I had a Leer car on my 01 and plan on putting one on my lmm. Did anyone notice a mileage gain after putting a cap on there truck? Im hearing with my 8' bed Im getting wind drag and may get 1or 2 more miles to the gallon by putting a cap on? Wondering if that is true?

I have heard the same theory before, but I thought I heard a study done once that proved it makes little to no actual difference...

No difference.

No difference here...

no difference. Once air pressure builds up in the bed, it creates an "invisible" cover and the wind flows right over. So unless you are looking to cover somethng up from the rain, tonneau covers and shells don't increase your milage any.


:D

Never could tell any difference.

Didn't Mythbusters do a show on this once? Or was it just the difference with the tailgate up or down. I don't remember.

Didn't Mythbusters do a show on this once? Or was it just the difference with the tailgate up or down. I don't remember.

It was tailgate up vs. tailgate down, they found that the truck with the tailgate up got better mileage. In a later episode they did a test that compared no tailgate to one of those fabric tailgate mesh things and found that the mesh gave better mileage than both having a tailagate and no tailgate.

Either way Im going to get a cap but thanks for the feed back. I personally like being able to throw things in the bed with a cap and not worry about weather getting to then. Its like having a shed on the back of your car.

I actually lost about 1-2mpg with my LEER 180CC cap. It does have a slight step to it so it's higher than the cab. It also has built in tool boxes which obviously have tools in them so I guessing it is part extra weight and part extra air resistance.

The one Im looking at is the xq 100 I believe which is not even in production for my long bed yet but it is the same height as the cab so I do not think it will have much drag to it? I hope.

It's in production. I ordered mine in July and recevied it in September. 8ft CC. It looks great, I did not see any decrease or increase in mileage with the top on and the bed empty.

By the way, nice truck, it's the same as mine, I love it...

Rich

It's in production. I ordered mine in July and recevied it in September. 8ft CC. It looks great, I did not see any decrease or increase in mileage with the top on and the bed empty.

By the way, nice truck, it's the same as mine, I love it...

Rich

You must have the 100 R cap? Leer's web site says the 100 XQ and 100 XL are not even in production yet and no release date is set yet? You didnt buy your truck off a dealer in Michigan did you? I ordered 2 exact same trucks at the same time and did not end up taking one of them so there is another truck out there that is exactly like mine.

You're right, I got the 100R cap.

Also, I did get my truck from Michigan. I purchased it in Wisconsin. My dealer went to Michgan to pick it up for me. I love the truck...

Never really saw much gain with the Roll n lock cover.

Loved it at high speeds though! And more dry storage is always a plus, and less of a PITA to remove when hauling large objects or a 5 er.

I have a Leer cap the same height as the cab and it seems to have helped out 1 mpg or so.(On the open road)

I'm waiting for delivery on my AFE cab high. I will only use it in the winter, I tow a 31' fifth wheel in the summer and the AFE fit my budget plus they through in a free carpet and interior light. I will let you know if I saee any fuel difference as soon as I can.

[quote=2007ChevyLMM;2057620;]You're right, I got the 100R cap.

Also, I did get my truck from Michigan. I purchased it in Wisconsin. My dealer went to Michgan to pick it up for me. I love the truck...[/quote


I bet you got the truck I ordered. It was at a dealer in Escanaba MI. Can you find out what dealer they got it from? If not too much trouble, just wondering.

Gained 1 mpg.........

After a month with the cap on I see a small gain (less than 1 mpg)

Mythbusters episode 64

Not a cap, but with a bed cover and tailgate up/down.


http://kwc.org/mythbusters/2006/12/episode_64_more_myths_revisite.html

Tailgate Up or Down Revisited: Mesh tailgate, hardcover, tailgate removal
See: Tailgate Up or Down

For the original myth they did a driving test and a water vortex test, both of which showed that you save more gas with the tailgate up. Their viewers suggested that they test three new conditions:

Hardroof cover over pickup bed
Mesh tailgate
Remove the entire tailgate
They had a much simpler test setup this time. They had an electronic flowmeter hooked into fuel line of Jamie's pickup. Adam: "For anyone out there that wants to e-mail telling me that we screwed up this test, we have already calibrated this thing, to this car. So it's going to be perfect!" They drove the pickup truck up and down the stretch of 101 around Candlestick and the Cow Palace.

Tailgate down: 5.2 gallons/hr @ 55mph. 1.2 gallons/hr @ 25.
Tailgate up: 5.0 gallons/hr @ 55mph. No reading for 25mph given, but tailgate up was once again confirmed as more efficient.
Hardcover over pickup bed: 5.0 gallons/hr @ 55mph. 1.2 gallons/hr @25mph
Tailgate mesh: 5% more efficient
Tailgate removed: about the same as tailgate up and hardcover
Mesh was most efficient by 5%

still busted

Back in the late 70's - early 80's I knew Lee Stockland who manufactured shells. He once told me they'd test mileage by filling a graduated glass beaker with fuel, mounting it on the dashboard, and then driving a particular route first without, then with the shell installed. Sounds kind of primitive and straightforward but it worked for them. They found that a shell was good for 1 to 1-1/2mpg. My own conclusions are that I have no conclusions. But the old gas truck got best mileage when there was something big and about rail high filling most of the bed.

there was something on myth busters not much difference.