Advice on rolling stops or full stops

[oldtamiyaphile]

Originally Posted by Vman455

4However, that 0.182 kJ does equal 0.05056 Wh, out of 33.1 kWh in one gallon of gasoline--or 0.0000015% of a gallon. You would need to roll through approximately 654,725 stop signs at 1 mph to save one gallon of gas, and that's assuming 100% conversion efficiency.

There are much easier, legal ways to save one gallon.

Well yes, it's more like 30% conversion so you need 100kWh of fuel to repay that stop, or a bit under 200,000 stop signs.

[redpoint5]

I better start rolling through stop signs now to get a jump on that 200,000 payback amount!

[Frank Lee]

I've owned my F150 for 25 years and it still has the original brake calipers, cylinders, pads, shoes, drums, and rotors.

[oldtamiyaphile]

Originally Posted by redpoint5

I better start rolling through stop signs now to get a jump on that 200,000 payback amount!

LOL. Thing is it's exponential. At 2mph it's only 50,000, at 4mph it's 12,500 and so on. You don't have to get fixated on the legality of stop signs, this is useful knowledge in general that applies to give ways, traffic lights and so on, hence why I've pointed out the minor error in a useful post.

I do my best to slow early and about 50% of the time it means I don't need to come to a full stop at a trafic light that's about to change. 50mpg in a 2 ton van is my best effort, and there's a $2000 clutch to consider as well.

Where I live I've never heard of anyone getting a ticket for rolling a stop, so no one stops. There was someone killed here on a motorbike because he came to a stop, and the SUV driver was having none of that.

If I'm on a bike I won't stop if I don't have to, it's too dangerous. A ticket is actually pretty cheap considering.

[redpoint5]

I avoid foot down stopping on a motorcycle, but I still come to a stop briefly.

[slowmover]

Originally Posted by Frank Lee

I've owned my F150 for 25 years and it still has the original brake calipers, cylinders, pads, shoes, drums, and rotors.

And 42,506 miles

[Frank Lee]

Wouldn't that be nice!

[Vman455]

Originally Posted by oldtamiyaphile

Well yes, it's more like 30% conversion so you need 100kWh of fuel to repay that stop, or a bit under 200,000 stop signs.

If you're assuming 30% efficiency, it's closer to 120,000 for a rolling 1 mph stop to save one gallon, 60,000 for 2 mph, and so on (because K = 42.9% of Q, which is itself only 70% of total E). Even if you have 5 different stop signs on your commute, and roll through all of them consistently, that's only 1250 stops per year assuming a two week vacation, no other holidays, and a five-day work week. At 4 mph, that's a payback time to save one gallon of 12 years. Now, how many gallons could you buy for the cost of one ticket? And how many people are consistently and constantly rolling through every stop sign at 4 mph? If this is really a concern, I would take slowmover's advice and find a different route!

[Fat Charlie]

Originally Posted by Frank Lee

I've owned my F150 for 25 years and it still has the original brake calipers, cylinders, pads, shoes, drums, and rotors.

Show off. My Fit just passed 5 years and 116,000 miles, and just a few weeks ago the front brakes started making scraping noises. I got the parts in yesterday and am hoping to have them done next week.

I went with the OE pads, because the original set did so well.

[MeteorGray]

I hope a newspaper reporter doesn't read this thread and write headlines:

Ecomodders run stop signs because they save a gallon of gas for every 120,000 they run!

They discuss how fast should a stop sign be run for maximum economy!

It's cheaper if the run-through speed is higher!