Starter Questions and Gear shifting problem

[maxitwist]

Hello ebike forum,

Ive installed a bbs02 mid drive on my trek 7x, heres some bits im not sure about that have popped up.

1) I needed to fit the chainring what looks like its is back to front, as there wasnt enough clearing on the frame to fit it the other way, is that ok? It has been running fine so far.

2) Some of my gears are unusable as the chain is not long enough to fit over them anymore with the bigger chainring, should i get a new longer chain?

3) NB - I am unable to change gears while the motor is engaged, just nothing happens when i try shifting gears. Do I need to buy the gear sensors to enable shifting through gears or is something wrong here? Are the gear sensors worth buying?

4) Because of being unable to change gears while riding, I set the bike to always be in the highest gear. Will this drain the battery faster?
b) How long should a 13ah battery last?
c) Will a larger battery increase the top speed as well as distance?

5) I live in a wet country, what should i be waterproofing ?
b) If im leaving the bike outside should i always cover the whole thing with a bike bag, should i disconnect the battery and take it with me.. etc

6) Is the programming cable worth getting?

7) The 6v headlight which came with the set doesnt seem to work, is that worth investigating or should i just get a proper one that doesnt need to connect to the motor.


Thanks for reading and if you can provide any help please do, Q3 is most important imo.

 

[dogman dan]

Definitely get a longer chain to start. Its possible this will fix it.

Ideally you would not run in the highest gear at all times. Starting on an uphill in too high a gear drains the battery more, and also can overheat the motor if you have enough of them. Like, a mile up a fairly steep hill with a stop sign every block.

But if you live where it's flat, and have few stops, less drain on the battery, and less heating the motor.

Last resort, switch to a primitive shift lever, non indexed, friction shifter like used in the 60's.

It should shift smoother if you are controlling the motor by throttle, and you can get off the power when you shift.

 

[simonov]

Could you or anyone else comment on why the OP would be unable to shift while using the motor? I never have any such difficulty with my mid-drive (not Bafang).

 

[E-HP]

Could you or anyone else comment on why the OP would be unable to shift while using the motor? I never have any such difficulty with my mid-drive (not Bafang).

I'm assuming the OP is shifting under load, with not enough chain, making it even more difficult. Nobody does that on a pedal bike, so even harder to do with three times leg power applied to the drive train by the motor. That's my guess. Shift sensors would help, but his forum name is "maxitwist" so maybe just not maxitwisting during shifting would solve that.

 

[dogman dan]

Fix the chain, and get off the throttle when shifting is my best guess still.

Hard to get more bike specific, when they won't even put up a link to what they have. Google doesn't seem to know what a 7x is. Seems to be an fx, and an ex7.

 

[E-HP]

Fix the chain, and get off the throttle when shifting is my best guess still.

Hard to get more bike specific, when they won't even put up a link to what they have. Google doesn't seem to know what a 7x is. Seems to be an fx, and an ex7.

A lot of bikes have small stock chainrings, so if the OP just swapped in a BBS02 with the standard chainring without using a new longer chain, that would cause issues. All guess work without more info, so might not ever know unless the OP circles back revisits the forum.

 

[maxitwist]

Sorry i guess our googles are giving us different results for trek 7x, its this bike https://www.trekbikes.com/ie/en_IE/bikes/mountain-bikes/cross-country-mountain-bikes/x-caliber/x-caliber-7/p/28062/

The chainring as listed here is 36T, and the bafang one is 44 or 42T, i think 44. So thats why I can barely get it to fit..
Ill be getting a new chain tomorrow and hopefully that might fix my gear shifting issue

 

[dogman dan]

Might have googled better if you said x caliber 7. But trek just has to have an x and a 7 in every bike name. Longer chain should make things better, though you might still need to tweak the rear derailleur adjustments to get it to run best.

 

[ilu]

You also said that you had to install the 44t chainring "back to front". If the chainring has normally offset towards the bike and by turning it around you increase the offset towards the other way, your chainline goes way too much outwards, as the motor itself already causes some disalignment. Thus you probably cannot get the lower gears to work properly. You might need to check out alternative smaller chainrings that fit the motor.

 

[maxitwist]

Yes I think that the chainline is too far out of line. Ill get a new chainring instead of a longer chain then.

Is there anything else i need to be looking for besides the size? will any chainring fit as long as its the correct size?