Will a Mid-Drive Motor Fit Your Redline Bicycle? Click Here to Find Out (FULL COMPATIBILITY GUIDE)

Mandatory Toseven Hardware Directives

Before assessing individual Redline frame platforms, you must strictly adhere to three universal engineering constraints:

• First, Carbon Frame Torque Limits Carbon frames are highly susceptible to crushing failures under torsional motor loads. The Toseven DM01 motor produces 160Nm of torque and is strictly prohibited from being installed on any carbon Redline frame. Carbon conversions are limited entirely to the DM02 motor. When installing the DM02 on a carbon frame, you must use protective interface pads between the motor housing and the frame, the primary lockring torque must be strictly limited to 35 to 40Nm, and the secondary lockring must be strictly limited to 15Nm.
• Second, The DM02 Shift Sensor Exclusion The Toseven DM02 kit does not include a shift sensor. Riders utilizing the DM02 must shift gears manually. You must intentionally pause pedal input during derailleur actuation to unload the motor torque from the chain. Failure to do so will result in accelerated drivetrain wear or immediate chain failure under load.
• Third, Motor Sizing Must Match Your Frame’s BB Shell Width The Toseven DM01 and DM02 are available in 68mm, 73mm, and 100mm variants relevant to Redline frames in this guide. You must order the motor variant that precisely matches your frame’s BB shell width. Ordering the wrong size will produce an uncorrectable chainline error and prevent proper frame clamping. Measure your BB shell width face-to-face with a caliper before ordering.

Foundational Terms To Navigate This Guide

• BSA (British Standard Cycle / Euro Threaded) A traditional threaded bottom bracket shell featuring a 1.37-inch diameter with 24 threads per inch, yielding an inner diameter of approximately 33.6 to 33.9 millimeters. This is the optimal standard for Toseven motors and is found on all non-BMX adult Redline platforms.
• Press-Fit A threadless shell design where bearings or bearing cups are pressed directly into a smooth frame bore using mechanical force. Found on carbon Conquest variants and the D26 Dirt Jumper.
• American BB (Ashtabula) An oversized, smooth, threadless BMX shell with a 51.3mm internal diameter. Found on vintage Redline cruisers and entry-level platforms. Not compatible with mid-drive motors under any standard installation protocol.
• MID BB The most common modern BMX standard. Smooth, threadless, approximately 41.275mm internal diameter. Found on most Redline race and freestyle BMX frames. Not compatible.
• Spanish BB A lighter BMX press-fit standard with a 37mm internal diameter. Found on select Redline BMX frames. Not compatible — the 1.75mm of clearance per side between the motor axle and shell is physically insufficient for any adapter.
• PF30 A press-fit standard used on the carbon Conquest Pro, Expert, and Elite. Features a 68mm wide shell with a 46mm internal bore. Requires PF46-to-BSA reducer bushings.
• BB86 / PF41 A press-fit standard used on the Redline Flight Carbon. Features an 86.5mm wide shell with a 41mm internal bore. Requires PF41-to-BSA reducer bushings and the 100mm motor axle variant.
• Mid-To-BSA Adapter Purpose-built pressed cups that convert the D26’s 41.2mm Mid BB bore to a BSA threaded interface. Requires Loctite 638 or 680 retaining compound for safe installation under motor torque.

What Is a Chainline?

Chainline refers to the distance measured in millimeters from the exact longitudinal centerline of your bicycle frame to the centerline of your front chainring teeth. For your drivetrain to function properly, the front chainring must align with the center of the rear cassette. Think of it like a train track — if the rails are not straight and parallel, the train derails. On a bicycle, a misaligned chain creates diagonal friction. Under the 160Nm of the DM01 or the 90Nm of the DM02, that diagonal friction becomes a catastrophic chain drop. Mid-drive motors naturally push the chainring outward. The raw, uncorrected chainline of a Toseven 68mm motor sits at approximately 59mm from the frame centerline. Left uncorrected, this produces severe cross-chaining in the larger cogs and immediate chain drops under motor torque.

Boost Versus Non-Boost Spacing

All compatible non-BMX Redline frames in this guide use either 130mm or 135mm rear axle spacing — none use modern Boost 148mm spacing. The target front chainline for these frames is 43.5mm to 49mm depending on rear spacing, making the 59mm raw motor chainline approximately 10 to 15mm outboard of ideal before correction.

The Offset Chainring Solution

Offset chainrings move the tooth profile inward toward the frame, reducing the raw chainline figure. Toseven provides 0mm, 3mm, 6mm, and 9mm offset options. The corrected chainline for each offset on all compatible Redline frames using the 68mm motor variant is:

9mm Offset — Platform-Specific Results

• Monocog 29er and D440/D460 (135mm rear spacing) 50mm corrected chainline sits 1 to 2mm outboard of ideal. Near-perfect alignment. Best shifting performance of any Redline platform in this guide.
• Metro Classic, Metro Sport, R-series, Urbis, PL-26, SQB-26, RL-275 (130mm rear spacing) 50mm corrected chainline sits approximately 5 to 6mm outboard of the ideal cassette center. Shifting across the middle of the cassette will be smooth. The largest cogs will show a slight diagonal chain angle — acceptable for commuting, not ideal for performance road use.
• Conquest Alloy (130mm rear spacing) Same 5 to 6mm outboard result as above.
• Zander (135mm rear spacing) Near-perfect alignment matching the Monocog.

DM01 Casing Clearance Warning

The DM01 motor houses heavy-duty primary reduction gears for its 160Nm output and has a significantly larger motor casing than the DM02. On compact frames — particularly the PL-26, RL-275, and SQB-26 with their wide BMX-style chainstays — a 9mm offset chainring may cause the chainring teeth to contact the motor casing or chainstay. You must always test-fit before final tightening. If the 9mm offset causes interference, step down to the 6mm offset and verify chainline is still acceptable before proceeding.

Why Bad Chainline Is Dangerous Under Motor Torque

On a standard pedal-powered bicycle, a slightly misaligned chainline produces grinding noise and accelerated wear. Under Toseven motor torque those same conditions become critical failures:

• Poor Efficiency The battery drains rapidly as the motor fights diagonal chain friction.
• Gear Skipping The chain skips violently over cassette teeth under load, producing dangerous loss of traction.
• Accelerated Wear Diagonal friction destroys the cassette, chainring, and chain within weeks.
• Chain Derailment Under Torque On a steep climb, the motor torque stretches the chain sideways until it snaps or derails, leaving the rider instantly without power or pedal resistance.

DM01 Vs. DM02 — The Shift Sensor Rule

• Toseven DM01 (160Nm) Includes a mandatory integrated shift sensor. This electronic sensor instantaneously cuts motor power when it detects gear shifter movement, allowing the chain to move to the next gear cleanly before reapplying torque. Shifting behavior is automatic and seamless.
• Toseven DM02 (90Nm) Does NOT include a shift sensor. You, the rider, must act as the shift sensor. The protocol is: pause pedaling — click the shifter — allow the chain to seat — resume pedaling. If you shift while the DM02 is under load, the chain will bind and break. This is not a malfunction — it is a fundamental characteristic of the DM02 that must be understood and respected before the first ride.