What sort of race? I’ve used my Dune for a local (easy) enduro and half thinking about using it in next year’s Vallelujah and other things, but also solo’d the Glentress Seven on it. It is completely inappropriate and stupid for all of these. Iditarod? Different 😆
You could build a lighter fatbike than mine, for sure- carbon frames, carbon 65mm rims, lose the dropper, some lighter drivetrain… but none of it would be gamechanging, some of it would be very expensive, and some of it would make it ride less well.
For the Seven I ended up running a 4.8 Jumbo Jim instead of a 4.0 on the front, just because I didn’t want to be without the bounce- 7 hours was hard enough tbh. The increase in drag isn’t huge imo but the differnece in fatigue could be- tired = slow.
Don’t go with the lightest tyres- that’s Juggernaut Pros and they’re draggier than Jumbo Jims. There’s faster than JJs out there but mostly heavier. I used what I had and it worked well.