Universal Fatbike Parts: What Fits the V8, C80, V20, S20 (and Your MTB or E-bike)
Brake discs, bolts, wheel covers, pedals and cranksets — a practical guide to which parts are truly interchangeable across fatbike models like the Ouxi V8, C80, QMWheel V20 and S20, and where you actually need to double-check compatibility.
One big advantage of popular fatbikes like the Ouxi V8, Ouxi C80, QMWheel V20 and QMWheel S20 is that they share a lot of common parts under the hood — and those parts often fit standard mountain bikes and e-bikes too. That makes maintenance and upgrades a lot cheaper and easier, as long as you stick to the right sizes. Here's a rundown of the most commonly replaced parts.
Brake discs: almost always 160mm, 6-bolt
Most fatbikes — including the V8, C80, V20 and S20 — ship with a 160mm brake disc on a 6-bolt mount (44mm bolt circle). This is also the most widely used size on regular mountain bikes and e-bikes, which makes 160mm discs one of the most universal upgrade or replacement parts in this category.
- Diameter160 mm
- Mount6-bolt (44 mm bolt circle)
- MaterialStainless steel
- FitsOuxi V8, C80, H9, QMWheel V20/S20/V30, most MTBs & e-bikes
Brake disc bolts: the standard size is M5x10mm
The bolts that hold the brake disc to the hub are almost always M5 x 10mm — the standard size for 6-bolt disc mounts on fatbikes, mountain bikes and e-bikes alike. A set of 6 bolts covers one disc.
- Tighten the bolts in a criss-cross pattern (like tightening a wheel rim) for even clamping
- Use a bit of threadlocker (e.g. Loctite) so they don't vibrate loose over time
- Always replace damaged or rounded-off bolts as a full set
Wheel covers for 20-inch wheels
Wheel covers (spoke covers/rim covers) for 20-inch wheels are universal across any fatbike with a 20" wheel — including the V8, C80, V20 and S20 — as long as you match the correct wheel diameter. They protect the spokes, give a cleaner look, and can be fitted in minutes without removing the wheel.
Pedals: 9/16 inch is the universal standard
Virtually every adult bike — from city bikes to mountain bikes, e-bikes and fatbikes — uses the same pedal thread: 9/16 inch (14.2mm x 20 TPI). That makes pedals one of the most universal parts out there, and yes, that includes the V8, C80, V20 and S20.
Cranksets: check the bottom bracket interface first
Cranksets are the least universal part on this list. Regular mountain bikes and e-bikes typically use a square-taper (BSA/JIS) or splined bottom bracket interface, but many fatbikes — including the V8, C80 and V20 — actually use a diamond-shaped spindle interface instead. A crankset made for these fatbikes isn't automatically interchangeable with a generic MTB crankset.
- Always check your bottom bracket's interface type (square, splined, or diamond-shaped) before ordering a crankset
- Cranksets sold specifically for the V8 / C80 / V20 typically use the diamond-shaped interface, which is why they interchange between these models
- Not sure? Compare the shape of your current bottom bracket spindle to the new crankset's interface before fitting
Quick reference
| Part | Standard size | Universal? |
|---|---|---|
| Brake disc | 160mm, 6-bolt | Yes — check orientation |
| Disc bolts | M5 x 10mm | Yes |
| Wheel cover | 20-inch wheel | Yes — confirm wheel size |
| Pedal | 9/16 inch | Yes — mind L/R |
| Crankset | Diamond / square / splined | No — check interface first |
FAQ
Do V20 parts fit the C80 without modification?
For brake discs, bolts, wheel covers and pedals, generally yes — these parts use industry-standard sizes shared across the V8, C80, V20 and S20 (and most MTBs/e-bikes). Cranksets are the exception: compatibility depends on the bottom bracket interface, so always check that first.
How do I know if my brake disc is mounted the right way round?
Look for an arrow or text on the disc showing the rotational direction, and compare it to the direction your wheel actually spins when riding forward. A disc mounted backwards usually shows up as reduced braking power or a squealing noise.
Can I use regular mountain bike pedals on my fatbike?
Yes, as long as the pedal uses the standard 9/16 inch thread — which covers virtually every adult bike, fatbikes included. Just make sure you don't swap the left and right pedal.
Shop these parts
These parts are available through the FatCustoms shop.
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