The need for a Chain Guide on a middrive? Is it required? Who uses one?

geosped

100 W
Joined
Mar 18, 2015
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Does anyone else have issues with chain popoffs? The chain pop offs used to be a real annoyance for me or at least they were. I thought I did everything right. I ensured I had a good chain line by using an offset chainring actually tried both the Lekkie and the Luna, I have a clutched derailleur, I'm using a narrow / wide chain ring, my chain is with in spec it's not too stretched all these things are to help prevent chain pop off's. It didn't happen all that often but one time it really got stuck and wound up making a mess of my nice Aluminum frame. Since then I put on a cheap Ali Express Chain Guide and I've yet to have a single pop off. Just wondering if anyone else is using a chain guide and or has had issues?


chain guide.jpg
 
geo, you might mention that you have that often wider than normal 68-73mm BB that most users are more familiar with..except of course on fat bikes. That really makes a difference, and I can see why you had problems. Nothing wrong with a good chainguide unless it's one of those that really drags on the chain to a point of unnecessary friction. Heck, even on most of my full suspension MTB's over the years...especially the long travel ones at and over 150mm...I fabricated an aluminum drop plate for my small chainring and used an MRP setup for the bigger chainring. I only ran two chainrings on these bikes. We didn't have the "pie plate" sized cassettes with more optimal gear choices back then...LOL! That's a nice, compact looking guide you have there. What kind of attachment to the downtube...or whatever...does it use?
 
TNC said:
geo, you might mention that you have that often wider than normal 68-73mm BB that most users are more familiar with except of course on fat bikes. That really makes a difference, and I can see why you had problems. Nothing wrong with a good chain guide unless it's one of those that really drags on the chain to a point of unnecessary friction. Heck, even on most of my full suspension MTB's over the years...especially the long travel ones at and over 150mm...I fabricated an aluminum drop plate for my small chainring and used an MRP setup for the bigger chainring. I only ran two chainrings on these bikes. We didn't have the "pie plate" sized cassettes with more optimal gear choices back then...LOL! That's a nice, compact looking guide you have there. What kind of attachment to the downtube...or whatever...does it use?

Sure your right this particular bike had a real chain-line alignment issue which was way off. Eye balling it the alignment with the chain ring was inline with the smallest cog on the rear cassette and not in the middle of the cassette where it should be. I also had to switch from the Lekkie 42T CR which has an offset of 18.3mm to a Luna Chain Ring which has an offset of 24.6mm I believe so considerable changes had to be dealt with. This particular bike has a 92mm PF Bottom Bracket and I used a lekkie extension kit to make my 68mm BBSHD mid drive fit. Better than replacing the entire unit and much easier to deal with than replacing the spindle.
So this bike I dont think is as conventional as I think a lot more people are looking to adapt an older type bike they have laying around in the garage looking to make new use out of it. Although on my other bike which had the same BBSHD kit albeit with the Lekkie Chain Ring and conventional threaded 68mm BB had the same issues with the occasional chain pop off's.

In any case a chain guide is cheap insurance and well worth it.
 
TNC said:
What kind of attachment design does it use?
It just attaches to the down tube with a wrap around clamp to a 4mm bolt. It works but I bought this for my other bike and when I sold it I just swapped it over. That little square bracket you can see in the pic is designed specifically for a chain guide and that's the kind I should get. But if you get the kind that attaches to the downtube make sure the welds are not In the way.

This might give you a better idea of what the clamp looks like
https://a.aliexpress.com/_mqlT4EN
 
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