LIGHTWEIGHT Wheels

[goodvibes]

LOL at all this angst. What the chatbot is trying to say (poorly as expected) is that the initial edge of the impact (harshness) is less transferred to the suspension as the tire deforms due to the inertia of the heavier system but after that it's rather insignificant. In fact more mass can cause other poor aspects of suspension movement but initial impact harshness of a lighter, easier to move wheel send more energy to the suspension. The difference is not great and easily projected either way. Sorry if science hurts but it's basic physics. It also won't be universally true either as system resonant frequencies can be involved. it's also unlikely that folks are swapping to the same tire when they make the wheel swap so lots of variables which can lead to different outcomes.

Next we can talk about lighter flywheels. Great for quick shift and autocross etc but only increase acceleration due to overall weight savings. When in gear, your rotational mass includes your clutch transaxle, wheels etc. crank axles etc. and unless you're spinning the wheels, add the mass of the car. Engine will definitely rev faster with the clutch depressed so awesome for autocross etc but will help less than pulling your spare for acceleration when putting down power.

Ducks.

 

[bnperrone]

Reducing rotational (or unsprung) mass has benefits. Reducing mass elsewhere (pulling the spare, as your example) has benefits. It’s not like you have to choose one or the other.

Have you ever replaced a set of wheels with a lighter but still strong version? On a car, or a bike, or anything else?

 

[goodvibes]

Reducing rotational (or unsprung) mass has benefits. Reducing mass elsewhere (pulling the spare, as your example) has benefits. It’s not like you have to choose one or the other.

Have you ever replaced a set of wheels with a lighter but still strong version? On a car, or a bike, or anything else?

Of course, they track better but smaller road imperfections are more noticeable because they track them instead of the tire deforming more due to it's greater inertia.

Mass is mass but the rotational part doesn't mean anything for acceleration if they're not spinning freely. Any speed increase comes from lowering overall mass and/or better tire traction. A car doesn't put more more measured horsepower or torque to the ground from losing weight in the drivetrain or wheels. It's what you put to the ground vs the weight you're moving that determines acceleration. Speed bennies are real but come from overall weight loss.

 

[Chris Leger]

So then, if I had a bicycle with 2 lb. wheel/tire assemblies, I'd be able to accelerate just as fast wearing a 40 lb. pack as if I moved 20 lbs ea. to the circumference of the rims? Stand by for universally beloved ChatGPT content:

 

[victorofhavoc]

Of course, they track better but smaller road imperfections are more noticeable because they track them instead of the tire deforming more due to it's greater inertia.

Mass is mass but the rotational part doesn't mean anything for acceleration if they're not spinning freely. Any speed increase comes from lowering overall mass and/or better tire traction. A car doesn't put more more measured horsepower or torque to the ground from losing weight in the drivetrain or wheels. It's what you put to the ground vs the weight you're moving that determines acceleration. Speed bennies are real but come from overall weight loss.

Yes and no.

Yes in the sense that peak horsepower will be in the 10hp error range of a dyno typically. Yes in the sense that a dyno is constant load and that's how it measures "wheel horsepower".

No in the sense that a lighter flywheel GREATLY reduces need for jerk (the acceleration of acceleration) . Your on and off throttle response greatly improves (even when in gear), when wheels slip they're more controllable faster which puts more power down, and the engine needs less overall torque to turn the wheels at the same rate. Also keep in mind gear changes are faster because your rpm will fall faster and going back on throttle will send more torque faster back to the drivetrain.

Real world example: on my racecar I had a carbon driveshaft and went from a 29lb flywheel to a 10lb flywheel. It picked up roughly 20whp on a dynojet. That example was extreme because of the tremendous weight loss in the turny bits. I will also point out I've seen 20whp differences when people go from trans fluid that's crapped out sludge to fresh, clean fluid.

I agree that lighter wheels can make small road imperfections worse. Not nearly as much as going to a metal top mount from the stock rubber would though... Which is why I recommend to people to change camber at the control arm or ball joint first where possible.

 

[goodvibes]

So then, if I had a bicycle with 2 lb. wheel/tire assemblies, I'd be able to accelerate just as fast wearing a 40 lb. pack as if I moved 20 lbs ea. to the circumference of the rims? Stand by for universally beloved ChatGPT content:
View attachment 323958

That bike would ride great, LOL.

Thanks for that. It's relative in this case. You're not wrong but I think that's a lot more difference than a .03% of vehicle weight than we're talking about. A negligible amount of rotational mass difference regarding acceleration, especially by seat of the pants. The overall weight saving does more in this case. What your describing is easily demonstrated wit differently weighted gyroscopes and the effort it takes to get them spinning but I believe it's a rather negligible extreme example in this case. Your conditions are understood as I've already mention how a lighter flywheel does allow faster shifting but you were correct to call me on overaerating "Mass is mass but the rotational part doesn't mean anything for acceleration if they're not spinning freely" as I didn't put that in context of the extreme we're discussing. Thanks again.

My intent here was to explain why the gains are negligible but not nonexistent for acceleration. The ride thing should be real but there's other factors that can contribute to perception of ride like someone may not be getting a softer ride but perceives better tracking as improved ride. Most that get new lighter wheels also get wider tires for them which can offset some of the weight savings though still overall lighter. The wider patch can also improve ride so may be what many experience. I think I wasn't clear enough overall as I never argue against actual experience since I'm not the one experiencing it. This was intended to be a discussion about why.

 

[victorofhavoc]

That bike would ride great, LOL.

Thanks for that. It's relative in this case. You're not wrong but I think that's a lot more difference than a .03% of vehicle weight than we're talking about. A negligible amount of rotational mass difference regarding acceleration, especially by seat of the pants. The overall weight saving does more in this case. What your describing is easily demonstrated wit differently weighted gyroscopes and the effort it takes to get them spinning but I believe it's a rather negligible extreme example in this case. Your conditions are understood as I've already mention how a lighter flywheel does allow faster shifting but you were correct to call me on overaerating "Mass is mass but the rotational part doesn't mean anything for acceleration if they're not spinning freely" as I didn't put that in context of the extreme we're discussing. Thanks again.

My intent here was to explain why the gains are negligible but not nonexistent for acceleration. The ride thing should be real but there's other factors that can contribute to perception of ride like someone may not be getting a softer ride but perceives better tracking as improved ride. Most that get new lighter wheels also get wider tires for them which can offset some of the weight savings though still overall lighter. The wider patch can also improve ride so may be what many experience. I think I wasn't clear enough overall as I never argue against actual experience since I'm not the one experiencing it. This was intended to be a discussion about why.

Are you specifically speaking to longitudinal acceleration or lateral (cornering force)? There's a substantial difference in what the gyro effect does here... Even a tiny toy gyro spinning in your hands you can feel the effect of trying to turn it.

 

[goodvibes]

Thought some might like this unbiased experiment.

Heavy wheel rides the curbs with less vibration etc but doesn't track as well. Acceleration differences are about equally affected by overall mass and rotational mass.

 

[bnperrone]

The 4-minute long laundry list of subjective benefits to the lighter wheels starting at 9 minutes in the video is exactly in line with what I’ve experienced daily driving multiple cars on OEM vs Neuspeed wheels.

If you skip ahead to 9 minutes you’ll miss the part where he mentions the brakes cracking when he used the heavy wheel setup.

I appreciate you sharing the source that says exactly what I’ve been (and many others have been) trying to explain. The feel and driving enjoyment, particularly on poor roads, is far enhanced by losing 8-10 lbs per corner by going to a lighter but as strong or stronger wheel than OEM spec’d for this platform.

 

[goodvibes]

The 4-minute long laundry list of subjective benefits to the lighter wheels starting at 9 minutes in the video is exactly in line with what I’ve experienced daily driving multiple cars on OEM vs Neuspeed wheels.

If you skip ahead to 9 minutes you’ll miss the part where he mentions the brakes cracking when he used the heavy wheel setup.

I appreciate you sharing the source that says exactly what I’ve been (and many others have been) trying to explain. The feel and driving enjoyment, particularly on poor roads, is far enhanced by losing 8-10 lbs per corner by going to a lighter but as strong or stronger wheel than OEM spec’d for this platform.

Those wheels were crazy heavy to exaggerate the issues on a non spec car. I don't recall anyone here cracking brakes on oem wheels regardless of suspension mods.

There's always tradeoff with anything you do. Light wheels track better but send more vibes into the suspension exactly as I postulated. The acceleration change is less than you expected and more than I did.

I'm out. The bias is strong here.

 

[bnperrone]

Those wheels were crazy heavy to exaggerate the issues on a non spec car. I don't recall anyone here cracking brakes on oem wheels regardless of suspension mods.

There's always tradeoff with anything you do. Light wheels track better but send more vibes into the suspension exactly as I postulated. The acceleration change is less than you expected and more than I did.

I'm out. The bias is strong here.

You don’t like the results shown in the video? You posted it!

The “send more vibes into the suspension” is a drop in the bucket against the myriad subjective benefits you leave out.

You want an experiment? Get a set of 20lb high quality wheels and put em on your car. Have you even done that? Or are you just guessing?

You’re a clown

 

[ChristopherNeil]

You don’t like the results shown in the video? You posted it!

The “send more vibes into the suspension” is a drop in the bucket against the myriad subjective benefits you leave out.

You want an experiment? Get a set of 20lb high quality wheels and put em on your car. Have you even done that? Or are you just guessing?

You’re a clown

There's still time to edit the douche out of this post.

 

[bnperrone]

There's still time to edit the douche out of this post.

Yeah, maybe I should’ve left that last part out. Reality is that this guy has posted multiple sources that directly contradict the point he’s been struggling to make, and every other person on this thread who has actually made this change has experienced the exact thing he’s trying to deny. It’s just trolling and I admit to taking the bait.

 

[DerHase]

The 4-minute long laundry list of subjective benefits to the lighter wheels starting at 9 minutes in the video is exactly in line with what I’ve experienced daily driving multiple cars on OEM vs Neuspeed wheels.

If you skip ahead to 9 minutes you’ll miss the part where he mentions the brakes cracking when he used the heavy wheel setup.

I appreciate you sharing the source that says exactly what I’ve been (and many others have been) trying to explain. The feel and driving enjoyment, particularly on poor roads, is far enhanced by losing 8-10 lbs per corner by going to a lighter but as strong or stronger wheel than OEM spec’d for this platform.

Those custom heavy wheels are insanely closed off to airflow - I don’t doubt that was also a major contributor to the brake heat problems.






To throw more shit into the mix to consider:
On cars I’ve had with enough suspension travel, lighter wheels have always improved ride. Small imperfections and all.

These cars even in stock form (and BMWs from the factory) heavily rely on the bump stops even in normal use. Golf Rs are on or just a couple mm off the front bump stops at stock ride height.

It’s entirely possible that lighter wheel hitting small imperfections is more jarring because there’s some additional “spring rate” at play earlier in the suspension travel. Whereas heavier wheels yes resist movement so deform the tire a bit more.

It all also will be affected by damping as well.

There’s no clear cut blanket statement for every case.

In all of my experiences, all the other obvious benefits of a light wheel outshine whatever minor (if at all even perceptible) downsides.

 

[EEeegolf]

One thing not mentioned here (I think), is that wheel stiffness affects interior noise. Stiffer the wheel reduces noise. Quality wheels tend to be stiff and the wheel design has a big impact too.
We just did an OE tire approval and I couldn't believe what difference the wheel makes.