wheel sizes / performance

[pulsarboby]

dont understand!:der: :lol:

question!
if you fit bigger wheels will this give you more acceleration but a lower top end, or is it the other way round?


im thinking smaller wheels will give you more acceleration but less top speed, but then i look at it from a different angle and confuse my little peanut brain.

only reply if you deffo know the answer or my head will explode with the confusion:lol:

 

[youngsyp]

The only way they SHOULD affect anything, is because of the extra weight. As they are larger, they will physically weigh more. Then, adding a larger tyre will also add more weight. It also puts the excess weight at the end of the springs and dampers so, it's all un-sprung. This being the worst type of weight, in terms of acceleration, braking and handling performance, as you well know.

By fitting larger wheels, you should choose a tyre that will give a rolling circumference as close to the rolling circumference or the original wheel/tyre combination (what the car was designed with) as possible.

The original sized tyre is 195/55-14. With a 15" wheel, you'd use a 195/50-15 and a 16" a 215/40-16. From memory, the best size tyre for a 17" rim is 205/35-17 but, I think these are few and far between. 215/35-17 might be easier to find.
Anything more that 2.5% either way, is deemed as excessive and your speedo will be quite a ways out.

To answeryour original question, if the rolling circumference of you larger wheel is greater than the OE set up, you will gain a higher top speed but, sacrifice acceleration. This happens as, the circumference of the tyre is greater so, for every full turn of that tyre, you'll cover a greater distance (top speed)but, as they're larger, they'll take longer to turn (acceleration).
The opposite is true for a tyre combo with a smaller rolling circumference.

This is a good tool for working out what size tyre to go for: http://www.miata.net/garage/tirecalc.html

Hope that makes sense.

Paul

 

[ashills]

big wheels give better top end
small wheels better acceleration
but the bigger wheel will normally be heavier so more unsprung weight which is never good
depends what speeds u need in each gear really to suit tracks and keep changes to a minimum

 

[Fast Guy]

I put the smallest diammeter 16" tyre on mine I could find, to help acceleration, and the expence of a couple of mph top end. Playing with tyre diammeters is just like altering the gearing.

Wheel diammeter in itself doesn't do anything(apart from any weight change), it's the tyre diammeter that changes the gearing.

 

[NismoDaveGTIR]

in a nut shell :

smaller wheels = better acceleration
bigger wheels = better top speed

but unless your goin on the track or quarter mile etc i dont think it makes enough of a difference performance wise to notice on normal roads at normal speeds

 

[olliecast]

Rotating weight is alot more noticable than stationary weight{on cars as its unsprung} (on downhill mountain bikes, light wheels can make so much difference, its just finding one that strong enough!!).

wider tyres have a larger contact surface area therefore more grip on tarmac.
If the overall diameter is different from large to small wheel size then the larger wheels circumference (the outer edge) will also rotate at a slower velocity (i.e. a 30 mph 17" wheel tyre surface velocity relative to the road is slower than that of a 15inch wheel, think of spinning your big cog and small cog on your pedal bike).
So there are less forces trying to overcome the friction coefficient of the rubber, hence more grip with large than smaller.

on smaller wheels you don`t get as larger surface area so may sacrifice some grip but the initial force required to turn the wheels will be less, thus allowing more power to be using in getting our lumps of flesh down the road instead of trying to turn the wheels. This improves acceleration.

hope this helps mate!

general cencensus seems to be
small = quicker acceleration (but sacrifice a bit of grip {and bloody brake clearence}
large= higher overall velocity, slower acceleration due to extra weight and extra ground to be covered
i noticed quite alot of difference going from my 17" tsw`s to my 15" ssr`s. Not only does it accelerate better, but the "feel" of the car has improved no end.

 

[pulsarboby]

thanks for the info chaps, ive got the picture now lol

didnt really want to do this but big big brakes are a must on the circuit, so guess im gonna have to sacrifice a bit of that oh so important acceleration out of bends:roll:

more boost please vicar:lol: :lol: fast in and faster out, tyre wall here i come:lol:

 

[olliecast]

more boost please vicar:lol: :lol: fast in and faster out, tyre wall here i come:lol:

don`t tempt fate mate!!

just get some sticky tyres on!!!

 

[jpward]

thanks for the info chaps, ive got the picture now lol

didnt really want to do this but big big brakes are a must on the circuit, so guess im gonna have to sacrifice a bit of that oh so important acceleration out of bends:roll:

more boost please vicar:lol: :lol: fast in and faster out, tyre wall here i come:lol:

Being a fellow biker Bob i would have thought changing chain wheels on different circuits would have left you with a better understanding of the physics of "ratio wheels" ;-)

 

[pulsarboby]

yep i understand that, but couldnt work it out with wheel sizes lol
but it seems my first quote was right afterall

 

[jpward]

yep i understand that, but couldnt work it out with wheel sizes lol
but it seems my first quote was right afterall

Yup old wise hunch was right

So are you going to fit 16" over those small 6 pots then? :lol:

 

[pulsarboby]

nope im now going for big 8 pot kit, they should slow things down quite nicely in my time of need lol

 

[jpward]

nope im now going for big 8 pot kit, they should slow things down quite nicely in my time of need lol

What! :shock:

You greedy b*^%^^&! :lol:

Tell the truth you are just missing doing stoppies coming in to the hairpins so now you think you can do it in the R hehe

What ever happened about the kits you were looking into then?
and may i ask how many kidneys an 8 pot set up runs a body?