32 inch LT tires and tundra brake upgrade owners what kinda mpg are you getting?

[sierra_summits]

Just curious about gas mileage? This is not my daily driver but just want some input. i have noticed since adding 32 inch LT tires that weigh 50 lbs each that my 4 runner is harder to stop. I was nervous about coming down some long mountain passes where brakes are working hard and having them fade away to the point of being dangerous. So i was going too then add the tundra brakes which would help but then thats 6 more lbs of unsprung weight to deal with. anyway, what kinda mpg do you get with both?

Sierra

 

[Socco]

So i was going too then add the tundra brakes which would help but then thats 6 more lbs of unsprung weight to deal with. anyway, what kinda mpg do you get with both?

Sierra

Your not going to notice any MPG drop from the weight of the larger calipers. More importantly, it shouldn't be a deciding factor on wether or not to upgrade your brakes...

 

[sierra_summits]

interesting.

the tundra rotors are heavier and its unsprung weight as well. i believe they are about 6lbs heavier than the 3rd gen 4runner. would that not reduce mpg?

 

[Socco]

the tundra rotors are heavier and its unsprung weight as well. i believe they are about 6lbs heavier than the 3rd gen 4runner. would that not reduce mpg?

Yes, but by such a small fraction that it hardly seems worth it to worry about.

 

[Brilliant]

the tundra rotors are heavier and its unsprung weight as well. i believe they are about 6lbs heavier than the 3rd gen 4runner. would that not reduce mpg?

A bag of grocieries would have a larger impact on mileage.

 

[JayRolla]

Just curious about gas mileage? This is not my daily driver but just want some input. i have noticed since adding 32 inch LT tires that weigh 50 lbs each that my 4 runner is harder to stop. I was nervous about coming down some long mountain passes where brakes are working hard and having them fade away to the point of being dangerous. So i was going too then add the tundra brakes which would help but then thats 6 more lbs of unsprung weight to deal with. anyway, what kinda mpg do you get with both?

Sierra

You will not lose mileage from 6lbs. Go on a diet!! LOL

Anyways any brake will fade. Dont madder how big. Once it gets hot the rotor is done and they will fade. You need to use the trans low gears to drive her down the passes. I get down with barely even using my brakes at all. Its all in the driving habit coming down and thats coming down Pikes Peak few times a year.

 

[slides]

the tundra rotors are heavier and its unsprung weight as well. i believe they are about 6lbs heavier than the 3rd gen 4runner. would that not reduce mpg?

...if you go mudding you will probably carry more than 6lbs of mud on your car, if you wear winter cloths you could have more than 6lbs on your self....its 6lbs man not 600.

 

[wake_rider]

A bag of grocieries would have a larger impact on mileage.

You will not lose mileage from 6lbs. Go on a diet!! LOL

Both of these claims are quite incorrect.

Read this article if you want a more academic/tested thesis. Anyone who has ever raced anything recognizes that unsprung and rotational mass reduction is one of the easiest and most efficient ways of increasing all around performance (considering acceleration/deceleration, wheel hop, suspension characteristics, etc...)

Now, this is just me playing devils advocate, but I will agree with both statements that it's not going to create CONSIDERABLE difference in mileage, yet by pusing more weight further from the hub, you will definitely see a difference.

Reading the listed article will give you a better idea of how this all works, and will explain it far better than I could ever begin to, so enjoy!

ps- if you don't want to read the rest of the article (though I'd highly recommend it, as it's chalked full of easy to read yet valuable information), just skip to "part 8" for the information about lighter wheel/tires.

Creating Rear Wheel Power - Popular Hot Rodding Magazine

 

[gamefreakgc]

I think what he is alluding to is that unsprung weight has more of an affect on mileage than sprung weight (weight supported by the coils). 1 lbs of unsprung weight ~ 2 lbs of sprung weight. But ~12 lbs isn't going to ruin anything either, a tool box in your truck will weigh more than that.

Wake Rider beat me to it

 

[slides]

how about rotation mass and how that plays a factor into weight. If i shaved 2lbs off my crank that could be potention weight savings of up to 10lbs when it is spinning.

Its why people go to a liightweight flywheel on race cars, not only does it save an initial 10-20lbs but the rotation mass is considerably less in weight.

 

[NHRunner]

To answer your initial question:

I have LRE LT 32s and Tundra brakes. No effect on mileage.

Do the tundra brakes. You'll see nothing but positive improvements.

 

[MasonT4R]

265 Duratracs, Tundra brakes, front bumper with winch, rear bumper, skid plates, sliders, roof rack full of 6 galls of gas and recovery gear, loaded down for camping last weekend...

18.3 mpg from Tulsa to Hot Springs, AR.

She isn't happy around town having to move all this weight from a stand still but once I'm rolling she's very happy. (usually around 13-14 mpg around town)

Before I added all the armor I did the 265's and the Tundra brakes and the Tundra brakes had no effect on my gas mileage. The 265's had a small impact but not the brakes. Do it, they are so much better than the stock brakes. There is some more pedal depression than before.

 

[ShooterMcGavin]

Unsprung weight can be non-rotating or rotating. If it is non-rotating, it will affect your suspension and handling. If it is rotating weight, it will affect your acceleration and braking (mpgs), and it will affect the suspension/handling too. The mass of the calipers have almost no effect on the mpgs you will get, not any more than a 6 lb brick in the passenger seat.

 

[turbo8]

I noticed a good change in performance and mpg when I switched from steel wheels with 285 bfg a\t to fj aluminum wheels and 275 bfg a\t i also put on the tundra brakes at the same time. I get ~17mpg combined.

 

[Brilliant]

Magazine racers will be quick to talk about unsprung weight, not as many racers. My comment was about tundra calipers. The sprung to vehicle weight ratio is about 1 to 6 effect on performance.

Not sure why anyone would care on a big lumbering 4runner.

Maybe fill your tires with helium to offset it.

 

[wake_rider]

Magazine racers will be quick to talk about unsprung weight, not as many racers. My comment was about tundra calipers. The sprung to vehicle weight ratio is about 1 to 6 effect on performance.

Not sure why anyone would care on a big lumbering 4runner.

Maybe fill your tires with helium to offset it.

To the first bolded statement, incorrect. With factory sponsored motocross, enduro, and hare scramble/x-country bikes, almost immediately the first concern with reducing weight is in the hubs, rims, sprockets and even tires. This is done for handling and for quicker response (although different weighted flywheels will almost always be added to bikes ridden in sloppy/variable/technical conditions). This is consistent across the board in racing.

To the second bolded statement, I would agree. This is a 4Runner, not a high-performance built race machine. It's built for comfort, moderate abilities, and longevity. Within reason, what you slap on the 4 corners will make small change and will be relatively low impact on performance.

 

[Brilliant]

To the first bolded statement, incorrect. With factory sponsored motocross, enduro, and hare scramble/x-country bikes, almost immediately the first concern with reducing weight is in the hubs, rims, sprockets and even tires. This is done for handling and for quicker response (although different weighted flywheels will almost always be added to bikes ridden in sloppy/variable/technical conditions). This is consistent across the board in racing.

To the second bolded statement, I would agree. This is a 4Runner, not a high-performance built race machine. It's built for comfort, moderate abilities, and longevity. Within reason, what you slap on the 4 corners will make small change and will be relatively low impact on performance.

.. but then we consider that motorcycles are a completely different application and mentioning them here is not relevant to the topic at hand. You also consider that most racers will tell you a few lbs with a lot of driver miles, and you will notice the few pounds on a track car.

After all, if we could notice a few pounds on a 4runner, we wouldn't be posting here. We'd be finishing up the day getting ready for 12 hours of Seabring.

Lets be real

 

[sierra_summits]

Thanks for all the real data!

i appreciate all the members that have given real data and experience! It seems as though the rotor weight is not a significant reduction in mpg. I think that i am going to pull the trigger and do the brake upgrade! Thanks for your help!