author
11Instructables857,051Views260CommentsOakland CAJoined April 8th, 2009
I am an ordinary guy. Except that I live in an RV, drive a 250cc motorcycle, have a truck that runs on bio-diesel, am vegetarian, and have had almost 30 jobs in 10 years, including armored truck driver, bicycle messenger, medical test subject, TV commercial actor, "adult" actor, ditch digger, lab assistant, liquor store cashier, secretary, non-profit fundraiser and carnie. Now I am running my own small business, which is the only one of its kind which has been certified green in the SF Bay A... Read More »

Achievements

100+ Comments Earned a bronze medal
10K+ Views Earned a bronze medal
Earthjustice United States of Efficiency Contest
Contest Winner Runner Up in the Earthjustice United States of Efficiency Contest
Show 2 More »
  • Vehicle Efficiency Upgrades: 30+ MPG in 2.5ton Commercial Truck

    Yup, I've read that a number of places. I even tried modeling a simulated air tunnel myself, when I was deciding on how to build my cover:

    View Instructable »
  • Vehicle Efficiency Upgrades: 30+ MPG in 2.5ton Commercial Truck

    1) This is really old! I don't even own the truck anymore...2) I actually did try a "boattail" fairing at once point, but my mileage actually went down slightly. No windtunnel for proper design and testing :(3) True, higher pressure can lead to more easily damaged tires from potholes and nails and such, and could possibly shorten life. But (outside of snow, mud, sand, etc) it should provide similar traction (on smooth roads) and actually better handling. The main sacrifice with higher pressure is ride quality (i.e. you feel more road vibrations - on a very bumpy road at high speeds it can decrease traction just because it bounces slightly over bumps). Besides, I did regularly carry maximum loads!4) I am unfamiliar with the chalk test, care to elaborate?

    I loved the truck, but I was doing mostly handyman work and very little hauling and moving, plus a baby on the way - no safe way to put a child seat in the truck. My new Jetta wagon has enough room for all my tools (and ladder, and materials), but can convert to a family friendly mode - it gets better mileage at its worst than the truck at its best; AND it still runs on biodiesel.As far as tire pressure, I don't claim to personally be an expert. But I can provide links to people who do:"If a vehicle's tires are overinflated by 6 psi, they could be damaged more easily when running over potholes or debris in the road. Higher inflated tires cannot isolate road irregularities well, causing them to ride harsher. However, higher inflation pressures usually provide an improvement in ste...

    see more »

    I loved the truck, but I was doing mostly handyman work and very little hauling and moving, plus a baby on the way - no safe way to put a child seat in the truck. My new Jetta wagon has enough room for all my tools (and ladder, and materials), but can convert to a family friendly mode - it gets better mileage at its worst than the truck at its best; AND it still runs on biodiesel.As far as tire pressure, I don't claim to personally be an expert. But I can provide links to people who do:"If a vehicle's tires are overinflated by 6 psi, they could be damaged more easily when running over potholes or debris in the road. Higher inflated tires cannot isolate road irregularities well, causing them to ride harsher. However, higher inflation pressures usually provide an improvement in steering response and cornering stability up to a point."https://www.tirerack.com/tires/tiretech/techpage.j..."One tire expert from the Edmunds.com testing team said that this slightly compromises braking distances but actually improves handling because it provides more "bite" as the tire flexes during sharp cornering. This expert said he chooses 4 psi over the specified level."https://www.edmunds.com/fuel-economy/edmunds-emplo..." the vehicle manufacturers specifications are either patently too low (for this area), or barely adequate."https://www.souzastireservice.com/tires-101/air-pr...However, almost no one ever specifies exactly what "overinflation" refers to exactly. Overinflated by more than the tire max is likely too much - although one company *doubled* max sidewall pressure and failed to find the limit of improvement (in wet conditions): "Michelin performed a hydro­planing resistance test using pressures above the “max press­ure/max load” rating. The test was motivated by the common practice among law enforcement officers of inflating their tires above that recommended by the vehicle manufacturer. The test almost doubled the “max pressure” without discovering where hydroplaning resistance reached a plateau."https://www.tirereview.com/can-psi-adjustments-fix...From the same site "Can we improve handling and ultimate grip by increasing tire pressure? You bet! I participated in several at-the-limit, race-track-style pressure tests. We found that increasing the pressure on the end with less grip worked wonders. " The car manufacture sets the recommended pressure with ride comfort as a significant factor:"Engineers determine how much pressure we require to support the vehicle and its load. With passenger vehicles they also consider ride comfort. With less air pressure the vehicle rides more comfortably. Less pressure allows the tire sidewall to flex, which absorbs roughness in the road. This flexing also damages the tire and promotes faster wear.This is why on passenger cars, the tire placard rating might be considered the minimum.Some tires experience excessive wear with the vehicle manufacturer’s recommended pressure. In such cases, they may base the recommendation too heavily on ride considerations. As tire pressure increases, ride comfort generally decreases. This is because we reduce tire flexing. More pressure may also increase tire life and fuel mileage, up to a point."http://www.agcoauto.com/content/news/p2_articleid/...The chalk idea makes a lot of sense, except it seems it would be most useful if done in real world conditions - i.e. with the tires at the average temperature they are at when in use, and at the average speed they are driven at.

    The boattail experiment:

    View Instructable »
  • Vehicle efficiency upgrades: 30+ MPG in 2.5ton commercial truck

    interesting theory. I suppose humans did not live in countries with hot weather before the early 1900s, when A/C was invented? That's funny, because I'm pretty sure people actually did live near the equator before 1900. Which would imply it actually is physically possible. Perhaps what you meant was that in the country you live in car windows can not be rolled down? This is equally surprising, but I haven't lived everywhere, so I grant that it is possible.

    View Instructable »