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It’s a 2019 Raleigh E-Bike Detour

I have two of these bikes and could not figure out why shifting to high gears would get no response on first click then jump 2 on the next click.

Going to low gears was perfect.

Cleaned lubed lines. Same issue.

Finally I swapped derailleurs and the problem went with the derailleur.

So I’d like to go up a notch or two or 3.

It has a mega 9 lite shifter.

I don’t know the size of the cage but my guess is medium.

Difference in prices on derailers is peanuts.

But I want one that will just drop in.

Any suggestions?

How do I know what cage I have?

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    If not aiming at the lowest expense, without spending too much either, modern entry-level and mid-range components are not that expensive, and a derailleur/cassette/shifter/chain upgrade may be a better long term investment. The transmissions I'm thinking about are: Shimano CUES and Microshift Advent/Advent X. Acera was used in 2019 because it was a cheap derailleur and it was available, but it has not been designed for single chainring ebikes (same for the M592, released in 2009, modern single chainrings did not exist).
    – Rеnаud
    Commented Sep 2 at 14:05
  • Thanks for that tidbit. Good to know going forward. I looked up the CUES in the spread sheet I linked in my answer. They all have a 1.1 pull ratio. My setup is all 1.7. So I think I’d have to change out more things to properly switch to CUES
    – mswlogo
    Commented Sep 4 at 7:16
  • You will indeed need to change the shifter as well, as I mentioned, but it's not very expensive (30€ for a U6000 - Acera is equivalent to U4000). The pull ratio only matters if you want to mix up families of products, but a shifter/derailleur of the same family, they will work. The gain is a nicer shifter operation (less effort to shift, and the index shifter works in both directions, so you can use it with your thumb as well — important for me, because I like to keep the index on the brake), more accurate shifting, more durability. And it opens also the possibility of using larger cassettes
    – Rеnаud
    Commented Sep 4 at 7:56

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It looks long cage to me, any long cage Shimano 9speed will drop in. To know if a medium cage will work look at the Capacity specification for the derailleur and work out you drive train capacity (Largest chainring - smallest chainring, plus largest cassette cog - smallest cassette cog).

You could also consider other manufacturers - e.g. Microshift do a Shimano compatible 9 speed range, but probably easer to stick to Shimano or the choices get too much.

While going up to a better deraileur will never hurt, don't expect big differences, the derailleur is just one part of a complex system. When I have a replacement such as this, I shop for the biggest discount component that meets spec without getting silly on upgrade. Usuaully I can find a couple of grades higher at no (or small) premium over replacing like for like.

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I found this spreadsheet (below) which helped a ton. You are correct I think it is a long cage (SGS). So I ordered a Deore RD-M592-SGS which was $50 instead of $30. My time is the biggest cost.

The derailleur that was on there stopped working. I only want to avoid that happening again prematurely. Be thrilled if it works the same but just lasts longer. I also bought a Shimano optislick cable outer and inner.

I learned that matching the 1.7 pull ratio is the most critical to match. I also stayed with the same cage size, mtb and brand. That narrowed it down a lot.

I copied the file locally and used excel to do multiple filters at once. I couldn’t figure out how to do that on google sheets

https://docs.google.com/spreadsheets/d/16C3Rz6qmzmurSNd-L3IeMSFukkBFV6D1DRbfS59EDrE/edit#gid=847158527

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