toolbox for Auto,SUV,Truck Tires etc https://
http://www.amazon.com/dp/B07GJND1PX/..._Ke4-EbTTG2C3M
Some pictures
Attachment 1
Attachment 425720
Attachment 425722
Attachment 425718
Attachment 425719
Attachment 425726
Attachment 425724
Attachment 425723
Attachment 425725
. Can you provide anymore info on your part number and where did you get the wheel/tire? Is that available for a 2020 or it does not matter? I have 18" wheels, unless there's issues with lug spacing, or other issues. Dealer parts says there's no donut available for the 18" wheels but there's a donut for 19". Very strange decision making on MB.California car.
Thank you for any help.
Last edited by SuperTuscan; Dec 12, 2021 at 10:03 PM.



I need a spare (as noted in my reply to DanD. under this thread) for my 2020 18". What are the part numbers or what part would work. The dealer said there's no part for the 2020. Part numbers please.




