Some advice needed please...

[AJ_P]

I still only have one chainring as waiting for parts. However, it is a flat chainring on the inner position and I can acces all 7 of the rear sprockets. The largest is a bit of a stretch but I think I can improve it a bit by removing a 2mm BB spacer I think is unnecessary. I'll have 12-32t on the back and 34 and 42t on the front.

The outer chainring, once fitted will almost certainly not work on the biggest sprockets but not a problem.

I have ordered a triple FD (hopefully it will have more travel than a double) and with a bigger band diameter than my seat post. My plan is to 3d print an eccentric offset spacer to move the derailleur right a couple of mm. A better option may have been a direct mount derailleur with a direct mount band as it is very easy to make an offset spacer for these. I may also be able to do a sturmey and modify the band but hope to avoid the need for that.

The derailleur is coming from AliExpress so might take a couple of weeks.

My front derailleur is a triple so if I go down this route that's at least one thing I don't have to buy. I just bought the motor and battery for my own bike so I'm hoping to get going with the conversion soon. I have the bottom bracket stripped so with a bit of luck I will get some time to start on it.

I'm going to have trouble with the battery though. Even though it fits easily within the frame triangle on this one, the nutserts are too low down on the frame to suit it and I really don't think they're going to be up to the task of holding a very heavy 19.2ah battery in place. I'm thinking of making up some sort of steel bed for the battery once more but this time it will have a few round clamps welded to the underneath which can then be secured around the frame with some rubber strips inside for some protection and to assist in grip. I'm not sure yet what approach to take but I'll know better once I start working on it. Something like these might be an idea.

Just as an aside, does anyone know how to tell for sure that the two motors I bought are actually 750w and not one of the lesser models? There's no labelling, not that that could be relied upon anyway but I am very curious indeed given how much money I have spent!

All the best,

AJ

 

[pedalfettal]

Just as an aside, does anyone know how to tell for sure that the two motors I bought are actually 750w and not one of the lesser models? There's no labelling, not that that could be relied upon anyway but I am very curious indeed given how much money I have spent

There might be a label on the controller (remove motor cover to reveal). My 750w motor controller label starts 48v15a...

 

[Bogmonster666]

I have got a new FD now but neglected to buy the small chainring. However, I am confident it will all work. I bought a FD with a larger diameter band and 3d printed an eccentric insert that offsets the derailleur to the right by 3mm. I 'think' that the extra 3mm is going to be needed with the derailleur on full articulation. I know it's only 3mm but by sight I would say the 3mm is necessary on my bike. A 68mm BB shell would require a bit less reach but a 73mm shell might pose a problem with a derailleur mounted as originally intended?

I can get up a long 16% hill on my current 28t / 42t setup on tour. By my calculations a 25% on 32t / 34t should be achievable. 20% gradients will be no problem at all. Ideally 34t on the back would have been better but on 7 speed that probably 14t on the small end and that's too going to be too slow for me. Not sure I can justify upgrade to 8 speed.

 

[AJ_P]

There might be a label on the controller (remove motor cover to reveal). My 750w motor controller label starts 48v15a...

I bought it as a 48v 15a but I can't open the case without voiding the warranty. If that's the only way to be sure then I'll just have to take it on faith for the time being.

All the best,

AJ

 

[AJ_P]

I have got a new FD now but neglected to buy the small chainring. However, I am confident it will all work. I bought a FD with a larger diameter band and 3d printed an eccentric insert that offsets the derailleur to the right by 3mm. I 'think' that the extra 3mm is going to be needed with the derailleur on full articulation. I know it's only 3mm but by sight I would say the 3mm is necessary on my bike. A 68mm BB shell would require a bit less reach but a 73mm shell might pose a problem with a derailleur mounted as originally intended?

I can get up a long 16% hill on my current 28t / 42t setup on tour. By my calculations a 25% on 32t / 34t should be achievable. 20% gradients will be no problem at all. Ideally 34t on the back would have been better but on 7 speed that probably 14t on the small end and that's too going to be too slow for me. Not sure I can justify upgrade to 8 speed.

I have fitted the motor to my bike and in order to avoid touching the chainstay, I had to add just over 6mm of shims to get a sliver of clearance. I suspect that this will rule out a second chainring as I don't think the chain line is going to be ideal even for what I've got at the minute.

I'm going to fit the chain, hook up the derailleurs and route the gear cables which will actually squeeze nicely between the bottom bracket and the motor each in a little length of 4mm outer housing. I will then have a better idea as to whether or not I can access the eight gears with the motor set out so far. I expected my B'Twin Rockrider 520 bike being the same brand as my wife's would have presented a similar installation to hers but apparently not. If it doesn't work then I've got some head scratching to do. Maybe a new rear wheel fitted with a cassette with a smaller number of carefully chosen gears but spaced out from the wheelhub, or simply a different bike. We'll see shortly....

All the best,

AJ

 

[Bogmonster666]

I have fitted the motor to my bike and in order to avoid touching the chainstay, I had to add just over 6mm of shims to get a sliver of clearance. I suspect that this will rule out a second chainring as I don't think the chain line is going to be ideal even for what I've got at the minute.

I'm going to fit the chain, hook up the derailleurs and route the gear cables which will actually squeeze nicely between the bottom bracket and the motor each in a little length of 4mm outer housing. I will then have a better idea as to whether or not I can access the eight gears with the motor set out so far. I expected my B'Twin Rockrider 520 bike being the same brand as my wife's would have presented a similar installation to hers but apparently not. If it doesn't work then I've got some head scratching to do. Maybe a new rear wheel fitted with a cassette with a smaller number of carefully chosen gears but spaced out from the wheelhub, or simply a different bike. We'll see shortly....

All the best,

AJ

Hmm, 6mm of shims is a lot - guessing the chainstays must be quite wide. I concur that a double chainring feels like an unlikely option. You may find you can hit all the gears with the dished chainring at a stretch. All is not lost, the 42t dished chainring will get you up steep hills with an 8 speed cassette. I can get up all my regular hills with 28t / 42t.

I think the ideal tsdz2 bike is a hybrid with a 68mm shell and narrow chainstays rather than a modern MTB with wide chainstays.

 

[AJ_P]

Hmm, 6mm of shims is a lot - guessing the chainstays must be quite wide. I concur that a double chainring feels like an unlikely option. You may find you can hit all the gears with the dished chainring at a stretch. All is not lost, the 42t dished chainring will get you up steep hills with an 8 speed cassette. I can get up all my regular hills with 28t / 42t.

I think the ideal tsdz2 bike is a hybrid with a 68mm shell and narrow chainstays rather than a modern MTB with wide chainstays.

If I fit the motor in accordance with Tongsheng’s instructions which involves having the frame block bolt locked at it's lowermost position, one of the bolts that fits into projecting sections around the circular housing behind the chainring touches the chainstay. That requires 6mm of shim. However, if I rotate the motor backwards a little, I can avoid that issue and get away with 4mm.

Before I removed the triple chainring etc I took a few measurements from the seat tube to the teeth and found that the largest chainring was 30mm away. The TSDZ2 chainring is 40mm from tooth centre to seat tube. I simply cannot get it any closer by any more than about 0.5mm if I were to shave down one of the shims a little. The only other way of closing the gap so to speak would be to cut into the offending part of the frame. That would require a piece of solid aluminium being shaped to fit tightly and then have it all tig welded up. That’s a bit drastic though and I’m not sure if I want to do that to my bike.

Anyway, as for chainline, it is straight when on 7th gear which I assume is not preferable. I can however access all eight gears but I'm really not sure if the amount it deviates from straight when on 1st gear is actually too much. I'll have to fiddle with it some more, fine tune the derailleur etc and see how quiet it is, or not.

Does anyone know if the Bafang fits any better than these in terms of chainline etc?

All the best,

AJ

 

[Sturmey]

.........The only other way of closing the gap so to speak would be to cut into the offending part of the frame. That would require a piece of solid aluminium being shaped to fit tightly and then have it all tig welded up. That’s a bit drastic though and I’m not sure if I want to do that to my bike.

You could consider putting a small dent/dimple on the chainstay at the area in contact to get a few extra mm's. The guy on one of the original installation videos had a special tool for this but it could be done with a hammer and suitable shaped soft/wooden implement. (One of the advantages of fitting motors to an older/cheaper frame is that your not afraid of getting the hammer out).

 

[AJ_P]

You could consider putting a small dent/dimple on the chainstay at the area in contact to get a few extra mm's. The guy on one of the original installation videos had a special tool for this but it could be done with a hammer and suitable shaped soft/wooden implement. (One of the advantages of fitting motors to an older/cheaper frame is that your not afraid of getting the hammer out).

View attachment 52273

Hello Sturmey,

There already is a factory indentation on the frame there. With the motor in the correct orientation, the little projecting piece sits just within it but in order not to hit it, I have to shim by 6mm. Rotating the motor allows me to use only 4mm but the chainline still looks uncomfortable to my mind at least.

AJ

 

[Sturmey]

Hello Sturmey,

There already is a factory indentation on the frame there.......
AJ

I suppose the suggestion in the video is to increase the indentation. To what extent this is acceptable is another story.

 

[AJ_P]

I suppose the suggestion in the video is to increase the indentation. To what extent this is acceptable is another story.

Yes but in this case I'm not sure just how much deeper the indentation could be made without collapsing the aluminium chainstay. It certainly isn't going to give me what I would need but I do have some good news.

As I said before, rotating the motor downwards a little so the protruding screw section on the circular housing behind the chainring no longer fouls the chainstay has given me a little leeway. I have managed to get the shims necessary down to 3.5mm in total using the two 1.5mm shims in the the kit along with some 0.5mm plastic material I cut to suit. I can easily get a sheet of paper to slide in the gap.

This is not permanent as I have ordered some 0.1mm shims off Ebay and may even get it down a tiny little hair further. As it is, the chainline is pretty straight on gear 5 which given that I have an eight speed freehub or whatever it is called, isn't too bad. It's not perfect but it is pretty close to centre.

I suspect that chainline is rarely great on these mid drives as they sit out so far from the bottom bracket by necessity. I'll maybe post a photo later of what the chainline looks like on the lowest gear. I'm no expert so I really don't know what is acceptable.

However, this is about as good as it is going to get and I feel that if my present gearing doesn't suit my needs, then a new rear wheel with a modified cassette may well be the answer. It does appear to me anyway that it should be a viable option.

I'm making progress with it and I at least now know that I cannot improve it much more. The next issue involves mounting the heavy 19.2ah battery on the downtube. More welding methinks. By the way, what a disappointment the Hailong Max case is compared to the Hailong G70. The G70 has ample mounting points on a full length strip of metal whereas the Max uses a ridiculously short piece with only two bolt holes to hold a significantly heavier battery thereby leaving the majority of it unsupported by anything other than plastic. The mind boggles....

All the best,

AJ