Doesn't sound any nerdier than researching anything else bicycle-related (they are all expensive kids' toys we ride in the woods), and you're far from the only person who is rigid curious - hence it making my Best-Of-2021!
Boost spacing is a must for most folks if they're going to be going back and forth between rigid and a suspension fork or trying to swap wheels between bikes, so that's a good eye.
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Wolf Tooth does a [**ZS56 headset cup extender**](https://www.wolftoothcomponents.com/products/wolf-tooth-lower-headset-cup-extender-zs-zero-stack) that may help if you're running a ZS44/56 headtube. It adds a centimeter. On a budget, if you tuck your head into any local Rocky Mountain dealer they can probably hook you up with a great deal on a lower cup as all the Instinct/Pipeline [**front triangles**](https://ca.bikes.com/pages/recall) they swapped came with them. The RMB lower cup fits an FSA Orbit NO.57E bearing (MR019 I believe).
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Niner's last-generation steel rigid fork w/ thru-axle was 490mm A-to-C. I think it's the longest I've come across in a stock steel option. The new Unit forks come up from time to time as take-offs but they're only 470mm A-to-C.
Dec. 27, 2021, 5:11 p.m. - Andrew Major
Doesn't sound any nerdier than researching anything else bicycle-related (they are all expensive kids' toys we ride in the woods), and you're far from the only person who is rigid curious - hence it making my Best-Of-2021! Boost spacing is a must for most folks if they're going to be going back and forth between rigid and a suspension fork or trying to swap wheels between bikes, so that's a good eye. ... Wolf Tooth does a [**ZS56 headset cup extender**](https://www.wolftoothcomponents.com/products/wolf-tooth-lower-headset-cup-extender-zs-zero-stack) that may help if you're running a ZS44/56 headtube. It adds a centimeter. On a budget, if you tuck your head into any local Rocky Mountain dealer they can probably hook you up with a great deal on a lower cup as all the Instinct/Pipeline [**front triangles**](https://ca.bikes.com/pages/recall) they swapped came with them. The RMB lower cup fits an FSA Orbit NO.57E bearing (MR019 I believe). ... Niner's last-generation steel rigid fork w/ thru-axle was 490mm A-to-C. I think it's the longest I've come across in a stock steel option. The new Unit forks come up from time to time as take-offs but they're only 470mm A-to-C.