I’ve got a pair of Revelation 426 U-turn forks that are knackered and I’m thinking of getting some rigid forks to replace them. Usually run them in 100mm mode and the axle to crown is 480mm, increasing to 510mm. Looking at the rigid forks out there, the forks with similar a2c are for 29er bikes, mine is a 26er.

Do I just need to buy forks with similar a2c lengths and that’s it? Or is there more to it?

Bear in mind that your suspension fork will sag, so the effective a2c measurement will be lower if you want to maintain the riding geometry you have now.

it depends on the frame to a degree. I used to run 29er forks on my 456 as they were roughly the same a-c as a set of 120mm rebas. On my more recent inbred i run 26″ correct forks. They are significantly shorter than the suspension forks I had (100mm).

The a-c on suspension is a compromise as it changes, rigid forks don’t change. I think they are generally shorter.

I’d say you need something around 440 mm or so. I swap riginds for sus forks on one of my bikes (100mm). the bike sits around 50 mm lower a the front with the rigids compared to with the sus fork

If you’re running 25% sag on your 100mm fork your actual a to c will be 455mm.

As above I used to run 29er rigid forks on my 456C.

445mm has been the most common rigid equivalent to 100mm forks on a 26er since the dawn of time. Doesn’t necessarily mean it’s right though…