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Looking to get the right brake adapter but can't figure out which darn'd post mounts your fork and frame use? We've been there, so we compiled this database full of post mount specs for popular forks and frames our customers have been searching for.
Getting the right size brake adapter seems tricky at first, but it's very simple. Your brake adapter needs to take up the difference between your fork's post mount size and the rotor size. If your fork or frame has 180mm post mounts and you want to use a 200mm front rotor, then you need a 20mm brake adapter. Just subtract your post mount size from your rotor size to get your brake adapter size.
Rotor size - Post Mount size = Brake Adapter size
Just about every brake manufacturer makes their own brake adapter, and we recommend getting the same brand adapter as your brake caliper. While most calipers work with most brake adapters, use the same brand to guarantee compatibility.
32 and 32 Step-Cast
2017+
160mm
34
2018-2022
2022-2025
180mm
34 Step-Cast
2019-2025
36
2016-2025
38
2020+
40
2016+
203mm
Bomber DJBomber Z1
Bomber Z2
Bomber 58
Pike
2013-2016
Lyrik
ZEBDomain
200mm
Boxxer
2015+
RXF 34 m1RXF 34 m2RXC 34 m1
RXF 36RXF 36 EVORXF 36 m2RXF 36 m3
RXF 38 m1RXF 38 m2DH 38 m1
Diamond D1Diamond D2Diamond D3Diamond E2Diamond E3Sapphire D1
Onyx SC D1Onyx SC D2Onyx SC E1Diamond 36 D1
Onyx D1 38Onyx DC D1
MattocR8R7Circus Gen 3Junit 34MarkhorMachete
MezzerMastodon Gen 3
Dorado
Helm MKIHelm MKII
Durolux 36Auron 36
Durolux 38Rux 38 DH
Ribbon SLRibbon SL RallyRibbon LTRavenBartlett
Nine.One
It's complicated.
Supreme V5FRSMeta SX V5Meta V5Meta SX V4Meta AM V4Meta TR V4Meta Power SX 400
TempoTempo Power
Meta Power SX BsochMeta Power TR V4
RS180RS205
E-Troy LiteE-Troy BoschChainsawTroy 2025
Spartan HP 2022+Spartan (2019-2021)
Epocalypse (2022+)
Following (2020+)Offering (2021+)Insurgent (2022+)Wreckoninig (2020+)
Dreadnought V2Supernought
Druid V1Druid V2Dreadnought V1
Oso
HD6HD5Ripmo V3Ripmo V2Ripmo V1Ripley V5
ExieRipmo AF V1Ripmo AF V2Ripley AF V1Ripley AF V2Ripley V4
Chilcotin (2024+)Fugitive (2024+)Delirium (2024+)Warden (2024+)Endorphin (2023+)
Process 153 (2024+)Process 134 (2024+)Process X (2020+)Process 153 (2018-2023)
Process 134 (2018-2023)
Range (2022+)
Shore (2021+)Sight (2024+)Optic (2024+)Sight VLT (2025+)Sight VLT (2024)Sight VLT (2023)Fluid VLT (2024+)Range VLT (2024+)Range VLT (2023Sight (2020-2023)
Optic (2020-2023)
Wild (2023+)
Rallon (2018+)Occam (2020+)Wild (2020-2022)Rise (2021+)
Wild (2018-2019)
Nomad V6Megatower V2Bullit V1ValaHeckler SL V1V10 V7
Hightower V3, V4Bronson V4, V55010 V4, V5Tallboy V5Megatower V1
Blur V5Highball V4Tallboy V4
Stumpjumper 15
Stumpjumper EVO (2021-2024)Stumpjumper (2021-2024)Levo (2022+)Levo SL (2024+)Enduro (2020+)Kenevo SL (2021+)Demo (2020+)Status 160Status 140Status 2 170Status 2 140
TR11 V2Relay Alloy
SpirePatrol V3, V4Sentinel V2, V3Smuggler V2, V3Scout V2, V3Repeater EP8Repeater PTRelay Carbon
SpurSentinel V1Scout V1Patrol V1, V2Smuggler V1TR11 V1
Slash Gen 6Rail Gen 5
Fuel EX Gen 6Fuel EX Gen 5Slash Gen 5Rail Gen 2Rail Gen 3Rail Gen 4Fuel EXe
160ESB160SB165 (MX)SB165 (27.5)SB140 (29)SB140 (27.5)SB135 (27.5)SB 130/130LRSB120SB150
ASR
Tues MK4Decoy SN
Capra MK1, MK2, MK3Tuess Mk3Jeffsy MK2, MK3Decoy MK1, MK2
IzzoJeffsy MK1
*this database is a constant work in progress and is subject to change at any time.
Still have questions? Feel free to reach out to us at sales@thelostco.com or 360-306-8827 for further assistance.
The Post Mount Size for your fork is the minimum rotor size, and if you want to use a 180mm brake rotor on a fork with a 180mm post mount, you will not use a brake adapter. Just install the brake caliper directly on your fork.
Rotor size - Post Mount size = Brake Adatper size
Unfortunately, you will not be able to use a 200mm rotor. You will need to use either a 203mm rotor without an adapter or a 220mm rotor with a 17mm adapter.
The Post Mount Size of your fork is the minimum rotor size you can use, and most forks will work with all rotors up to 220mm perfectly. Step-Cast forks are a notable exception, and are not designed to be used with larger rotors.
Older frames and some modern steel frames use a different style of brake mount. IS stands for International Standard, and getting the right brake adapter for an IS system is very straightforward. To mount a 180mm rotor on a frame or fork that uses an IS mount, you need a IS to 180mm brake adapter. Don't overthink it, just get the IS to X brake adapter where X is your rotor size.
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