Rigid fork upgrade
 

I have a sun tour xct 100mm 27.5” suspension fork that I would like to upgrade to a rigid fork. Says my axle to crown for the suspension fork is 497mm. Finding a straight steer fork in that length is challenging. I have found several forks with axle to crown of 470mm. I’m primarily going to gravel ride. Will 470mm allow for comfortable riding? Thank you

Don't forget that your suspension fork sags somewhat when you are on the bike.

will 470mm be okay when accounting for sag? I feel like it’s currently to high so being lowered wouldn’t bother me. Thank you

Before sweating details, get the correct axle to crown measurement.

Measure the fork yourself with the bike leaning on the wall.

Next account for sag by wrapping a pipe cleaner, cable tie, or similar around the stanchion, then sitting on the bike. Sag will push the wrap up and it will stay there. Get off, measure how far it moved, and subtract that from the unloaded length to get the sagged length.

Once you know the sagged length, you can make smart decisions regarding the replacement. IMO dropping an inch or less probably won't cause issues, especially if the rake is increased. However, combining drop with reduced rake may cause some handling issues. On the bright side, gravel riding is less sensitive to steering issues than on the road.

a 470mm fork will fit fine... i've done a few such conversions... 27mm is a bit over an inch. and that approximates the fork when it compresses as you sit on the bike, if it was set up with the correct preload, or "sag".

your bike will be two to three pounds lighter, and you will waste less energy on fork bouncing when you pedal.