MPG Impact due to bike rack

i've head that hitch mount is minimal impact. roof might be a different questions. this is only what i've read. i'm sure others will post soon enough.

1st post congrats

 

I just put a Thule bike roof rack on and haven't had enough time to see if it takes a big hit on MPG.

One thing I did notice is that without the fairing the roof rack whistle is quite loud. With the fairing the exterior sound is no worse than normal. Whoever does answer this post - I would be interested to know if the fairing help or hurts MPG.

 

Here is a guy who gets 50 normally, who says a rear bike rack drops his mileage to 39

http://wvgazette.com/section/ConsumerInsig...ight/2005042826

 

I can confirm a similar drop
I got 52mpg @65mph on a previous trip with no bike
I just got back from a trip where I got 38mpg @ 65mph with two bikes on a hitch mounted rack. The rack holds the bikes relatively high compared to the spoiler -- perhaps holding the bikes with a lower rack would help...

 

Welcome, dannyc.

I get infinitely better mileage on the bike than I do in the car.

 

I have a Hollywoood Prorider hitch rack that holds the bikes relatively low. I'm not into tracking numbers, but there's definitely a small decrease in MPG with a bike on there. I think that a roof rack would have a much larger impact on efficiency.




<div class='quotetop'>QUOTE(dannyc @ Apr 28 2005, 11:03 PM) [snapback]85459[/snapback]</div>

 

A roof rack lets the bike ride in its designed orientation to the wind. A rear rack presents the bike broadside. If your concern is mpg, I suggest you point the bike front into the wind, per the bike's design.

Getting aero crossbars should also help, if you're not using a fairing.

 

Any ideas how mileage would be affected with a simple roof rack with crossbars? What I'm getting at is if you install a Toyota roof rack, what can you expect? I'll bet it's not much without the actual bike and bike rack on top of the roof rack with crossbars.

Obviously, with the extra drag with a bike and a not-very-aerodynamic Yakima rack, the mileage isn't good, but I'd just like to have a rack on the top in case I need to toss my bike up top instead of in the back with the seat folded down.

So, to say it a slightly different way, is there much mpg effect from a simple low-lying roof rack with crossbars?

 

Depends on your speed. At 55 MPH, the Prius MPG Simulator predicts 59 MPG without a rack and 54 MPG with. This assumes steady speed on level terrain, 80F outside air temp, no winds, automatic climate control set to 75F, Goodyear Integritys inflated to 44F/42R, and a 350# load (driver, cargo ... and rack). At 65 MPH the numbers are 52 without and 46 with.

 

I just purchased a bike hitch and will install it tonight. Looking at the hitch, it only weigh apx. 40 to 50 lbs. and with a rack...I also do not think it will affect mpg significantly. Being in the rear, the air that would hit the bike rack had already left the car side. Can't wait to be able to haul my bicycle anywhere I want to go.

 

i'm now going to recommend the roof rack. I've been hauling around with the hitch with very surprising results. Around town, i'm fine... i can still average about 40..

On the interstate, my rear hitch and double bike mount will drop me down to 28mpg..... I met someone with a honda fit and civic hybrid who report similar numbers with the hitch mount...

without bikes, it's somewhat normal.. ( low 40's)

 

There is VERY little hit in terms of fuel economy for a hitch mounted rack. Post some pix when you get it all mounted! Here's my setup:




... Brad

 

I put my bike inside the hatch and get no change in mpgs. The bike also stays dry and clean and is (relatively) theftproof. It fits with enough space for luggage, and one passenger. Maybe two people if you remove the wheels. That's one reason I bought the Prius. My Impreza uses Rhode Gear rear rack and I find it a pain, though I never checked the mileage differences with/without.

 

I use a hatch mounted rack (with usually 2 bikes on it), and my mileage drops MAYBE 2 mpg, if that. I also have a roof rack, and with my surfboard up there see only a 2 or 3 mpg drop.

 

Nice setup. Now that I have the hitch, I have 2 choices of bike rack. Either the THULE or Yakima. I think both racks are great products. Saturday morning I am headed to the toy store.

I agree, with the very little hit on mpg...I'll just slow down for another 2 to 3 mph and be even.

 

I just asked a fellow Santa Barbara Prius Driver/Roof Rack user this same question, since I am contemplating racks for my Prius. He is using Yakima racks with a fairing. Here in SB, we don't get optimal mileage in City driving due to most commutes being so short, but the impact is apparently between 3 to 5 MPG for this guy. That would be on a average of 44mpg for around here (so would drop to around 39-40).

I am still on the fence. Most of the time, I will just have the rack on the car, but I would be putting a Thule box on it when we go on trips up to the Mojave desert. I know we need the extra space on these trips, but still not comfortable with a potential drop in mpg's, and I don't want to have to take the rack on and off all the time, just the roof box. Any input?

 

We're using a Saris bones hatch-mounted. With 2 crank-forward bikes (they sit a little higher than "normal" bikes due to the different bar geometry), our usual mileage dropped from about 54 mpg to 43 mpg at moderate highway speed (averaging about 60 mph).