I would like to custom build a crankset which would like the one I have on my ebike, but with more teeth. My current chainring is 52T, and I would like to go up to 58T. What I have is a four bolt, crankset, with two chain guards. Unfortunately, I am told that it is one piece, forged together somehow, and cannot be taken apart. So, I need to make one myself from parts found in ebay and aliexpress. What I was thinking was buying a 58T chainring, two chainguards, and a 130BCD crankset. Does this make sense? Would it all fit? Are chainrings all metal? Should I worry about plastik? Would it be about the thickness?

Why would I want one? My ebike reaches 30KMH, at which speed I am spinning out... I have 6 gear shimano, but with the motor, I never use anything but the highest gear. I would like at times go faster, pedal assisting the motor, so as to gain few KMH.

The objective is a relatively cheap speed + exercise combination.

I figured out the math that in adding 11.5% (58/52 - 1) to the number of teeth, I could be spinning out at 33 km/h. This is not very much, but it may be cost-effective vs the alternative of changing the motor and controller.

My rear wheel is 20", so the relatively large and not so common chainring does make sense.

enter image description here

  • 1
    1. Will a chainguard be as big as a 58t chainring? 2. Why do you need 2 chainguards? 3. A 58t chainring might interfere with the chainstay. 4. Apart from some very exotic carbon-fiber ones, chainrings are aluminum (or perhaps steel for very cheap ones). 5. It looks like you've got an integrated chainring/spider. Hard to say. It might be replaceable, but you'd need to know how it mates to the spindle to find a replacement.
    – Adam Rice
    Oct 14, 2021 at 20:15
  • I found a crankset on ebay, ebay.com/itm/… with 58T. My current has two guards, which seems to be the standard. I edited the question to explain why I would want one.
    – Yossi Gil
    Oct 14, 2021 at 20:30
  • "Spinning out" at 30km/h on a 54 chain ring. What's the wheel size and rear cluster sizes. A 58 won't make that much difference.
    – mattnz
    Oct 14, 2021 at 21:07
  • 1
    "ebay and aliexpress" your LBS will also be able to get parts that will work and will be far less likely to maim you Oct 14, 2021 at 21:42
  • Replacing your cassette might also be a much easier and cheaper option to consider Oct 14, 2021 at 21:43

1 Answer 1


The "two chainguards" is a cheap way of keeping your chain on and keeping clothes off the chain. You could use a narrow-wide chainring to assist in chain retention, and tuck your trouser cuff into your sock.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.