Thread: Effects of lightweight wheels (unsprung weight)

Discuss.

Apparently some people don't see lightweight wheels, or reduction of unsprung weight, as an effective or worthy mod. From everything I've read, this seems to be one of the best places to put some thought into because it has so many positive effects on the car, especially when racing on a track.

From what you have experienced/read, what kind of impacts does the reduction of unsprung weight make?

I heard it greatly reduced rotational mass, much like lightweight pulleys

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Some benefits I have read are additional traction because it allows wheels to flow better with bumpy roads, faster acceleration and deceleration, higher whp on the dyno, and for every 1lb of unsprung weight it is equal to 4lbs sprung.

So what is unsprung weight? It seems to be rotational mass on a car, from what I can understand. This would include wheels, tires, rotors, hubs, bearings, axles, etc. and sometimes people say calipers although I'm not sure if this is really the case. The people who include calipers say pretty much everything within the wheel is unsprung.

I suppose this would include flywheel, and the pulleys as well?

i heard if its to light it increases wheel hop but i dont know i am just a noob sentra owner

I have heard the 1lb unsprung=4lbs sprung as well....to put that in perspective if you were to go from stockers to nismo rims....the equivalent would be about that as taking out 160lbs in your car. So imagine the acceleration difference as that as having a passenger in your car.

It does help with traction because the suspension components have less weight to push back down on the road.

Bottom line.... as long as the product is structurally sound, then it is beneficial in all aspects.




ps yes this concept applies to pulleys, flywheel, axles, camshafts, crank as well. There is more physics that comes into play but it still applies

...for every 1lb of unsprung weight it is equal to 4lbs sprung

This is one of the major factors I've been looking at when I've been hunting for new wheels. I realized my 1.8 may not have power, but If I can lighten her up a bit it'll be a bit more fun.. I don't remember all the physics details from my last course, but in general it just makes sense as to why it's something defiantly worth taking a closer look at

Originally Posted by kktohot

ps yes this concept applies to pulleys, flywheel, axles, camshafts, crank as well. There is more physics that comes into play but it still applies

I agree these are all examples of unsprung weight, but I would not include calipers as unsprung weight.

[QUOTE=thesammythecurse;408004]1lb of unsprung weight it is equal to 4lbs sprung.
QUOTE]

I always thought it was 1lb of unsprung weight is equal to 5lbs of sprung weight, but I was told that by others.

I first learned about unsprung weght when I was looking at tires and wheels for my racing quad in my picture. Where I live I have a lot of rock land and I need to run 6ply tires (to those who dont know waht 6ply tires are they are ATV tires that are virtually bulletproof and have a very thick sidewall so you dont cut tires on rocks). When basic trail riding I need to have 6ply tires, but if I am racing a friend or at a track I can pick up a lot of speed by switching wheels. My 6ply tires weight almost 8lbs a piece more than 2ply tires. They equals 32lbs of unsprung weight (4*8) and 108lbs of sprung weight (4*32). When an ATV only weights 400-450lbs and you add 108lbs of sprung weight it makes a huge difference.

I know we arent dealing with Quads or ATVs , but the principle is the same. On a quad I can feel a huge difference when switching between tires. So, I agree unsprung weight can make a huge difference in how a car feels in general everyday driving. Less weight is almost always better.

Unsprung weight is anything not supported by the vehicles suspension if anyone wasn't clear on that already. And I see lightweight wheels as being a very worthy mod I mean seriously a 10lb wheel is going to get into motion faster and easier than a 30lb wheel will.

Unsprung weight is anything not supported by the vehicles suspension if anyone wasn't clear on that already

this is what i wasn't clear on. i thought it was just anything that had to be rotated basically

Originally Posted by thesammythecurse

Some benefits I have read are additional traction because it allows wheels to flow better with bumpy roads, faster acceleration and deceleration, higher whp on the dyno, and for every 1lb of unsprung weight it is equal to 4lbs sprung.

So what is unsprung weight? It seems to be rotational mass on a car, from what I can understand. This would include wheels, tires, rotors, hubs, bearings, axles, etc. and sometimes people say calipers although I'm not sure if this is really the case. The people who include calipers say pretty much everything within the wheel is unsprung.

I suppose this would include flywheel, and the pulleys as well?

Don't forget rotors.

one of the reasons i would run 15's on the streets


and the reason i wanna go 13inch

Originally Posted by White_Spec-V

one of the reasons i would run 15's on the streets


and the reason i wanna go 13inch

holy tiny wheels batman! what rubber would you wrap on those?

Originally Posted by mongoose64

holy tiny wheels batman! what rubber would you wrap on those?

Mickey Thompson Performance Tires & Wheels

thats a whole lotta rubber haha

Originally Posted by MisterNuts

Don't forget rotors.

Re-read what you quoted me on those 350z rotors are 20lbs a piece. Kinda killer :/

***Butt dyno results...NOT actually dyno'd so before someone starts in I wanted to make this VERY clear***

I just recently installed a JWT lightweight flywheel and their clutch (recently as in two months ago). I noticed an instant difference in the way the car started after everything when back together, after it cranked the engine always revs up as it starts and it did this much quicker after the install. Over all the engine responds and revs quicker than with the oem setup. Once I got through the break-in I noticed a definite increase in how the car pulled through out the rpm range. (Again, this is MY opinion. I have nothing other than driving the car for almost 4 years with the stock set up to base my opinion on).

I am a firm believer (for other reasons as well) in removing weight from the drive line to free up power that is lost on rotational mass of heavier parts. I also noticed a slight difference in the revs when I installed my light weight pulley last spring. This can also be applied to rims. The less weight the drive line has to turn the more power you can free up (you don't gain power here, you only stop wasting it on turning heavier objects). In my opinion anything that will remove rotational mass will help.

Just my $.02

There is a difference between unsprung weight and rotational mass. Like SkinnyPete said unsprung weight pertains to any component not being supported by the vehicle's suspension while rotational mass pertains to any parts that the motor has to turn. Lighter parts for both will increase your vehicle's performance in different ways.

Yeah, this is true. It just so happens that most unsprung items spin. Lol.

I kinda don't feel like calipers are truly unsprung weight, but by that definition "any part not support by suspension" they are I guess.

I have also read that the tires weight make the most significant differences because they are the farthest piece front the center hub. Makes sense to me.

I remember one honda kid a while back said he only ran two lugnuts per wheel to save weight lmao all I could do is

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