If small wheels were faster...

[obi_waynne]

If you found out that smaller wheels - say 13 inch rims made the car much faster and improved acceleration would you fit them?

Which is more important to you looks or performance? Where do you draw the line?

 

[Two Tone Tribe]

haha, i'm back, after a long time without remembering password and user name. thanks for the email Waynne, even if it was probably posted to all inactive member.
anyway, to get to the point, there is no way that 13 inch rims could be better performance wise. there is too little rubber on the ground which means less grip. which means less control and acceleration. thats why drag cars and drift cars have really fat tyres at the rear. and although to me its performance before aesthetics all the way, they would look way way too dumb.
Enjoi

 

[obi_waynne]

Hi Two Tone Tribe and welcome back. Glad you got in without your password/username - if you ever need this resetting let me know. What are you driving now?

I'll let this debate continue a little before I leap in with some interesting info on wheel size. Remember we are not talking narrower wheels we are looking at smaller wheels.

 

[Izo Azlion]

If small wheels were faster, surely it'd then become cool to have tiny wheels? Lol

 

[Two Tone Tribe]

hah, i knew you would start this debate with a couple of cards up your sleeve. i know that due to the size of them more power should be able to be transferred from driveshaft to wheel meaning quicker acceleration. but i cant see them being brought in to production. look at the amount of suspension which wouldbe required to soften the impact of pot holes and stuff. you would also have to raise your suspension therefore leading to more roll and therefore far more dangerous driving due to the fact that the 13 inch tyres would decrease ride height
on another note, i am not driving anything currently but will be looking to get my hands on a good specimen RX-7 within the next couple of years. until then i think it will be a laguna until then. not yet acquired it, but soon.
Enjoi
PS i do remember my password/user name now.

 

[Prince]

I would be somewhere in the middle...13 inch rims would just look silly! 18s look much better! Smaller rims do help with acceleration (I think) because you often see the old Mustangs with 15s and 14s on despite much bigger rims would fit!

Izo, if 13 inch rims became popular at least they'd be a lot cheaper!

 

[pgarner]

the only problem with performance wise with small wheels is the small brakes behind them. you could easily get some wide 13" tyres made up.
smaller wheels would mean lower unsprung mass so would give you a better handling as well as giving your car less weight overall.
how many of you have picked up a 18" wheel complete with tyre then picked up a 13" ? BIG DIFFERENCE. ive noticed a difference between the weight of the 17"s over the standard 16" on the bora the now.

Are Ferrari not testing smaller wheels and more powerful carbon brakes.
i have also heard about another company looking at testing new brakes that could be a lot smaller as they use 5 calipers rather than 1 to cover more of the disc. this would allow you to have high performance brakes along with small wheels.

i dont know how much of a difference this would make as youd have lighter wheels and lighter discs but youd have 4 more calipers and pads

 

[Izo Azlion]

Surely smaller wheels and brakes means the centre of gravity is higher in the car, more roll, etc. And as theres less circumference, you'd surely get faster tyre wear?

 

[pgarner]

better suspension setups would stop this roll.
13" tyres cost me £17 ( 195 /xx/13 )for the prelude the 15" were £45 (195/50/15) and the 17" £100 (225/45/17). average size for a wheel is now proberly sitting at 16" so your looking at £80 ish for a decent one. so as long as you werent going through tyres 4 times as fast you could be saving money

 

[pgarner]

ok done some quick sums using excel and the tyre sizes ive used.
circumference of wheel is PI x Diameter ( Please say this is right )
ok the 3 sizes of tyres ive used are

195/50/15 that were fitted to my civic. 205/55/16 standard on bora and my 225/45/17s that are standard for the 17s on bora audi etc

to get the diameter of the wheel is easy inches multiplied by 25.4.
to get tyre diameter its the width multiplied by the ratio ( second numbers expressed as a percentage) then multiplied by 2 for the top and bottom of the wheels
added both numbers to get a full diameter then multiplied by 3.1415 for PI

so

195/50/15 = 1810mm
205/55/16 = 1915mm
225/45/17 = 1992mm

so if i was to downgrade to 15" , i cant because of the brake discs, id have 10% more wear on tyres due to the lower circumference.

 

[obi_waynne]

Quite a bit of maths there PG. (I won't point out our wheel size calculator in the alloy wheels article in tuning as that would be unfair )

If you fit smaller wheels you are actually changing your final drive ratio. The complex laws of gearing kick in here. So smaller diameter wheels will be like dropping in a low ratio gearbox.

Tires will also warm up more quickly so you get grip sooner.

Who's for some 13' mini lights now then?

 

[Massive]

in my opinion the bigger the better in most cases, sod it if it slows you down abit they look great and at the end of the day you can only (technically) go so fast on roads anyway

 

[pgarner]

Quite a bit of maths there PG. (I won't point out our wheel size calculator in the alloy wheels article in tuning as that would be unfair )

If you fit smaller wheels you are actually changing your final drive ratio. The complex laws of gearing kick in here. So smaller diameter wheels will be like dropping in a low ratio gearbox.

Tires will also warm up more quickly so you get grip sooner.

Who's for some 13' mini lights now then?

:shock::shock: need a head banging smiliy

 

[obi_waynne]

What about || as a head banging smilie?

 

[sbtUK]

Indeedy

The physics behind it says that the smaller the wheels, the more force you're applying to the road. If (for example) your car's putting out 80ft-lb of torque at the wheel and your wheels (including the tyres) are 26 inches in diameter, then you'd be putting out about 74lb of force onto the road. But if your wheels were 22 inches in diameter then you'd be putting about 87lb of force onto the road instead.

You'd get better acceleration and a lower top speed... But as a few people have mentioned: you'd probably get a slightly rougher ride, and your tyres might wear out quicker too. You've also got less room for those all important brake discs.

If you're interested in the maths...

Torque = Force * Distance
T = FD
Therefore:
F = T/D

With 80ft-lb of torque applied to the axel and a 26 inch diameter (13 inch radius) wheel you would have...

80lb-ft = 80lb * 1ft
Therefore:
F = (80*12)/13 = 73.85ft-lb

(The *12 is because we're using ft-lb as a unit, but working in inches... 12 inches in a foot etc...)

And for a 22 inch diameter (11 inch radius) wheel....

F = (80*12)/11 = 87.27ft-lb

 

[HDi fun]

This is just arithmetic. It's arbitrary and irrelevant.

 

[sbtUK]

This is just arithmetic. It's arbitrary and irrelevant.

With all due respect: I thought it pretty relevent when I wrote it :/

I figured a bit of maths / physics behind why small wheels might provide better acceleration in a thread about how small wheels might actually be better was pretty relevent

I don't really see how it's arbitrary either, to be completely honest. That is the bulk of the physics involved in explaining why smaller wheels provide better acceleration. As Waynne pointed out: smaller wheels have the effect of creating a lower overall drive ratio, meaning more force can be applied to the road. I just figured that people who hadn't studied physics might want to know a little about why

I know it's hard to judge tone over the internet, but trust me when I say that I mean this in the most polite way possible. If I've completely missed the mark here, please let me know

 

[nseries]

If I'm to downgrade my wheels size, surely i would say no.Planning to upgrade to bigger size actually but there's a lot of parts need to upgrade along with the wheels :Examples: disk brake, absorbers,springs,calipers,maybe some bodyworks to fit in bigger wheels size ,etc

Maybe from 13" Wheels upgrade to 15" is fine for me as I'm trying so save money for the other accessories.

 

[obi_waynne]

I too am glad we have had this discussion, the maths is useful to support the "theory". The fact though is that most of us would not fit smaller wheels because they would look silly.

We can also take from this that larger wheels (ignoring weight difference) would do the opposite and slow the cars acceleration and increase the top end. This would also increase your fuel economy - so now we have an eco arguement for bigger wheels

 

[pgarner]

wheres hansi ? see if he can ship over some 42" for the bora
yeah :twisted::twisted::twisted::twisted:

 

[DimmaThanDim]

Your theory would be right for saving fuel by fitting bigger wheels to your car provided your car has sufficient power to pull the extra ratio created along without having to apply more throttle to achieve the same speed, or worse still having to select a lower gear on a long uphill section of road. I have raced many cars around tracks and still do. I have had much quicker times on smaller diameter rims than on larger rims on circuits where there are shorter straights and tighter turns than i have achieved on rims of 1" larger. However, on the longer circuits with longer straights and smoother corners i go for the bigger rims to raise the gearing to save on the revs and amount of up and down changes required.

 

[JG1]

Having changed my 14" standard steels for a set of 17"s i can definately say that the bigger the wheel the slower you go. I lost 20mph from my top end after changing. Had 120mph with the 14s (out of a 1.2 litre clio i hasten to add, downhill with the wind behind me lol!) now when i hit 90 i crawl up to 100 then stop at bout 105 max.

James.