TSDZ2 - advice please

[Charlie1]

Hi,

I have just converted an old giant terrago mtb into an ebike using a TSDZ2 500w motor and 48v yosepower battery. It works fine, but I'm having problems with the rear gears/cassette. I have an 8 speed rear cassette or freewheel, but can only uses 4 of the rear cogs/gears without the chain coming off on the front. Is this normal? I am I being too hopeful expecting to get all 8 gears? Any advice on the best set-up or number of gears/cogs (i.e would a 5/6 speed be more appropriate). Thanks for your advice and comments.

 

[Nealh]

Obviously chain line is way out, a freewheel will have a worse chainline then a cassette. A chain keep or old derailleur might help or one could think about converting the tsdz with a double chainwheel to use all the gears better. They aren't to dissimilar to BBS and these are quite easy to convert to double chainwheel.

 

[Charlie1]

Thanks Nealh, I will have a play with the chain line and see if I can improve it, if not I will put the front derailleur back on. I am pleased to hear I should be able to select all 8 gears. If I cant improve the chain line I will try setting it up on another one of my old bikes!

 

[Sturmey]

Hi. I was able to dismantle the freewheel cluster and re-arrange the cogs. I now only use the 14,16,19,24 & 34 (at 4.8mm c/c spacing) moved to the outside to reduce chain crossover. I have 44/34 on the front. (36v Tsdz2)
I also re-spaced the axle with washers (and a little re-dishing to re-center wheel afterwards) to get the cluster as far outwards as possible.

How to rework rear sprockets for mid drive systems... - Electricbike.com Ebike Forum

UPDATE: We now have a video showing this. Highly recommended if using gearclamps as shown in video to use both of them to hold cassette in position https://youtu.be/1WBMpZv-pqE Here’s a photo show and tell about the wonderful rear cassette modification I’ve learned from other mid drive users...

electricbike.com

 

[Nealh]

How do you find the TDZS Sturmey ?
I know the 2 Pete's say the 48v is the dogs compared to the 36v, so apart from the Blue gear that some have issues with any other probs ?

 

[Sturmey]

I got this for a number of reasons. It was going cheap, I already had a suitable donor bike, I had plenty of 36v battery power (that I can transfer quickly) and I wanted something legal that could be easily be put into the back of a car. I though it might be a suitable and legal replacement for my twin hub bike that I use on the hills.
I have about 1500 km clocked up with no problems. It will heat up if you keep it in a high gear. It works great if you can keep the motor (and pedals) spinning fast. I fitted ordinary steel 155mm smaller cranks (from a youths 24" mtb with chainwheel ground off) to make faster spinning easier. But I dont like the torque sensor and find myself using the throttle a lot.
I live close to lots of mountain bike trails, so the low gearing makes it ok and its good for climbing at slow speeds. I believe its not recommended to ride off the saddle standing as the crank axle have been know to break.
I did go to the rounds of correctly fitting the anti rotation bracket properly and getting the chainline reasonably straight (with a 2x5 gear arrangment), so I have no problems so far with things coming loose. The 7/8 speed chain does wear quick but are cheap. I have loads of steel freewheel cogs so I dont see myself as having to waste money on cogs.
(Being able to dismantle/service freewheels has the advantage that you can often refurbish the individual worn cogs with a chainsawfile.) So far, no problems with the blue gear.
Having said all that, I much prefer my hub motor bikes. So I find myself only using this bike on mtb trails or when I need to stuff a bike into the car (as the wheels can quickly be taken off)