better gearing for a folding pedelec

[nogelt123]

Hi,my name is Jan
I have a problem with the gearing on my folding bike.
this topic may have come up before.
The bike is a 6 speed,with a pedelec bottom bracket ,the chainring is not replaceable.I want to pedal at a lower cadence while maintaining a decent speed.the rear freewheel is 14-28 I was thinking of getting a 7 speed freewheel,11-28 but I understand there is a shortage of them.So my option is to bolt a 50 tooth chainring on to my
exsisting 44 tooth chainring the bolt pattern is144mm
but the holes are to small in the current chainring.
CouldI drill the holes out and fasten the 50 tooth chainring?I would no longer have a chain guard as I would be using the holes for the larger chainring

 

[flecc]

Yes you can do that Jan, its been done before as you'll see in a post of mine some while ago:

Adding a chainring to a chainwheel
.

 

[UrbanPuma]

Could I drill the holes out and fasten the 50 tooth chainring?I would no longer have a chain guard as I would be using the holes for the larger chainring

Could this be done on all folding bikes like mine with 16" wheels? If so, surely this would solve the problem of low gearing?

 

[flecc]

Could this be done on all folding bikes like mine with 16" wheels? If so, surely this would solve the problem of low gearing?

Yes it applies to any folder, but the gain isn't very large in most cases so it's far from a complete solution. I did solve the problem just about enough on my 20" wheel Q-bike but it needed a 60 tooth chainring and that can bring other potential problems such as lack of ground clearance over speed bumps and the chain very low to the ground. With 16" wheels those problems are very much greater.

You can see what I mean in this photo

That huge 60 tooth chainring on a 20" wheel bike gives me a 92" top gear which is just average for a bike, so you can see that a 50 tooth on a 16" wheel bike would still fall well short of what is desirable.
.

 

[skrivener]

Is that pedlec sensor really part of the chainring Jan?

I was told mine was but the chainring pulled off without disturbing the sensor disc. The sensor disc seems to be separate on the few I've seen.

I've been unable to find a large single chainring cheaply. I replaced my 40 tooth ring with a cheap dual ring with 40 & 52 teeth . It works fine & if the battery runs out you can always lift the chain over to the small 40 tooth cog by hand to ride home easier.

I'd still like to try a cog with more teeth if I can find a cheap, non specialist one.

How grim was the price of your 60 tooth cog & crank flecc?

 

[flecc]

How grim was the price of your 60 tooth cog & crank flecc?

I can't remember the individual prices, but from memory the spider, left crank and chainring were a little over £100 together. Luckily the 60 tooth chainring was a Zenith French made one in stock with Highpath Engineering, so they didn't have to make it specially, or it could have been dearer.

I think Shimano make a chainring at about 55 tooth.
.

 

[frank9755]

You can get a TA ring up to 67T.

 

[BertYardbrush]

You can get a TA ring up to 67T.

Thanks for the tip. I've been looking for something to speed up my ancient throttle only Quando. Spa Cycles are sending me a 65T chainwheel and a chainset to go with it. This will transform me from 53 gear inches to 72. The man on the phone said he used to have a fixie with 72 and it's ok. I reckon I should get up to 16mph unassisted. It may not sound much but it's better than the 11 that I can do at present.

I'm still flummoxed by my 18T freewheel thread. It's not BMX, Mr Ezee told me that - but he didn't tell me what it is.

I'll let you know how the fitting goes.

 

[flecc]

I'm still flummoxed by my 18T freewheel thread. It's not BMX, Mr Ezee told me that - but he didn't tell me what it is.

It's probably just a standard freewheel thread as that's the usual with 18 tooth freewheels. Later Quandos had the 14 tooth freewheel on a BMX thread of course, giving them an almost 70" gear with a 48 tooth chainwheel.

St Johns Cycles have a Shimano freewheel with recessed back thread that comes in 16, 17 and 18 tooth versions, so the 16 tooth could up your gear a bit more to around 79". You'll need to check with SJS to ensure the thread is standard, but it seems it is.

SJS freewheel
.

 

[BertYardbrush]

It's probably just a standard freewheel thread as that's the usual with 18 tooth freewheels.

SJS freewheel
.

I am not at all clear on this one. As far as I can gather there are two sizes of freewheel thread, one for the smaller wheels, e.g. 14T - this is the small BMX thread and one for the larger, from 16T upward, this is also sometimes known as BMX.
Tell me, is there a third type, possibly known as standard English thread, that might be 1.37 x 24? And could this be the Holy Grail that I am seeking?

 

[flecc]

That I don't know I'm afraid, and I've even found the cycle engineers Highpath Engineering unclear about all possible freewheel thread options. Confusingly SJS also have freewheels with what they call "junior thread" for kids bikes.

The only ones I know are the "standard", mainly on 18 tooth but with the odd 16 tooth like the one I mentioned, and BMX thread with 14 tooth upwards options.

It would seem surprising if Suzhou Bafang who made your motor or eZee specified an alternative called the Standard English Thread that you mentioned. However, the steel inserts in the casing sides have the outside diameter set by the band brake that was fitted on the left of the original version, so that's possibly too small to accept a "standard" freewheel thread. That still begs the question why they wouldn't use a BMX thread as they did on the later motors, given the free availability of BMX freewheels of 14 to 18 teeth at that time.

Have you tried mailing Wai Won Ching, it might be worth it to clarify?

Contact eZee principals
.

 

[BertYardbrush]

Have you tried mailing Wai Won Ching, it might be worth it to clarify?
Contact eZee principals
.

Yes, I asked him if it was a BMX thread and he said no.

[I'd like to say thanks to Jan for starting this topic - do you think I'm straying rather into technical?]

My 65T arrived this morning and cor, what a whopper!
Looks like it will interfere with the rear brake cable solid tube sleeving. Any way round that one that does not involve major surgery?

 

[flecc]

Yes, I asked him if it was a BMX thread and he said no.

[I'd like to say thanks to Jan for starting this topic - do you think I'm straying rather into technical?]

My 65T arrived this morning and cor, what a whopper!
Looks like it will interfere with the rear brake cable solid tube sleeving. Any way round that one that does not involve major surgery?

I hope we all appreciate that the technical is necessary at times with e-bikes.

I solved a potential collision problem of the brake noodle and chainwheel on another bike by using a front brake on the rear, putting the noodle on the other side. V brakes can be bought cheaply and the rear one isn't really critical. Your Quando probably already uses a front brake there since it's mounted upside down under the rear frame, so it's a rear brake you need now. Here's a pic of the front one I fitted:

 

[BertYardbrush]

so it's a rear brake you need now.

Thanks once again, Flecc. I'll pay a visit to JE James tomorrow for a rear V brake and a long chain and then set to for an interesting few hours.

Kind regards ............

 

[BertYardbrush]

Here's some pics of my Quando 65

It would appear that all V brakes are the same hand so I've got a more curvy noodle and just tweaked it some more. I have yet to go on a test drive. The rear brake is a bit 'sticky' so I'm not fully sure that it's OK.

I've also replaced the saddle, the old one being about 4 inches thick. That means I can lower it a couple of inches further so my short legs can tip toe on the ground.

Next job is to make a grease gaiter to keep my trousers clean.