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The 18" Wheel Debate

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mentioned in another thread in this forum

http://www.which.co.uk/cars/driving/sat-navs-tyres-and-accessories/how-to-buy-tyres/the-energy-label-for-tyres/

one of many similar reviews of Michelin energy tyres

http://www.telegraph.co.uk/sponsored/motoring/driving-routes/9408787/michelin-tyre-test.html
 
I wonder if the MPG will increase as the new tyres 'bed in' to your vehicles geometry?

The previous vehicle to which they were fitted would have had particular tracking/camber/castor conditions, resulting in a certain tread wear. Now those tyres are on a different car there will be a degree of 'scrub' while the tread beds in to the alignments present on your vehicle. This would manifest as increased rolling friction, but only until the tyres fully bed in.

So maybe you should give it a few hundred miles and see if the MPG improves before getting rid of them?
 
* yeah I wouldn't get rid of them, they do look nice ....hmmm Brigg ...not too far :lol:
 
Nala Nesnej said:
I KNOW my car, and I KNOW that the mpg has dropped - I'm not wingeing or complaining, I'm stating a FACT. All you can do is spout off about the fact that it's impossible for the drop in mpg to be due to fitting bigger wheels. Well, I'm sorry mate you are wrong. I fitted 18" wheels and immediately I notice a drop in mpg. And all I get is people asking - has your car been serviced? Was the weather different? Were you driving differently? You refuse to believe that my mpg has dropped, you tell me my guage isn't accurate, tell me weather conditions are differeent, tell me that 20kg weight in a car will have absolutely no effect at all. Well you are wrong, sorry mate, my mpg has dropped - period!! A 20kg weight in the boot might not make any difference to the car. Add 20kg to the flywheel and you will notice a difference. Add 5kg od weight to each piston and you will notice a difference, add 10kg of weight to each drive shaft, and there will be less of an effect due to the way the forces are applied to the long narrow drive shaft - so 20kg of weight can make a difference..
Click to expand...

If you know for a fact already, before starting this thread, why start one on the premise of discussion? You clearly think someone who doesn't agree with you is outright wrong, and you knew this before you opened the thread because of the previous thread's dispute.

I don't know what your aim is with this thread. Perhaps you want a solution to your problem of MPG, but it doesn't seem that way. Perhaps you're baiting Brian into another dispute for some reason. If I'm honest, it reads like it at times.

Further still, the OP has clearly just disregarded the majority of all suggestions other than the ones that go along with his original train of thought. It's hard to tell the aim of this thread (resolution of an issue, or contentious arguments with other forum members), and therefore I think this thread should be closed.

Nothing personal at anyone, no hard feelings, in the Catchphrase fashion, I'm just saying what I see ;) .
 
http://www.physicsforums.com/showthread.php?t=406860

interesting read
 
Steve - The purpose was simply to say that since fitting 18" wheels my mpg has dropped, and to ask out of interest if anyone else had experienced the same, I was hoping to get some feedback, and learn something eg - Were Falken tyres renowned for causing a drop in mpg? Were my tyre pressures wrong?
had suggestions that my car needs servicing. Perhaps the weather has been a factor. Have I been driving differently? Although my car has done nearly 150k miles, I doubt if you will find a tighter and better Accord. Full main dealer Honda history on the dot since new, last major service under 500 miles ago, etc etc. I noticed the drop in mpg very quickly, I always like playing at trying to increase the mpg readout on known journeys. I regularly travel to leeds, I use the same route every time, and always drive like Miss friggin Daisy, and always get between 55 to 56.6, my personal best. Last saturday I did the same journey and it was down to 51 ish. When I drove back it was just over 50.
I did a back to back test yesterday, identical journeys, one with the 16" tyres, and one with th 18" - and the results are displayed above. SInce I started the thread, I;ve been a bit nerdy and googled the subject, and the common consensus seems to be that 18" wheels do reduce the mpg, despite the theorists who say it can't happen. I'm a pretty chilled person, knowledgeable about cars, but yeah I get a bit annoyed when someone belittles me and thinks I was making a very serious comparism between my car and a F1 car,

SO now, if anyone is thinking of upgrading to 18", they now know that they will probably experience a drop in mpg, what causes it? We still dont know, but it would appear the the extra 5kg per wheel has some bearing on it, so try and go for an 18" alloy that weighs as close as possible to the standard one - about 17kg with a tyre. A bit of helpfull info I reckon.
 
Mr Honda said:
http://www.physicsforums.com/showthread.php?t=406860

interesting read
Click to expand...
Yeah I found that on Tuesday when the original "discussion" started.

Difficult to comment on another thread in another forum, and the main problem is the ambiguity.

I think that the original meaning would be worded "would increased wheel radius and increased wheel mass mean that a car would coast further, and woudl this transate to improved mpg".

Increasing wheel radius does, in general, reduce rolling resistance (emphasis on "in general"). This would mean that you can coast further, and that would translate to improved mpg.

Increasing wheel mass is same as invreasing car mass. ***uming that rolling resistance has not been severely compromised (emphasis on these two words) then increased wheel mass or increased body mass will mean that a car will coast further. But, this does not translate to increased mpg for obvious reasons.

Many of the posts in that link go off onto tangents about other aspects such as gearing and BSFC, etc, etc, all relevant, but need a defined context for the comparisons.

Try googling "low profile tyres mpg" and you find a lot more discussion and reference. Some same low profile reduces mog, some say it might increase mpg, one place I found actually said that low profile wheels are mainly a fashion accessory ...and I agree.
 
Nala Nesnej said:
Steve - The purpose was simply to say that since fitting 18" wheels my mpg has dropped, and to ask out of interest if anyone else had experienced the same, I was hoping to get some feedback, and learn something eg - Were Falken tyres renowned for causing a drop in mpg? Were my tyre pressures wrong?
had suggestions that my car needs servicing. Perhaps the weather has been a factor. Have I been driving differently? Although my car has done nearly 150k miles, I doubt if you will find a tighter and better Accord. Full main dealer Honda history on the dot since new, last major service under 500 miles ago, etc etc. I noticed the drop in mpg very quickly, I always like playing at trying to increase the mpg readout on known journeys. I regularly travel to leeds, I use the same route every time, and always drive like Miss friggin Daisy, and always get between 55 to 56.6, my personal best. Last saturday I did the same journey and it was down to 51 ish. When I drove back it was just over 50.
I did a back to back test yesterday, identical journeys, one with the 16" tyres, and one with th 18" - and the results are displayed above. SInce I started the thread, I;ve been a bit nerdy and googled the subject, and the common consensus seems to be that 18" wheels do reduce the mpg, despite the theorists who say it can't happen. I'm a pretty chilled person, knowledgeable about cars, but yeah I get a bit annoyed when someone belittles me and thinks I was making a very serious comparism between my car and a F1 car,

SO now, if anyone is thinking of upgrading to 18", they now know that they will probably experience a drop in mpg, what causes it? We still dont know, but it would appear the the extra 5kg per wheel has some bearing on it, so try and go for an 18" alloy that weighs as close as possible to the standard one - about 17kg with a tyre. A bit of helpfull info I reckon.
Click to expand...
Alan, I wasn't belittling you about the comparison with F1 car. If you want a serious discussion, don't throw spanners into the works.

You say that your drop n mpg is due to increased wheel weight, but as a qualified engineer, I am telling you it is not.

People who have changed to bigger wheels and not reported a drop in mpg will be out there, but you won't find them on the internet for obvious reasons.

If you have experience a dop in mpg, It is down to different tyres and possibly down to change in tyre profile.

Mods, I agree with Streve, this is going nowhere, please lock it.
 
Ok guys this debate has gone on to long imo.Its causing bad feelings between members and its got to stop right now.
Please do not open another debate on this subject.For more info please take my advice and log onto Wheels in motion as per my link as these guys will give you a straight answer Tony is an expert in this TOPIC CLOSED
 
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