Bought a PACE 303 just after they came out, roughly Oct 2006. Lasted about 7 months before breaking at seat tube. PACE warranty kicked in & received updated 305 about 5 months later.
Ran 305 until current date. Suffered terrible chain suck which began to mark chain stay, fabricated 'baked bean can' chain stay protector.
Recently noticed a crack on the non-chain stay side, checked under 'baked bean can' also broken.
Conclusion – Chain suck weakened chain stay broke; baked bean can held it together. Stresses on non-chain stay excessive and then broke.
Comment – Frame suffers abnormal chain suck, bad design? (New model has built in anti chain suck device).
HELP / IDEAS / COMMENT – Should I just put this down to experience. Should a hardtail frame last longer than 3 1/2 years. Have I any warranty claim or issue due to bad design (I think 2 year warranty on paper).
Thanks in anticipation.

Never had any chainsuck damage problems on my 303 though mine did snap at the seat tube/gusset weld like most…

I think you have to accept that this is just bad luck – you won't have any luck with warranty (even if it was inside the 2 years since chainsuck is clearly your fault, not theirs) though it's always worth asking Pace very nicely if they do replacements as most brands will do a cheap (cost + VAT ish) replacement for out of warranty frames.

Quite a bit of recent-ish Pace "warranty" talk on here if you do a search. I think the general conclusion was that you may have better luck extracting some blood from a stone.

Yeah – longish thread here

http://www.singletrackworld.com/forum/topic/noooo-bike-frames-busted

Chainsuck due to components rather than frame Shirley?

Should a hardtail frame last longer than 3 1/2 years

YES

Comment – Frame suffers abnormal chain suck, bad design? (New model has built in anti chain suck device).

In my experience, yes, definitely. Although I take cynic-al's point that components and set-up can help mitigate, or worsen, the problem.

Also, 5 months to receive a warranty replacement first time around?!?

No, the frame has nothing to do with chainsuck happening (eg the chain not releasing from the chainring). The frame's design (low clearance between rings and chainstays) means that if you get chainsuck, the effect will likely be bad. An important distinction and one you may argue about as poor design but then you could argue that about all sorts of things. What it doesn't do is make it a warranty claim.

Clubber – yes, that was my point, the poor design worsens the effect of getting chainsuck, bacause of the low clearance between rings and chainstays. Also agree that it's not a warranty claim – and I didn't even consider it would be when this happened to my frame.