© 2003 Post Falls Highway District
HOW TO CALULATE YOUR GROSS VEHICLE WEIGHT TO COMPLY WITH THE
LOAD LIMITS

The Load Limits are as follows:  
1)  10,000 lbs Maximum on steering axle (Tires must be 9 inches in width or greater).
2)  300 lbs Maximum per inch of width for all tires that are not on a steering axle.
3)  25 MPH Maximum speed limit for all trucks whether loaded or empty.

Metric Tires

The tire size is written on the side of your tires. The first set of numbers give the tire width.
Example: 295/75R 22.5. The first number is 295. The metric conversion table below indicates
that it is 11.60 inches in width and that equates to 3,480 lbs. per tire. You then need to
calculate per axle weight, this is how the law is enforced. If you are figuring for a 10 wheel
truck, the steering axle has a 10,000 lb maximum and the remaining 8 tires (4 tires per axle @
3,480 per tire = 13,920) x two axles = 27,840lbs. Add the steering axle of 10,000 lbs for a total
GVW of 37,840 lbs. REMEMBER the vehicle will be weighed by axle. In this example the
axle weight from front to rear can NOT exceed: (Steering Axle - 10,000 lbs.) (Front drive axle
- 13,920 lbs.) (Rear drive axle - 13,920 lbs.).

Standard U.S. Tires

   These are easier. Example: A tire size marked 11R22.5 is 11 inches wide. 11 x 300 lbs = 3300
lbs per tire. 3300 x 4 tires per axle = 13,200 lbs. per axle. Although the total GVW with this
size tire is 36,400 lbs., a 10 wheel truck with 11R22.5 tires can NOT exceed by axle: (Steering
axle - 10,000 lbs.) (Front drive axle - 13,200 lbs.) (Rear drive axle - 13,200 lbs.)

 
METRIC CONVERSIONS FOR TIRE SIZES
Millimeters to Inches (Divide by 25.4)

165 mm =   6.50 in.    6.50 X 300 = 1,950 lbs. per tire
175 mm =   6.89 in.      6.89 X 300 = 2,067 lbs. per tire
185 mm =   7.28 in.      7.28 X 300 = 2,184 lbs. per tire
195 mm =   7.68 in.      7.68 X 300 = 2,304 lbs. per tire
205 mm =   8.07 in       8.07 X 300 = 2,421 lbs. per tire
215 mm =   8.45 in.    8.45 X 300 = 2,535 lbs. per tire
225 mm =   8.85 in.    8.85 X 300 = 2,655 lbs. per tire
235 mm =   9.25 in.    9.25 X 300 = 2,775 lbs. per tire
245 mm =   9.65 in.    9.65 X 300 = 2,895 lbs. per tire
255 mm = 10.00 in.  10.00 X 300 = 3,000 lbs. per tire
265 mm = 10.40 in.  10.40 X 300 = 3,120 lbs. per tire
275 mm = 10.80 in.  10.80 X 300 = 3,240 lbs. per tire
285 mm = 11.20 in.  11.20 X 300 = 3,360 lbs. per tire
295 mm = 11.60 in.  11.60 X 300 = 3,480 lbs. per tire


LAST UPDATED 2/7/2012
                                        
© 2008 Post Falls Highway District
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       UPDATED 2/7/12 

LOAD LIMITS HAVE BEEN REINSTATED - EFFECTIVE UNTIL MARCH 15TH.

ONLY ESSENTIAL SERVICES WILL BE GIVEN PERMITS.  ALL VEHICLES MUST MEET POSTED WEIGHT RESTRICTIONS.
             Exceptions to Weight and Speed Restrictions.
The following are exceptions to posted vehicle weight and speed restrictions as allowed by Idaho Code 49-1005:
·        Vehicle weight and speed restrictions shall not apply to emergency vehicles or school buses;
·        Providers of essential services shall be allowed to apply for a permit that will allow the provider to haul half-loads at restricted speeds.  Each vehicle must be issued separate permits.  Each vehicle must have a valid permit on board during vehicle operations in the City of Hayden.  Failure to comply with the conditions of this permit will revoke the permit and result in full weight enforcement under Idaho Code 49-1005.  The following vehicles are entitled to apply for essential service permits: providers of heating fuel and propane; hay or feed providers; septic pumping services; and garbage trucks;