do the size of wheels affect speed/accel

[VirIIx]

I was having a discussion the other day with some friends about this topic, whether the size of your wheels affect speed or acceleration.

From what i've heard from others, smaller wheels give you more acceleration, however, larger wheels will equate to a higher speed?

I know a mate who had a honda crx, and he switched to 17's from his 15's and on the dyno it was slower.

just wondering what other people think, or could shed some more factual light on the situation :)

I really want 18's over 17's that's all, and would not like to sacrifice the fact the car looks nicer, but is slower/weaker/worse - that's ynderstandable right? :b

[REV888]

I was having a discussion the other day with some friends about this topic, whether the size of your wheels affect speed or acceleration.

From what i've heard from others, smaller wheels give you more acceleration, however, larger wheels will equate to a higher speed?

I know a mate who had a honda crx, and he switched to 17's from his 15's and on the dyno it was slower.

just wondering what other people think, or could shed some more factual light on the situation :)

I really want 18's over 17's that's all, and would not like to sacrifice the fact the car looks nicer, but is slower/weaker/worse - that's ynderstandable right? :b


Well from 17" and onwards the rider just gets firmer also note the higher specs you go, you will be carring more weight so of course your bound to go slower.

Its personal preference. My current car has 17" wheels which for me is a perfect ride but I know if I go any higher the ride will just be to rough.

Its your choice at the end of the day

[aaronng]

The rim size only determines the wheel weight. The rolling diameter determines the car's acceleration. So if you upsize from 15" to 17" but use a lower profile tyre to keep the rolling diameter the same, then the only change in acceleration is determined by the increase/reduction in the weight of the wheel. You know, 2nd gear gives harder acceleration, but 3rd gear gives higher top speed? Same as with the overall wheel diameter. It acts as a gear ratio too.

[Dominik]

when you buy larger mags, you compensate for this by getting lower profile tyres. The overall diameter will stay the same (if done correctly!). When i went from the stock 15"s to 17"s i actually got a lower profile than recommended, so the end result is that my wheels are smaller than the stock 15"s! When i do 105km/h (accordignt o my speedo), i'm actually only doing 100...

[poid]

sae with my 18's, they are about 5mm or so smaller than the rolling diameter of the stock 15's. Its usually the wieght that has the biggest effect and not the diameter unless you get a stupid wheel/tyre combo

[sodaz]

Larger wheels:

Pros: Better top speed, sharper handling, better braking, looks great
Cons: Slower acceleration (inertia of wheel), twitchy handling, less comfy ride, heavier car (slows down the car a bit)

The opposite goes for smaller wheels. So putting big wheels on a car isn't always the best thing to do. It's like riding a bicycle with big wheels. You'll have a harder time getting a bicycle with big wheels to start moving compared to one with smaller wheels. So imo, big wheels are for higher HP cars.

18" on the Euro is not a good idea imho.

[Pum[Z]]

Yes Bigger wheels do affect acceleration & Speed...

I agree with what Sodaz is saying...

My car is living proof...

[yfin]

Larger wheels:

Pros: Better top speed, sharper handling, looks great
Cons: Slower acceleration (inertia of wheel), twitchy handling, less comfy ride, heavier car (slows down the car a bit)

The opposite goes for smaller wheels. So putting big wheels on a car isn't always the best thing to do. It's like riding a bicycle with big wheels. You'll have a harder time getting a bicycle with big wheels to start moving compared to one with smaller wheels. So imo, big wheels are for higher HP cars.

18" on the Euro is not a good idea imho.
What you are saying is not always right - what if the larger wheel is lighter than the stock wheel? Also - what is the problem with 18" on the Euro?

[Sp3rMz]

This has been discusses before. Search is you're friend. Bigger the wheel slower the accerlation. Same theory with you're fly wheel. Heavier the fly wheel slower it turns. Lighter its get less load to turn. Same with wheels bigger heavier load to turn.

[sodaz]

But what are the chances of 18" wheels being lighter than 16" wheels? See with the larger wheel the mass is spread out more, making it more difficult to initiate spinning from a standstill. So unless the 18" wheels are a LOT bit lighter than the 16" wheels you will have slower acceleration. However, if you have a very powerful engine that problem will be less noticable.

The reason why i think 18" wheels might not be suitable for the Euro is because i believe it would make the ride more uncomfortable and slugglish overall.

Just my 2 cents.

[yfin]

But what are the chances of 18" wheels being lighter than 16" wheels? See with the larger wheel the mass is spread out more, making it more difficult to initiate spinning from a standstill. So unless the 18" wheels are a LOT bit lighter than the 16" wheels you will have slower acceleration. However, if you have a very powerful engine that problem will be less noticable.

The reason why i think 18" wheels might not be suitable for the Euro is because i believe it would make the ride more uncomfortable and slugglish overall.

Just my 2 cents.
What are the chances-you ask? Look at any forged rim made in Japan and you will find the answer. There are plenty of light wheels around that are MUCH lighter than the 9kg+ stocks. Lower unsprung weight means better acceleration, better braking, etc.

My car with 17" rims accelerates faster than when it had the stock 16". Sluggish, more uncomfortable - baloney. The suspension on the Euro is quite soft and the ride is not adversely impacted by 17" or 18".

Give it a try - you will be pleasantly surprised how 18" rims ride the Euro. It is not as harsh as you might think.

[razaman]

Anyone know the weight of the factory 15" alloys from the 5th gens? My overall diameter has increased slightly (on purpose) although I don't think my weight has changed much.

I noticed a small torque decrease when I went to 17's from the 15's however I feel this is somewhat offset by the taller gears.

This is most noticeable in second and to a lesser extent third (due to actual speeds towards the end of third is not something I try to do often). However I recently went on vacation - about 5 hours open road driving and 2nd gear definately lasts longer,as does 3rd. As noticeable or more than the torque decrease.

Raz (they are subjective of course)

[sodaz]

If you can find wheels that are significantly lighter than the stock ones then it's a different story. The topic was really about how "wheel size" affects speed/acceleration, and not how "weight" affects speed/acceleration.

Personally i think the Euro is best with 17" wheels. I don't know how 18" wheels will perform on the Euro but according to my experiences with this on other cars, i would say that 18" wheels will bring more drawbacks than advantages for this car. I also think the suspension on the Euro is on the firm side for a mid range luxury car.

[redliner]

simple physic really, greater the diameter of a of a circle or wheel the the slower the RPM (rotation per minute) is. Forgot the formula, but i saw it experimented on in lecture :)

[Type R Positive]

What are the chances-you ask? Look at any forged rim made in Japan and you will find the answer. There are plenty of light wheels around that are MUCH lighter than the 9kg+ stocks. Lower unsprung weight means better acceleration, better braking, etc.

My car with 17" rims accelerates faster than when it had the stock 16". Sluggish, more uncomfortable - baloney. The suspension on the Euro is quite soft and the ride is not adversely impacted by 17" or 18".

Give it a try - you will be pleasantly surprised how 18" rims ride the Euro. It is not as harsh as you might think. :thumbsup: - its like putting 17" x 7" on a lancer coupe, a HUGE improvement. Sweet!

IMO 18" just perfect. 17" for the track boys and 19" for the gangsters (hey Pum[z] !)

[yfin]

simple physic really, greater the diameter of a of a circle or wheel the the slower the RPM (rotation per minute) is. Forgot the formula, but i saw it experimented on in lecture :)
Why do you need to change the diameter- you can retain overall rolling diameter by fitting lower profile tyres.

[razaman]

Why do you need to change the diameter- you can retain overall rolling diameter by fitting lower profile tyres. I can only speak for myself but the 215/40/17 tyre is almost a perfect match diameter wise however I wanted more comfort from some extra sidewall so I chose a 215/45/17.

Daily driver family car - no worried about the track or racing etc. Definately show over go here.

Raz

[PERTH_EURO]

']Yes Bigger wheels do affect acceleration & Speed...

I agree with what Sodaz is saying...

My car is living proof...
so u wanna run LOL jj :p



IMO 18" just perfect. 17" for the track boys and 19" for the gangsters (hey Pum[z] !)
I totally agree i run 18's and the ride is just fine n dandy.
We will be the true gangsters matt when we steal Michael's 19" rims, and i might give it a go top get that mugen spoiler :D

In terms of acceleration, are we talking 2/10ths of bugger all between the factory 16" rim and say a set of 18's.
So many other variables in terms of acceleration, like air temp, driver skill blah blah. ???

[Type R Positive]

I totally agree i run 18's and the ride is just fine n dandy.
We will be the true gangsters matt when we steal Michael's 19" rims, and i might give it a go top get that mugen spoiler :D
He he, Im going to get your stereo when you aint lookin! :p

20's would be better. Michael's 19's look too small! :D

[PERTH_EURO]

hahaha classic

It will be a bloody swap meet

:)

[VirIIx]

what have I done? :b

we're all gonna be rolling around in bling bling wheels that are all 20" :D

don't forget the spinners!

on a side note, back on track. I think it would be worthwhile looking for lightweight 18", as you would end up with a lower profile anyways.

I think 18" fills up the gap better, 17's still look a tad too small

[Type R Positive]

Some wheel and tyre weights for ya.

~18kg 16" Stock rim with Dunlop tyre
~15kg 17" Prodrive GC07C rim with 225/45 Falken 512 tyre (yfin's :) )
~16kg 18" Volk CE28N rim with 225/40ZR18 Toyo proxes T1-S tyre
~17kg 18" Volk TE37 rim with 225/40ZR18 Toyo proxes T1-S tyre

So +1 and +2 rims with wider tyres can be had for less weight than OEM.
Grip and handling improvements would by far outweigh any loss in acceleration if any at all.
A gain is quite possible, just ask yfin. I know which ones I would have!
( CE28N's :p )

[razaman]

Nice research numbers!

What does an average 17" 215/45 directional tyre weigh?

My 5zigen 17's are 8.5kg's without tyres.

Raz

[VirIIx]

nice stats type-r cheers for that. :)

[Type R Positive]

Nice research numbers!

What does an average 17" 215/45 directional tyre weigh?

My 5zigen 17's are 8.5kg's without tyres.

Raz
Around 9kgs for 17"

I found some tyre weights at www.toyo.com
They list their tyre weights for all their tyres (they list in pounds)
1 lb = 0.4535924 kg
1 kg = 2.20462 lbs

[blahblah]

good stuff

[DaPlaya]

any idea how much stock 15" aluminium ITR rims weigh?

[SSML]

Around 9kgs for 17"

I found some tyre weights at www.toyo.com
They list their tyre weights for all their tyres (they list in pounds)
1 lb = 0.4535924 kg
1 kg = 2.20462 lbs

Just wondering if the dry weight of a rim + the dry weight of a tyre = total weight of a fitted tyre/rim combo.

I assume tyre/rim combo will be heavier considering the air valve + the compressed air inside the tyre..

So we cant really find out the total weight until they a trye has been fitted and pumped up... :confused:

[Sonlyte]

No, size doesn't affect hp however weight does...more the rim weighs, the more rotational inertia, which has is a force that has to be overcome by the motor but the future of rims are larger and lighter rims so let review

size doesnt affect HP if wheels are same weight
Weight of rims does affect HP.

Just like lightweight cam gears increase HP

The word of the day is rotational inertia, class.