Hi, i am thinking of going rigid on my commuter. It takes an 80 mm suspension fork.

Do i need a 420 mm rigid or a 440 mm or will it not make a great deal of difference?

Thanks

Depends on whether is an 'older 80mm' fork which typically have lower axle to crown heights- if thats the case go for 420 (though there's a decreasing number of 420 forks around)
a lot of current 80mm forks seem to have similar A to C heights as 100mm versions, so go for the 440 if that's the case.
Unless you want to steepen the HTA, lower the BB, on purpose.

The 80 mm fork i have been using is a Fox Terra-logic.

I've owned the forks for about 5 years so guess they are fairly old. Guess i will need a 420 mm rigid.

Anybody know anything about Exotic forks ?