Another wheel/tire discussion

[hat_man]

I have been reading here about the difference in lightweight wheels and heavier wheels and wanted to ask if my thinking was at least "in the ballpark". I know there has been much discussion and debate with this issue, and I'm not trying to open up another can or worms. I just wanted to see if I have the general idea.

Lighter wheels can be good for FE because of the static (?) weight savings and the rotational weight savings. Lighter tires also for the same reasons and maybe even a bit more savings as the lighter weight (over stock tires) is farther from the rotational center. This would be good in city/stop and go type driving as it would be easier on the engine to "get moving". At highway speeds it may not matter as much.

Heavier wheels may help when coasting (EOC/or MT in neutral) as they work as a "flywheel" but would be worse for FE in city driving as it would take more energy to "get moving". At highway speeds (consistant speeds) they may not make a difference.

Combining heavier tires and wheels may be over kill and not help in any type of driving.

The reason I ask is I was wondering if the combination of good LRR tires on factory "steelies" would be good. The advantage of LRR tires over regular ones would give an FE bump, but would it be offset by the heavier wheels?

For me, my typical drive is 20% city and 80% 2-lane asphalt backroads with numerous opportunities to coast 1/2 to 3/4 mile to stop signs. There are even two places that I can coast 1 mile.

Would the "steelies" only hurt a little as they would weight less than the tires, making the combination a "dual mass flywheel" of sorts. If the combination (steelies/LRR) weighed in at somthing similar to what you have right now, could it be a "best of both worlds" situation? Better FE from the tire design and better FE from the stored energy of the steelies?

I'm not a really smart guy, I am just wondering what the opinion of the ecomodders here is.

[ksa8907]

If all you have is steel wheels, use them and make some wheel covers. That way you don't feel bad about covering pretty wheels. My personal opinion is that the lighter the wheels/tires the better, period.

[hat_man]

I've got alloys now but this is more hypothesizing than anything. I would love to change to LRR's but it seems they only come in 15's or 13's. My truck rides on 14's now and has quite a bit of tire wear left, but they won't last forever.

Just trying to explore some options for when that day comes and to see what the general concensus of the local "knowledge base" is.

Is there a tire "calculator" here somewhere that can compare tire dimesions? When these tires do wear out I may have to switch to 15's but I would want something similar in diameter to what I have now to keep the speedo and odometer as close as possible.
225/70R/14's must be comparable to something in the 15's.

This leads me to another thought but I'll post it in a different thread.

[euromodder]

Originally Posted by hat_man

Heavier wheels may help when coasting (EOC/or MT in neutral) as they work as a "flywheel" but would be worse for FE in city driving as it would take more energy to "get moving".

The problem is you have to accelerate that flywheel first.
Combining al the various inefficiencies along the way - starting with the engine - you'll never get back what you put in.

Coasting is mostly driven by your car's kinetic energy versus its mechanical / aero drag. Rotational weight isn't going to alter that very much either way.

At highway speeds (consistant speeds) they may not make a difference.

You still have to accelerate them to highway speed first - which is a loss.

Unless they are aerodynamically clean and mostly closed, they won't give an advantage.

I get around the same fuel consumption on heavy "aero" summer wheels with LRR summer tyres, than I get with the considerably lighter "open" winter wheel and LRR winter tyres.

The reason I ask is I was wondering if the combination of good LRR tires on factory "steelies" would be good.
The advantage of LRR tires over regular ones would give an FE bump, but would it be offset by the heavier wheels?

Steelies aren't all that heavy.

Some alloy wheels with a lot of metal - like my summer wheels - are actually heavier than steel rims of the same size.

I'm not a really smart guy, I am just wondering what the opinion of the ecomodders here is.

I wouldn't bother too much.

Don't buy lighter alloy rims just for the reduced weight and FE benefits - they'll never repay themselves.

If you want buy them (for looks), buy light wheels.

Though if you cover them for the improved aerodynamics, the good looks are gone as well ... unless you get Vekke's clear covers or make some yourself.

[2000mc]

tallest LRR 14s i see on tirerack are 205/70-14 a 4.2% reduction ...which might be fine if you were 80% city instead of 80% hwy.
going to 15's a 205/70-15 would give you only a .4% reduction. 215/70-15 would be a 1.7% increase in either of the 15s you can get goodyear fuel max, mich defenders, mich x-ice, and yokohama avid ascend.

[Weather Spotter]

The situation you drive is almost identical too what I do every day. I have OEM steel wheels with smooth wheel covers and I coast 1-1.2 miles a lot

As for LRR, I just put a set on my car and noticed a 5-10% improvement in FE. If you plan on getting some just find the cheapest set of rims you can, lighter is better but only if they are in the same range. I went to my local discount tire and explained what I wanted and that I was going to drill and tap them for smooth covers and the manager said he would watch out for a set. I was looking for some winter tires and asking in August, so I expected to wait a month or so. three weeks later he had a set,of OEM aluminum, slightly scraped up but not bad and gave me a discount on them which brought the price to the same at steel wheels. right now they are on my winter ties.

[hat_man]

I was surfing through TireRack this morning after reading the thread about the Michelin Energy Saver A/S tires. I frequently have to drive the same 120 mile round trip in the winter and it looked like the Energy Savers didn't do that well in snow. I don't know much about the Bridgestone Ecopia 422's other than they are all season also but it seemed they do just about as well as the Energy Savers in all area but do a bit better in the snow.

This is my daily driver but it is a truck, and just my work truck at that. I'm not all that interested in looks. Maybe steelies with moonies is the way to go. I won't be making any changes until these tires wear out anyhow. Just trying to do my research early.

Thanks again for all the advice.....keep it coming.

[hat_man]

WeatherSpotter....what tires did you end up with? You guys get a lot more snow in MI than I see here in Northern Illinois. Wet driving doesn't bother me at all but sliding around in the winter with poor traction scares the "stuff" out of me.

[Weather Spotter]

I put on the bridge stone ones and they work well in the summer. I am not sure any LRR tire works well in the snow. I will likely not find out as i have snow tires to use.

[hat_man]

Ironic, I just started another thread and mentioned that I was looking at the Bridgestone Ecopia 422's. Hmmm.....