Unsprung Weight

"Supreme Chancellor and Glorious Leader SaveTheIntegras" (jegoingout) 07/12/2016 at 11:50 • Filed to: Education time yo

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Oppo educate me, because I want to learn and I don’t know anything here.

How much unsprung weight would one have to lose in order to really feel a difference?

This all ties into the debate on which wheels I plan to get. Currently the stock wheels are 23lbs and the one’s I want are 14.6lbs.

Much thanks <3

themanwithsauce - has as many vehicles as job titles > Supreme Chancellor and Glorious Leader SaveTheIntegras 07/12/2016 at 11:59

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Even ~5 pounds on a wheel will be noticeable in the steering IMO. Maybe it’s just me but going from my heavy, stock 17" alloys to some 10ish lb lighter 16" wheels I noticed a lot “lighter” steering feel and it seemed a little easier to dial in the right steering angles for turns.

RamblinRover Luxury-Yacht > Supreme Chancellor and Glorious Leader SaveTheIntegras 07/12/2016 at 12:02

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At least partly it would be down to how much of a percentage you’re losing. Lighter wheels on a Wrangler, pretty much unnoticeable. A Teggi, much more noticeable. You really ought to feel 8lb, at least a little.

ateamfan42 > Supreme Chancellor and Glorious Leader SaveTheIntegras 07/12/2016 at 12:04

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The degree of improvement depends on a lot of factors: amount of sprung weight, how much other unsprung weight is present (brakes, steering knuckle, etc.), tire mass.

A reduction in wheel weight from 23 lbs to 14.6 lbs is pretty substantial. I’d be surprised if you didn’t notice a significant difference.

I could tell a difference dropping from 24 lbs to 17.8 lbs on a heavy (3600 lb) car. On a smaller/lighter car, a drop of nearly 10 lbs per wheel should be hard to miss.

jariten1781 > Supreme Chancellor and Glorious Leader SaveTheIntegras 07/12/2016 at 12:05

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I don't know what my 'noticeability' threshold is, but nearly 9 lbs per corner is well beyond it. That said, if you get new tires at the same time that will likely overwhelm the changes in weight in 'noticeability'.

Smallbear wants a modern Syclone, local Maple Leafs spammer > Supreme Chancellor and Glorious Leader SaveTheIntegras 07/12/2016 at 12:05

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Depends where it is. unsprung weight in things like calipers, axles, the springs and shocks themselves... that’s going to be pretty much equal to losing sprung weight.

Any rotating mass has far more effect. IIRC 1lb change in the tire is worth ~8lb and 1lb in the rim is worth 3-4lb.

Future next gen S2000 owner > Supreme Chancellor and Glorious Leader SaveTheIntegras 07/12/2016 at 12:05

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C&D or MotorTrend did a test a few years ago on wheels size and weight. They put a 16" wheel up through a 20" wheel on a Jetta, keeping the overall OD the same, and recorded 0-60 mph times. For every wheel size they went up, the time increased by .1 secs.

Lighter wheels will increase your speed - lower rotational inertia, are easier for your suspension to control, and probably make your steering more responsive.

However, if you do it for looks, that is one thing, but if you are doing it to be faster or build a race car, work on the driver first. Your skill set will improve lap times faster than a new set of wheels. Also, when you can drive better, you are better able to nuance the differences between wheel weights and how the car responds.

Whether or not you can feel it, lower unsprung weight is always better but work on the loose nut behind the wheel first.

jjhats > Supreme Chancellor and Glorious Leader SaveTheIntegras 07/12/2016 at 12:13

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the only example you need. imagine running a marathon. now imagine running it with a 20 lb backpack on. now imagine it with shoes that weigh 20 lbs. which one is harder? generally speaking the golden rule is never go heavier than an oem wheel but any weight you can ditch from wheels/tires improves your car more than simply removing that weight from the body

Supreme Chancellor and Glorious Leader SaveTheIntegras > Future next gen S2000 owner 07/12/2016 at 13:22

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I’m doing it for looks and runs up by Hawks Nest

Supreme Chancellor and Glorious Leader SaveTheIntegras > jariten1781 07/12/2016 at 13:23

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Wait so new tires will take away that noticeable feel?

jariten1781 > Supreme Chancellor and Glorious Leader SaveTheIntegras 07/12/2016 at 13:29

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Not really, it’s just that new tires are soooo much more noticeable that you won’t be able to tell what is coming from the weight and what is coming from the rubber and most of it will be coming from the tire. For giggles I’ll make up a noticeable scale (out of ten): Tires Compound/sidewall/tread 7-8; Tire weight 3-4; Wheel weight 2-3; caliper weight 0-1.