Chain ring too close to frame

[jfny1978]

I am installing my Bafang Mid-Drive Kit on my Trek Marlin 5, and it's going ok enough so far. One issue is that the chain ring is way too close to my frame for comfort.

I really wanted the larger 52T ring for torque.

The question is...should I order a new smaller chain ring, or would it be safe enough to just get a few washers to use as spacers to get the chain ring a few MM further out from the motor?

 

[JES2020]

Either way I suppose.
You may need to "adjust" the cassette with some washers too.

 

[Headdamage]

Three options that come to mind for me are shimming the whole motor to the right, using a different chain wheel, or spacing the chain wheel to the right.

 

[jfny1978]

Three options that come to mind for me are shimming the whole motor to the right, using a different chain wheel, or spacing the chain wheel to the right.

Thank you. I definitely don't have space on a 73 mm bottom bracket to move the motor any further to the right. I just am trying to figure out if I am risking my safety at all by doing some spacing.

 

[jfny1978]

Either way I suppose.
You may need to "adjust" the cassette with some washers too.

Thanks. I like the spacer idea because I don't have to wait for new parts, but not sure if it's the safest idea.

 

[JES2020]

Thanks. I like the spacer idea because I don't have to wait for new parts, but not sure if it's the safest idea.

Do the spacers until you get the new chain ring.
I don't know what kind of danger there would be using spacers , but if it worries you...Do the spacers until you get the new chain ring.

 

[jfny1978]

Do the spacers until you get the new chain ring.
I don't know what kind of danger there would be using spacers , but if it worries you...Do the spacers until you get the new chain ring.

Haha. Thank you. I like your attitude.

 

[tomjasz]

I really wanted the larger 52T ring for torque.

I'd use a 42T. Unless you have a BBSHD a 52T is a poor choice in my experience.

 

[Headdamage]

I'm using the 42T bling ring myself but I have no idea if that will fit your bike. As for the spacer the only problem is if the screws are too short, if they are just get some longer ones.

 

[jfny1978]

I'd use a 42T. Unless you have a BBSHD a 52T is a poor choice in my experience.

Thank you. I did always assume I might end up switching chain rings at some point. I just never thought I'd buy one that wasn't sized right for my bike. But I guess that's how I learn. Trial by fire.

 

[jfny1978]

I'm using the 42T bling ring myself but I have no idea if that will fit your bike. As for the spacer the only problem is if the screws are too short, if they are just get some longer ones.

Thank you. Yeah I will need longer screws and some spacers. I live near a Fastenal. I will bring in the existing motor, chain ring, and screws. The guys in there live for helping figure out stuff like this.

 

[tomjasz]

Fastenal

I live near there corporate headquarters. Great resource!

 

[JES2020]

Wouldn't get a smaller ring for torque?

Correct, I'm gona go from 42 t to 48 t for more speed, so I can help pedal at 25 mph, maybe 31 mph.

 

[jfny1978]

I just discovered that buying appropriate spacers isn't as easy as I imagined. I ordered a Bling Ring and will have to wait a few days. I'll try to practice patience!

 

[PedalUma]

This is a real problem with boost spacing and wide chainstays. If you use the spacers you will likely drop the chain when shifting to the largest cog of the cassette. You could use a chain guide or repurpose a front derailleur to help protect the frame.

 

[tomjasz]

You might mess up the chain line though?

https://bike.bikegremlin.com/wp-content/uploads/2017/01/good-vs-bad-chainline_dobra_i_losa_linija_lanca2.jpg

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[Gionnirocket]

What's your actual space between the chainring and chain_stay? Is your rear solid?
If it's not touching and you have a few mm I don't think it a problem.
Chainline is just as important, how's that now?
fyi.. The Bling Ring I believe has a total of 9mm of offset towards the frame which is 5mm more than the stock Bafang Chainring which is 4mm

 

[jfny1978]

What's your actual space between the chainring and chain_stay? Is your rear solid?
If it's not touching and you have a few mm I don't think it a problem.
Chainline is just as important, how's that now?
fyi.. The Bling Ring I believe has a total of 9mm of offset towards the frame which is 5mm more than the stock Bafang Chainring which is 4mm

When everything was tightened it was touching. I emailed California Ebikes and they recommended a 42T chainring so I ordered that. I think I will be happy.

 

[PedalUma]

When everything was tightened it was touching. I emailed California Ebikes and they recommended a 42T chainring so I ordered that. I think I will be happy.

What size, outer diameter tires do you have? And can you fit larger? The reason I ask is that if you can fit larger tires this will have the affect of a larger chainring.
The 42-T Bling Ring does not pull in the chain line as much as the 48. This is good because it is less likely to rub but you still may loose the lowest gear in the rear. That is okay also, because you will have plenty of power on tap.

 

[Gionnirocket]

When everything was tightened it was touching. I emailed California Ebikes and they recommended a 42T chainring so I ordered that. I think I will be happy.

Well touching is a bit more than too close
Just keep in mind that you may still need spacers as the offset on the Bing ring is more than twice that of the stock chain ring.
I believe California eBike has them if need be in roughly 1mm thickness.
Good luck and post some pics once you get it rolling

edit.. Just looking at the Marin 5 pics... The stock ring looks as close as your photo.