Does Wheel Balancing & Cheap Tires Affect MPG Much???

hi chaps, i just got a 01 golf gt tdi 115bhp with 146000 miles on it, i drove home 200m and the computer is telling me 43 mpg, i drove at 65 - 70mph mostly on motorways.

I have been having bad vibration problems on my steering wheel, the last owner just put new 'runway' very cheap chinese tires on just last week, so these have been causing the vibration problem, i swapped the fronts and bakcs and got them rebalanced and its much better but there is still a little vibration there at 50-70mph.

anyway i was wanting to know if these cheap nasty tires can be giving me poorer mpg on my car, also if the wheels are off balance can this affect my mpg??

if so is it ok to just change the fronts to get rid of the vibration but will having the cheap tires on the rear still affect my mpg? I cant afford new tires all round but i will change the fronts to get rid of this vibration.

As long as they are inflated properly, I don't think the bad mileage is from the tires. If the alignment is out, that could be a cause. Is it a manual or automatic?

Is the tread on the tires even or no? Is there a lot of road noise from the tires? Have you checked the wheels for bends near the edge of the rims?

I've had periods of vibration from the tires, just after rotating. I try to give it 1000-2000 miles, to let the tires 'wear' into their new location.

If you want to chase the vibration a little more, try another tire shop and rebalance.

Tony

mystic.bertie said:

i just got a 01 golf gt tdi 115bhp with 146000 miles on it, i drove home 200m and the computer is telling me 43 mpg,

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If you just got the car, then it does not know your driving style and conditions, which can cause errors in the computed mileage since that mileage computer is making certain adjustments based on the past calibration of the computer (before you got the car.

Frankly I can't see why you would complain about the mileage you are getting based on the driving style you reported.

For problems with front-end vibration, I would check to make sure wheels are balanced, no unusual wear on tires, no damage to rims and check suspension/ball joints for wear.

Out of balance tires are hard on your cars suspension. Be that my car I get rid of those chinese junk tires before they decide to separate or blow out on you.

chromeBuddha said:

As long as they are inflated properly, I don't think the bad mileage is from the tires. If the alignment is out, that could be a cause. Is it a manual or automatic?

Is the tread on the tires even or no? Is there a lot of road noise from the tires? Have you checked the wheels for bends near the edge of the rims?

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i just got the car and the tires are brand new, they are inflated properly so the tyre condition is good and they have been rebalanced my a good tyre shop. I checked all the rims inside and out, only one has a bit of a buckle and its on the inside so i put it on the back so the front rims are defo good.

TonyJetta said:

I've had periods of vibration from the tires, just after rotating. I try to give it 1000-2000 miles, to let the tires 'wear' into their new location.

If you want to chase the vibration a little more, try another tire shop and rebalance.

Tony

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im not sure i can wait a while to change these, the steering feels all light as though there is play in the steering rack but when stopped with engine off there is no play in the steering when you wiggle the steering wheel, the bad feeling i get is off the rubbish tyres.

Joe_Meehan said:

If you just got the car, then it does not know your driving style and conditions, which can cause errors in the computed mileage since that mileage computer is making certain adjustments based on the past calibration of the computer (before you got the car.
Frankly I can't see why you would complain about the mileage you are getting based on the driving style you reported.

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when i picked it up i drove 200m home on mostly motorway so my driving style does not really affect it i was just crusing mostly between 65 and 70,ph, however judging by the computer i was actually doing less than that maybe its over reading by 5mph. 43mpg is not good as an average on a 200m tip mostly on the motorway, peaople report getting high 50's drivng at 70-80 mph.

DogParkGuy said:

For problems with front-end vibration, I would check to make sure wheels are balanced, no unusual wear on tires, no damage to rims and check suspension/ball joints for wear.

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i have had the wheels rebalanced at a good tyre shop, the tyres are new so no wear at all. I have not checked the suspension yet but it seems sound, no noises or anything when driving or going over bumps or round corners.

fossill said:

Out of balance tires are hard on your cars suspension. Be that my car I get rid of those chinese junk tires before they decide to separate or blow out on you.

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i intend to at least change the fronts for now, i cant afford to change 4 tyres a si just bought the car, so im gonna buy 2 good brand part worn tyres for the front and see how i get on.

Never mind the tyres, is all the routine stuff (oil, filters) up-to-date? Might be worth checking the camshaft too...

DPM said:

Never mind the tyres, is all the routine stuff (oil, filters) up-to-date? Might be worth checking the camshaft too...

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yeah im gonna service it though the guy before me changed the oil every 10k, there is a k&n air filter, ill change it for a proper paper air filter and clean the maf as i have read scary stories about k&n filters clogging the maf with oil.

A thought just occurred to me...

The cheap tires may have a higher than average rolling resistance. Without comparing the specs, there is no way to know. Also, many tire manufacturers do not publish rolling resistance data.

Tony

TonyJetta said:

A thought just occurred to me...

The cheap tires may have a higher than average rolling resistance. Without comparing the specs, there is no way to know. Also, many tire manufacturers do not publish rolling resistance data.

Tony

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thats interesting tony, i searched and found this, it does not sound like it would make much difference

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=29

During stop-and-go city driving, it's estimated that overcoming inertia is responsible for about 35% of the vehicle's resistance. Driveline friction is about 45%; air drag is about 5% and tire rolling resistance is about 15%.

Overcoming inertia no longer plays an appreciable role in the vehicle's resistance during steady speed highway driving. For those conditions it is estimated that driveline friction is about 15%; air drag is about 60% and tire rolling resistance represent about 25%.

Let's explore a scenario where a high performance replacement radial tire has a whopping 20% increase in rolling resistance over a low rolling resistance Original Equipment standard passenger radial. To calculate the potential change in mpg resulting from using the high performance tires in place of the Original Equipment tires, we would multiply the tire's percentage of influence on the vehicle's overall resistance (15% in the city and 25% on the highway) times the high performance tires' 20% increase in rolling resistance.

If the vehicle equipped with standard Original Equipment, low rolling resistance passenger tires normally provided 25 mpg in the city and 30 mpg on the highway, installing tires with 20% greater rolling resistance would only drop fuel mileage by a calculated 3% (to 24.25 mpg) in the city and a calculated 5% (to 28.5 mpg) on the highway. While this is a measurable difference, it probably isn't much more of an influence on real world fuel economy than being stuck in rush hour traffic a couple of times a week or being stopped at every red light instead of continuing through a string of green lights.

The easiest way to reduce rolling resistance to enhance fuel economy is to make certain that the tires are properly inflated. A vehicle that requires its tires to be inflated to 35 psi (based on the vehicle's tire placard) will have an increase in rolling resistance of approximately 12.5% if the tires are allowed to become underinflated to just 28 psi. Therefore, maintaining the vehicle manufacturer's pressure recommended for light load and heavy load conditions may almost be as important as the tires being used.