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Availability seems to be spotty, reviews are mixed and compatibility is also a bit of a lottery.
Proto
Legendary Member
- Location
- East Devon/West Dorset
Thread resurrection. I've just been through all this with my latest build. This is what I found.
Flat mount forks come in two flavours, one for 140 or 160mm rotors, the other 160 or 180mm. The former more likely to be found on road bikes, the latter on gravel or cyclocross bikes. Both need an adaptor to mount the calliper to the forks. The difference between the fork type being the distance from the lower mounting hole and the hub axle, the 'gravel' fork being greater at 32mm versus 23.5mm for a road fork.
The calliper has to be mounted with an adaptor plate, irrespective of the fork type (see above). The adaptor is basically a stepped spacer usually marked '140/160', sometimes '0/+20' and sometimes 140/160 &160/180. The adaptor mounted one way gives zero offset (apart from adaptor thickness). Inverted, the adaptor moves the calliper further away from the fork to allow fitting of a +20mm rotor.
So on a 'road' fork
140mm rotor needs an adaptor orientated with '0' offset or '140'
160mm rotor needs an adaptor orientated with '20' offset or '160'
On a 'gravel' fork
160mm rotor needs an adaptor orientated with '0' offset or '140'
180mm rotor needs an adaptor orientated with '20' offset or '160'
Note you cannot fit a 180mm rotor to a road fork (unless you have a bespoke adaptor, not freely available)
Flat mount forks come in two flavours, one for 140 or 160mm rotors, the other 160 or 180mm. The former more likely to be found on road bikes, the latter on gravel or cyclocross bikes. Both need an adaptor to mount the calliper to the forks. The difference between the fork type being the distance from the lower mounting hole and the hub axle, the 'gravel' fork being greater at 32mm versus 23.5mm for a road fork.
The calliper has to be mounted with an adaptor plate, irrespective of the fork type (see above). The adaptor is basically a stepped spacer usually marked '140/160', sometimes '0/+20' and sometimes 140/160 &160/180. The adaptor mounted one way gives zero offset (apart from adaptor thickness). Inverted, the adaptor moves the calliper further away from the fork to allow fitting of a +20mm rotor.
So on a 'road' fork
140mm rotor needs an adaptor orientated with '0' offset or '140'
160mm rotor needs an adaptor orientated with '20' offset or '160'
On a 'gravel' fork
160mm rotor needs an adaptor orientated with '0' offset or '140'
180mm rotor needs an adaptor orientated with '20' offset or '160'
Note you cannot fit a 180mm rotor to a road fork (unless you have a bespoke adaptor, not freely available)
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