48T or 52T chainring

[Mark Wermuth]

This is my first mid-drive build (BBS02 750W-with-48V 18650 Panasonic PF) going on a Trek Marlin 7 29er MTB.
I'm looking for a happy medium.
I want a quick take off and a high top end speed.
For top end speed I would want the 52T chainring. But if I want a quick take off torque I would go with the smaller.
44T chain ring. Where is the sweet spot? I plan to do more street riding (commuter) but may end up in some sand here in Florida. No hills....
Anyone?

[Galroc]

I am switching to the 46T from the 42T on the BBSHD to gain more speed, rather than more take off torque. I can gear down for more low end torque, but I am limited in top speed due to the 42T. Right now, I maintain 25 mph with a reasonable cadence, but I would rather be doing 27/28 mph on straights...

[Louis]

Taking off in 1st-3rd gear can be really hard on the BBS02 with 52T. You need to keep it at high RPM and use your gears.
Running a 52T will also increase the chances of over heating if you start taking off in those gears.
If I were riding in FL heat I'd add a temp gauge like Karl showed here.... https://electricbike-blog.com/2015/0...he-bbs02-unit/

Personally I'd run the 42T Lekkie or the 44T OEM.

I did run the 52T but found by watching the watts used that the 52T put a strain in the motor. Ride it like you would without the motor and run through the gears to top speed.

IMO anyone wanting more than 25MPH ought to run the BBSHD. Treat the BBS02 well and it's a great motor.

I think Karl runs 52T, and is happy with it, but I'm certain he uses the bikes gearing to get to top speed.

[Mark Wermuth]

You guys are awesome. Got it! You just saved me my first unnecessary expense.
I will be doing a lot of stopping and starting.
Thanks

[Arboh]

I am installing my first BBSHD. What is the best chain ring to use and why? I have the Luna 42 (not the Eclipse) and am wondering if I should swap for the Eclipse? What are the key differences?

[Arboh]

Clarification... I have the BBSHD chain ring adapter and the 42 tooth chain ring... the $50 unit.

[JPLabs]

I am installing my first BBSHD. What is the best chain ring to use and why? I have the Luna 42 (not the Eclipse) and am wondering if I should swap for the Eclipse? What are the key differences?

The Eclipse has more offset, so it moves the chainline further inboard. Not sure how far, several mm. That's good for bikes which need it, bikes with narrower rear dropouts. But, on wider bikes, the inset position of the Eclipse teeth may not work. An Eclipse won't fit my Motobecane Sturgis fat bike with 197mm rear dropout spacing; it hits the rear triangle just behind the bottom bracket. ( I modified it to fit, but that's not easy).

The Eclipse also has more aggressive tooth profile, which is great for not dropping the chain. The $50 42T adapter + chainring uses more traditional teeth.

Which is better for you will depend upon your own bike's geometry, and it's unfortunately not easy to predict. If your chain is too far outboard at the front, and you have room for the Eclipse, then the Eclipse would be a nice upgrade for you.

The dimensions are out there someplace, I just don't recall where....

[Louis]

Chainwheels compared.


http://electricbike.com/forum/forum/...heels-compared