What can I upgrade on my bike?
Seven places on a bike where a part can be changed, and the one measurement that decides whether each swap fits. Pick a number on the drawing. 191 curated parts sit on this map, every one with its fitment recorded from manufacturer specifications.
Tap a number. The fork is drawn as a straight crown-to-axle line; everything else is solved from the geometry above.
Cranks, bottom bracket & pedals
- Fitment turns on
- shell width, bore & thread
- Curated parts
- 30
Everything here hangs off the frame’s bottom bracket shell. Its width, its bore diameter and whether it is threaded decide which spindle you can run, and the spindle decides the crank. Get the shell wrong and nothing else in this group matters. Pedal threads are the one interface that is near-universal, at 9/16 inch on anything with a three-piece crank.
In the catalog: 10 cranksets · 10 pedals · 6 chainrings · 4 bottom brackets
Cassette, chain & shifting
- Fitment turns on
- freehub body, speeds, largest cog
- Curated parts
- 46
A cassette fits the freehub body on your rear hub, not the frame. HG, Micro Spline and XD are different splines, so moving between them needs a new hub or a new wheel — not an adapter. The derailleur then has to reach the largest cog and wrap enough chain for the range.
In the catalog: 16 rear derailleurs · 12 cassettes · 10 shifters · 8 chains
Wheels & tyres
- Fitment turns on
- axle standard, freehub, rim width
- Curated parts
- 41
Hub spacing and axle diameter have to match the frame at the back and the fork at the front. The freehub body on the rear wheel then decides your cassette choices, and the internal rim width decides which tyre widths sit at the right profile on it.
In the catalog: 10 front wheels & hubs · 10 rear wheels & hubs · 9 tires · 9 wheelsets · 3 tubeless kits
Brakes, rotors & pads
- Fitment turns on
- mount standard + rotor diameter
- Curated parts
- 29
The caliper mount on the frame and fork, together with the rotor diameter, decide which adapter you need and whether you need one at all. Pad compound is the cheapest change in this group and the one most riders never make.
In the catalog: 10 brake pads · 7 brake sets · 4 brake calipers · 4 brake rotors · 3 brake adapters · 1 brake levers
Seatpost, dropper & saddle
- Fitment turns on
- seat tube diameter + insertion depth
- Curated parts
- 25
Seat tube diameter is the hard gate. Insertion depth is the one that catches people out: a dropper with more travel than the frame can swallow will not go in far enough to sit at your riding height. Internal routing has to already exist in the frame.
In the catalog: 8 seatposts · 7 dropper posts · 7 saddles · 3 dropper remotes
Bar, stem & grips
- Fitment turns on
- clamp diameter
- Curated parts
- 6
Bar clamp diameter where the stem grips it, and grip diameter where your hands go. This is the least expensive group on the bike and the one that changes how it fits you the most.
In the catalog: 2 grips · 2 handlebars · 2 stems
Fork & headset
- Fitment turns on
- steerer shape + head tube bearings
- Curated parts
- 14
The steerer has to match the bearings your head tube takes. Axle-to-crown length then changes the head angle of the whole bike: fit a longer fork and every other number on this drawing moves with it, which is why this is the upgrade to think hardest about.
In the catalog: 8 headsets · 6 forks
Why the drawing is to scale
A bike is a closed linkage. Fix the head angle, the chainstay, the bottom bracket drop and the fork’s axle-to-crown length, and every remaining point is determined — which is why the 627 mm stack and 1135 mm wheelbase in the caption are calculated from the other numbers rather than typed in. That matters for more than looks: it is the reason a longer fork changes the head angle of the whole bike, and the reason hotspot 7 is the one to think hardest about.
The frame shown is a 29-inch trail hardtail in a middle size, the most common shape among the bikes people bring here. It is a diagram of that class rather than any one manufacturer’s chart — check the numbers against your own bike’s geometry table, which every brand publishes. A further 19 tools and consumables in the catalog have no place on the drawing; they are in the full catalog.
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