Marin Muirwoods + TSDZ2, which chainring?

[skestans]

Hi all,

Very happy with my muirwoods and TSDZ2 along with the open source firmware. Been riding for 7 years now with a 52V battery.

I’m doing a serious service of the bike now, taking everything apart to clean/lubricate, replace worn parts etc.

And so I’m considering replacing the chainring. It’s the stock one with 42T, and with this I could never go past the 6th gear out of 9. It’s just too hard. One of the screws in the spider is seized and corroded and won’t come out so I’ll have to replace the spider anyway. Was thinking of getting a 104 BCD adapter to have a more standard setup and get less teeth on the chainring.

Cassette is 12–36T with 29” wheels. Assist cuts off after 25kph (I used to have it unrestricted to 45–50kph but that was too dangerous and illegal so I put the limit back).

How many teeth do you reckon I should get? What about clearance with the motor’s body and the chain line? I’m a little lost and don’t know how to choose.

Thanks!

 

[E-HP]

Cassette is 12–36T with 29” wheels. Assist cuts off after 25kph (I used to have it unrestricted to 45–50kph but that was too dangerous and illegal so I put the limit back).

How many teeth do you reckon I should get? What about clearance with the motor’s body and the chain line? I’m a little lost and don’t know how to choose.

Thanks!
[/QUOTE]

Which adapter are you planning on using? If you’re going with a smaller chainring, it’s less likely that you’ll have clearance issues, if the adapter has the same offset. Different adapters have different offsets, so selecting the one that gives you the best chainline is the main concern.

 

[skestans]

I don’t know which adapter I’m getting. The offset is how dished in it is inwards/towards the frame? How offset is stock, 2mm?

 

[Nomadstealth]

If only one of the screws in the spider is seized and corroded I'd recommend a bit of perseverance in getting it out . If it was all five that would be a different story . There's no real gain in changing the spider when 110BCD narrow wide chainrings are readily available . I'd go with a 36T or 38T Deckas for 29" wheels . You'll lose the original offset a bit but if you're mainly using the middle sprockets of the cassette it shouldn't be too bad (every bike is different) .

 

[skestans]

If only one of the screws in the spider is seized and corroded I'd recommend a bit of perseverance in getting it out . If it was all five that would be a different story . There's no real gain in changing the spider when 110BCD narrow wide chainrings are readily available . I'd go with a 36T or 38T Deckas for 29" wheels . You'll lose the original offset a bit but if you're mainly using the middle sprockets of the cassette it shouldn't be too bad (every bike is different) .
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Thanks. Would you have recommendation on how to persist? I could grab the less corroded one with pliers in the back but the more corroded one would just slip and slip and now the edge is not a flat surface anymore: it’s rounded from the pliers ripping so there is no leverage to be had there anymore. And I can’t use the grooves because I only have an 8 screwdriver when this seems to require a 10 or 12 (but would the tip be too thick wouldn’t it?)

 

[Nomadstealth]

Thanks. Would you have recommendation on how to persist? I could grab the less corroded one with pliers in the back but the more corroded one would just slip and slip and now the edge is not a flat surface anymore: it’s rounded from the pliers ripping so there is no leverage to be had there anymore. And I can’t use the grooves because I only have an 8 screwdriver when this seems to require a 10 or 12 (but would the tip be too thick wouldn’t it?)

The last really stuck one I had I looked around for anything metal that was the correct width and thickness . It ended up being a right angle bracket . I held that with some vice grips and pushed into the slot with one hand and used the Allen key with the other . A good soak with some penetrating oil can help as well . If all else fails a drill is the last resort .

 

[Nomadstealth]

I still use that little metal bracket for tightening chainring bolts that slip !

 

[Zambam]

I’m doing a serious service of the bike now, taking everything apart to clean/lubricate, replace worn parts etc.

How many miles on your TSDZ2? I was thinking of taking mine apart last winter to service it but have not done so because there was no serious issues and I didn’t want down time on the bike.

Try heating/ cooling the corroded screw with a small butane torch?

 

[E-HP]

And so I’m considering replacing the chainring. It’s the stock one with 42T, and with this I could never go past the 6th gear out of 9. It’s just too hard.

I don’t know which adapter I’m getting. The offset is how dished in it is inwards/towards the frame? How offset is stock, 2mm?

I’m not sure I know what you are trying to achieve. Are you going with a smaller chainring in order to be able to ride past 6th gear with leases pedaling effort, or are you steering it up to utilize the lower gears, and have even lower gearing for hills, etc.? If the existing chainline allows you to access all gears, would that be you goal with the smaller chainring, or do you want the chainline to work better/best for higher or lower gears? My only point is offset matters for getting the chainline that will work for your riding, so something to consider when buying and aftermarket spider.

 

[skestans]

How many miles on your TSDZ2? I was thinking of taking mine apart last winter to service it but have not done so because there was no serious issues and I didn’t want down time on the bike.

Try heating/ cooling the corroded screw with a small butane torch?

It has 3500 km but I rode in harsher conditions (salty winter), and there was some rust I needed to address at the contact points with the motor.

 

[skestans]

I’m not sure I know what you are trying to achieve. Are you going with a smaller chainring in order to be able to ride past 6th gear with leases pedaling effort, or are you steering it up to utilize the lower gears, and have even lower gearing for hills, etc.? If the existing chainline allows you to access all gears, would that be you goal with the smaller chainring, or do you want the chainline to work better/best for higher or lower gears? My only point is offset matters for getting the chainline that will work for your riding, so something to consider when buying and aftermarket spider.

Yes I’m trying to make the high gears less hard so that I can actually use them. The chain line isn’t the worst at the moment, it’s more of a gear ratio thing.

 

[Zambam]

It has 3500 km but I rode in harsher conditions (salty winter), and there was some rust I needed to address at the contact points with the motor.

My TSDZ2 with zero miles was put into service (after replacing the broken case) in May 2024. Currently @ 4533 miles (7295 km). I do not ride in rain or snow. Kept indoors so no corrosion issues. At this point I think I will keep riding it till something serious goes wrong, then swap in my spare Varstrom TSDZ2B (still in the box), before opening it up.

Please take pics when you have your motor apart.

 

[skestans]

My TSDZ2 with zero miles was put into service (after replacing the broken case) in May 2024. Currently @ 4533 miles (7295 km). I do not ride in rain or snow. Kept indoors so no corrosion issues. At this point I think I will keep riding it till something serious goes wrong, then swap in my spare Varstrom TSDZ2B (still in the box), before opening it up.

Please take pics when you have your motor apart.

I’ve already serviced it and closed it back. There was nothing to show, the main gear was fine all I did there was put some fresh ptfe grease and cleaned the white seal around the edge: a bit of grime made it to the seal but not inside the motor. Would probably be fine without that as none of it made it past the seal and into the gear chamber.

What did rust a little was the flat metal parts that goes around the bottom bracket shaft and screws into the motor. I had to brush this to remove the rust and paint it with frameto rust converter. The silver ring that goes over that part also had a bit of rust but I’m not sure if it’s this part that rusted (I though it was aluminum), or if it’s from another part that “dripped” rust on it. Same for the flat “piece of candy” metal bit that goes in the rear triangle and keeps the motor from rotating when it’s running.

The rest was maintenance to the bicycle itself, not the motor. There was pitting in the paint from the motor where you’d expect, at the contact points with the “piece of candy” and underneath it, from the rotational force being applied by the motor there.