Lighter wheels make a difference for you?

[eddiebx]

Eddie please don't take this as a personal attack, I'm enjoying the discussion! Having said that I think you've got it backwards. The effects of additional weight is most pronounced at the far edge of the circumference - I agree with that. But the engine doesn't have to work very hard to spin that additional mass.

Ahh yes, I should've clarified more, I meant "much more" compared to putting the weight at the center of the wheel. In the grand scheme of things, I don't think it makes a huge difference, because like you said, it's a 5000 lb brick.

I can tell you one thing for sure is, after throwing on my new tires (~10-11lbs heavier than OE tires), I barely noticed a difference in acceleration. But I'm also known to not have a very sensitive butt-dyno, lol.

Interesting to read the calculations BTW, now I know exactly how many extra TRD stickers I need to add to gain my lost 2.6667 hp

 

[Canazes9]

Ahh yes, I should've clarified more, I meant "much more" compared to putting the weight at the center of the wheel. In the grand scheme of things, I don't think it makes a huge difference, because like you said, it's a 5000 lb brick.

I can tell you one thing for sure is, after throwing on my new tires (~10-11lbs heavier than OE tires), I barely noticed a difference in acceleration. But I'm also known to not have a very sensitive butt-dyno, lol.

Interesting to read the calculations BTW, now I know exactly how many extra TRD stickers I need to add to gain my lost 2.6667 hp

Sorry, that's the limitation of a written conversation like this - nuances that would have been clear face to face are missed when typing out long posts...


David

 

[racerjb]

I agree you are not going feel the diff in weight that much on a street vehicle. In a racing environment you will for sure experience a diff when going after every tenth of second by reducing unpsrung weight. However, I do feel in the long run there will be less wear and tear on the vehicles driveline components by having lighter wheels. Toyota probably designs the parts based on stock component.

I recently ordered konigs from fn wheels after extensive research. I figured once I powder coated stock wheels, added wheel spacers, and went to e rated duratracs I would be adding weight. However, by going with the konigs and e rated duratracs. I get the performance of the better tire, the better offset while maintaining stock wheel/tires weight. Since the tires will add about 10lbs and the wheels will drop 10lbs.

 

[1engineer]

Hello All

I just read a post by FN Wheels http://www.toyota-4runner.org/1370909-post4.html and was thinking a good set of wheels would enhance my driving performance. I checked his referenced sources and the evidence seem to make sense. That said I was wondering if any of you could comment on real world results going from stock wheels to a lighter better-engineered wheel. I have 2010 Trail with stock wheels and Michelins LTX MS2 265-70 -17. I do about 10% off road so maybe you guys can tell what you running. Thanks……

I have seen the claims of unsprung weight being equivalent to xx sprung weight also. I think I saw a claim once that "Porsche engineers claimed 6X"! I've never seen any reputable links or proven auto manufacturer's documentation though. I don't know how to calculate the differences in handling from unsprung weight - it may be true that the effects on handling are factored with a multiplier at high speeds. Handling on a M3 at 150mph unsprung weight might factor in a larger way. Acceleration on an otherwise stock 4Runner and even handling at legal(ish) highway speeds you will be very hard pressed to tell any difference other than the affects of reducing 72 pounds total from the vehicle. I would be interested to read up on the claimed auto engineer multiplier effects for unsprung vs sprung weight if you or anybody else can find anything on it (other than just the claims - that's all I can find).

David

I think it really all depends on where the unsprung mass is going, in order to determine how big of an affect it has; that multiplier is probably just more like a rule of thumb and not necessarily all too accurate depending on the circumstances.

Look at it this way, if you put on 10 lbs worth of lead lug nuts, lol, it's not going to be all that much harder for the engine to spin it since it's so close to the center of the hub. Now instead go add on 10 lbs worth of extra rubber on the treads...the engine will struggle much more to spin that since it's further away from the hub. I think this is just due to the longer moment arm requiring more torque to spin the same amount of added weight.

Hence why lighter wheels probably would not "feel" as fast as getting a set of lighter tires (reducing unsprung mass further away from the hub).

As far as suspension dampening goes, it does not matter where you lose/add the weight because the springs/shocks trying to dampen an 80 lbs tire+wheel, is not going to know the difference of where the weight resides, if that makes sense?

However, I do agree with the general consensus here, I doubt most of us can feel the difference with plus or minus an extra few pounds on a truck this heavy. We're not dealing with 2000 lb sports cars where every ounce matters, lol.

Think about it this way, do you really feel the difference in speed before and after you gas up an empty tank? That's like 100+ lbs right there

Hey guys! Was in the woods doing trail maintenance most of the day so sorry I could not join in.
I will attempt to explain the long and short of flywheels and unsprung mass from my perspective. I will try not use any formulas for a simple reason: As far as I know there is no "Unified" formula to calculate ALL the effects of sprung vs unsprung mass on a vehicle. There are different formulas depending on different applications, even with the same vehicle!

In a vehicle such as ours, there are three primary criteria that could be impacted by changing the unsprung mass: 1) Acceleration, 2) Turnability and 3) Efficiency. Out of the three, let's forget about turnability because there would have to be too many mods (besides wheels and tires) to both the sprung and unsprung mass to get this thing around the track a lot quicker.
Now, acceleration can and will be improved by dropping the unsprung mass. How much? Not very in average daily driving. Probably not even enough to feel with your seat of the pants dynos by just dropping a few pounds at the corners. Where acceleration WILL come into play though is the third part of story - Efficiency.

If you primarily use your 4Runner in the city, lighter wheels and tires could actually improve your efficiency. The constant acceleration and deceleration of the tires and wheels at every stop sign and light just suck the energy right out of the fuel. By getting these as light as possible, you could get slightly better fuel economy, maybe even enough to see on the gauge! Why not out on the highway? Two things: 1) You are not constantly accelerating that mass from stop in a short amount of time and 2) Aerodynamics play a much greater part of the efficiency equation at higher speeds.

So why not any formulas? There are several formulas you could use to calculate the effects of reduction in unsprung mass. [MENTION=96409]Canazes9[/MENTION] did a fine job earlier on in this thread! You could also use flywheel formulas too. Then again, you could use basic acceleration of mass formulas and several others. Point is, depending on what area of performance you are trying to improve will dictate the formulas used.
What about the "factors" of ratios of sprung vs unsprung mass floating about the internet? You know, the ones that say "X amount of unsprung mass reduction is equal to Y amount of sprung mass. The simple answer is they could all be right lol. Anyone who has ever designed anything that moves knows the importance of testing, testing, TESTING! That's where all those cool "K" factors come into play! What's a "K" factor? I liken it to a "fudge" factor. Basically someone once upon a time did a lot of controlled tests to determine what different multipliers went with what different materials or circumstances. For example, how well do tires adhere to a surface? Well, if you take the same tire across ice, it will have a coefficient of adhesion for ice. If you take it across concrete, it will have a different coefficient. Anyway, suffice it to say that those ratios, ranging from 2X to 10X (from what I read) were extrapolated from testing.
The problem with those ratios is they only work during different applications.

If I had a Porsche 911 GT3 and I was trying to get around Willow Springs as fast as possible by only changing unsprung mass then during testing I could come up with a "factor" to compare reducing unsprung mass to sprung mass.
Conversely, if I had a 100K lb machine that I wanted to accelerate (over a precise time) to 15 mph, I could again determine a factor that compared sprung to unsprung mass.

The two above examples are vastly different but the basic physics are the same.

Bottom line for our 4Runners is this: In my opinion the only real performance parameter that would be improved by reducing unsprung mass would be efficiency, and that would be accomplished by changing the acceleration characteristics in mainly city driving. I think the same efficiency gain could be accomplished by changing your driving style slightly. OP, buy the wheels for style in this application. I know I rambled a lot but I hope it helps some of you.

 

[Canazes9]

[MENTION=66316]1engineer[/MENTION]mthanks for joining the discussion. Efficiency wasn't an aspect I had really considered. Upon reflection you are absolutely right - calm, part throttle acceleration in city traffic the motor is making only a small fraction of the total available hp, but the hp requirements for stored energy in the rotational mass will be the same. Meaning the hp stored in the wheels is a much larger percentage and the effects on fuel mileage will be noticeable.

David

 

[Stifler]

so prepping my rig for a faster 1/4 mile time is futile? damnit

 

[philsey]

so prepping my rig for a faster 1/4 mile time is futile? damnit

Buy the supercharger, silly.

 

[N2GLOCK]

I'm running the SCS Stealth 6 wheels in combination with a 6 ply tire in the factory size. I for one noticed a difference in acceleration but it is most obvious when getting onto the freeway and driving up long grades. Many on this forum are running larger and heavier tires w/ their aftermarket wheels. Some of those tires I see other members running are so heavy, that by the time all is said and done, they're back to the equivalent weight of the factory wheel/tire setup. As far as gas mielage goes, I'd say that the jury is still out on that one. Going out to my mother-in-laws house end up being a 130 mile round trip. We go there alot and come back the same day. It seems like when I get back, I've got a little extra in the tank. However, I have no hard numbers to back this up. Driving around town there definitely is no difference.

 

[wsmc831]

Ah, I've re-read your post & now noticed where you mention the increase in handling due to less unsprung mass. I thought you were summing up what you said about your previously discussed calculations, and I didn't understand how you had gone from discussing rotational mass to unsprung mass, if that makes sense (basically just a reading comprehension issue on my end).

Still, I recall reading about some auto engineers discussing each pound of unsprung weight lost as being equal to something like 5-10x of sprung mass?

In the motorcycle world it's considered about 4x, can't imagine it would be any different on a cage. Huge gains on a bike, and much more expensive than truck wheels, generally.

 

[Stifler]

Buy the supercharger, silly.

PHHT! I already have a stubby antenna and antman cupholders..... you trying to get me killed?!

 

[Eagle]

Bottom line for our 4Runners is this: In my opinion the only real performance parameter that would be improved by reducing unsprung mass would be efficiency, and that would be accomplished by changing the acceleration characteristics in mainly city driving.

All this math and science cannot refute my flawless and unbiased anecdotal experience:

I put on lighter wheels and moved closer to work. Now my commute takes half as much time and I fill up my tank far less often. CLEARLY lighter wheels improve both acceleration and efficiency.

/s

 

[kevy511]

This thread has been a real education...at some point I will go with the best looking, best price and lightest wheel. I will not discount weight because my experience with my latest motorcycle suggest lose weight= go smooth and fast... for the most part. :thumb:

 

[M1911]

[MENTION=92348]kevy511[/MENTION] I am hard pressed to think that even 100# has anything but the most minute effect on fuel consumption or performance.

The issue is rotational inertia. The higher the rotational inertia, the more energy required to accelerate and brake the rotation. Whether it is enough to notice is a question that I can't answer...

 

[G8RB8_12SR5]

In the motorcycle world it's considered about 4x, can't imagine it would be any different on a cage. Huge gains on a bike, and much more expensive than truck wheels, generally.

Yes, but your power to weight ratio is significantly better in a motorcycle so that makes a difference.

On a separate note, while lower rotational weight can lead to improved proficiency, it's probably lost completely based on other factors like tread pattern and tire pressure both of which I think play a bigger factor in efficiency through increased rolling resistance than lighter wheels ever would.

 

[JdMeF9SiR2]

Yes, but your power to weight ratio is significantly better in a motorcycle so that makes a difference.

On a separate note, while lower rotational weight can lead to improved proficiency, it's probably lost completely based on other factors like tread pattern and tire pressure both of which I think play a bigger factor in efficiency through increased rolling resistance than lighter wheels ever would.

A lot has been said and addressed and readdressed, but I just wanted to address a couple of things.

Power to weight ratio is relevant in all applications, not just motorcycles. It might be more noticeable a motorcycle, but power to weight ratio is not irrelevant in a 4Runner. A higher power to weight ratio is always more desirable than a lower power to weight ratio. I think we can all agree on that.

Also, un-sprung weight and changes in rotational inertia are undeniable factors. While rolling resistance and tire pressure (and don't forget changes in overall diameter of the tire) are probably more significant factors, there is a cumulative effect that should not be ignored.

Most of us on an enthusiast forum such as this are modifying our vehicles with performance and aesthetics in mind. We make changes to our 4Runners to improve aspects that we feel could use improving. If we're installing taller diameter, heavier tires with a more aggressive tread pattern that creates a higher degree of rolling resistance, and you have an opportunity to upgrade your wheels to lighter weight wheels to help offset some of that performance that you've just lost why not take advantage of that opportunity?

Of course the style factor is subjective. If there is a heavier wheel and you prefer that design, and part of the reason we're upgrading is for style, then I can understand trading off style for performance. However, a lot of what I'm reading is that the Level 8 wheels are less expensive than the FN Wheels or Konig Wheels, and while folks prefer the design, lighter weight, and reputation of the FNs or Konigs, they're considering settling on Level 8s due to price.

There is an anecdote that I'd like to draw, and this isn't intended to alienate any non-4Runnner owners, but a Jeep Cherokee and a Nissan Pathfinder are essentially lower priced equivalents to a Toyota 4Runner. As 4Runner owners we all drew the line somewhere regarding price shopping and decided that the 4Runner was worth the extra money. Why then try so hard to justify a few hundred dollars for a heavier set of wheels over something else that is lighter?

I understand if we're comparing a $3,000 set of forged racing wheels to a $500 - $1,000 set of wheels. That's a significant price difference. We can debate the amount of performance gained from installing lighter weight wheels over heavier wheels, but we can all agree that to some degree (whatever that might be) heavier wheels perform worse than lighter wheels. So for a difference of $50 - $100 per wheel on a premium SUV such as the 4Runner why sacrifice the performance?

Also, speaking from 15 years experience around the wheel industry, there are a number of reasons one wheel might weigh more than the other. However, significant weight differences between wheels with similar designs, sizes, offsets, and load ratings are often attributed to the quality of the alloy being used.

All Konig wheels and FN wheels are manufactured with high-grade, 100% virgin aluminum alloy. Over the years other manufacturers have offered a lower cost wheel to me. Often it is a much heavier product, and they were using a lower grade of aluminum alloy (often a higher content of recycled material). Because of the porosity and the impurities in the alloy, these manufacturers would have to make the wheels heavier (use more material) to get the wheels to meet load requirements. This may or may not affect anyone's decision in buying wheels, but it is something that we always consider. I will not offer anyone inferior wheels manufactured with low grade alloy.

Again, I'm definitely not trying to alienate anyone here, but I do sincerely believe that there is a benefit to installing high quality, light weight wheels when upgrading any vehicle over a set of heavier wheels. That philosophy is part of the basis for the foundation of FN Wheels.