A loose crank arm shows up first as a creak on every pedal stroke, then as wobble that makes climbing feel harder than it should. You notice it on a steep fire road, on a pump track session, or on the ride home when a worn bottom bracket starts grinding under load. Replacing the crankset and bottom bracket together solves that cluster of problems in one job, provided the length, bolt pattern, and shell width match the frame.
That match matters more than finish or color. BCD means bolt circle diameter, the measurement across the chainring bolts, and a 104mm pattern will not accept a ring drilled for a different spacing. Crank length changes leverage and ground clearance, while bottom bracket width determines whether the included spindle and cups fit a 68mm or 73mm shell.
A Fast Comparison Of The Options
BNVB Bike Crank Arm Set 170mm 104 BCD (Red)
MSRECK Bike Crank Arm Set 170mm 104 BCD (Colorful)
BUCKLOS 104 BCD Mountain Bike Crankset 170mm
DECKAS Bike Crank Arm Set 170mm 104 BCD (Colorful)
DECKAS 170mm Crankset 104BCD Round 32T Chainring (Black)
DECKAS 170mm Crankset 104BCD Oval 36T Chainring (Black)
Why These Options Stand Out
You get a complete replacement package here, with forged aluminum arms, a bottom bracket, four chainring bolts, a crank screw, and an Allen wrench in the box. That completeness helps a rider refreshing an older MTB or BMX without hunting for separate hardware. The red finish gives the build a clear visual identity, unlike the more muted options later in this list.
At about 675g, the set leans light for its category, and the hollow structure keeps material where strength matters most. A 170mm arm length suits average leg length and standard trail geometry, while the 104mm BCD leaves room for single, double, or triple rings. For most trail riders, that combination keeps pedaling leverage familiar after the swap.
Notable Upsides
- Full hardware kit reduces separate parts shopping
- Aluminum construction keeps rotating weight down
- 104mm BCD accepts a wide range of chainrings
- 170mm length matches common MTB geometry
Things To Consider
- Chainring itself is not included in this package
- Shell width must measure 68 to 73mm for fit
Compared with the BNVB set, this MSRECK package trims stated weight to about 615g, which matters on a bike that sees repeated climbing. The same 170mm arms and 104mm BCD keep the fit familiar, and the colorful finish sets it apart from plain black builds. It reads as a straightforward refresh for a rider who wants the drivetrain sorted without extra parts.
Compatibility lists Shimano, FSA, and Giant models including ATX770 and XTC 750, plus single and double chain setups. Depending on frame clearance, the included bottom bracket suits 68 to 73mm shells, and the 15mm crank screw is part of the package. That broad compatibility makes it a sensible match for older MTB frames still in regular rotation.
Everyday Advantages
- Lighter stated weight than the BNVB option
- Bottom bracket and bolts included for installation
- Works with single or double chainring setups
Worth Noting
- Chainring is not part of this package
- Colorful finish may not suit a understated build
Who It Suits Best
Riders refreshing an older MTB or BMX who want a light, complete crank and bottom bracket package.
Where Another Pick Suits Better
BUCKLOS 104 BCD Mountain Bike Crankset 170mm suits riders who want a chainring included for a single-speed setup.
This BUCKLOS set moves beyond arms alone by pairing them with a narrow-wide chainring, a tooth profile that grips the chain more securely on rough terrain. That design helps a single-speed rider keep the chain seated through bumps and quick direction changes. Unlike the first two picks, the chainring is part of the proposition, not a separate purchase.
You can match tooth count to terrain, with round or oval options from 30T to 38T in the listed range. The threaded bottom bracket fits 68 to 73mm shells, and the crank is listed at 550g before the ring. In our view, that combination favors riders converting a multi-gear bike into a simpler trail setup.
Features That Help
- Narrow-wide teeth improve chain retention on rough ground
- Multiple tooth counts allow gearing tailored to terrain
- Round and oval ring shapes cover different pedaling preferences
- CNC aluminum keeps the crank light at 550g
- Threaded bottom bracket simplifies installation for beginners
Trade Offs
- Single-speed focus limits multi-gear drivetrain use
- Tooth count choice needs care before ordering
The DECKAS crank uses 6061 alloy for the arms, a common choice for balancing weight and strength on road and MTB builds. A hollow spindle design trims material from the center, which helps on longer rides where rotating weight adds up. The colorful finish gives this version a distinct look compared with the black DECKAS kits that follow.
Hardware follows the same complete pattern as earlier picks, with bottom bracket, four bolts, crank screw, and Allen wrench included. For most backyards and garage workbenches, that means the job stays contained to a single package. The 104mm BCD and 68 to 73mm shell range keep compatibility broad across Shimano, FSA, and Giant frames named in the listing.
A Few Strong Suits
- 6061 alloy arms balance weight and strength
- Hollow spindle reduces unnecessary material
- Complete installation hardware in the box
Minor Gripes
- Chainring is not included with this version
- Steel ring material in related kits adds weight
- Shell width check remains essential before fitting
Your current setup gets simpler with this DECKAS kit, because a round 32T narrow-wide chainring rides in the same box as the arms and bottom bracket. That 32T size sits in a middle range for trail use, easing steep pitches without making flat sections feel spinny. It builds on the previous DECKAS crank by adding the ring that earlier version left out.
The hollow spindle and 6061 alloy arms carry over, along with the 104mm BCD and 170mm length. Assuming a standard threaded shell between 68 and 73mm, installation stays straightforward with the included bolts and wrench. The black finish keeps the build understated, a contrast to the colorful DECKAS option.
Positive Points
- Round 32T chainring included in the package
- Narrow-wide profile helps chain retention
- Black finish suits a clean, understated build
- Complete hardware set for a single-session swap
Room For Improvement
- Fixed 32T ring may not suit flatter terrain
- Steel chainring adds weight versus alloy alternatives
Made For
Riders converting to a single-speed trail setup who want a mid-range 32T ring included.
Consider Something Else When
DECKAS 170mm Crankset 104BCD Oval 36T Chainring (Black) suits riders who prefer oval ring shaping and a larger 36T gear.
An oval ring changes the pedaling feel in a way a round ring cannot, smoothing power through the top of the stroke and easing the dead spot at the bottom. This DECKAS kit pairs that oval 36T shape with the same 170mm 6061 alloy arms used in the round-ring version. The larger 36T gear favors flatter routes and stronger riders who want more top-end speed.
Unlike the BUCKLOS listing, tooth count here is fixed at 36T, so the choice is simpler but less flexible. The package still includes the bottom bracket, four bolts, crank screw, and Allen wrench for a complete swap. Depending on riding style, the oval shape may feel natural quickly or may take a few rides to appreciate.
Useful Touches
- Oval ring alters pedaling leverage through the stroke
- 36T size suits flatter terrain and stronger riders
- Complete hardware included with the crankset
Points To Note
- Fixed 36T ring offers no gearing flexibility
- Oval shape may feel unfamiliar at first
Key Factors Before Selecting Bmx Cranks
Crank Length And Fit
Crank length affects leverage, cadence, and clearance over obstacles. A 170mm arm fits most adults and standard frame geometry, while shorter arms help smaller riders and tighter trails. Measure leg length and check frame clearance before committing to a length.
BCD And Chainring Compatibility
BCD is the bolt circle diameter, measured across the chainring mounting bolts. A 104mm pattern accepts many single, double, and triple rings, but only rings drilled for that spacing. Confirm the pattern on the current ring before ordering a replacement crank.
Material And Weight Trade-Offs
Aluminum alloy keeps weight down, which matters on climbs and during repeated accelerations. Steel chainrings add durability at the cost of rotating mass. Riders focused on long climbs benefit from lighter arms, while riders prioritizing ring longevity may accept the extra weight.
Bottom Bracket Shell Width
Bottom bracket width must match the frame shell, commonly 68 to 73mm on the bikes covered here. A mismatch blocks installation entirely, regardless of crank quality. Measure the shell first, then match the included bottom bracket to that measurement.
Key Considerations Across These Picks
Common Shopping Slip Ups
A frequent mistake is matching color or finish before checking BCD and shell width. Another is assuming a crankset includes a chainring, when several kits here require a separate ring. Measuring the frame and reading the package contents prevents both problems.
What The Higher Tier Buys
Higher tier setups in this category often pair lighter alloy arms with a chainring shaped for chain retention, such as narrow-wide teeth. Oval rings and wider tooth count ranges add tuning options for terrain and rider strength. The upgrade pays off when a rider wants that tuning, not merely a fresh set of arms.
Frequently Asked Questions
What does 104 BCD mean on a crankset?
BCD stands for bolt circle diameter, the spacing across the chainring bolts. A 104mm BCD requires a chainring drilled for 104mm mounting. Checking that number prevents a ring that cannot bolt on.
Will a 170mm crank fit most bikes?
A 170mm arm fits most standard MTB, BMX, and road frames with 68 to 73mm shells. Rider height and frame clearance still matter for comfort and obstacle clearance. Measuring the shell and considering leg length gives a safer fit check.
Do these cranksets include a chainring?
Some kits include a narrow-wide chainring, while others supply only arms, bottom bracket, and bolts. The BUCKLOS and the two DECKAS ring kits include a ring, and the BNVB, MSRECK, and colorful DECKAS kits do not. Reading the package list confirms what arrives in the box.
What is a narrow-wide chainring?
Narrow-wide teeth alternate widths to grip a matching chain more securely. That grip helps reduce chain drops on rough, single-speed setups. It matters most on trails with bumps and quick direction changes.
Round or oval chainring, which suits trail riding?
Round rings deliver a familiar, even pedaling feel for most riders. Oval rings vary leverage through the stroke and suit riders who prefer that shaping. Terrain and rider strength guide the choice more than any universal rule.
Wrap Up
For a complete refresh on an existing frame, the BNVB and MSRECK kits cover the basics with hardware included. Riders moving to single-speed trail use gain more from the BUCKLOS set or the DECKAS ring kits, with tooth count and ring shape as the deciding factors. Measure the shell, confirm the BCD, and match the ring to the terrain ahead.