old track tyres

I have a set of federal 595rsr's that are about 4 years old, I bought them when I was doing a lot of track days but shortly after I had to limit my track time to once a year so they are only half worn.
I'm concerned they may have aged and are now a bit past their best, anyone have any experience with aged tires going off?

 

I would use them and not give it a second thought. Have they got 50 laps left in em?
Jon

 

They would not be what they were new, but if you only go once a year you'll not notice any difference in performance, so long as they don't have cracks/blisters they should be fine.

 

Track day, not racing, they will be fine

As above if the have visible drakes it is an issue, others wise do you really care about half a second when you can get a second in your driving?

 

LOL. Not racing? I run 10+ year old 8.2/20/13 'soft' Avons on my mk1 for the British championship sprint at Croft.
Think they may be starting to 'go off' as I was second in class this year
Jon

Have you seen the price of a new set................

 

Thanks for the replies! Didn't want to have to buy new but a couple of guys I know were saying they'll be like driving on nylon by now so I thought i'd ask where there are people who actually know what they're talking about

They have no cracks or blisters and I'm not driving to the limit as I haven't done the ring in 3 years now so i'm a bit rusty, just want to enjoy it without any problems

 

Do a few laps get them up to temp let the cool and repeat 2-3 Times, this will soften them up.

 

Oldies (slicks) tend to scare the holy be jesus out of you for the first few corners after being dragged out of the shed a year later.
Zero grip, massive under oversteer.
Then they settle down with a bit of heat in them
Be aware
Jon