Smegger wrote:
MINImal effort wrote:
(I don't think they "explode" if put on the wrong way

- but may degrade optimum handling performance. )
If the tread pattern is directional [edit:
and fitted incorrectly], it wont displace water as effectively, leading to poor handling in the wet. In dry conditions I wouldn't imagine it'd affect handling too much; there's the same amount of rubber on the road at any given time..
The other danger with directional tyres (although I don't know if this is still an issue) when mounted backwards is the tread can strip away from the core. I have memories of this happening previously, but it could be an old wives tale

The belt structure of (some?) directional tyres are designed to roll one way also. I got a car back from a service years ago when directional tyres were still a rarity and couldn't keep the car on the road over 80kph because the sparkplug jockey at the dealership had rotated the tyres all around the car. They can also cause excess rubbing of the belts against each other causing overheating and de-laminating.
BTW, how far is this chart going to go? I think it is a great idea and should be "stickied" when it's finished, but if you're going to designate which models are directional, do you also list which ones have an inside and outside edge to the tread - which aren't directional but must be fitted onto the rims a specific way? The dry and wet ratings should give anyone a good enough idea of what to look for before going out to shop for tyres. The more complex the chart gets the more work will be required to keep it up to date - I'd even get rid of the $ value and replace it with a rating as the cost can vary from one shop/city/state to another and will always increase with time. Just my $0.02