Suspension differences between 17" and 18" wheels?

[Exonian]

Both 17 and 18'' Monzas are 7.5J and ET51.

[Ess_Three]

Both 17 and 18'' Monzas are 7.5J and ET51.

Odd. I expected at least 1/2" wider on the 18".

Ah well, for any aftermarket wheel choices there will be further gains to be had going to an 8" wide wheel...but by 8.5 it's getting perilously close to no rim protection if you have a wee mishap!

[RickS]

I think the major difference is caused by the larger radius not the weight; this gives a slight mechanical disadvantage to the drive train for 18's as compared to 17's, so theoretically the acceleration will be slightly slower, but I defy anyone to categorically state they can tell the difference.

The difference in radius equates to around 6 revolutions per MILE difference...if you can spot that, you are a robot.

It's actually  approx 65 revolutions/mile. But that's not really what I'm saying, what I'm saying is that the ½" longer radius makes it slightly more difficult to turn the wheel from the centre where the drive is as it's a slightly longer "lever" if you get my meaning. But I still say that you wouldn't be able to tell the difference.

[Steve30]

This is the most anal thread for age's 

[Ess_Three]

It's actually  approx 65 revolutions/mile. But that's not really what I'm saying, what I'm saying is that the ½" longer radius makes it slightly more difficult to turn the wheel from the centre where the drive is as it's a slightly longer "lever" if you get my meaning. But I still say that you wouldn't be able to tell the difference.

65?
You sure?


Toyo T1-R:

WHEEL SIZE RIM LOAD/SPEED INDEX TREAD DEPTH (mm) OVERALL DIA. (mm) OVERALL WIDTH (mm) STATIC RADIUS (mm) REVS PER MILE WEIGHT (KG) MEASURING RIM (inch) PERMITTED RIMS (inch)

225/45ZR 17 94Y RF 8.2 633  222  294  834
225/40ZR 18 92Y RF 8.2 637  231  299  828

A difference of 6 rotations of the tyre, per mile.

A diameter difference of 633mm vs 637mm

You won't be able to tell that...


65 revs/mile is like going from a 225/40/18 to a 185/50/16
That, you'd spot straight away...it'd be like being a gear down every time.

[RickS]

It's actually  approx 65 revolutions/mile. But that's not really what I'm saying, what I'm saying is that the ½" longer radius makes it slightly more difficult to turn the wheel from the centre where the drive is as it's a slightly longer "lever" if you get my meaning. But I still say that you wouldn't be able to tell the difference.

65?
You sure?


Toyo T1-R:

WHEEL SIZE RIM LOAD/SPEED INDEX TREAD DEPTH (mm) OVERALL DIA. (mm) OVERALL WIDTH (mm) STATIC RADIUS (mm) REVS PER MILE WEIGHT (KG) MEASURING RIM (inch) PERMITTED RIMS (inch)

225/45ZR 17 94Y RF 8.2 633  222  294  834
225/40ZR 18 92Y RF 8.2 637  231  299  828

A difference of 6 rotations of the tyre, per mile.

A diameter difference of 633mm vs 637mm

You won't be able to tell that...


65 revs/mile is like going from a 225/40/18 to a 185/50/16
That, you'd spot straight away...it'd be like being a gear down every time.

I just did it on the rim diameter which is obviously not accurate, so I stand corrected :embarassed:

[Ess_Three]

I just did it on the rim diameter which is obviously not accurate, so I stand corrected :embarassed:

No need...
You have to go down a profile size too don't forget, which pretty much cancels out.

The Toyo figures won't be super accurate for all tyres of the same size, but rought speaking a difference of 5-10 revs/mile won't be noticable on a car weighing 1500Kg and with a torquey engine.

[herbie911]

18' wheels = gorgeous looking girl who you need to sacrifice something to please her (Botox etc..!)
Cons
£400+ option
Easier to kerb
Tyres cost more
Harder ride wears out the bushes quicker
Cost more to insured
Pros
Look fantastic
Sharper steering
More fun than 17s on a smooth tarmac or race track

17' wheel= ordinary looking girl who will cost one next to nothing to make her happy
Pros
Better unsprung mass and softer riding=better handling and grip on our uneven B road
Cost less to repair or replace
Easy to clean
Probably the best riding hothatch with the ACC option
Can change this to 17s OZ or BBS if one not happy!
Cons
Looks so ordinary!

[Ess_Three]

So the answer is to buy aftermarket 8" or 8.5" wide 18" or 19" wheel, in as light a weight as you can.
No more unspring weight = no more wear.
Sharper turn in.
Make sure the car has ACC...then you can tailor the ride to suit.

Win, win, surely?
Except the cost of tyres...

[R32UK]

Ok just to clarify...
Mine was delivered with 17" wheels which I then swapped to 18". No difference in ride what so ever.

Gilly, just realised you were going to post pictures of your 'new' wheels a couple of weeks ago.

Ah, just seen your signature! I did guess they were Audi split-rims at some stage!

Nope... nothing to do with the wheels for sale in my signature.

Havent had a chance to change my wheels as yet. Still needs to go back to the bodyshop for repair on my rear bumper... so thought I would wait until I got my car back first.