earthworm
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Pardon my armchair engineering, but has anyone felt Tesla might be sandbagging their tow specs after reading Wes's tweet? I've seen more than one youtuber express disappointment that it's not a definitive tongue limit in all cases. But after looking at pictures on google of vans and SUV's bending their frames trying to haul a motorcycle, I think these are pretty realistic truck hitch limitations which would be generally applicable to all trucks simply because of physics. The further your leverage, the heavier force it exerts as Wes mentions.
Because the manual discloses the length and weight for the bike carrier and motorcycle examples, we can reverse calculate tongue force. The motorcycle imposes 1,575 lbs of tongue weight while the bike carrier exerts 1,298 lbs. For comparison, if you tried this with an F150 you'd exceed Ford's recommendations by about 50%.
Cybertruck's specs get better because Wes said this is taking into account a vibrational profile. I don't have any way to demonstrate this, but try to visualize slaloming between lanes; the motorcycle would rock left and right and apply more twisting force on the hitch than you ever possibly could towing a trailer. Since the dynamic limits of hauling a motorcycle seems more demanding on the hitch in terms of torsion and flex, I feel there's a large safety margin at play here.
And this assumes you maintain the 7.3" distance between the receiver and ball. Say we shop around and pick out a hitch that's an inch shorter with 6.3" horizontal distance between the ball and the hitch pin - that would give us 1,815 lbs of allowed tongue weight versus the 1,575 from the example. Again, this is just physics - by shortening the leverage an inch you're getting about 15% advantage no matter the vehicle.
There's also some factor of safety at play, and we don't know what that number is. SAE J2512 spec suggests an industry norm of 50%. So the actual limits could be 3,630 lbs tongue weight.
So why might it be advertised at 11k lbs? The limit of what you can safely tow comes down to how much you can safely brake. A safety advantage over diesel and gas is that we have two braking systems - friction & regen. From personal experience, Cybertruck regen alone can comfortably stop a 9,000 lbs trailer from highway speeds without using my friction brakes or my trailer's. I think the real reason we don't see 15,000+ lbs of towing spec is because the limit probably assumes worst case scenario, say when it's cold outside with 100% state of charge and no regenerative braking available. This also doesn't take into account the larger rotors, brakes, and CV axels present on Cyberbeast which give it even better friction braking capability.
It's hard to say what the real limits are. I read through Chevy and Ford's owner manuals and couldn't find any detailed examples like what Tesla gives us. After going through tons of pictures on Google of other steel-framed vehicles with hitches sagging and permanently bending from trying to carry a motorcycle, I have a feeling Cybertruck's aluminum subframe has higher limits before failure.
From what I understand, the failure mode for a Cybertruck's subframe is tensile failure of the aluminum shearing, whereas on a steal frame it would be yield failure due to bending. Google shows Ford has 340-MPa yield strength for high-strength steel, versus Tesla with 325 MPa tensile strength for their aluminum casting. What I'm trying to say - I think the strength is actually comparable where it practically counts in the real world. The main difference being when you crash test far outside the design limits your result is a bent frame vs a sheared one.
And while we're comparing metals, a steel framed truck would lose strength over time as it rusts from underneath. You don't have these same rust concerns with aluminum front/rear subframes on the Cybertruck. You do have the same high-strength steel on both trucks but with Cybertruck that's not what's being exposed to the elements underneath the vehicle.
Because the manual discloses the length and weight for the bike carrier and motorcycle examples, we can reverse calculate tongue force. The motorcycle imposes 1,575 lbs of tongue weight while the bike carrier exerts 1,298 lbs. For comparison, if you tried this with an F150 you'd exceed Ford's recommendations by about 50%.
Cybertruck's specs get better because Wes said this is taking into account a vibrational profile. I don't have any way to demonstrate this, but try to visualize slaloming between lanes; the motorcycle would rock left and right and apply more twisting force on the hitch than you ever possibly could towing a trailer. Since the dynamic limits of hauling a motorcycle seems more demanding on the hitch in terms of torsion and flex, I feel there's a large safety margin at play here.
And this assumes you maintain the 7.3" distance between the receiver and ball. Say we shop around and pick out a hitch that's an inch shorter with 6.3" horizontal distance between the ball and the hitch pin - that would give us 1,815 lbs of allowed tongue weight versus the 1,575 from the example. Again, this is just physics - by shortening the leverage an inch you're getting about 15% advantage no matter the vehicle.
There's also some factor of safety at play, and we don't know what that number is. SAE J2512 spec suggests an industry norm of 50%. So the actual limits could be 3,630 lbs tongue weight.
So why might it be advertised at 11k lbs? The limit of what you can safely tow comes down to how much you can safely brake. A safety advantage over diesel and gas is that we have two braking systems - friction & regen. From personal experience, Cybertruck regen alone can comfortably stop a 9,000 lbs trailer from highway speeds without using my friction brakes or my trailer's. I think the real reason we don't see 15,000+ lbs of towing spec is because the limit probably assumes worst case scenario, say when it's cold outside with 100% state of charge and no regenerative braking available. This also doesn't take into account the larger rotors, brakes, and CV axels present on Cyberbeast which give it even better friction braking capability.
It's hard to say what the real limits are. I read through Chevy and Ford's owner manuals and couldn't find any detailed examples like what Tesla gives us. After going through tons of pictures on Google of other steel-framed vehicles with hitches sagging and permanently bending from trying to carry a motorcycle, I have a feeling Cybertruck's aluminum subframe has higher limits before failure.
From what I understand, the failure mode for a Cybertruck's subframe is tensile failure of the aluminum shearing, whereas on a steal frame it would be yield failure due to bending. Google shows Ford has 340-MPa yield strength for high-strength steel, versus Tesla with 325 MPa tensile strength for their aluminum casting. What I'm trying to say - I think the strength is actually comparable where it practically counts in the real world. The main difference being when you crash test far outside the design limits your result is a bent frame vs a sheared one.
And while we're comparing metals, a steel framed truck would lose strength over time as it rusts from underneath. You don't have these same rust concerns with aluminum front/rear subframes on the Cybertruck. You do have the same high-strength steel on both trucks but with Cybertruck that's not what's being exposed to the elements underneath the vehicle.
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