Max Hitch Rise When Towing With the Model Y

[Hamson007]

Long time lurker here.

I have recently started towing with my model Y and am currently using a 2" riser with a 8.25" length even though the manual specifies a max 0.75" rise and 8.5" length. I have been looking all over online and I can't find any articles or math on how a riser or drop impacts the leaver/max tow capacity of the hitch.

I feel pretty comfortable with using the 2inch riser since my trailer is about 2200lbs and 210lb of tongue weight. I am still curious though what the hard numbers are for something like this.

I think this math checks out but i'm not sure (Thanks ChatGPT):

To calculate the new maximum weight capacities with the new rise and length, we need to account for the change in leverage. We’ll treat the rise and length as components of a right triangle to determine the change in leverage effect.

    1.    Calculate the original leverage factor:
    •    Original rise: 0.75 inches
    •    Original length: 8.5 inches
The original leverage factor can be determined using the Pythagorean theorem:

\text{Original Leverage Factor} = \sqrt{(0.75^2 + 8.5^2)}


\text{Original Leverage Factor} = \sqrt{(0.75^2 + 8.5^2)} \approx \sqrt{(0.5625 + 72.25)} \approx \sqrt{72.8125} \approx 8.53 \text{ inches}

    2.    Calculate the new leverage factor:
    •    New rise: 2 inches
    •    New length: 8.25 inches
Similarly, the new leverage factor is:

\text{New Leverage Factor} = \sqrt{(2^2 + 8.25^2)}


\text{New Leverage Factor} = \sqrt{(4 + 68.0625)} \approx \sqrt{72.0625} \approx 8.49 \text{ inches}

    3.    Calculate the ratio of the new leverage factor to the original leverage factor:

\text{Leverage Ratio} = \frac{\text{New Leverage Factor}}{\text{Original Leverage Factor}} = \frac{8.49}{8.53} \approx 0.995

    4.    Adjust the maximum tongue weight and trailer weight:
    •    Original max tongue weight: 350 lbs
    •    Original max trailer weight: 3500 lbs
Using the leverage ratio, we adjust the capacities:

\text{New Max Tongue Weight} = \text{Original Max Tongue Weight} \times \text{Leverage Ratio} = 350 \text{ lbs} \times 0.995 \approx 348.25 \text{ lbs}


\text{New Max Trailer Weight} = \text{Original Max Trailer Weight} \times \text{Leverage Ratio} = 3500 \text{ lbs} \times 0.995 \approx 3482.5 \text{ lbs}


Summary

With the new rise of 2 inches and a length of 8.25 inches, the new capacities are approximately:

    •    New Max Tongue Weight: 348.25 lbs
    •    New Max Trailer Weight: 3482.5 lbs

These calculations show that the increase in riser height is almost fully offset by the slight reduction in length, resulting in a minimal decrease in capacity. Nonetheless, consulting with the hitch manufacturer or a professional engineer is always recommended to ensure these calculations align with the specific design and safety factors of the hitch.

 

[HyperionMark]

Surprised you didn't get any feedback on this. Keep us up to date with how everything is going.

 

[QtownTaxiGreg]

Rise gives rise to a ttwisting uplift to the bar under braking. I think that would be your main concern. Hard acceleration the reverse but easier to be in control of the situation.