Reducing rim size on vRS

[DunlopRS]

Thanks guys,
I must work out how to ensure cynicism comes across right. I always like instruments to be accurate....

I thought it was 92? (as per your first post)....... /looks at placard on own car....... OIC - 91 it is.

For some reason on my car 16&17" are marked as load index 91 & 18" as 92.
Am well aware of this anyway.

Off shopping next week.....

[brad]

Off shopping next week.....

Have a look at tirerack. You'll get ContiExtremeContact DW in 225/50x16 for <AUD900 landed in ACT. Yokohama S-Drive for about $40 less. Some very nice performance tyres there if you want to pay a bit more.

Allow $25 for bank fees & $80 for fitting/balance

[Diesel_vert]

I hope the tyres used as replacement have the same/better load rating and what about the speed rating?

The Road Transport Act 2000 (ACT) basically says that any tyre you fit should be capable of at least 180 km/h (for passenger cars) or the vehicle's top speed - whichever is the lesser of the two.

Therefore, he could fit tyres with a speed index of S (which corresponds to 180 km/h) on his vRS if he really wanted to.

It also allows the operator to fit winter tyres (which often have a speed index several categories below a typical summer tyre) without contravening regulations.

I usually end up with something out of the Michelin/Yokohama/Pirelli range and this is again the likely end point (an early experience with wide BF Goodrich TAs on a 265 charger brought physics into the real world (or at least my world) as wider tyres do not always mean more grip – as you are putting the same mass onto a bigger area – while great on the black top, unsealed roads were a real joy (those torsion bars..) – learnt a lot about predicting what the car was going to do when the surface changed……..).

When it comes to modifying cars, the benefits or advantages of most mods often do not increase in a linear fashion.

There have been a few posts on tyre size. While leaning towards the std 16” fitment of 205/55 the comments about that 225/55s are worth following up on. This would also give more protection of the rim from the potential for brushing against the kerb parking….. And it would be nice to have a speedo that gave a slightly more accurate indication of speed (I reckon its about 5-8% fast – but remedying this will also likely increase indicated fuel consumption….)

In terms of rolling circumference:

205/55 R16 is the near equivalent of 225/40 R18 (and 225/50 R16 as well)
215/55 R16 is the near equivalent of 235/40 R18
225/55 R16 is the near equivalent of 245/40 R18


Both 215/55 R16 and 225/55 R16 tyres would also benefit from 7.0 J x 16 wheels due to their width, but it's perfectly acceptable to fit them on 6.5 J x 16 wheels as well (in fact, the lowest you can go with is 6.0 J x 16).

If the comment on that webpage that +/-15mm D is all that’s legal is correct it looks like the 225/55 is out?

Different states and territories have different regulations.

The Road Transport Act 2000 (ACT) says that as long you don't fit a tyre with a section width over 30% (or, for a four-wheel drive built for off-road use, 50%) larger than the largest optional tyre specified by the vehicle's manufacturer, you'll be fine.

225/55 R16 is perfectly acceptable.

I understand 215/55-16 is an uncommon size?

Any tyre that isn't fitted to an Australian or Japanese car is uncommon.

Though as sales of European cars increase, tyre importers/distributors will have more incentive to bring in Euro-centric sizes at cheaper prices. For example, prices of 225/45 R17 tyres (a common European fitment) have gone down a lot.

For some reason on my car 16&17" are marked as load index 91 & 18" as 92.

A standard load 225/40 R18 tyre has a load index of 88, whereas a reinforced or extra load 225/40 R18 tyre has a load index of 92.

The load index of the standard load tyre was probably a bit too low for comfort, so they went with the extra load version.

Have a look at tirerack. You'll get ContiExtremeContact DW in 225/50x16 for <AUD900 landed in ACT. Yokohama S-Drive for about $40 less. Some very nice performance tyres there if you want to pay a bit more.

Allow $25 for bank fees & $80 for fitting/balance

The price of smaller tyres here usually aren't exorbitant enough to justify importing a set, but depending on what's available here compared to overseas, it may (or may not) be worth it.



Finally, choosing which non-original tyre size to go with is mostly a personal decision. As as long as it doesn't contravene any regulations, there really isn't a right or wrong choice - it all depends on what you want from a tyre.

[applesee]

DunlopRS, have you taken any photos of the car with the 16" alloys on?
I'm planning to do the same, but purely for taking the car above the snow line (so that snow chain can be fitted).

Haven't had much luck finding a set of 16" in Victoria though.

[brad]

Haven't had much luck finding a set of 16" in Victoria though.

You must be joking? There are heaps of suitable rims in VIC. I have the audi 16x7.5 on my car - cost me $400 in new condition with near new michelins.

eBay Australia: Buy new & used fashion, electronics & home d

VW GENUINE WHEELS, VW PASSAT WHEELS, 16X6.5_ USED, IN A GOOD CONDITION | eBay

16" GENUINE AUDI A4 ALLOYS AND TYRES | eBay

16" Rims & Tyres from an Audi A4 B8 2009. 4 in total. | eBay

Audi A4 Alloys 2010 16" 7.5" | eBay

These are in Sydney but Freight isn't overly difficult to organise or expensive ($120 tops)
VW Golf Mk5 Pacific 16" Wheels | eBay

VW TRANSPORTER T4 AUDI A4 USED 16 INCH MAG WHEELS | eBay

[applesee]

You must be joking? There are heaps of suitable rims in VIC.

Sorry, I should have been more specific when making a general statement like that...
I am looking for the exact same wheel/tyre size combination as the standard 16" rims. i.e. 205/55 R16 6.5J ET50...

[brad]

Sorry, I should have been more specific when making a general statement like that...
I am looking for the exact same wheel/tyre size combination as the standard 16" rims. i.e. 205/55 R16 6.5J ET50...

A few of those links I posted match that description. you just have to be in the right place at the right time. I tried to sell mine for many months & practically gave them away in the end.

6.5/7/7.5 won't make a lot of difference as long as you stay close to ET50. 205/55x16 will fit on any of those widths.

Why not the 225/55x16? Would there be a clearance issue with chains? (not a skier, so don't know)

[Diesel_vert]

Sorry, I should have been more specific when making a general statement like that...
I am looking for the exact same wheel/tyre size combination as the standard 16" rims. i.e. 205/55 R16 6.5J ET50...

Skoda says to use;

195/65 R15 tyres on 6.0 J x 15 ET47 wheels (max. chain size 15 mm)
195/65 R15 tyres on 6.5 J x 15 ET50 wheels (max. chain size 15 mm)
205/55 R16 tyres on 6.0 J x 16 ET50 wheels (max. chain size 15 mm)
205/50 R17 tyres on 6.0 J x 17 ET45 wheels (max. chain size 9 mm)

if you want to fit snow chains.

[applesee]

the reason for going 205/55 R16...
thinking that I might be able to get away with 6.5J instead of 6.0J

[brad]

OIC. That makes sense.

Wow! 15mm chains sound big.

[DunlopRS]

Well Guys,
Was going to leave an update for a few more km but following applesee‘s question, I have recently travelled ~1300km from the ACT across the Hay plain into rural SA (5.5L/100 km indicated…..).

For my driving I am VERY happy with the change to 16” rims. I went with 205 55 continental conticomfort 5s. I no longer feel every join in the concrete on the hume in spine and there is no reason at all to slow down at places on the Hay plain for fear of breaking the car (or the significantly worse council maintained roads off the major tracks). They are much quieter and get the power onto the road better (much, much harder to make the wheels spin).

There is a very small but noticeable reduction in handling “quality” around roundabouts on good roads (as would be expected), but overall the car is much better behaved on uneven and broken surfaces and is a real joy to drive (not sure what the “v” stands for but is it is “variant” perhaps I could ‘dub’ the car now as sub-variant GT). On examination of the 18s there is some evidence that most of them have touched the road surface or something very hard on the road surface – so it seems it would have been only a matter of time before a bend or fracture…..
Again, for me, I think only going down to 17s would have left me with a slower car (in my world).

Not sure (have no idea) if any VW group 16 would fit over a RS disk/caliper (there is enough but no excess in clearance with mine) – but it seems that you may be able to find 3rd party alloys that fit if you can find a salesman that is interested in spending the time……
Good luck (will be taking my wife’s focus to the snow…).

...... not sure how to get a photo in - anyone point me in the right direction?

[brad]

I cant quite see how a 205/55x16 would have more resistance to wheelspin than a 235/40x18 unless the 18s were crappy tyres.

You realise that the smaller diameter of the 205/55x16 will make your fuel economy look better even though it's not? Also, 15,000km on the odo will now be more like an actual 13,500km (I think that's what I worked out mine was).

Sounds good though.

[Transporter]

...... not sure how to get a photo in - anyone point me in the right direction?

Photos have to be hosted. Try Picasa in google.
The instructions are here http://www.vwwatercooled.org.au/foru...ges-45153.html

...also if you have an Android phone, you can upload the photos easier using the Tapatalk.

[DunlopRS]

Photos have to be hosted. Try Picasa in google.
The instructions are here http://www.vwwatercooled.org.au/foru...ges-45153.html

Thanks – will have a go later

I cant quite see how a 205/55x16 would have more resistance to wheelspin than a 235/40x18 unless the 18s were crappy tyres.
Sounds good though.

OEM Dunlop maxx GT (or something like that). It’s all very subjective – not real sure of the physics but I understand a bit more sidewall flex can occur in the higher profile tyre rather than just breaking contact with the road. Its real for me in normal driving…….
Also, I reckon the car “points” better on the 16s as on the dunlop’s with only 35psi in them (dunlops were a bit “doughy” at 35psi….)

You realise that the smaller diameter of the 205/55x16 will make your fuel economy look better even though it's not? Also, 15,000km on the odo will now be more like an actual 13,500km (I think that's what I worked out mine was).
Sounds good though.

Yes – perhaps – “indicated” fuel economy as noted. Even if this is 10% out its still great….
From the tool on carbon black the 205/55-16s are 17mm less in circumference that the 225/40-18s (<0.1% reduction in circumference).
Not sure how this really works out in practice. On those 5km check strips on highways I travel about 5.1 kms on the odo – about 2% out (with a large potential error – and if it really is 5 km). Also on radar speed “checks” the speedo seems to be about 5% faster than the radar reports – and I would assume that the radar units are generally set a bit high?
Next time I have a few hundred kms between towns which should remove some of the measurement errors I will take note of indicated distances and see if that tells me much.
I guess the Columbus sat nav does not report apparent ground speed anywhere like a navman does?

[DunlopRS]

Thanks – will have a go later