Do lightweight wheels make a noticeable difference in acceleration?

[Based]

I'm just curious. I'm brainstorming ways to make my car faster as usual and I am wondering if lightweight wheels are really worth it for straight line speed.

I was thinking about even going to 15 inch wheels. I think 15x7 oz ultraleggera wheels are 12lbs... Then I can get some 205/50/15s and be good to go... Probably lose 12-15lbs a corner.

I don't go to the track I just like roll racing.

 

[kprocivic]

you got a st to do roll racing, that's about as backwards as I've heard.

and for roll racing the stockers will do just fine.

 

[Based]

you got a st to do roll racing, that's about as backwards as I've heard.

and for roll racing the stockers will do just fine.

I got the ST because I wrecked my Miata and needed a car for work that day and that's all I could afford.

 

[kprocivic]

I got the ST because I wrecked my Miata and needed a car for work that day and that's all I could afford.

gotcha.

 

[frankiefiesta]

Light weight wheels are a great start

 

[BRGT350]

any reduction in rotational mass helps with acceleration, deacceleration, and turning. The reduction in mass reduces the inertia, which means it takes less torque to accelerate the wheel, less torque (brake) to slow it down, and less effort to change the direction. You also get less unsprung mass. I notice a big difference between my 17" summer wheels and 15" winter wheels.

 

[Accel Junky]

It helps a little but to be honest they shouldn't be a high priority if you want bang-for-the-buck speed. Better to pick up a Cobb RMM, AccessPort, FMIC, and a Stratified tune first. Then you need to put down the power. Better tires maybe LSD depending on your traction woes. No sense in making more power if you can't hook up as it is. Now if you are going to the track, I would recommend other mods before touching either the wheels or the power mods.

I have -15lbs per front corner and -6lbs per rear corner all said and done (lighter wheels, Wilwood brakes) and to be honest the difference is not that noticeable. My AP with the stock tune showed pretty much the 1/4 mile same trap speed as stock but I had 100lbs of weight reduction including all that unsprung weight loss. So it didn't do much for me that I could feel.

 

[BronxBomber]

In my Opinion, knowing that you're already getting your power adders taken care of, I would definitely say to invest in some light weight wheels. I'm still on 17" wheels, but my Advanti's weigh 16.8lbs. That's 6lbs less per wheel, and I can feel the difference. Plus there is the added benefit like BRGT350 said of less stress on the suspension and quicker turn in and braking. If you want to make the car faster, try weight reduction. Wheels, brakes, lightweight battery, remove spare and false floor in trunk and anything else you can to remove weight. Carbon fiber hoods are super expensive at $750 a pop.

P.S. if you're going to get light weight wheels, don't forget to get aluminum open ended lug nuts to save additional weight. Changing Lug nuts saved a pound per wheel for me.

 

[Based]

In my Opinion, knowing that you're already getting your power adders taken care of, I would definitely say to invest in some light weight wheels. I'm still on 17" wheels, but my Advanti's weigh 16.8lbs. That's 6lbs less per wheel, and I can feel the difference. Plus there is the added benefit like BRGT350 said of less stress on the suspension and quicker turn in and braking. If you want to make the car faster, try weight reduction. Wheels, brakes, lightweight battery, remove spare and false floor in trunk and anything else you can to remove weight. Carbon fiber hoods are super expensive at $750 a pop.

P.S. if you're going to get light weight wheels, don't forget to get aluminum open ended lug nuts to save additional weight. Changing Lug nuts saved a pound per wheel for me.

I want to keep my car as stock comfort as possible meaning keeping the back seats and all the carpet etc. so I don't think I can get a huge weight savings. Maybe doing all that stuff you said will save me like 100lbs? That's a decent bit but the cost probably outweighs the performance lol.

What brakes can I get to lose weight? And what battery?

 

[M-Sport fan]

The Wilwoods (and any other big brake kits out there) are generally lighter than the factory calipers (despite having more pistons in them) because of the bodies being aluminum alloy vs. cast iron.
Their rotors are also lighter because of alloy 'hats' (center sections) to which the rotor rings are bolted, IF you use those instead of a factory style one piece rotor.

My problem with the current crop of very light (AGM) 'racing' batteries is that none of them come even close to the CCA, reserve capacity, etc. of the factory size (and weight) batteries whether they be lead wet acid, or Absorbed Glass Mat, and this CAN BE a problem in climes where it gets very cold, and the car sits out overnight, even if the car is used every day and charges the small capacity battery.

I keep hoping for the new breed of lithium based batteries (and their chargers) to come WAY down in price from where they are now, and for transformers to become available to enable the current factory alternators/generators to charge them properly.
THEN we can have a high CCA AND reserve capacity power source which is also extremely light weight.

 

[spoon]

Yes.

 

[kprocivic]

After the 1000s of dollars spent making a slow car light, you might wanna think about autocross.

 

[LILIKE16ST]

yes in my opinion it definately helps acceleration I got some 15x8 pro race 1.2 i weighed them at 15.4 lbs each before the tires which are 21 lbs stock tires were 20 lbs (michelin pilo sport a/s 3 were stock on mine they had the optional all season) so I saved like just over 7 lbs per corner from stock. I could have saved 2 more lbs per corner if I went with 205/50/15 star specs as opposed to the bfg sport comp 2 in 195/55/15 (very wide 195) but I wanted more treadlife as I drive alot. The weight loss on the wheels makes the car feel so much lighter and more nimble even more so than it already was from the factory. I don't have data outside of the butt dyno to back this up but the car definately felt quicker to me. Those oz you are referring to would be a solid bet as they are only 12 lbs but I wanted an 8 inch wide wheel otherwise I'd have probably gotten those. If you want a little cheaper check out the rota slipstream in 15x7.5 they're just like in the 13 lbs range I hear for under 600 bucks a set! You can also check into the pro race 1.2 like i have except in 15x7 i'm thinking they too are in the 13 lbs range. If you want to lose as much as possible I'd recommend the dunlop star spec 205/50/15 (19 lbs) and those oz that would be 31 lbs per corner stock is like in the neighborhood of 42.5 so that's 11.5 lbs per corner you should for sure feel that as I felt mine was quicker and more nimble with just 7 lbs per corner gone. I also have a braille 11.5 lbs battery that is going to go in mine that's around 18 lbs or so off the front end based on what I've read about the stock batterys weight. you can shave 20 lbs combined from dhm front and rear crash bars. After the battery I will have around 100 lbs or so off mine and I have the lightest optioned st (no moonroof no heated recaros) which comes in at I THINK 2720 based on what i've seen. My muffler and resonator delete was around 20 lbs removed the spare and jack was around 40 my wheels took off around 25 total that's 85 lbs the depo racing front mount I have on the way is 9 lbs heavier than stock the battery will offset that and take off 9 more approximately so I should be in the 94-95 lbs range give or take. I have other things in mind I want to get below 2600 lbs without my big ass in the car all while still having the ac the back seat the radio all speakers and all creature comforts. At the track you can lose the passenger and rear seat and drop an additional 100 lbs give or take. I'm thinking a fidanza 9 lbs flywheel whenever I do a clutch change should drop at least 10-12 lbs more rotational mass these dual mass flywheels are heavy based on my experience with my old svt focus. I may potentially do the deadhook front and rear crash bars as well in the future and possibly add a couple fixed back corbeau seats to the front and shed a good 30+ lbs. Street weight without me would then be in the middle 2500 lbs range and race weight at the track (minus passenger and rear seat and a quarter tank of fuel) would likely be in the low to middle 2400 lbs range. Giving this car a pretty good power to weight ratio. Sorry if I sound like I'm rambling I'm a bit tired and need my bed lol.

But to answer your question yes lightweight wheels do help even on acceleration (as well as everything else) and IMO it is noticeable even with just 7 lbs per corner gone. If you lose 11-12 lbs per you should for sure be able to tell. There are a lot of ways to shed weight on the car and rotational mass is the most important. There are ways to do it without hurting the practicality of the car (aka rear seat delete etc). Just do some research on weight reduction. If you take off 200 lbs of weight on the car, particularly if 40-50 lbs of that is rotational mass, that would probably have a similar effect on acceleration as say adding 10-15 horsepower would, possibly more. It all adds up. I agree it's not bang for buck compared to things like a tune but it's nice to have in addition to a tune and other things. I personally like the way 15s look on this car particularly when they're lowered and it doesn't hurt tires are much cheaper and the car rides much better on them as well Every little thing adds up...10 lbs may not matter...but when you add 10 to 10 to 20 to 40 to 20 to 25 to 15 to 30 that's getting close to 200 lbs of total weight reduction and it does start to add up after a bit particularly on a car that's only int he 2700 lbs range to start with...that's nearly 10% of the total weight of the car. This car comes stock with a power to weight ratio of around 13.8 lbs per horsepower. A stock focus st is around 12.7-12.8 lbs per hp. With some lightweight wheels, minor weight reduction, drop in filter and a tune my car is already in the low 12 lbs per hp power to weight ratio range and that's being on the conservative side of guessing etc. Add a little power and drop a little weight next thing you know these little cars start getting alot more respectable I've surprised a few people with mine. They can't believe it when I tell them I'm likely not making much over (if any) 200 whp on a dynojet with my mods...then I explain to them what power to weight ratio is good luck and happy modding!

 

[spoon]

Just to help reinforce this, on my last car (AWD Audi, the thing was a pig!) I went from 33lb Touareg wheels to 18lb RPF1.

Now, obviously that is a drastic difference in unsprung weight savings and much more than what we are likely to see on our Fiesta ST, but, I have to tell you that just swapping the wheels out made a huge difference. So huge in fact, I consider it the best mod I ever did to that car to this day. The car accelerated quicker, much quicker. Stopped quicker and turned quicker. The suspension works a bit less when you have lighter wheels as well, I think.

Less noticeable on these little cars, surely, but to keep it simple yes indeed lighter wheels do make a difference.

 

[kprocivic]

It's almost as if Noone even read the original post. He is looking to roll race his fiesta. Roll racing means whoever has the fastest car wins. Almost All the advantages to having light weight wheels would roll right out the window during roll racing.

 

[spoon]

It's almost as if you didn't read the part where I said my car "accelerated quicker". That's probably the whole point.

If you're going to act like a little prick at least do it right. Your comment doesn't even help. What are you even doing here?

 

[kprocivic]

It's almost as if you didn't read the part where I said my car "accelerated quicker". That's probably the whole point.

If you're going to act like a little prick at least do it right. Your comment doesn't even help. What are you even doing here?

he want's to make his st into a better roll racing vehicle. Although lighweight wheels will help with accerleration marginally, roll racing is about power and speed. If he is changing to smaller wheels, then he is also going to have to get smaller rubber as well. Let's say he get's some wheels and tires for 1000 bucks, he might be .01 quicker to 60 which roll racing isn't about that. Now he could buy a tune with some minor bolt ons for about the same price, and maybe save 1.0 second off his 0-60, along with making more hp because that is what roll racing is all about.

I'm here to get ideas on modding my fiesta spoon is that okay with you?

 

[spoon]

This thread is searchable, and is titled "Do lightweight wheels make a noticeable difference in acceleration?" The info I provided addressed his questions, and contained a few more bits of info that he may not have necessarily asked for (turning, stopping, suspension effort) but still can help benefit people in the future when it comes to wheel buying decisions when considering the effects they have on acceleration. Just because you don't have intentions for tracking your car doesn't mean you wouldn't benefit from the information that lightweight wheels can also help prolong suspension life. I mean, it's nice to know.

On topic tho... you obviously feel the effects of lightweight wheels on acceleration is marginal. I personally feel that the effects on acceleration are much greater than marginal, and there are also some side benefits to be had from a lightweight set of wheels as well. We are both in California, but I didn't break any laws by including the extra info did I?

 

[Goingnowherefast]

There was a thread on the Miata forums about a wheel weight vs. track times. With a setup that was ten pounds lighter per corner (Huge deal on a Miata) on the same tire, on the same day, same driver they found that there was absolutely no noticeable difference in track times between the two. So while on paper it provides a benefit, in the real world I highly highly doubt you will ever see the benefit in a quantifiable way.

 

[M-Sport fan]

There was a thread on the Miata forums about a wheel weight vs. track times. With a setup that was ten pounds lighter per corner (Huge deal on a Miata) on the same tire, on the same day, same driver they found that there was absolutely no noticeable difference in track times between the two. So while on paper it provides a benefit, in the real world I highly highly doubt you will ever see the benefit in a quantifiable way.

^^^This is interesting, and goes totally AGAINST what all of the wheel weight 'weenies' on here (AND physics) say about this topic, and how they can actually "feel" the 'seat of the pants' difference.

Maybe I SHOULD just go get those "heavy" 17x8 1.2s, and stop fretting about a couple of pounds?