What does "Range" mean on the dashboard of a 2011 Kia Sportage?
"Range" is the calculated distance you can travel on the remaining fuel in the fuel tank. The vehicle computes this based on fuel level, throttle and brake application, vehicle speed, and possibly more like engine temperature. Range will decrease if you accelerate fast and brake hard, and idle a lot. Range will increase if you are constantly driving with cruise control on or at a constant speed. It can be useful on long distance road trips, for figuring out how far you can make it without having to stop for fuel. it can be helpful when commuting as well by figuring out how many times you can go back and forth to and from work without having to re fuel.
How does a car's wheel size (17 in vs 18 in) affect the performance? Is performance based on how fast the wheels turn, or how wide the tread can be?
Generally speaking, larger wheels allow for stiffer suspension setups, as they have less sidewall flex. Tire sidewalls can "roll over" during hard cornering, especially as they become tall. Larger wheels allow for lower profile tires, and low-pro tires allow for stiffer suspension setups and better handling.However, there are a lot of moving parts here (bad pun, I know), so there are a few things to consider:Heavier wheels have greater rotating mass, which means they can hamper acceleration. The difference between a 17" and 18" wheel isn't usually too significant, but if you take 15's off an old Civic and put 20's on in their place, you'll note a decrease in acceleration...but you'll look cool as hell!Typically, larger wheels can accommodate wider tires, but that's often because tire manufacturers offer wider tires for larger rim sizes, and also because larger wheels are often manufactured to be wider. ...There's nothing about the wheel diameter in and of itself that dictates width (at least not if we're talking about a normal range of wheels).Tire width helps with traction, at least in normal driving conditions (wide tires aren't too helpful in the rain, for example). Hence, a high horsepower Countach would have wide tires.If you look at wheel diameters, they've exploded in the last 20 years. 15" rims were common in the early 90's, now 17" rims are common. This is mostly about styling, but it's important to note that larger wheels are often needed to fit around large disc brake systems.Still, back in the 80's, a 20" rim was rare on a typical passenger car...even on a Lambo. ;)
Changing tire size on my honda accord?
I drive the same car, 03 Accord. Factory were 16's (mine's a V6), and I put on HFP 17" wheels on there, and the first set were 225/50 R17's. Now I'm on my second set, and I got the slimmer tire, 215/50 R17's. Just go tirerack.com, I'm sure there are many good information on the cars. If you can wait until a week-day, call them and ask, and I'm sure they have very accurate information as to what the widest size your (and my) car can take. My own preference is that the 225/50 R17 is the max width I'd go with 17" wheels. Tires does not protrude out of the wheel wells, and does not rub anywhere. It handles like an all-wheel-dirve car (just sticks to the ground), but my gas mileage went down noticeably. Hence the slightly narrower tire the second time around.
Why do the front and rear tires of a car have different pressures?
Tyre pressure on a family car depends on the load in the car - I mean passengers. On a car with no passengers and only the driver, the weight on the front tyres may be more because of the engine weight. On a small car the engine weight could be around 150 kg and on an SUV it might be 300 kg. We will take examples of rear-wheel drive cars.Most cars have the fuel tank in the rear. Small cars have capacities of around 40 litres whereas SUVs may take up to 65 litres of fuel. The specific gravity of Diesel is 0.90 or so, therefore a full tank of fuel may weigh around 36 Kg on a small car and about 60 kg on an SUV. With passengers in the car - 3 in a compact car and 5 in an SUV - the weight on the tyres is more - anywhere between 200 and 300 kg. And then there is luggage in the trunk.Considering all this, the tyre pressure in the rear is kept higher than the front. Added advantage of extra pressure on the rear tyres is lesser tyre wear.Image courtesy of Tyre MaintenanceSo if there is a full compliment of passengers and luggage, it is recommended to pump up the rear tyres to compensate - otherwise it will amount to under-inflation. If it is only the driver without any load, then equal pressure on all tyres is also OK.