Load Limits and Towing Capacity

How Much Can I Tow in this Trailer? Mac & Cheese for the Local Food Bank!

Yesterday, I used my "free to me" trailer for grocery shopping - it's nice not to have to worry about fitting everything in a bag or even two, and backpacks can be a PIA. Starting out, however, cargo capacity became a question when I started out up a little slope in the parking lot to leave for home. Further on, I felt doubly privileged to shop in a place as flat as Ocean Shores, Washington.

In the motor vehicle world, load limits and towing capacity are pretty cut and dried. What's more, manufacturers publish their values, though these are not always highlighted when the numbers don't support selling vehicles to people.

Two major values include:

• Gross Vehicle Weight Rating (GVWR) - this is the maximum amount the vehicle is rated which includes the vehicle itself, fuel and oil, and all payload (passengers, pets and luggage, including any roof racks and contents thereof). Our Subaru Outback has a GVWR rating of 4,695 pounds, since its empty weight is 3,600 pounds, that means we can carry a bit less than 1,000 pounds. If there are five people in the car, that doesn't leave a whole bunch leftover for luggage.
• Maximum Towing Capacity - this is the maximum amount the vehicle can safely tow. Some so-called utility vehicles, such as the Vokswagen Allroad have no approved towing capacity at all. Our Subaru Outback has a rated towing capacity of 2,700 pounds.

There are lots of other ratings, such as "Gross Combined Weight Rating," but these are not so easy to track down. It appears that Subaru simply lets you tow 2,700 pounds whether the vehicle itself is full or empty.

How Does This Apply to Bikes?
In the bicycle world, these values are not so easy to find. It's pretty easy to find out the "empty weight" of most new bicycles, but payload - not so much. It's pretty clear some bikes have a lot more payload capacity than others - tandem bikes, for example, have uprated wheels to support the extra weight, but these values are NOT easy to find, though I have noticed that motorcycles and even electric scooters now specify a maxium payload (typically 240 pounds, and up to 400-500 for motorcycles). It gets even tougher when you start towing stuff with your bike. As in the case of cars, you can tow a lot more weight than the vehicle payload suggests. Our Subaru can tow nearly three times its payload. The Volkswagen that claims it is an Outback competitor can't tow anything. But how much is too much? Inquiring minds want to know! Does that spendy Trek Madone have a GVWR higher than the "Wallyworld Cheapie?" And what about that Dutch Cargo bike versus a Touring versus a Cyclocross bike?

I HAVE found a few items that relate. For example, here, they have a "calculator" and the site also lists weight capacities of 300 pounds for pretty heavy-duty looking trailers. Here, a site lists payload capacities for some bikes from major makers (sorry Surly owners, but no number for you!). Apparently, some manufacturers note that wheels are the weak link (Raleigh notes "All frames are tested to 550 pounds. It is the wheels that limit rider weight more than frames."), but there, the trail grows cold.

Harley Does it Different
While motorcycles are somewhere "in between," Harley Davidson uses a frame decal sticker with the GVWR on it. They also list the individual axle capacities. There's a discussion on motorcycle weight capabilities on Northwest Motorcycling Sound Rider, here. The link even has a couple of photos and discusses how difficult it was for him to find weight carrying capacity for some motorcycles.

Short Bike Commutes Can Be Costly

Andy Cline, at Carbon Trace, has a short bike commute. He knew where he was going to be working for many years to come and picked a house nearby. I confess that, despite a slight bittersweet taste when ending a memorable commute, I was quite pleased to trade my 20 mile v2 commute for my 7 mile v3 commute. However, I have discovered that there really IS no such thing as a free lunch and that a shorter commute does carry some cost. You might wonder, HOW is anyone worse off in any respect whatsoever by suddenly living closer to work without even having to have moved? Andy Cline might wonder, “Have I missed something?” Well, yes.

I have now made my new v3 commute long enough to project my weekly commute mileage. Conveniently, I also tracked my weekly mileage on both the v1 and v2 commutes. I find it interesting to note that the results do NOT show I double my bike mileage if I double my commute length, but the bike mileage does increase. In the case of a bike, decreased bike commute mileage means decreased calorie burn. Decreased calorie burn means either one must cut down food consumption or make special trips to go work out to maintain equilibrium. Acch. Diet and exercise!

That is bad enough, but it transpires that I can be more specific than that. Since I’ve kept commute logs, I can quantify things and determine precisely the penalty I shall have to pay for my new, short and easy commute.



Published Calorie Expenditure Chart

 To start off, if you look at the published table, riding a bike will cost somewhere between 40 and 50 calories a mile for the vast majority of us. While wind resistance plays a role, going slower doesn’t help much with basic rolling along, and few of us are going to be riding to work at an average speed over 20mph. For purposes of the analysis, energy expenditure on a bike commute is about 45 calories per mile and I use that for the calculations below.

The NEXT table shows how my own, historical daily average mileage related to different commutes. Remember in this table that daily average mileage uses seven days per week while the commute takes place in five (if you work seven days a week, we need to talk). In addition, you don’t commute when sick, on holidays, or vacation. Finally, remember that working at a more remote location means there will be more days in which driving is needed, simply to make it to appointments or other things where the bike simply isn’t fast enough to make it between two distant points in the needed time. The really short commute assumes that I’d be able to ride even a bit more frequently than my new, 7 mile commute. Even if you work at home, there will occasionally be appointments and such that simply mandate a motor vehicle, whether it is an owned car, a taxi, or a rented car.

Bike Commute Cost Comparisons

The table sorts things into increasingly long commutes. As you can see, based on historical numbers, commutes start to require significant payments as they get shorter, and the penalties in weight gain for not making those payments get more severe as well. Of course, there are many ways to vary the payments; for example, I personally could avoid the 17 pound gain by omitting 2 cheese sticks per day. Looking at the table, I thank my lucky stars that I work in an engineering job rather than the barista or Walmart greeter jobs that might fall within the theoretical “very short” commute. I’d be stuck going to the gym twice a day every day or undergoing serious food deprivation. How DO those motorists (and Andy) stay slim and trim? Perhaps they dollarize their time savings and spend it on bariatric surgery and Jenny Craig…

The Cost of a Short Commute - Extra Workouts, Dietary Rationing, or Weight Gain!

Simple Commuter CRM

Low Cost Digital Scale will Weigh Items up to 6Kg (13Lb)

Chandra is both my inspiration and my fear. In his post, here, he discussed the merits of "CRM." CRM stands for "Poop Reduction Management." He's my inspiration because there are few of us that can't find something we can do without while riding and he got a scale to help his CRM program. He's my fear because I'd hate to wind up lugging a handlebar bag weighing over 14Lb.

I travel fairly light. While I run Buddy with a trunk bag and fenders, and carry four lights for the commute (2 in front and 2 more in back), I try not to carry too much extra stuff. For example, I do not bring a lock along with me on my commute, my bike does not utilize a kickstand, and for the cool mornings, I only fill my water bottle up half way. However, inspired by Chandra, I invested in a small scale and decided to do a little impromptu CRM of my own.

Sure enough, I managed to validate a bit of past CRM and found some new items to omit.

First off, I found that carrying a CO2 pump along on my commute cost me 81g. Considering that my Topeak pump is perfectly workable, and I only get a flat every few thousand miles, it seemed worth leaving behind. Next, I've been taking the Bontrager multitool along that I got at the HH100. It is a deluxe multitool, but for commuting purposes, the Park multitool includes enough for roadside purposes. Swapping for the Park saved another 79g. Finally, I removed the valve cap and loose hardware on my spare tube for another 2g savings. It isn't much, but there seems little point to carrying around stuff that duplicates items that don't fail and aren't strictly necessary in the first place. Total savings: 162g (nearly a half pound) for a net cost of nothing, an investment of about five minutes and a net loss of no functionality. Crimeny, this is MUCH EASIER than a diet!

Hmm, this weight savings thing looks like it has promise...