You need to hunt down JamesO on here. He designed it...

I suspect it'll be fine, if you're happy with slack angles higher BB etc. (I presume that's why you're doing it)
I was advised against over-forking a previous frame because the designer thought allowing longer forks encourages people to ride harder (which it sort of does), so the greater loads, combined with longer bending moment on the headtube could be a bad thing. If you're just using it for "normal" riding, and just want a plusher longer fork, I'm sure it'll be fine.

But James will be able to confirm yay or nay.

When I was mocking up my iO I tried 120mm forks and it didn't seem right at all and I like slack riding bikes!

100mm does seem to be a sweet spot.

Having said that what do I know ..... I am currently running mine rigid with forks designed to replace 80mm forks 😆

Well it seems like a sturdy enough frame and i do want the slacker angles....100mm not enough for the hills where i live.

Cheers for the dyfi ticket by the way was a good event as usual even if i did crash and smash my hand ha ha

Bump 🙂

I have some 120mm sitting in the shed which I was wondering about sticking on my iO too

I have 120 Revs on mine, feels spot on to me. You could just run it with plenty of sag and see how it rides, nowt to lose 😉

Tried 120mm on my iO and it felt OK. Usual side affects, but IMO the trade off is worth it.