Five calculators that do arithmetic on numbers you already have, for any machine, with impossible inputs rejected instead of quietly corrected.
Tools
Use these calculators to compare entered trailer loads, tie-down ratings, tire dimensions, gearing and service counters. The model’s approved fitments and limits remain necessary inputs.
Checks a load against the trailer’s GVWR and the tow vehicle’s combined rating at once, gives a tongue weight target, and subtracts that tongue weight from the truck’s remaining payload.
Runs both federal securement tests, the minimum count by length and weight, and the aggregate working load limit. Reports whichever demands more straps.
Converts a metric or an inch size into overall diameter. Then reports the change in diameter, revolutions per mile, speedometer reading and axle height.
Turns a sprocket change into a ratio change. Adds an engine speed at your usual cruising speed, and an estimate of the chain length difference.
Takes the intervals from your own manual and your current readings on all three counters, and reports which one arrives first and roughly how many weeks away it is.
| Your question | Calculator | What it reports |
|---|---|---|
| Is this load within my trailer and truck? | Trailer load match | Load against trailer GVWR and combined rating, tongue weight target, truck payload left |
| How many straps does this machine need? | Tie-down requirement | Minimum strap count and aggregate working load limit, whichever demands more |
| What will bigger tires do to my speedometer? | Tire size change | Diameter change, revolutions per mile, speedometer reading, axle height |
| What does a sprocket change do? | Final drive gearing | Ratio change, engine speed at cruising speed, chain length difference |
| What service is due next? | Service interval planner | Which of miles, hours and time arrives first, and roughly how many weeks away |
A calculator result does not know the condition of your straps, whether the trailer plate is legible or what a load does when it shifts through a bend. Where a result and the plate on the equipment disagree, the plate wins. Where it disagrees with your manual, the manual wins.
Where it disagrees with a rule as enforced where you are, the rule wins. Most mistakes these tools catch are not close calls. They are a rating nobody looked up.
Or a counter nobody checked.
References
Five calculators cover the arithmetic a powersports owner actually needs: whether a load is within the trailer's and truck's ratings, how many tie-down straps a machine needs, what a bigger tire does to the speedometer, what a sprocket change does to gearing and which service interval arrives first.
Each takes numbers you already have (your machine's weight, the trailer plate, your sprocket teeth, your odometer and hour meter) and shows the formula and a worked example with the result.
Yes, entirely, with no account and no sign-up. There is nothing to unlock and no premium tier. The inputs you type are used to compute the result in your browser and are not stored or sent anywhere, a consequence of how the tools are built, not a policy that could change.
The forms are plain forms and work before any script loads. The script that computes results in your browser is an add-on; if it fails to load, the form still submits instead of the button doing nothing. That is the intended failure mode.
You get an error naming the field, and no result. Values outside the accepted range are rejected instead of adjusted into range, because a calculator that turns an impossible input into a plausible-looking output is worse than one that refuses: nothing on the screen tells you that it happened.
So that a result you saved or copied stays meaningful after a formula is revised. The version is recorded with the result, so a figure you wrote down last year can be traced back to the exact formula that produced it, not silently reinterpreted under a new one.
Each tool carries test cases covering ordinary values, values at the edge of every accepted range, invalid values that must be rejected, and the conditions that should raise a warning. The build runs all of them and refuses to publish a tool whose cases fail, and it separately proves the browser and server versions agree on each case.
No, and where the two disagree the manual wins. The manual describes the machine that was built, including tolerances and design decisions no general formula knows about. These tools apply published rules and geometry to numbers you supply; that is useful and it is not a substitute for a document about your specific machine.
Four categories, labelled on each page: regulation, where a federal rule sets the figure; convention, where manufacturers publish it and everybody uses it but nothing mandates it; geometry, which is true by definition; and rule of thumb, which is a working approximation and is always identified as one.
No. The calculation happens in your browser, and the inputs are not transmitted or recorded. There is nothing to opt out of because there is nothing being collected, so there is also no saved-results feature. That would require storing exactly the data these tools do not keep.
They are not a certification and no enforcement authority is bound by them. What the tie-down calculator produces is the federal rule applied to the numbers you entered, useful for planning and for understanding what the rule requires. Whether a specific load as secured complies is a judgement made by whoever inspects it.
Because those depend on machine-specific data, such as internal gear ratios, power curves and aerodynamics, that cannot be entered as a few numbers. A calculator that asked you to guess them would return a confident answer built on a guess.
Yes, through the contact form. The test for whether one gets built is whether it can be computed from inputs an owner has, using constants that come from a published rule or from geometry. If it needs a specification table we cannot source, it does not pass that test however useful it would be.
Use the corrections page and include the page, the exact inputs you entered, and the result you got. Because each tool is versioned, a report with the inputs can be reproduced exactly against the formula that was live at the time, making a correction actionable and not a difference of opinion.
Protection Against Shifting and Falling Cargo: general securement rules : U.S. Government Publishing Office (eCFR), 49 CFR §§ 393.100–393.114.
How is the working load limit of a tiedown determined? : U.S. Government Publishing Office (eCFR), 49 CFR § 393.108.
Cargo Securement Rules: driver and carrier guidance : Federal Motor Carrier Safety Administration.
Year Book: standardized tire, rim and valve dimensions, load and inflation tables : The Tire and Rim Association.
Short-pitch transmission precision roller and bush chains, attachments and associated chain sprockets : International Organization for Standardization, ISO 606.
Trailer load match: start with the weights; The rating nobody looks up is usually the tow vehicle’s payload.