Tucano Deluxe Gearing

[Uningles]

Hi.

I have a Tucano Deluxe 36v folding bike, which has a 250w rear hub motor on 20" wheels, with Shimano 6 cog rear gearing, pedelec sensor and throttle.

I am finding the bike too easy to pedal on the flat, when flat out and would like to be able to put more pedal effort in for a higher speed return. As it stands, I reach my physical pedalling speed limit, but I am nowhere near my physical effort limit.

Effectively I would then hope to get a faster top speed (currently around 22 kph) and more range due to the pedal input being more - at least when on relatively flat roads.

So my question is, what can I do to achieve this and what would be the trade-offs if any?

TIA.

 

[flecc]

If you have no problem with hill climbing and don't have to use the lowest gear, just changing the chainring for a larger one will do the trick. Just count the number of teeth on your chainring, then multiply that by the percentage increase in pedalling kph you want to reach and get a chainring that size fitted.

I'm not familiar with the Tucano chainring arrangement, but hopefully it is a bolt on ring that will be easily changed. If not, you'll need a new chainwheel complete.

On the other hand, if you need the lowest gear for hill climbing at present, you will need a new multi-sprocket freewheel on the hub with a smaller top gear sprocket, but those are not too easy to source now.

I can't be more definitive without knowing the number of teeth on your low and high gear rear sprockets, the number of teeth on the chainwheel and whether it has a chainring or not.
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[Uningles]

Thanks for your input Flecc.

Since my wife's Tucano Deluxe suddenly developed a rear wheel puncture today, I had the opportunity to inspect the drivetrain. Actually, it was a 2 inch piece of packing staple, by the looks of it, that she picked-up somewhere, riding into town this morning. Luckily for her, the can of "inflate and seal" that I taped to her bike got her back home for me to be able to change the inner tube at leisure.

My chainwheel has 44 teeth and looks like it is somehow attached/pressed onto the left side crank (no bolts immediately visible) - so I guess this is not a chainring. I'll take the crank and chainwheel off later, but it definitely looks like this is the situation.

The 6 rear cogs are 14T, 16T, 18T, 21T, 24T and 28T.

I definitely need 1st gear on some of the hills (more like mountains) around here (Murcia, Spain).

So if I understand you correctly, maybe changing the chainwheel to a 50T or 54T one and looking around for a rear cogset with 11T in 6th gear and maybe 34T in 1st might be worthwhile (if such a thing exists)?

And this would be a freewheel unit, not a cassette? Would the existing chain need to be replaced? I know nothing about the rear drive train on a bike, so thanks again for any help

 

[flecc]

The parts you need are a 6 speed megarange freewheel, 13 to 34 tooth. The 11 tooth top gear ones don't seem to be available any more, but the 13 to 34 should be ok with a bigger chainring. A new rear mechanism that can reach the 34 tooth sprocket will be necessary, your present one won't do.

The chainring will have to be replaced with a spider crank and a chainring to mount on it. The chain needed is a 7/8 speed derailleur chain, not a 9 or 10 speed one since they are too narrow to fit those other parts.

All adds up to some expenditure, but that's unavoidable when a new bike is built with low cost options in the first place.
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[Uningles]

Excellent info Flecc. Thanks. Yes, it does seem like "building your own ebike" is a tempting option once you start finding the shortcomings of some eBike products - which unfortunately for us inexperienced noobs only happens after you get into it with hard cash on an impulse (or because the doc said get more exercise, or you're gonna die, lol).

The Tucano Deluxe seems to have some of these shortcomings. The bottom bracket has also given me trouble. I posted about that here and temporarily solved the issue by removing the original caged bearings and repacking with a larger number of higher grade, loose ball bearings and plenty of grease - although I am tempted to use the 153mm sealed bearings I bought, especially if I'm thinking about replacing the whole chain drive system (I might be able to compensate for the change in the chainline at the same time). An earlier search revealed a couple of other eBike models and conversions suffering from inadequate gearing ratios. Still, I digress.

Anyway, you've given me plenty to think about. I'll let you all know how it turns out when I've made the changes. Thanks again.

 

[flecc]

The chainline won't be a problem once the changes are applied since the chainring can be mounted either inside or outside the spider arms and variable spacers can be used as well for fine tuning the chainline.
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