Wheel weight vs over all weight.

[GreenHornet]

Upsized wheels can have a benefit on MPG if done properly ie they are lighter such as going from a a heavy stock 13" steel wheel to a lighter weight 15" alloy wheel. However often times many people make the mistake of getting a lighter and larger diameter alloy wheel and not checking on tire weights and options. So they may get the lighter weight wheel but end up with a heavier tire negating the potential benefits! If your goal is MPG then you want a light weight, tall, and narrow tire. If your goal is a street racer and mpg is of no concern then you will want the extra meat on the pavement so go for a wider wheel and tire selection but still pay attention to both the wheel and tire weights as they both make a difference in performance!

GH.

[Sven7]

Originally Posted by California98Civic

2) A car and driver test of different wheel sizes, showing acceleration, braking, and MPG: Effects of Upsized Wheels and Tires Tested - Tech Dept. - Car and Driver

That shows that the 14 pound difference between the wheel/tire packages- 15x6" and 19x8.5"- was 2.2mpg over their test, with the smaller wheels being better. The roadholding also drops 0.05g with the skinnier 195 tires compared to 235's.

Also note that the 2.2mpg improvement also equated to 0.2 seconds and 2mph quicker in the quarter mile. Braking 60-0 mph is 4 feet worse with the skinny tires.

The smaller wheels and tires have lower prices, lower weight, better mpg, better acceleration and marginally lower road noise.

_________________________________

Relative to this thread, I will say that if the cars are the same weight, whichever car has less rotational mass will be better for mpg in stop and go situations. Whether the difference is multiplied by 1.5 or 10, you're still going to benefit by reducing rotating mass.

[HypermilerAX]

A lot of things change with the different tires, not only the weight but also rolling resistance, CdA (235 vs 195), circumference : the 235 is 2% bigger which means worse accelerations but also small benefit for mpg (outweighed by CdA and weight).
The worse performance is not only due to the weight.

To make the test consistent, they should have use always the same set of tires and put heavy balancers on the rims.

[freebeard]

Here is what I want for my next set of tires. Hopefully Bridgstone will have them on the market by then.

Bridgestone “Large & Narrow Concept Tire”

26" 155-55/19 on Model A Ford wire wheels in under the fender wells of my 1961 VW Type II panel van.

[aerohead]

Originally Posted by Honda

Let say we hove 2 identical cars that weigh 3000 LBS, one has light rims and the other has heavy rims with rear seat delete or any other component to make it stay at 3000 LBS.
Will the fuel economy be affected comparing the 2 cars?

In the SAE HANDBOOK (4-volumes) they address your question in the paper dealing with coastdown testing.
They show how the values can be estimated and also the pendulum apparatus they use to actually measure the inertial effects as a contribution to overall dynamic mass.
All rotational mass should be accounted for including engine and gear train.
The SAE material is probably the best 'science' you're apt to find.

[Honda]

Originally Posted by GreenHornet

Upsized wheels can have a benefit on MPG if done properly ie they are lighter such as going from a a heavy stock 13" steel wheel to a lighter weight 15" alloy wheel. However often times many people make the mistake of getting a lighter and larger diameter alloy wheel and not checking on tire weights and options. So they may get the lighter weight wheel but end up with a heavier tire negating the potential benefits! If your goal is MPG then you want a light weight, tall, and narrow tire. If your goal is a street racer and mpg is of no concern then you will want the extra meat on the pavement so go for a wider wheel and tire selection but still pay attention to both the wheel and tire weights as they both make a difference in performance!

GH.

My main goal is fuel economy, I thought heavier rims will have positive effect when coasting down than lighter rims but I understand that going up hill will be the opposite.
I have 15'' not so light rims right now, the over all weight tire+rims are heavier than the stock ones, I will put them on a scale when I have a chance.
The test is still in progress, so far I noticed that I can go further when coasting down or on flat road.
According to this site I need to get 195/50R15 tires instead of 195/60R15 that I have right now. http://www.1010tires.com/Tools/Tire-...0R13/195-50R15

[California98Civic]

Originally Posted by Honda

My main goal is fuel economy, I thought heavier rims will have positive effect when coasting down than lighter rims but I understand that going up hill will be the opposite.
I have 15'' not so light rims right now, the over all weight tire+rims are heavier than the stock ones, I will put them on a scale when I have a chance.
The test is still in progress, so far I noticed that I can go further when coasting down or on flat road.
According to this site I need to get 195/50R15 tires instead of 195/60R15 that I have right now. http://www.1010tires.com/Tools/Tire-...0R13/195-50R15

Here is my list of possible wheel swaps for 5th/6th gen Civics like ours, from my car's garage site:

Possible wheel swaps for gearing/weight advantages:
13" Civic VX 8 spoke (higher RPMs but only 9.7 lbs.)
14" Civic HX 8 spoke (approx 11 lbs)
15" Mini Cooper R81 Imola 7-hole (12.1 lbs)
15" Mini Cooper R86 star-spoke (15 lbs)
15" Mini Cooper R96 7-spoke (13.8 lbs)
15" Enkei Classic J-speed (14.1 lbs)
15" Acura Integra GSR (94-95, 16lbs)
Other size specs: Offset 35-45; bolt patter 4X100; lug size 12mmX1.5; hub center bore 56.1mm.

-james

[MPGranger]

Anybody tracking supercapacitors or ultracapacitors? A little off topic but whatever. Basically, people are trying to make hyrbid hybrid batteries. So take a smaller Li Ion battery and join it to some suped up capacitors and you can dump a load of electricity (for a nice boost to the ICE) or drastically increase the energy recovered from regen braking. So much so that you might be able to eliminate the drive wheels friction brakes.

Benefits in summary
1. Lighter battery pack
2. Deletion of friction brakes of at least two wheels
3. Explosive type acceleration boost from electric motors to ICE

I see this would benefit Honda's IMA system better than the Toyota's synergy drive.

[freebeard]

You might take your question here:
About 84 results (0.10 seconds)

Originally Posted by California98Civic

Other size specs: Offset 35-45; bolt patter 4X100; lug size 12mmX1.5

-- VW uses 4x100 with 12mm bolts, but I'm not sure about the offset. Is the wheel centered on the hub or the lug bolts? I wonder if you held up the one against the other where the interference would be.

[California98Civic]

Originally Posted by freebeard

VW uses 4x100 with 12mm bolts, but I'm not sure about the offset. Is the wheel centered on the hub or the lug bolts? I wonder if you held up the one against the other where the interference would be.

The Civic has a hub plate for the wheel, so I assume it is hub centric. But I don't know the center bore sizes. These wheels on my list I have found online mounted by others onto Civics (Miata, Mini, Enkei, Integra), cross referencing with other sites to confirm fitment. I don't recall anyone using spacers. I suppose the Prius wheel is one I should check out some more. Hmmm...

[EDIT: list of sizes with bore info: http://adaptitusa.com/referencebook.htm Center bore for Civics 1992-2005 seems 56.1. Many Minis are identical, some slightly different. Miatas and Prius are listed 54.1.