18" alloys on a golf

Kermitt

There is no THICK forum:D

There is a motors forum - where we talk about cars - and not take things so personally on an internet forum

Anan1

Big Balls wrote:

I understand it all fine thanks Anan. Have you learnt that roundabout thing yet? Seeing as we're giving out the lessons?

Try not to get too upset. I understand that nobody likes being wrong, but it happens to all of us from time to time. It just so happens that your day was today (and yesterday). A bit of friendly advice, though - stop digging now. Tomorrow's another day.;)

VeVeX

I dont see anyone talking from experiance really. Mathematical theories based on tyre to road friction etc to rivel pythagoras theorem do not really convert into the real world noticeably in my opinion.

If you have a 1.4 golf and fit 205/55/16 Gti spec alloys I doubt you would feel any change in performance from the standard size alloys or steelies. I know I didnt when I fitted the Gti alloys to my old 1.4.

Now, if you fit 17's with a 205/40/17 the wheel will have a smaller radius so based on that the car should perform better. Its unlikely or people would have shaved a bit off oe 0-60 times just by changing wheels?

http://www.miata.net/garage/tirecalc.html

With a 225/35/18 wheel size you still have a slightly smaller rolling radius then the orginal Gti wheels. Obviously with the extra tyre width theres more tyre on the ground needing more power to rotate the tyre. How much more power is the question. I dont think from experiance that the extra power drain is noticeable what so ever.

Different tyres have different rolling resistance anyway so maybe the extra 'friction' could be counter acted by a more efficient tyre.

VeVeX

Big Balls wrote:

The arches are also not any bigger on a GTI. It's a normal production car, VW are not going to make the arches bigger than the rest of the Golf range.

Audi made the arches on the S3 8L bigger then the standard A3. Dont know if this is true for the rest of the S range.

maidhc

VeVeX wrote:

I dont see anyone talking from experiance really. Mathematical theories based on tyre to road friction etc to rivel pythagoras theorem do not really convert into the real world noticeably in my opinion.

Possibly very true. A set of light 17" with Michelin Energy's should be at least as good as the standard 15" steels with whatever-you-are-having-yourself tyres.

I suspect though things start getting a bit noticeable when people start fitting 17" wheels to corsas and 18" wheels with wide rubber to 1.4 Golfs.

esskay

One thing about changing you wheels is that it can affect the speedo. check out the Tire Size Calc http://www.miata.net/garage/tirecalc.html to see what percentage you speedo will be out with new wheels

Anan1

maidhc wrote:

Possibly very true. A set of light 17" with Michelin Energy's should be at least as good as the standard 15" steels with whatever-you-are-having-yourself tyres.

I suspect though things start getting a bit noticeable when people start fitting 17" wheels to corsas and 18" wheels with wide rubber to 1.4 Golfs.

In terms of rolling resistance, that's quite possible. With regard to aerodynamic drag, though, a wider tyre is always going to come off worse.

peasant

Seenashow nobody has mentioned it yet, there is another important factor to consider, especially in a wet country like Ireland:

AQUAPLANING

The wider the tyre the more quickly the car becomes an uncontrollable object once it meets surface water.

On my Jimny I run factory spec 205/70 tyres ...during winter time, when most of our by-roads become lakes even the 205's are too wide for such a light car. I'm seriously thinking about changing to 195/80's next time I need new tyres.

Anan1

peasant wrote:

Seenashow nobody has mentioned it yet, there is another important factor to consider, especially in a wet country like Ireland:

AQUAPLANING

The wider the tyre the more quickly the car becomes an uncontrollable object once it meets surface water.

This is quite possibly the best point to date, I'm amazed it hadn't occurred to any of us until now.

Cyrus

if you have good tryes its a non issue

i have 18" goodyear eagle f1s no aquaplaning issues

Anan1

Cyrus wrote:

if you have good tryes its a non issue

i have 18" goodyear eagle f1s no aquaplaning issues

Any tyre will aquaplane if you hit standing water fast enough. The wider the tyre, the lower the speed (assuming the same car with the same tyre tread & pattern). A 255 Goodyear Eagle F1 will therefore, all other things being equal, aquaplane at a lower speed than a 205.

mmenarry

The chances of aquaplaning are increased if you increase the width of the tyre. You'd think you'd have a bigger contact patch with a bigger tyre, but that's not the case.

Regardless of the tyre, the size of the contact patch is actually only affected by the tyre pressure and wieght of the car.

For the same weight/pressure, a thinner tyre has a longer/thinner contact patch aligned front-back. A wider tyre has a contact patch (of the same size) aligned more side-side. A contact patch aligned front-back "cuts" into puddles much better, reducing the chances of aquaplaning.

M.

Cyrus

Anan1 wrote:

Any tyre will aquaplane if you hit standing water fast enough. The wider the tyre, the lower the speed (assuming the same car with the same tyre tread & pattern). A 255 Goodyear Eagle F1 will therefore, all other things being equal, aquaplane at a lower speed than a 205.

all things arent equal thats why i paid €200 a corner for tyres, cmon lads use yer noggins

Cyrus

http://tfe.goodyear.co.uk/company/news/pr/eaglef1tyretest.html

http://eu.goodyear.com/uk_en/images/GoodyearAutocarAwards_tcm64-7644.pdf

mmenarry

Cyrus wrote:

all things arent equal thats why i paid €200 a corner for tyres, cmon lads use yer noggins

Cyrus, I think he meant that a 255 width Eagle F1 will aquaplane at a slower speed than a 205 width Eagle F1

maidhc

Cyrus wrote:

all things arent equal thats why i paid €200 a corner for tyres

Ouch. Ouch again.

I have a sort of related question:

I have a Ford Focus TDCi, and sometimes when I floor it the standard 15" 195/60s struggle, in fact I had a weird experience one day when overtaking something slow going up a hill in the wet the front wheel spun on the (broken) white line in the middle of the road.

I need new tyres soon, should I:
a) Replace the present white label tyres with something grippier (it so what, and i'm not spending €800 on a set, maybe ~€100 a corner absolute tops).
b) Get a set of wider 17" alloys with slightly harder wearing rubber than the above.

I am slow about getting the 17" wheels because the roads I drive are prone to potholes and the Focus is stiff enough without making it even harsher.

mmenarry

maidhc wrote:

I need new tyres soon, should I:
a) Replace the present white label tyres with something grippier (it so what, and i'm not spending €800 on a set, maybe ~€100 a corner absolute tops).
b) Get a set of wider 17" alloys with slightly harder wearing rubber than the above.

Lots of good tryes in 195/60 - the aforementioned Eagle F1, Toyo Proxes, Pirelli P6000. Those are in teh range of €75-€100 each.

Wider tyres will not improve your grip, they'll have the same size contact patch.

M.

Anan1

mmenarry wrote:

Lots of good tryes in 195/60 - the aforementioned Eagle F1, Toyo Proxes, Pirelli P6000. Those are in teh range of €75-€100 each.

I've been trying to get F1s in 205/60 15 for a while now - they seem to have discontinued some of the smaller sizes.

Cyrus

maidhc wrote:

Ouch. Ouch again.

I have a sort of related question:

I have a Ford Focus TDCi, and sometimes when I floor it the standard 15" 195/60s struggle, in fact I had a weird experience one day when overtaking something slow going up a hill in the wet the front wheel spun on the (broken) white line in the middle of the road.

I need new tyres soon, should I:
a) Replace the present white label tyres with something grippier (it so what, and i'm not spending €800 on a set, maybe ~€100 a corner absolute tops).
b) Get a set of wider 17" alloys with slightly harder wearing rubber than the above.

I am slow about getting the 17" wheels because the roads I drive are prone to potholes and the Focus is stiff enough without making it even harsher.

changing the wheels to 17" will give you more traction when you floor it, thats why i changed the 16 on my golf to 18 when i got it remapped, with 200 bhp and 16" front wheels with a turbo charged engine i was just standing still

however theres no point getting bigger wheels and cheaper tyres to be fair, tyres are one of the most important components you can get and a good set may save your life one day

maybe look for a set of second hand wheels with decent tyres on? i thought the tdci came with bigger wheels than 15 tho???

peasant

maidhc wrote:

I had a weird experience one day when overtaking something slow going up a hill in the wet the front wheel spun on the (broken) white line in the middle of the road.

Just try and avoid driving on the white lines in future.
When wet they are slippery as hell ...which any biker will confirm for you

peasant

mmenarry wrote:

Cyrus, I think he meant that a 255 width Eagle F1 will aquaplane at a slower speed than a 205 width Eagle F1

What happens during aquplaning is that the tyre creates a kind of bow wave as it hits standing water. The grooves in the thread are designed to channel away that water. Above certain speeds and/or certain water depths the grooves can't cope any more and the tyre will mount its own bow wave and ride on a cushion of water ...the car becomes totally uncontrollable.

Now, with the same thread / pressure / speed / etc a wider tyre will create a wider bow wave, ie. more resistance. At the same weight of the car (ie. downward force) it will lift off sooner then a narrower tyre as it has less downforce per length of bow wave as the narrower tyre.

Simple really.

So the Eagle F1 might have a better thread than any other tyre to disperse water and delay aquaplaning ...but on the same car at the same conditions the wider F1 tyre will still aquaplane sooner (i.e at lower speeds) than the narrower F1 tyre.

And if you still don't believe me ...try surfing with a downhill ski !