Pro Connect Gears

[Burnsey]

I hope someone can help me decide what gearing I might need before I order a Pro Connect. At the moment I ride a 21 gear mountain bike, I rarely use the lowest gear on the 3 cog but use the highest gear on the 3 cog when going down hills. I never use the first gear on the 7 cog, but use all the rest. The lowest sprocket is 46 and the highest is 28 on the 3 cog, and on the 7 cog the highest is 13 and the lowest is 63. I live in a hilly area which is why I'm thinking of an electric bike. Any ideas out there

 

[mk1]

You could try this software K Gear, it's quite good for comparing different gearing systems. It obviously doesn't take into account the electric assist though!.

 

[Burnsey]

You could try this software K Gear, it's quite good for comparing different gearing systems. It obviously doesn't take into account the electric assist though!.

Thanks for that Martin, unfortunately I haven't got the software to launch the programme.

 

[flecc]

Help me on this Burnsey, I can't make sense of some of it. At the end you say

and on the 7 cog the highest is 13 and the lowest is 63

This seems an odd mixture of sprocket teeth and gear inches. If the smallest sprocket on the 7 speed cassette is 13 teeth, the largest isn't 63 teeth?

I gather you mean the chainwheels are 46 teeth to 28 teeth. Is that so?
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[Burnsey]

Sorry Flecc my technical jargon isn't up to much! When I mention the 3 cogs I mean the 3 tooth sprockets together on the pedals, similarly the 7 cogs are the 7 tooth sprockets together on the back wheel. The figures mentioned are the teeth on the sprockets. Hope this is a little clearer to give you some idea.

Thanks
Frank

 

[flecc]

I guessed that was what you meant, but the 63 has to be wrong. The cassette at the rear wheel can have a 13 tooth small sprocket, but it won't be a 63 tooth large sprocket, that will usually be between about 24 tooth and 34 tooth.

Let me know that rear large sprocket number of teeth, and also whether you ever use it.

You've said you don't use the smallest chainwheel at the front, so could you tell me the number of teeth on the middle chainring there.

With those two bits of information I can give you a good idea of the change for the Pro Connect.
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[Burnsey]

I guessed that was what you meant, but the 63 has to be wrong. The cassette at the rear wheel can have a 13 tooth small sprocket, but it won't be a 63 tooth large sprocket, that will usually be between about 24 tooth and 34 tooth.

Let me know that rear large sprocket number of teeth, and also whether you ever use it.

You've said you don't use the smallest chainwheel at the front, so could you tell me the number of teeth on the middle chainring there.

With those two bits of information I can give you a good idea of the change for the Pro Connect.
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Right Flecc - I've being back out and counted again and yes you are right. The rear large sprocket is 28, and I never use it. The middle chainring is 38. Hope this helps again and thanks for your perseverance.

Regards
Frank

 

[flecc]

Thanks, I've worked that out now.

It means that you aren't using your 34" bottom gear with the middle chainring, but are using about a 40".

Unfortunately the rear sprocket size on the Pro Connect isn't given on the website, but judging from the photos of both bikes, I'm almost certain that it's a 22 tooth, the same as the Agattu.

Therefore an 18 tooth rear sprocket will comfortably give you a low gear below what you need and similar to your present one, and also raise the final power assistance cut-off to over 18 mph.

That could shorten the range if power is switched on all the time, but that might not be important to you. Switching off when the going is easy will compensate to some extent though.

You could even have a 16 tooth rear sprocket and still have a low enough gear for you, but that would make top gear extremely high, making power assist cutoff at over 21 mph, but I think the range could suffer a lot then, and it could be a bit too much for the motor to drive.
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[Burnsey]

Thanks, I've worked that out now.

It means that you aren't using your 34" bottom gear with the middle chainring, but are using about a 40".

Unfortunately the rear sprocket size on the Pro Connect isn't given on the website, but judging from the photos of both bikes, I'm almost certain that it's a 22 tooth, the same as the Agattu.

Therefore an 18 tooth rear sprocket will comfortably give you a low gear below what you need and similar to your present one, and also raise the final power assistance cut-off to over 18 mph.

That could shorten the range if power is switched on all the time, but that might not be important to you. Switching off when the going is easy will compensate to some extent though.

You could even have a 16 tooth rear sprocket and still have a low enough gear for you, but that would make top gear extremely high, making power assist cutoff at over 21 mph, but I think the range could suffer a lot then, and it could be a bit too much for the motor to drive.
.

Hi Flecc

Thanks for that, you must of being very good at maths when you were at school.

I think the shortening of the range isn't important as I will only be travelling 14 mile round trip.

I had thought an 18 tooth would do but was needing confirmation from an expert.

Thanks again for your help and I will put my order in today.

Regards
Frank

 

[flecc]

Hi Flecc

Thanks for that, you must of being very good at maths when you were at school.

I would have been if I hadn't been expelled!

I did take A levels later though, and got a distinguished pass.
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