Shimano RT-MT905 Front Rotor
What the checker says122will not fit3check before you buy64worth knowing
Run variant by variant through the mountain bike builder’s own engine. Every sentence below is the checker’s, unedited. Nothing here says this part fits your bike; it says what it does and does not fit among the parts we hold.
Checked against 5997 verified mountain bike parts in this catalog. 5820 produced no finding of any kind; that is RT-MT905 203mm (6-bolt). RT-MT905 180mm (6-bolt) clears 5778. Each variant produces 12 to 112 distinct errors and 0 to 3 distinct warnings.
Will not fit
- Will not fiterror · Front WheelFront rotor: a 6-bolt rotor does not mount on a Center Lock front hub as it is - the two use different rotor interfaces. The part that bridges them is a Center Lock adapter, and the ones makers publish fit one-piece rotors only. A shim or adapter may make other sizes or standards work, but that is a modification, not a fit. On 61 of the 270 verified front wheels in this catalog. Applies to all 2 variants.
- Will not fiterror · Front HubFront rotor: a 6-bolt rotor does not mount on a Center Lock front hub as it is - the two use different rotor interfaces. The part that bridges them is a Center Lock adapter, and the ones makers publish fit one-piece rotors only. A shim or adapter may make other sizes or standards work, but that is a modification, not a fit. On 16 of the 40 verified front hubs in this catalog. Applies to all 2 variants.
Front rotor min, Fork. 108 more findings from the same check, on up to 1 of the 490 verified forks each.
Front brake rotor max, Front Brake. 10 more findings from the same check, on up to 1 of the 92 verified brakes each.
Front brake rotor excluded, Front Brake. 2 more findings from the same check, on up to 1 of the 92 verified brakes each.
Open a variant in the builder to see the ones that apply to your own parts.
Check before you buy
- Check before you buywarning · ForkFront rotor: 203mm exceeds the fork max of 180mm. A post-mount adapter is the part that steps a caliper up to a bigger rotor, sold in the maker’s own discrete size steps (commonly +20mm, e.g. 160 to 180mm or 180 to 200mm) rather than for any gap - and not every step is offered for every caliper model, so check the maker’s own fitment before buying. On 31 of the 490 verified forks in this catalog. Applies to 1 of 2 variants.
- Check before you buywarning · ForkFront rotor: 203mm exceeds the fork max of 200mm. A post-mount adapter is the part that steps a caliper up to a bigger rotor, sold in the maker’s own discrete size steps (commonly +20mm, e.g. 160 to 180mm or 180 to 200mm) rather than for any gap - and not every step is offered for every caliper model, so check the maker’s own fitment before buying. On 22 of the 490 verified forks in this catalog. Applies to 1 of 2 variants.
- Check before you buywarning · ForkFront rotor: 203mm exceeds the fork max of 185mm. A post-mount adapter is the part that steps a caliper up to a bigger rotor, sold in the maker’s own discrete size steps (commonly +20mm, e.g. 160 to 180mm or 180 to 200mm) rather than for any gap - and not every step is offered for every caliper model, so check the maker’s own fitment before buying. On 5 of the 490 verified forks in this catalog. Applies to 1 of 2 variants.
Worth knowing
Front rotor interface unstated, Front Wheel. 58 more findings from the same check, on up to 1 of the 270 verified front wheels each.
Front rotor interface unstated, Front Hub. 6 more findings from the same check, on up to 1 of the 40 verified front hubs each.
Open a variant in the builder to see the ones that apply to your own parts.
$105.00 to $110.00 MSRP·147 to 187 g
What the maker states
- Size
- 180 mm rotor (on 1 of 2 variants); 203 mm rotor (on 1 of 2 variants)
- Mount
- 6-bolt
A value shown as a set or a range differs between this model’s variants and is never one variant’s spec.
2 verified variants
| Variant | Size | Price (MSRP) | Weight | Source | Last checked | Build |
|---|---|---|---|---|---|---|
| RT-MT905 180mm (6-bolt) | 180 mm rotor | $105.00 | 147 g | maker’s page | 2026-07-12 | Build with this |
| RT-MT905 203mm (6-bolt) | 203 mm rotor | $110.00 | 187 g | maker’s page | 2026-07-12 | Build with this |
The rest of what the maker states1 not published
1 further field the checker looks for is not published by Shimano, so we leave it blank rather than estimate it, and that check stays silent on this front rotor. It is thickness. Each is recorded as “not stated by the maker (not checked)”.
Source: each variant links the maker’s own page in the table above. Last checked 2026-07-12.
Checked against
The checker ran this model against every verified part below that it has a slot for, the same way it checks a build in the builder. What follows is the verdict it actually produced for that specific pairing — not a recommendation, and not a guarantee any of these parts fits your own bike.
- 5DEV R-SPEC Trail/Enduro Cranks (Crankset) No conflicts found
- 9point8 Fall Line (Dropper Post) No conflicts found
- 9point8 Stout (31.8, 30mm) (Stem) No conflicts found
- ACID SLX 30 front (Front Wheel) Will not fit
- ACID SLX 30 rear (Rear Wheel) No conflicts found
- Acros ZS44/ZS56 (Headset) No conflicts found
6 of 1861 counterparts with a page of their own that the checker actually probed this model against, in alphabetical order by brand and model — never by price, popularity or the verdict itself.