Phssthpok

So what exactly IS the lug patern on my truck,
('77 2WD longbed), and how wide can I go with the rims/tires?

I want to get some taller rims/tires for the rear to increase milage.

4x4Lamm

I don't know anything about a 77, but Summit Racing's website and catalog has instructions on how to measure the different patterns, got a ruler?

Lamm

wrenchmonster

LOL. Taller rims and tires won't improve your gas mileage, they'll only change your odometer and speedometer readings. You were kidding right?

As for wheel offset you'd have to do some research and talk to others who have done it or have tried to do it.

Here's a trick for your lug pattern though. Take a wheel off and place a piece of corrogated cardboard against your lugs and press to make the pattern on the back side. Now you have a template for looking at rims at the next swap meet.

-Wrench

Phssthpok

Nope. Dead serious.

A taller overall wheelset will allow the vehicle to mantain a given speed (say..60mph) at a LOWER engine RPM, thereby utilizing less fuel. It's like changing the ring-n-pinon set without having to go through all the work.

I had 215/75/15's on the rear of my '73 Charger, and that car would do 70mph@2250 RPM.....and get 25+MPG all day long. Not bad for a tired 318/auto in a 3700lb car. Currently the truck has 4.11 gears, which makes for 60MPH@3000rpm (ish). I'd like to drop that down to 2500rpm(ish) if possible. That leaves the engine within it's powerband, but reduces the overall fuel consumption.

Now, if I did a lot of stop and go city driving I could see how the reduction in leverage could possibly even INCREASE fuel consumption. However, about 90% of all the driving I do is freeway at @ 55-60 MPH, so I should see an overall REDUCTION in fuel consumption.

Ilovemountains

My 88 4x4 gets worse gas mileage with 31s! I had 225/70 sport suv tires on it when I was commuting; it ran higher RPMs but got much better gas mileage! I guess its a weight to power issue, I’ve got the 3.0 though so it sucks fuel anyway, among other things....

Mad Chemist

I think all the toyota rims have the same pattern- 6 lug, 5.5" spacing- the rims from my 98 4runner fit on my '73 Land Cruiser. Someone else can jump in here, but I'm pretty sure thats it. Do a search, I know this has come up before.

Flamedx4

Dear Dead Serious,

Lowering your cruise rpm to save fuel on the highway is a worthy concept. But, there are a couple of flaws in your logic. First, Lowering your overall gear ratio to gain economy can work fine with big torquey engines that can do the job effortlessly at 3000 rpm or 1500 rpm, and this can even work with smaller engines to a much lesser degree on small aerodynamic low-drag passenger cars. But, a small very low-power engine like the one in your '77 does not make enough power to overcome the drag (and the truck is not very aero smooth) if you drop it out of the rpm range needed for efficient highway cruising. The reality of it is that once you are cruising outside the optimum area of the horsepower/torque curve, the engine will need more throttle to maintain the speed, not less, and as a side effect will also be subject to increased wear due to 'lugging' the engine, which is disastrous for 4 cylinder Toyotas.

Take the advice of thousands who have been there before you - the engine/transmission package was well designed, and you will see maximum fuel mileage if you keep the engine in tune and keep very close to the stock tire size.

Sincerely,
Beenthere Donethat, for the
It's Been Well Documented Countless Times Institute

Flamedx4

Oh, and the bolt pattern on the 2wd Toyota is the small 5 lug Ford pattern, still is today. That's 5 on 4.5.

Glenn

What he said. The factory engineers are aiming toward an overall package that works for most driving conditions. Your idea would work OK if you had plenty of reserve power at cruising speed. If you go ahead with your plan, just about any hill or passing situation will put you out of your powerband pretty quickly.

Flamedx4

You will get some real world gains by going with skinny tires by the way. Skinny tires have lower overall drag, and combine that with higher inflation pressures give less rolling resistance. Many years ago I had a Honda Civic (1976) and with the stock tires got 40-41 mpg on trips to Seattle. After I put wide tires and fender flares on it, I nverr got more than 23 regular use and 27 on those same trips to Seattle. The tires were the same diameter, but much wider.

Phssthpok

I understand that dropping RPMs down to 2500 (an optomisitic number actually) is approaching the bottom end of my powerband (though still WITHIN it), but thats also in fifth gear, and casual cruising @60MPH. If I need to climb a hill or pass thares a nifty little maneuver called a 'downshift'. Quite honestly, I'll probbably be averaging 70 MPH anyway once I get the front suspension freshened up, which will bring me back closer to the middle of the powerband.

5 on 4.5 you say? I happen to have a set of 15x8 aluminum rims lying around with a 5 on 4.5 pattern.

Flamedx4

There you go! Sounds like you did understand the sitchyation with the gearing after all then!

Where's the land of beer and coffee? Sounds like heaven!

Phssthpok

Yer' livin' in it man..

(I call the Pac NW the Land of Beer and Coffee due to the plethora of Micro-brews, and for being the birthplace of the recent coffe craze <read: Starschmucks, et al>...)

Flamedx4

Amen!
Beer and Coffee, my anti-drugs....