Tire pressure low, or sensor bad?
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From: Boston Area
2021 Mojave Silver E450, 2024 Black on Black Jaguar F-pace P400, 2011 335d (RIP), 2010 E350 (sold)
Good point, but a full size wheel is twice as big and twice as heavy, this 81 mph spare is a good compromise.
At any rate, I sent a message to Discount Tire head quarters, they asked the regional managers to deal with it and yesterday I got a call from the manager
at my local Discount Tire store: He was very nice and invited me to come in with the spare and have it balanced.
Will do just that tomorrow.
Stay tuned.
At any rate, I sent a message to Discount Tire head quarters, they asked the regional managers to deal with it and yesterday I got a call from the manager
at my local Discount Tire store: He was very nice and invited me to come in with the spare and have it balanced.
Will do just that tomorrow.
Stay tuned.
Thread Starter
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From: Palm Coast, Florida
2019 E-450 Wagon
Yeah, I didn't plan on traveling continuously @ 81 mph, but not limited to 50 either.
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Interesting, does it use the same kind of weight (flat/glued) as normal aluminium wheels or the old style for steel wheels? I think we have not had any spare on our cars (small or normal) since W211, 2003 and it may have been aluminium already then. Way out of my memory.
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2019 E300
Not sure if you ever driven on a compact spare, it is unstable at high speed. The thread pattern, traction and construction are different from a full size spare. The side walls are weaker and more susceptible to a blowout if you hit a pothole.
Thread Starter
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From: Palm Coast, Florida
2019 E-450 Wagon
Yeah I know, for emergencies only.
Got the spare balanced today:
While at the tire shop the tech said this is limited to 50 mph only, I said no, M rating to 81mph. Then he pointed out what is written on the sidewall: Max speed 50 mph.
Not sure why it is M rated then, but obviously I won't be driving faster than 50 now.
He also pointed out that the spare is a nylon belted radial rather than a steel belted radial and that could be why I felt some vibration or thumping.
At any rate, all is well: Got the balance done and also got the conflicting information on 2 speed limits, 50 and 81, of course I will stick to the more conservative limit,,
Thread Starter
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Joined: Aug 2009
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From: Palm Coast, Florida
2019 E-450 Wagon
A few more comments from the manufacture of Modern Spares after I asked for clarification on M rating vs Max 50 mph written on the spare:
Sorry if we missed your email.
All of the tires that we use are DOT M Rated.
This M rating indicates the tire has been tested to safely operate at constant speeds up to 81 mph. Although it is rated at 81MPH, Many tire manufacturers will state the speed should not exceed 50mph due to the tire’s narrow size.
Typical spare tires, once provided by the carmakers, had range limits of 50 miles or less. This is primarily due to the small size of the spare relative to your factory tires. The 50-mile limit was considered a safe distance to avoid putting undue strain on the vehicle’s running gear. As vehicles have become more sophisticated, many newer models are less tolerant of tire size differences. Just one of our many design goals here at Modern Spare, we set out to build spare tire kits that are still space-saving but are also more compatible with your vehicle’s drivetrain. By having a spare tire size that is closer and more properly matched to your factory tire’s diameter, you can travel farther than the typical 50-mile range limit. If your Modern Spare is not exactly matched to the overall diameter of your factory tires, rest assured we have sized the spare with careful consideration for an allowable size variance of your particular model. Although we do not state a specific range limit, you will find the Modern Spare to be significantly more capable than traditional spare tires. Just as with speed, this very modern setup is not meant to replace your factory tires, rather, is designed to get you safely home or to the repair facility you choose without the stress of a 50-mile range limit.
I hope it helps,
Thank you,
All of the tires that we use are DOT M Rated.
This M rating indicates the tire has been tested to safely operate at constant speeds up to 81 mph. Although it is rated at 81MPH, Many tire manufacturers will state the speed should not exceed 50mph due to the tire’s narrow size.
Typical spare tires, once provided by the carmakers, had range limits of 50 miles or less. This is primarily due to the small size of the spare relative to your factory tires. The 50-mile limit was considered a safe distance to avoid putting undue strain on the vehicle’s running gear. As vehicles have become more sophisticated, many newer models are less tolerant of tire size differences. Just one of our many design goals here at Modern Spare, we set out to build spare tire kits that are still space-saving but are also more compatible with your vehicle’s drivetrain. By having a spare tire size that is closer and more properly matched to your factory tire’s diameter, you can travel farther than the typical 50-mile range limit. If your Modern Spare is not exactly matched to the overall diameter of your factory tires, rest assured we have sized the spare with careful consideration for an allowable size variance of your particular model. Although we do not state a specific range limit, you will find the Modern Spare to be significantly more capable than traditional spare tires. Just as with speed, this very modern setup is not meant to replace your factory tires, rather, is designed to get you safely home or to the repair facility you choose without the stress of a 50-mile range limit.
I hope it helps,
Thank you,
