Here's my trusty 12yr old Toyota Hiace. The Cats behind are worth thousands more. The A on top of the F16 belongs to my friend who is in the picture below (left unfortunately) but I thought you might like the link between the photo's.

What about a Miata? <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Just for the information of those who are comparing, American Gallons are smaller than Imperial (British/Canadian). Here is the conversion.
1 imperial gal = 1.2009 U S gals = 4.5446 Litres
1 USG = .8327 Imp. Gal = 3.7843 L.
10 Litres = 2.6425 USG = 2.2004 Imp. Gal.

From http://www.roadogz.com/productionoffice/calculate.htm

Auto trannys have become a very good at power transfer so there is very little difference. I still prefer a manual as I’m an old guy who learned with one.

It’s a combination of the two. Inertia will be overcome by drag and wheel friction.

There’s a number of things to consider when looking at wheels. The larger the wheel diameter, the more energy to get it spinning. There’s also bearing and road friction. One thing that would reduce drag would be to make the tire and rim narrower but the trade off would be weight capacity.

I'll try again. It helps if you attach the right file!!

The vehicle in the bottom left picture is missing its backup lights.

Wow, I never thought about that before, but I guess that's why the tires on horse-racing sulkies are very skinny -- and on racing bicycles.
* * * * *
As far as wind drag, has anybody ever come up with a way to make the rig more aerodynamic for trailering?

Some road bikes use tires that are only 18 cm across. Really skinny but they still have to carry the same weight of the rider and bike so they may bulge out more where the tire contacts the road.

Removing the tramp might reduce drag.

Same, but 4x4, only 132,000 mi and no kids. Also, AirRaid instead of K&N.

Hey, Chris, that sure is a sharp-looking runabout! Oh, and the scooter is cute too.

What scooter?

My skipper should win for worst MPG's. He tows with a GMC motor home. It gets about 7MPG but sure makes the "camping" better. <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

Ok...after towing double stacked N20's today for the first time, I'll chime in...because I think I should get a couple of awards....
I drive a Black 2003 GMC Sierra Denali with a 6.0 litre V8, AWD, and Quadrasteer (yes all four wheels turn). I love my truck for a lot of reasons...it just "goes" anywhere I want in any conditions, and does so with comfort and class....only one (major) flaw....you'll read in a moment. Sooo....IMHO...we're WAY up there on the "Cool" factor!! Picture (sorry I don't have one to share at the moment!) 2 gorgeous Nacra 20's stacked and flyin' down the hiway behind a beautiful shiny black truck that stands out against most other trucks all on it's own to begin with!!!

Now...for the bad part.....and all my Euro friends can get their rocks ready to throw!!! I definitely get the gas guzzler award. Normal (non-towing) MPG is 12.7 city/hiway combined 50/50, doing 85 on the hiway. Towing a single boat at 75 on the hiway...11.7. Now for the really bad news.....(Do the Euro's and Aussies have rocks ready with arms ****??)...Double stacked and only 65MPH down the hiway....a whopping 9.3MPG!!! And I'm starting a 1000 mile trip to Florida Monday!

I think I either need to buy an oil well...or start looking for a "less cool" tow vehicle!!

JL
(dodging the stones from across the pond!!)

Yeah double stacked 20's is rough. We got 7mpg or thereabouts with Trey's truck with double stacked 20's on the way to tradewinds.

Joe,
I even get better than that with a 35' RV weighing 19,500 lbs and pulling a double stack. I got around 9.5 mph on the trip up to the F18 Na's driving around 70mph. On the flat lands I can get 10 to 12 mph and better if going slower. My F250 gets around 15 to 17 towing at 70 mph.

Depends on the car. If it is underpowered for the load and constantly changing between the top two gears, a manual in 2nd top gear is probably the go. Holding an auto in 2nd top and making sure it has a cooler attached should be fine but don't run it at top speed for hours on end.



Whilst you are accelerating most you are fighting the weight at lower speeds and a combination as it increases. When you are cruising, it's mostly windage that is the problem. You are in effect driving with a big parachute out the back of your car.



Not with regard to MPG. I do like the idea of larger trailer wheels though. A 15" wheel will do far less RPM than a 11" wheel and thus your wheel bearings and tyres etc etc will give far less trouble.

Tiger Mike

There’s a number of things to consider when looking at wheels. The larger the wheel diameter, the more energy to get it spinning. There’s also bearing and road friction. One thing that would reduce drag would be to make the tire and rim narrower but the trade off would be weight capacity. [/quote]

IMHO the friction from larger dia wheel/tyre combo on a boat trailer would be virtually nil compared to that of overall wind-drag at 40+ mph. I think it would be a no-brainer in most cases.

Tiger Mike

Has anybody heard of, or tried, air tabs? www.airtab.com

My old tow vehicle..... Vintage Sports Car I guess

1977 Ford XC Fairmont GXL Coupe

Engine
351 ci Cleveland
2V Close chamber heads
4V Exhaust Valves
2V inlet Valves

Fuel
Methanol
Custom Nitro Methane Injection

Drive Line
Gear Box - Top Loader
Diff - 9 inch with 3.5 gears
4 wheel disc breaks
13 inch x 15 inch rear wheels (12 slot rims)
11 inch x 14 inch Front wheels (12 slot rims not pictured here)

Factory wind back sun roof.

Towing is easier on a manual tansmission. Most or some (well especially older vehicles) automatics will have a tendancy to shift in and out of overdrive more often than normal during towing, due to the additional drag and weight of the boat and trailer. Except in the case of larger vehicles with huge towing capacities, this heats up the transmission fluid more than normal operation. Check your owners manual for recommended towing practices. Some will suggest turning the overdride off (if function is available) or keeping the transmission selector in the next to highest gear (3 or 4). In either case this is preventing the transmission from making more frequent shifts.

A transmission cooler may be added by any competent mechanic and are available at all chain auto parts stores. The transmission fluid lines are routed to the front of the vehicle for cooling anyway making it a fairly easy modification that should cost less than $200. If you feel your vehicled is overworked, it's a fairly inexpensive insurance policy to have. Or, have your transmission serviced at the "Heavy use" interavals. Personaly we change the fluid more often.

Since the old days and "sport" vehivles were brought up...

Had great fun towing the spanking new '81 H16 with our '67 Camaro, 327ci/275hp. Wish we still had that little rascal. <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

1991 Shasta (McNasty)



Also use a scooter for local transport - '85 Honda 150 Elite - gets 72mpg and can sustain 60mph.



For local stuff where I've got somewhere to put my head...a 2000 Nissan 4WD crew cab Frontier that's gets a dismal 16mpg towing on the highway.