Things you didn't know about Crank for Ebike
Lynxcle-Tommy
Things you didn't know about Crank for Ebike
You're about to find out *why* your ebike crank is so confusing. This guide reveals the things you probably didn't know about your ebike's crank, from the real source of "creaking" to the surprising, old-school reason it might be stuck on your bike right now.
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Part 1: The Core of Your Drivetrain
Before we get to the secrets, let's cover the basics. The first thing you might not know is that crank arms for bikes aren't just "levers." They are a core part of your bike's fit, feel, and efficiency.
Size and Length
The most obvious choice is length, measured in millimeters (e.g., 165mm, 170mm, 175mm). This is a critical ergonomic choice. Shorter cranks can help you "spin" at a higher cadence and may reduce knee strain, while longer cranks offer a touch more leverage with each pedal stroke. "Size" also refers to the spindle interface—the axle standard (like Square Taper, DUB, or Hollowtech II) that must match your bike's bottom bracket.
Crank Types
Not all cranks are created equal. What works for a featherweight crank for road bike (where stiffness-to-weight ratio and aerodynamics are king) wouldn't survive a week on a downhill trail.
This is why finding the best crank for mountain bike and ebike is a different challenge.
FYI: Here's a key detail: E-bikes introduce massive, motor-assisted torque that demands extreme durability. This requires robust forged alloy materials and, most importantly, a secure, non-slip spindle interface to prevent the arms from loosening or being damaged.
Part 2: Tools & Maintenance (And the Secret Source of 'Creaks')
A silent bike is a happy bike. But a huge percentage of those mysterious 'creaks' and 'clicks' come from the crank area. Here’s what you might not know about proper maintenance and why "creaking" is rarely what you think it is.
1. The (Dreaded) Crank Puller
For anyone working on a bike from the 1970s through the early 2000s, this is the big one: the crank puller tool for bikes. As we'll see in Part 3, this tool was essential for physically "pulling" the crank arm off the bike's spindle.
2. The (Essential) Torque Wrench
If the puller was the most-feared tool of the 90s, the torque wrench for bike crank is the most important tool of today.
Pro Tip: Almost all modern "creaking" and "loosening" problems are not a part failure, but an installation error. A torque wrench is your best defense against creaks. Always use it to tighten bolts to the manufacturer's exact specification.
3. The (Unsung) Grease
Finally, the unsung hero: the right grease for bike crank.
The Secret: Here's another thing you didn't know: This isn't just lubrication. It's an assembly compound that serves three purposes: it blocks water, stops corrosion (metal-on-metal seizure), and eliminates the microscopic movements between parts (spindle, bolts, pedal threads) that are the true source of creaking.
Part 3: The Big Secret: Your Ebike Crank's History
So, why do we even have a tool as specific and brutal as a "crank puller"? Why did an entire generation of mechanics live in fear of it?
Here is the biggest thing you didn't know about your ebike crank: there's a good chance it's using 30-year-old technology. The answer lies in a painful, multi-decade history of design.
Gen 1: Cottered (~1900s-1970s)
The original system. A steel pin (the "cotter pin") was literally hammered through the crank arm and spindle to lock them together. Removal was just as brutal, often requiring a hammer and a sacrificial punch. see below video at 11years ago :
Gen 2 & 3: Square Taper & Splined (~1970s-2005)
This is the system that defined cycling for three decades. The crank arm was pressed onto a tapered (Square Taper) or splined (Octalink, ISIS) spindle. It was strong, but it had a fatal flaw: removal.
When it was time for a replacement crank for bike, you needed that special puller. The problem? The puller's steel threads had to grip soft aluminum threads on the crank arm. If the threads weren't perfectly clean or were just slightly damaged, the tool would strip the crank arm, leaving it permanently stuck.
The Pain Point: This is the secret: Many expensive, modern ebikes were built using this exact system. This is why, even today, modern, younger bike mechanics, when encountering these old-style cranks for the first time, often have to search online for "how to remove a crank without a puller"—a problem their daily work on modern bikes never prepared them for.
Gen 4: The Modern Solution (~2003-Today)
The frustration was so universal that it forced a complete revolution in design. Modern cranks, led by designs like Shimano's Hollowtech II and SRAM's Self-Extracting systems, finally solved this. This new technology was so effective it has been widely adopted by many brands across the industry.
How Gen 4 Solves Creaking & Maintenance
So, what does this new world look like? It means less time wrenching and more time riding, all thanks to two key innovations you can now look for.
1. No More Pullers
The puller is officially obsolete. Modern systems use one of two ingenious methods:
- Pinch-Bolt (Shimano-style): You simply loosen two side-bolts, pull out a small safety tab, and the arm slides off the spindle by hand.
- Self-Extracting (SRAM-style): The "puller" is cleverly built into the main crank bolt. You just use a hex key to unscrew it, and the bolt automatically "pushes" the arm off the spindle as it backs out.
The result is that daily maintenance and cleaning—once a high-risk shop job—are now incredibly simple. You can remove, clean, and re-grease your crank in minutes, not hours.
2. Solving Creaking
Creaking on older systems often came from the press-fit taper interface itself. Modern systems solve this with much stiffer, more secure splined interfaces and outboard bearings.
And this is the final thing you probably didn't know: 99% of modern "creaking" is not a design flaw. It is an installation error. It's solved by simply cleaning the parts and using the two tools we mentioned earlier: the correct grease to silence the parts, and the torque wrench to lock them in place at the perfect tension. The puller is dead. Long live the torque wrench.
Frequently Asked Questions (FAQ)
Why does my ebike crank keep creaking?
99% of modern "creaking" is not a design flaw. It's an installation error. The two most likely causes are: 1) The bolts were not tightened to the correct specification (use a torque wrench). 2) The metal-on-metal contact points (like the spindle or pedal threads) were not properly cleaned and assembled with grease.
What is a crank puller tool and do I need one?
A crank puller is a tool used to remove older-style cranks (like Square Taper or Octalink, Gen 2/3). It threads into the crank arm and "pushes" it off the spindle. You do not need this tool for most modern bikes (Gen 4). Modern cranks use "self-extracting" bolts or "pinch-bolts" that only require a standard hex key (Allen key) for removal.
What's better, a "pinch-bolt" or "self-extracting" crank?
Both are excellent, modern systems that eliminate the need for a puller. "Pinch-Bolt" (like Shimano Hollowtech II) is often considered the simplest to service. "Self-Extracting" (like SRAM DUB or the e*thirteen shown above) is also very simple, integrating the puller into the main bolt. Both are a huge upgrade over older systems.
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