Small cracks in tyres - replace or keep?

[nitten_traveller]

Another post on tyres!

My car still has three of the original four tyres (date code 5012), ContiPremiumContact2.  I was thinking of replacing the front two and moving the rear tyres forwards as they still have 4mm of tread left on them. However a closer inspection shows that both have cracks all the way around the very edge of the tyres, where the tread meets the sidewall. 

I've attached some photos which, as they're close up, look horrific but it's really not as bad as they look.  The four main grooves look OK as far as I can see.  The sidewalls are also OK, at least on the outside.

I saw that KwikFit often have promotions on premium tyres plus there's another on Continental tyres this month.  So, two questions:

1.  MOT time is next month. Will small cracks cause a problem?  Nothing is down to the cords at all.  I think from my reading of the MOT manual I'll be fine, but who knows?

2.  Is it worth keeping these or should I just spend the money and replace all four tyres?  They'll be six years old in December.

 

(I do wonder that, if I feel the need to ask the question I already know the answer and should just replace them all the next time Kwik Fit have 20% off premium tyres!)

 

[iantt]

There fine for mot, but I would get them changed as you mentioned. 

[nitten_traveller]

3 minutes ago, iantt said:

There fine for mot, but I would get them changed as you mentioned. 

Thanks - I now hope the 20% off offer comes around again before the Continental offer expires!