K2 GTi
Member
Registered: 21st Oct 04
User status: Offline
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can someone please explain, how bigger wheels will effect performance... just to prove someone wrong, cheers  
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Ant
Member
Registered: 12th May 02
Location: Hereford and Worcester
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they will making the gearing longer so acceleration will be slower
theoreticly could hit a higher top speed if you had a high powered car
Also bigger rotating mass which isnt good for performance either
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Marc
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Registered: 11th Aug 02
Location: York
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The bigger the wheel diameter the further it takes for it to make one revolution. So, a 17" wheel is going to take longer to make 1 revolution compared to a 14" wheel.
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big eck
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Registered: 20th Apr 03
Location: Tullibody. Drives - Audi B8 S4 & Fiesta Zetec-S
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All depends or now big the wheels are before and after
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Jules
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Registered: 26th Nov 04
Location: Ipswich, Suffolk Status: Happy
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The rolling radius of the wheel will be bigger there for slowing down acceleration
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K2 GTi
Member
Registered: 21st Oct 04
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more please keep coming thanks for replies 
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Ry_B
Banned
Registered: 1st Dec 05
Location: Solihull, W Mids Drives: 45BHP beast!
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So a 1 inch wheel will accelerate quicker than a 15 inch?
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Gaz
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Registered: 24th Aug 03
Location: Widnes, Cheshire
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yes..
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Mattss Corsa
Member
Registered: 11th Jan 03
Location: Milton Keynes (BUCKS)
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Wouldnt advise gettin bigger wheels mate, slows you down loads 
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Steve
Premium Member
Registered: 30th Mar 02
Location: Worcestershire Drives: Defender
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dont forget to add tyre profiles to, a 16" rim with a 40 profile tyre will be the same rolling radius as a 15" with a 50 profile
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Ian
Site Administrator
Registered: 28th Aug 99
Location: Liverpool
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quote:
Originally posted by Rcb
So a 1 inch wheel will accelerate quicker than a 15 inch?
Wheel size alone has little to do with it.
For one single revolution the 15" wheel will cover a far larger distance Formula is 2 x PI x radius or 6.28 x radius if you don't need it accurate, but don't forget tyres are not included in that 15".
The problem with covering a larger distance, which on the surface of it might suggest that acceleration would be improved, is that it takes far more power to take advantage of this. The wheels are better small, for identically the same reason as you don't drive everywhere in fifth. You cover very large distances for every engine revolution in fifth, which is good while you're already travelling, but not good for acceleration.
The differences are minor and nowhere as profound as rendering your car unusable as it would be if you lost low ratios all together, but the difference is present enough to certainly be noticable if you're familiar with the car and also you'll notice it in the figures when you time the car.
Furthermore, larger wheels are heavier, which means the unsprung mass is larger (ie. all your bits of wheel/brakes/hub that hangs off the car) and therefore less responses to changes in the road, which is bad for handling as the wheel spends less time touching the road and more time floating about recovering from the last bump.
Furthermore, larger wheels tend to be wider, which means the contact patch on the road is larger, which means it exerts less pressure on the road, which means it displaces less water.
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Steve
Premium Member
Registered: 30th Mar 02
Location: Worcestershire Drives: Defender
User status: Offline
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...and slide in snow/ice easier
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Mattss Corsa
Member
Registered: 11th Jan 03
Location: Milton Keynes (BUCKS)
User status: Offline
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Jas
Member
Registered: 13th Oct 04
Location: Mid Wales
User status: Offline
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so i have 16's on my car... would it accelerate better with 15's
providing the tyres wer low porfile
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Sam
Moderator
Premium Member
Registered: 24th Dec 99
Location: West Midlands
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At the moment on my Astra I have 15" wheels with 195/55/15 tyres (they are stock alloys), I am going to be getting some 17" wheels with 205/40/17 tyres.
On http://www.miata.net/garage/tirecalc.html it says that there will be 0.1" difference in diameter, and that revolutions/mile are the same (860.0), so it looks like I won't notice much if any difference in terms of speed etc.?
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ed
Member
Registered: 10th Sep 03
User status: Offline
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It's mostly to do with the rolling radius of the wheel. But most people on this website refuse to belive that.
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Gaz
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Registered: 24th Aug 03
Location: Widnes, Cheshire
User status: Offline
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Can i askthis then,
if you was on a rolling road, and you was mesuring Brake AT the wheels...
whats the best rims to put on to get the most accruite figure, or would it not matter
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Adam_B
Member
Registered: 13th Dec 00
Location: Lancashire
User status: Offline
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also bigger wheels and tyres are heavyer. heavy means slow.
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alistairolsen
Member
Registered: 21st Jan 06
Location: glasgow
User status: Offline
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on a rr it will make no difference to the peak power reading. unsure as to differences in the torque curve tbh.
I run 195/45/15 is this has a similar rolling radius to the 175/65s that omes as std. You only have to wory when you get up into 17 inch rims, as really 40 profile is as low as you want to go on a road car, so you end up adding the inch to the overall diameter as opposed to taking it up in the tyres.
Always makes me lauch how folk go on about lightening flywheels etc, then post a pic of their car with massive 308s and chrome wheels! If your goignt o lighten the flywheel you want alloy belled disks and lightweight wheels too
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truman69
Member
Registered: 12th Jan 06
Location: mansfield, notts
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i may be putting 17" on my 1.4 16v sport good or bad?
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Gaz
Member
Registered: 24th Aug 03
Location: Widnes, Cheshire
User status: Offline
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bad, unless your going for a styling approch to car's
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Steve
Premium Member
Registered: 30th Mar 02
Location: Worcestershire Drives: Defender
User status: Offline
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the smaller the rims the better the reading on the rr will be. mainly effects torque tho
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All Torque
Member
Registered: 17th Nov 05
Location: Milton Keynes Drives: Ford Focus TDCi
User status: Offline
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what about tire width? like 10" rears compared to 7.5"? i know the tires at the front would have to be thinner to corner better but do wider tires drag more?
It depends on engine size too. i remember that SPL drag saxo in Max Power that weighed two tons and had 18s...... could get past 60 mph as it was still 1.2.
Also the amount the tire is inflated helps too, think about drag racing where when the rear wheels spin the air in them expands and the tires seem fuller. I cant see how that will affect a corsa but still.... 
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richysport
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Registered: 15th Apr 05
Location: Flintshire, north wales
User status: Offline
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quote:
Originally posted by truman69
i may be putting 17" on my 1.4 16v sport good or bad?
bigger than 16's aint the best thing on a corsa unless your going for looks, 17's seem to bog the car down when starting from a stand still
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ed
Member
Registered: 10th Sep 03
User status: Offline
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Duuuhhhhh, here we go again. With the correct tyres a 17" wheel will have the same rolling radius as a 16" wheel. The only difference is the weight.
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