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Discussion Starter #1 (Edited)
It all started back in April when it was confirmed that the US spec GLA45 came with NON run flat summer performance tires. An air pump and sealant was included with the car, but of course that is fine for a puncture such as a nail and will do nothing if it is a catastrophic failure such as a side wall tear.

In April, I procured via Ebay a used [never used] GLK jack and accessories which work perfectly with the GLA>>


That turned out to be the easy part… finding a space saver (aka 'donut') spare tire was more problematic short of going the route of buying thru a MB dealer at a cost of $850+ (does not include the jack etc.)

My search again ended on Ebay in early December when there was a listing for a used [not used] ML63 AMG spare (donut) wheel/tire. The bolt pattern (5 112), wheel diameter (19") and offset (45-48 mm) were a match for the 19" AMG wheel that is standard on the GLA45. This is an alloy wheel set up as opposed to a steel wheel>>>



Did a pre-fit (just set the wheel on the hub) and clearance for the larger front brakes was the same as the wheel clearance for the wheels that came with the car



BUT (always a but) the lug bolts that fit the AMG wheel that came with the car were too short for the AMG alloy of the spare wheel (the center area of the spare is thicker). The search for the extended lug bolt was tedious… first MB uses measurements for the lug bolts that are based on the overall length of the entire bolt whereas most listings use the length of the bolt shaft.

So, the OEM bolt is a 14 x 1.5 x 49mm (shaft length is 27mm) with a ball style seat (NOT conical). The lug bolt I finally found that works is 14 x 1.5 x 64mm (40mm shaft)>>>


After wrestling with removing/installing the wheels several times, it quickly became apparent the the OEM AMG wheel/tire weighing in at 52.3 lbs and I were not getting along. Since MB uses wheel BOLTS and not wheel NUTS there are not lugs/studs in the hub to 'hang' the tire on while trying to get the bolts in to hold the tire in place. Solution… a Wheel Stud Pilot>>>


Which you screw into the hub>>>


Then allows you to hang the wheel on the hub while you install the lug bolts and once 4 have been installed remove the stud pilot and install the final lug bolt>>


So to the finish…the donut style space saver spare tire installed (not inflated… can inflate using the air pump that came with the car) and once spare is used can be deflated back to the smaller size as seen (deflated diameter is 24" and inflated is ~27.5")>>


For transporting and dressing up a bit (instead of the tire alone) and if need to change out a flat the 'old tire' can go into it too, I already had 4 Tire Rack Tire Totes and it works perfectly including having a handle


Total cost (AMG space saver tire/lug bolts/jack & accessories/stud pilot): $578

I posted this in the General Discussion area since I can see no reason that a GLA250 could not use the same set up… run flat tires are great for small punctures, but will fall victim to catastrophic failure for things like a side wall tear.
 

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Awesome! And looks absolutely silly mounted - but I'd rather look silly than look bored on the side of the road!
 

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the caliper clearance with the doh-nut is scary, surprised you didnt nick the red paint with all this,

thanks for info like this, helps out the community a lot
 

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Bloody good work SSBGLA45
MB wanted over 2k for the space saver here in Australia but having a full size rim suits me better because of the distances the wheel might be required for in the worst case scenario
You've done well and thanks for the comprehensive report that im sure will help a lot of others after they get stranded with the goo and compressor, you need more than goo to fix a shredded tyre


Cheers
http://www.glaowners.com/forum/members/ssbgla45.html
 

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Discussion Starter #5
the caliper clearance with the doh-nut is scary, surprised you didnt nick the red paint with all this,


It is the angle of the picture… the clearance is the same as the OEM wheel that came with the car. What was a concern was removing and re-installing the OEM wheel while trying to center on the hub and not hit the caliper..those who have removed a wheel know what I am talking about. Thus another benefit of the wheel stud pilot tool!
 

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the caliper clearance with the doh-nut is scary, surprised you didnt nick the red paint with all this,


It is the angle of the picture… the clearance is the same as the OEM wheel that came with the car. What was a concern was removing and re-installing the OEM wheel while trying to center on the hub and not hit the caliper..those who have removed a wheel know what I am talking about. Thus another benefit of the wheel stud pilot tool!
Awesome job, thanks for posting it.

BTW, the wheel stud pilot tool (wheel centering bolt) is normally part of the standard Mercedes Jack Tool Kit, Genuine Mercedes Benz Jack Tool Kit W176 A Class C117 CLA | eBay
 

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SSBGLA45 -

Can you post the Mercedes part numbers for the spare wheel and lug bolts?

Thanks!
 

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Discussion Starter #8
First, part number… I got the MB compact on Ebay and as such no part number, but on the back of the alloy might be a part number (lower number)



Same with the lug bolts… Ebay and are not OEM bolts.

This video shows how the compact spare works… the tire in the video is the same (Vredestein) as I got just the wheels are different>>> https://www.youtube.com/watch?v=mRiRldQQzLY
 

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Good info SSBGLA45.

Can't help but wonder that since the GLA is front wheel drive biased (even the 4Matics) if it would be better on the drive train to run the temp tire on the rear. But then you've got to wonder if running the temp on the rear would cause activation of rear wheel drive assist. Sure would be a major PITA to get a flat on the front and have to put the rear wheel on the front and then put the temp on the rear.
 

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Discussion Starter #10
Took a day to get reply, but MB said no issue (as long as you keep it at or under 50 mph for less than 50 miles) of having temp on front. The only thing that would go a bit wonky is the tire pressure monitoring system since the temp tire does not have a TPMS unit.
 

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First, part number… I got the MB compact on Ebay and as such no part number, but on the back of the alloy might be a part number (lower number)
Thanks.
As you thought, the lower number, A1644012702, is the part number.
 

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Discussion Starter #12
Final installment… just how does the space saver tire work? You go from a compact spare tire-inflate-after use deflate. So in the glory of pictures>>



Inflating and notice the side wall starting to bulge>>


Inflated and on the ground>>


After use remove the air stem valve and deflate


 

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Discussion Starter #15
Correct on the first item (tire on the front) and after removing the valve stem valve deflates right back to it original compact size… just have to watch and do nothing. Pretty cool design
 

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Saludos!

Question: Does it fit the "storage space" under the cargo floor?, photo if possible of it in the cargo area?... great post btw. Wasn't aware of the guide bolt thing and just purchased a couple from ebay to keep them handy.

JSR:.
 

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Discussion Starter #17 (Edited)
Saludos!

Question: Does it fit the "storage space" under the cargo floor?, photo if possible of it in the cargo area?... great post btw. Wasn't aware of the guide bolt thing and just purchased a couple from ebay to keep them handy.

JSR:.
IF you have the Harman Kardon Logic 7 stereo (in pic the amp and sub woofer are at bottom) and/or non run flat tires such as found on the GLA45 (the air inflator with sealant is at the top), then 'no' there is no room under the cargo area>>



If you have an empty storage space then 'YES' the space saver tire will fit (tire in its deflated condition is 23.5" dia and ~6" high and the space is 24+" wide and 7" deep); since you will need an air inflator, it would fit nicely inside the alloy cavity.
 

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After looking closely at the spare mounted on the car, I can't tell if the spare wheel is hub-centric, i.e., the diameter of the wheel hub opening corresponds exactly with the hub diameter thereby causing the hub to be the centering mechanism for the wheel as opposed to the lug bolts. If not, I can understand the necessity for a pilot bolt.

My understanding is that using a non hub-centric wheel will potentially promote a wobble that will eventually cause the lug bolts to work loose. If it is not hub-centric, that may be another reason why the 50 m.p.h/50 mile directive is given.
 

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Discussion Starter #19
The alloy spare wheel is hub centric…would never use a non hub centric alloy in this case…would be dangerous. Even though there is a small lip on the hub (thus hub centric), getting the wheel (ones that came with the car or the space saver) in place (lifting and centering) (remember the OEM AMG 19" wheel/tire weighs 52.3 lbs) and to carefully clear calipers and to set on the small hub lip is difficult. The wheel stud pilot eliminates this issue and makes for a much easier installation.
 

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Ok,thxs!. I have the 250 with the audio 20 system so no equipment in the storage space. Do have the plastic carrier for the air pump but that can be easily removed.

JSR:.
 
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