I currently have Goodyear F1 GSD3 on my car, but one of them suffers from a slow punture which is too close to the sidewall to be repairable. Is it safe to replace just the one tyre? Will it affect the handling?

I usually will replace a pair on the same axle, but I'm hoping to swap to Eagle F1 Asymmetric, and my understanding is you can't mix directional tyres (GSD3) with non-directional ones (Asymmetric, or at least I think it is non-directional)?

Use the spare in its place and buy a new spare to repalce the orginal spare

I read an article once, think it was in What Car about this guy who had a Volvo V70, replaced one tyre and after 2500 suffered a bizarre ECU failure. Volvo said the culprit was replacing one tyre because although it's only a tiny amount, a new tyre will spin slower than a worn one which creates a difference in mileage readings which causes the engine computer to go crazy. What car (or whatever magazine it was - think it was WC) said they were right but should have warned about it blah blah.

always replace in pairs that way gaurantee even wear etc.

Ask the centre to send the tyre for a major repair?.... This is a hot vulcanized repair that exceeds the normal shop standards... costs around £20 and will solve your problem.

sorry but NO dont do it. you will be ok to replace the directional f1 with another directional but if you switch to an assymetric design it must be on both sides. the idea of switching the spare if its directional would be a good one or just buy a directional toyo and switch the rest when funds allow.

i am sure on this and have even heard of insurance companies trying not to pay out for this reason alone

it will affect the handling in the wet as an assymetric directs water to the outside of the car.

also if you do get another gsd3 make sure its made in germany as they have recently switched production to china and the quality has reduced. (its written on the sidewall btw)