Automotive manufacturers agreed in 2008 to standardize tow ratings as specified in the SAE's Surface Vehicle Recommended Practice J2807 to take effect by 2013. An article dated December 21, 2009 Tow Ratings Finally Pass the Sniff Test - The Society of Automotive Engineers (SAE) - Automobile Magazine in Automobilemag.com gives a good overview of the new standards. Prior to this, manufacturers pretty much advertised whatever tow ratings they wanted, and there was no "apples to apples" comparison between brands or models.
The reason I am posting this information now, is that beginning with the 2010 models, Toyota is using the new SAE tow ratings standards which includes the 2010 5th Gen 4Runner. If you are trying to compare tow ratings between Toyota and other manufacturers, you will have to do the research yourself to see whether the other companies are using the SAE standards or their own numbers since they have until 2013 to comply.
Although the new standards will give a more realistic tow rating and allow this "apples to apples" comparison, it does not speak to the durability and longevity of chassis/power trains/etc. However, for Toyota customers you should understand that Toyota builds in a performance buffer or margin. For example, if Toyota is claiming a 5,000 lbs tow rating, the vehicle is actually engineered and designed for a higher number (5,500 - 6,000 lbs. or whatever---a number for legal reasons Toyota may not want us to know). The vehicle is designed for this higher tow rating, and engineered so that it will tow "X" number of days per year, "X" number of miles per year and perform and last through the warranty period of the vehicle. Then the lawyers figure out the statistical probability of performance and failure for the warrantied life of the vehicle to come up with the final tow rating. So for Toyota it's a two step process were they now meet the SAE standards, but also make sure that the advertised tow rating is well within what the maximum capability of the vehicles actually is. Note: Do not exceed the recommended tow rating of your vehicle, and make sure you are towing smartly and safely, taking all variables into account when you tow. This should just give you some peace of mind that your Toyota was designed for both capability and longevity.
The reason I am posting this information now, is that beginning with the 2010 models, Toyota is using the new SAE tow ratings standards which includes the 2010 5th Gen 4Runner. If you are trying to compare tow ratings between Toyota and other manufacturers, you will have to do the research yourself to see whether the other companies are using the SAE standards or their own numbers since they have until 2013 to comply.
Although the new standards will give a more realistic tow rating and allow this "apples to apples" comparison, it does not speak to the durability and longevity of chassis/power trains/etc. However, for Toyota customers you should understand that Toyota builds in a performance buffer or margin. For example, if Toyota is claiming a 5,000 lbs tow rating, the vehicle is actually engineered and designed for a higher number (5,500 - 6,000 lbs. or whatever---a number for legal reasons Toyota may not want us to know). The vehicle is designed for this higher tow rating, and engineered so that it will tow "X" number of days per year, "X" number of miles per year and perform and last through the warranty period of the vehicle. Then the lawyers figure out the statistical probability of performance and failure for the warrantied life of the vehicle to come up with the final tow rating. So for Toyota it's a two step process were they now meet the SAE standards, but also make sure that the advertised tow rating is well within what the maximum capability of the vehicles actually is. Note: Do not exceed the recommended tow rating of your vehicle, and make sure you are towing smartly and safely, taking all variables into account when you tow. This should just give you some peace of mind that your Toyota was designed for both capability and longevity.
