Gravity Bike Rack

[Elfin]

My assumption is that the weight limit is pending tow mode or some other structural approval... it does seem bizarrely low.

It's only 10lbs less than the Model X (which uses the same stupid hitch manufacturer)

There is no car where the bike rack capacity is the same as the tongue weight limit. Some manufacturers just don't get involved and list the tongue weight limit and leave it at that. There is a standard for measuring the tongue weight limit and they follow that, but there is no standard for measuring rack weight limits so you rarely see them mention it.

But, there is no cheating physics. The leverage of a bike rack makes it far less likely that you can use the tongue weight limit as a guide. Lucid is making this explicit as do some other manufacturers. The physics isn't unique to Lucid, they did not skimp on design, they're just honest about something that other players in the industry don't bother with. Here's an article from a rack distributor.

The ugly truth and confusion about Class I Hitch Bike Racks and the 1.25

We get questions daily about using RockyMounts hitch bike racks on Class I hitches as we do not approve our racks for use on Class I. Why? Read below, it requires understanding the loads a rack puts on the hitch and a brief history lesson. Both Class I and Class II Hitches have a 1.25"...

rockymounts.com

Tongue weight on real trucks and SUVs is limited by the weight on the rear axle so the derating is the relative distance from the rear axle.

Note that the Model Y has a 160lb max bike rack rating while the Model X is only 120lb. Why is that? The Model Y doesn't add a pointless weak spot it the system.

 

[jered]

It's only 10lbs less than the Model X (which uses the same stupid hitch manufacturer)

Ahh -- thanks. I thought the difference was larger from comments I had been seeing here (and didn't go back to check the spec). I have the OEM Tesla (i.e. Yakima FullTilt 4) rack; I haven't put it on the Gravity yet but I assume it will be fine. It seems to me that the tongue-weight (and then rack lever limits) all relate back to the hitch class -- while I assume you could make a hitch with a higher tongue weight class but lower tow class, nobody seems to do so...

 

[Elfin]

It seems to me that the tongue-weight (and then rack lever limits) all relate back to the hitch class -- while I assume you could make a hitch with a higher tongue weight class but lower tow class, nobody seems to do so...

If you're going to design the rear suspension of the vehicle to handle a higher tongue weight you might as well spec it to tow the standard 10x the tongue weight.
I think the rack weight limit relative to the tongue weight limit is very dependent on the design of the receiver. For example I would be very comfortable driving with a bike rack weighing close to the maximum tongue weight on an F-150. The frame bends before the hitch breaks!

 

[flarbear]

If you're going to design the rear suspension of the vehicle to handle a higher tongue weight you might as well spec it to tow the standard 10x the tongue weight.

Absolutely not. The tongue weight is not the determiner of how much you can tow. Making a stronger hitch doesn't mean you can tow more.

 

[Elfin]

Absolutely not. The tongue weight is not the determiner of how much you can tow. Making a stronger hitch doesn't mean you can tow more.

I was trying to say if you make the compromises necessary to handle the tongue weight you might as well design it to handle the corresponding tow weight.
The hitch receiver itself really should never be the limiting factor.

 

[flarbear]

I was trying to say if you make the compromises necessary to handle the tongue weight you might as well design it to handle the corresponding tow weight.
The hitch receiver itself really should never be the limiting factor.

Tow weight is determined by a number of factors of which the hitch is only one. A 1000lb car cannot tow a 10,000lb trailer no matter how beefy the hitch is designed. A big truck with skimpy little wheels and a basic suspention cannot tow much no matter how strong its frame or how beefy the tow hitch you attach directly to that frame.

The amount you can tow goes far beyond the structure of the back end. Structure is one of its limits, but not the only one.

If you can't tow more than 6000lbs then you only need a hitch that can carry 600lbs vertical weight. You can design it for more than that, but it won't increase your towing capacity if other factors are already limiting it. It's more likely that they figure out how much the entire vehicle can handle swinging from a ball joint and then aim for 10% hitch weight.

Once you know those figures, you can design a hitch that could completely out-perform the 10% figure, or you can design one that just meets it and no further.

If you design one that just meets the 10% of your towing capability then you won't be able to carry a rack of equal weight because it is not supported on the outboard end.

But, you can't just advertise more towing weight because you built a really beefy hitch. It doesn't work that way.

Many of these EVs trying to get a really long range are designed to take a hitch that can stow completely out of the way because the aerodynamics of the design of the back end play a big role in efficiency and range. They either use these retractable or removable hitches or they advertise a much lower range. Granted, they could advertise a lower range only if you equip the tow package, but that would still cause issues especially because many owners want the hitch for only a small percentage of their trips and they don't want to pay the range price for every trip.

 

[Elfin]

Tow weight is determined by a number of factors of which the hitch is only one. A 1000lb car cannot tow a 10,000lb trailer no matter how beefy the hitch is designed. A big truck with skimpy little wheels and a basic suspention cannot tow much no matter how strong its frame or how beefy the tow hitch you attach directly to that frame.

The amount you can tow goes far beyond the structure of the back end. Structure is one of its limits, but not the only one.

If you can't tow more than 6000lbs then you only need a hitch that can carry 600lbs vertical weight. You can design it for more than that, but it won't increase your towing capacity if other factors are already limiting it. It's more likely that they figure out how much the entire vehicle can handle swinging from a ball joint and then aim for 10% hitch weight.

Once you know those figures, you can design a hitch that could completely out-perform the 10% figure, or you can design one that just meets it and no further.

If you design one that just meets the 10% of your towing capability then you won't be able to carry a rack of equal weight because it is not supported on the outboard end.

But, you can't just advertise more towing weight because you built a really beefy hitch. It doesn't work that way.

Many of these EVs trying to get a really long range are designed to take a hitch that can stow completely out of the way because the aerodynamics of the design of the back end play a big role in efficiency and range. They either use these retractable or removable hitches or they advertise a much lower range. Granted, they could advertise a lower range only if you equip the tow package, but that would still cause issues especially because many owners want the hitch for only a small percentage of their trips and they don't want to pay the range price for every trip.

A 1000lb car would have the front wheels in the air with a 1000lb tongue weight. I keep saying that structure is the least limiting factor in tow capability. Watch the video of the F-150 being dropped a couple feet onto the tow hitch. If someone crashes their F-150 because they exceeded the tow rating it's not going to be because the receiver failed.

I doubt that a design like this makes any difference to range. I am sure the reason Lucid chose to use a detachable hitch is aesthetics.

 

[cerb1958]

Page 114: https://lucidmotors.com/media/document/Lucid-Gravity-Owners-Manual_en-US.pdf
Weight limit is 110lbs.

Ignore all the other answers - this is the correct answer. It is a very low weight - inadequate really for racks and bikes and cargo boxes. I hope Lucid can address this in the future. My Porsche Macan has a vertical load weight of 441pounds - literally 4 times as much!!