Wondering if anyone has experieced a significant loss in MPG or brake/rotor life after making the jump to a 20" rim. I was looking to put aftermarket rims on my '05 TL but was ill advised by my mechanic.

Any tips/advice?

 

I went from stock 17" to 20" and I did noticed a mpg loss of about 3 to 5 mpg and I do mostly highway driving

 

Yea I mostly drive on the highway as well. How long has it been since the switch? Any notice in brake life?

 

It also highly depends on the tires. I went to an 18" rim but got higher performance tires and I'm noticing about a 2-3 mpg loss.

 

^ I'm surprised you lost any mpg especially since you went with a lighter rim, depsite the fact of what tires you chose.

But OP, you most likely will see a drop in mpg going from a 17 inch stock rim to a 20 inch rim because of the weight increase. How much depends on your driving stlye and if you do a lot of city or highway driving.

 

Yeah. I feel like I'm driving the same but idk

I looked at my MID this morning and I'm getting 20mpg

 

This is a little blurb from car bible:

"Simply put, sprung weight is everything from the springs up, and unsprung weight is everything from the springs down. Wheels, shock absorbers, springs, knuckle joints and tyres contribute to the unsprung weight. The car, engine, fluids, you, your passenger, the kids, the bags of candy and the portable Playstation all contribute to the sprung weight. Reducing unsprung weight is the key to increasing performance of the car. If you can make the wheels, tyres and swingarms lighter, then the suspension will spend more time compensating for bumps in the road, and less time compensating for the mass of the wheels etc. The greater the unsprung weight, the greater the inertia of the suspension, which will be unable to respond as quickly to rapid changes in the road surface. As an added benefit, putting lighter wheels on the car can increase your engine's apparent power. Why? Well the engine has to turn the gearbox and driveshafts, and at the end of that, the wheels and tyres. Heavier wheels and tyres require more torque to get turning, which saps engine power. Lighter wheels and tyres allow more of the engine's torque to go into getting you going than spinning the wheels. That's why sports cars have carbon fibre driveshafts and ultra light alloy wheels."



They don't touch on heavier wheel/tire combos affecting MPG, but it stands to reason that if the engine is working harder to propel the new setup, then that's why you would experience lower gas mileage.

IMO, adding extra weight in wheels is ludicrous no matter how good they look. Been there done that, and the car drove like crap and was noticeably slower to boot.

Spend time and do research and find a combo that is as close to or lighter than stock. You won't regret it.