Mythbusters tests "golf ball" dimples

[Xist]

In some places they gave good information and in others they were completely unscientific. One guy said he overinflated his tires, but then called it a scam.

No, it is absolutely tested science, and if it didn't work it would be a myth that could be busted.

Who is benefiting from it?

Is it a scam if nobody benefits from it? So, here is their questionable video.
Maybe people who know what they are saying can guide this conversation:

https://www.youtube.com/watch?v=p1AksSQB1Yc

Someone mentioned "Gears and Gasoline bought a first-gen Honda Insight" and I found this:

https://www.youtube.com/watch?v=9WYypHmERtw

For all that I know someone posted it here and I commented on it, but it was new to me [today]!

Someone commented he loved his Gen1 Insight "392k miles lifetime FE 57.3 mpg" and people said he was bad and his car was bad.

Well, it wasn't this video:

https://www.youtube.com/watch?v=eLmLG52La58

This was kind of interesting:

https://www.youtube.com/watch?v=3_vQebs8S-U

This is the only other Insight video I see by these guys:

https://www.youtube.com/watch?v=ti-JqQ2btoQ

People may complain about me necroing this thread, but if nothing else, original links broke. Here is a current link: Car Aerodynamics - A2 Wind Tunnel - Wind Camp Tech Theory

[freebeard]

"[N]ecroing this thread..." Is that like posting a broken hyperlink?

The Insight's bubble-top coupe body reminds me of this concept from Vaughn Ling.

vaughanling.blogspot.com/2010/09/more-honda.html

It has narrow sail panels with a smol pickup bed, and removable utility bins over the rear wheels.

[Xist]

That was supposed to work!

Of course, so was my log-on--the first two times.

https://www.motortrend.com/how-to/car-aerodynamics/amp/

[Xist]

Garrett Graf commented "How much fuel you would save driving on 4 small spare tires?"

Does anyone know who tried that?

People keep mentioning tailgate up, tailgate down, and mesh instead of a tailgate. I found the clip, which will undoubtedly die eventually, but they said the mesh was 5% more efficient than tailgate up or a tonneau cover:

https://www.youtube.com/watch?v=r3aqHbD-O9E

Jamie said that instead of e-mailing them with any further fuel efficiency questions, "Just drive the way you want."

[oil pan 4]

Some one on here used to run their car on doughnut spares. But I don't remember who it was.

[Xist]

I am pretty sure they put "Real" tires on the spares, but I don't remember anything else.

Edit!

I didn't use the search box. I used google to search Ecomodder and just saw people talking about removing their spare.

However, when I used the search box I found:

Originally Posted by MetroMPG

SPOILER ALERT:

Peakster'll probably be mad at me for posting the results here in the thread, but here's what he observed in an A-B-A test, with a pair of donuts (on the rear) for the B test:

A - 55.9 mpg (US) average (regular tires)
B - 60.9 mpg (US) average (donut tires)

Video: Can Skinnier Tires Increase Fuel Economy?

Peakster wrote: "I purposefully put the smaller tires on the rear so that my speedometer and gearing would remain the same as with the larger tires."

Metro put 4 spares on his Forkenswift and they did significantly worse:

Originally Posted by MetroMPG

To help visualize just HOW bad the donuts were compared to the RE92's (which henceforth shall be known as the Tires Of The Gods), a photo with the car at actual starting & stopping points:



I used a big parking lot that's empty on weekends. The starting "hill" isn't huge - maybe a couple of feet elevation change where the entrance/exit goes up to meet the road grade.

But it was enough of a slope that the car rolled...

• 216.9 feet on the RE92's @ 51 psi (average of 5 runs).

• 155 feet on the donuts @ 70 psi (average of 2 runs).

• just 138.8 feet (!!) on the donuts @ 51 psi (average of 3 runs).

https://ecomodder.com/forum/showthre...tml#post265031

The last comment on Metro's thread was:

Originally Posted by iveyjh

When I bought 5 doughnut spares from a Altima I tried them out on my Metro before I put the Continental eco tires on. Results similar to what you had, that's why I picked the RE92's.

I also found

Originally Posted by SuzukiSteve

I been running this set up for 6months/15,000 miles. Nissan Altima spare rims fit my suzuki siwft/geo metro lug pattern. They are DOT stamped and dont look like donut wheels. I have nice 155/80R15 BF Goodrich tires. rated to 55psi andlike 140mph. The rims are 4" wide so technicaly im one size (1cm) too wide, dont notice and dont care. They do rub the fender well a little in tight turns but its acceptable.

As far as mpg gains. My car is rated 32city 38highway. With good amounts of hypermiling i manage ~44mpg (mostly city) before correcting for tire size. Thats ~50mpg. Did not aba them, and my driving route changed at the same time as the tires so im not sure of the gains from them. but i suspect they get me ~5mpg.

I love how they look too! And I just covered the rims with $3 walmart pizza pans.

My boss Glenn did a write up of it over on GMF. Pictures Included!
15" Wheels and VW Tires

https://ecomodder.com/forum/showthre...els-16886.html

That was the term. Someone put spacesavers on his car, which were lighter than Insight rims.

Unfortunately, the link is dead, and I cannot find it archived, although I believe that he referred to it elsewhere, so that may have some information.

Well, I need to drive to see 1-4 clients!

[Daschicken]

Metro did the test with spare tires on the spare wheels, it didn’t turn out well for rolling resistance.
https://ecomodder.com/forum/showthre...e92-19126.html

[Isaac Zachary]

[QUOTE=Xist;672131]Is it a scam if nobody benefits from it? So, here is their questionable video.
Maybe people who know what they are saying can guide this conversation:

https://www.youtube.com/watch?v=p1AksSQB1Yc

That video isn't the best made by Donut. It's very general, and of course designed for a very general audience. I think they messed up when they mentioned Top Tier fuel and then go on to talk about octane as if they were the same thing. Still, over all I like the video.

[aerohead]

Originally Posted by Xist

Garrett Graf commented "How much fuel you would save driving on 4 small spare tires?"

Does anyone know who tried that?

People keep mentioning tailgate up, tailgate down, and mesh instead of a tailgate. I found the clip, which will undoubtedly die eventually, but they said the mesh was 5% more efficient than tailgate up or a tonneau cover:

Jamie said that instead of e-mailing them with any further fuel efficiency questions, "Just drive the way you want."

In the 1990s, SPORT TRUCK Magazine did an extended pickup truck aerodynamics article which included comments by aerodynamicists of many of the truckmakers.
It all came down to case-specific analysis.
GM's Cd 0.14 Aero 2002 of 1983 had 145mm tires, similar to space-saver spares.
Many researches have all indicated for lower drag when discussing tire width. Today's M-B EQXX was kept small and 'light' in order to run 185mm section tires, avoiding wider tires required in more 'massive' vehicles.
Tailgate issues are not universal. What helped an F-150 would hurt a RAM.
I have no reporting which provided evidence of cargo nets reducing drag, only the opposite.
RIVIAN has an OEM tonneau cover, and CYBERTRUCKS drag coefficient.
Had a cargo net been more efficacious, we'd have probably seen a RIVIAN OEM net.

[Phase]

I have ecopias at 195 width. I wonder how much of an mpg gain is even get by dropping down to 175?