Tyre size options!

[mikeyr]

Need some help choosing tyres for the girlfriend's 2002 Polo 9n.

It's currently on 175/70/14 but the recognised sizes on the various tyre provider sites is 165/70/14, 175/65/14 and 185/60/14.

It's on bog standard wheels (not alloys) and I know the 175 relates to the width. I'm not sure whether to keep the current size or revert to 165/70/14 if that gives a wider (by which I mean cheaper!) choice of rubber.

Any thoughts?

[Krikkit]

I'm not sure I'd go down to 165's, as that means a reduction in tyre width (and thus contact patch). Either the 175 or 185 would be my choice, depending how the rolling radius compared to the current tyres (to preserve the speedo etc)

[V8forweekends]

Sounds like it's on the wrong size tyres now - is there a sticker anywhere (filler flap, passenger/driver door jamb?) or anything in the handbook that gives details of original fitment? BTW - as you prolly know, the 65, 70 etc is a percentage and indicates the relationship of the sidewall height to the width.

[mikeyr]

Thanks - that is partly why I was curious as the 175s currently fitted are not a standard manufacturer spec size for the Polo.

[mikeyr]

V8forweekends said:

is there a sticker anywhere (filler flap, passenger/driver door jamb?)

Good thinking V8, will check this after work!

[kambites]

Stick your registration number into one of the online tyre sites like black circles or camskill. It should tell you the standard tyre size(s) and give you an idea of the price of the various options.

Personally I'd put on the narrowest tyres that were available OEM.

[mikeyr]

Kambites...

mikeyr said:

the recognised sizes on the various tyre provider sites is 165/70/14, 175/65/14 and 185/60/14.

[kambites]

Ah, that's by number plate? In that case I'd take the 165s in the best tyre I could justify, if it was me.

[golfdsg]

correct me if i'm wrong people, but doesnt a narrower tyre = less grip?

[kambites]

golfdsg said:

correct me if i'm wrong people, but doesnt a narrower tyre = less grip?

You are, in generality, wrong.

For the same model of tyre, wider will give you fractionally more grip in the dry up to a point; for a given price of tyre, it will often give you less grip in all conditions; on standing water, it will almost always give you less grip.

Edited by kambites on Tuesday 2nd September 14:20

[OldBuoy]

golfdsg said:

correct me if i'm wrong people, but doesnt a narrower tyre = less grip?

No, if the tyre pressures the same the contact patch will be the same, just a different shape.


http://www.performancesimulations.com/fact-or-fict...

[mikeyr]

kambites said:

Ah, that's by number plate? In that case I'd take the 165s in the best tyre I could justify, if it was me.

Thanks KB

[John145]

OldBuoy said:

golfdsg said:

correct me if i'm wrong people, but doesnt a narrower tyre = less grip?

No, if the tyre pressures the same the contact patch will be the same, just a different shape.


http://www.performancesimulations.com/fact-or-fict...

When braking or cornering loads predominantly onto a pair of wheels.

A wider tyre, for the same model/brand, will have a high vertical load capacity before saturating.

Therefore typically a wider tyre does indeed increase possible grip level.

I would not worry about aquaplaning on tyres so thin. If you were at 205 or above it would be more of a concern.

If you are concerned just remember to replace tyres when they reach 3mm of tread and ALWAYS have the best tyres on the rear axle.

[OldBuoy]

doogz said:

OldBuoy said:

golfdsg said:

correct me if i'm wrong people, but doesnt a narrower tyre = less grip?

No, if the tyre pressures the same the contact patch will be the same, just a different shape.


http://www.performancesimulations.com/fact-or-fict...

Have you read that article?

There's an awful lot of 'probably's in there, along with a 'I haven't actually looked at the data' or two.

I have a 205 wide rear tyre. Say the contact patch is maybe 40mm long.
Then I remove my car tyre and fit a bike tyre, what happens?

I'll give you a clue, the area, does not remain constant.

Tiny, tiny differences. This one explains it better.

http://www.carbibles.com/tyre_bible_pg3.html

[BritishRacinGrin]

People, people- this is a polo and all of the sizes mentioned by the OP were bought up by number plate search.

The answer is already in this thread- VW would've printed a sticker with approved tyre sizes and stuck it to the door shut area or inside the fuel filler flap. Remember also to take note of the speed and load ratings.

For what it's worth, I'd just check the range of available tyres for each size and fit whatever took my fancy. Probably the narrowest option- marginal reduction in dry cornering grip, which would not be noticable, the payoff being that the tyres are often cheaper comparing like-for-like, better road manners and will be less likely to get you stuck in snow than the wider tyre.

Edited by BritishRacinGrin on Tuesday 2nd September 15:28

[John145]

Get 4 of these and everyone will be happy:

http://www.camskill.co.uk/m4b0s393p109318/Goodyear...

Because the same thinner tyre is more expensive:

http://www.camskill.co.uk/m4b0s386p109334/Goodyear...