Gazelle gearing help

[mastanlem]

Hi Flecc,

I was reading your posts re the Agutti gearing and now realize that this is probably the problem that I am having re my Gazelle.

I can get up the hills in a high gear but on the flat there is hardly any power.

Is this the same as the Aguttu, if I change the rear sprocket to 18 teeth It will be faster on the Flat.

Thanks in anticipation.

Marina

 

[flecc]

Yes indeed Marina. though what you change to depends on your present rear sprocket. If it's a 22 tooth, the 18 tooth in the circumstances you mention would help considerably, despite you not having a high power mode on your bike.

The problem is that the power phases down in steps as the pedal speed increases, and from about 12 mph is at a low level in top gear. This is done to match the two EU law requirements, that power phases down towards the maximum, and that the maximum is 25 kph (15.5 mph). By changing the sprocket and gearing up, the power phasedown is shifted upwards, gaining you a couple of mph extra with a given assistance level.

Depending on how you find it, you may be able to have a smaller sprocket yet for even more speed. The way to check is if you need your low gears on the steepest hill you climb. If you don't, the sprocket can be smaller, though there's a limit to how much speed that small motor can really help to. 30 mph is not in the picture.
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[mastanlem]

Thanks Flecc for your quick response.

I hardly ever use the Gazelle as I use the Sparta as it seems to go quicker albeit I have to work more up the Hills.

I will check the Gazelle up the hills but from what I remember one of the hills I was able to do in 7th Gear.

What is the smallest sprocket to use.



Thanks again Marina

 

[flecc]

A 16 tooth is probably the smallest practical size Marina, though there is a 14 tooth available in the 1/8" size.

A 14 tooth would make the final power cut-off at nearly 25 mph, but the motor would never drive the bike at that speed in it's final power phase down stage, so it would be pointless.

Even the 16 tooth with final cut-off at over 21 mph would be a bit marginal, since you'd need to do most of the work at that speed.
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[mastanlem]

Thanks Flecc,

I will probably go for the 18. Now to find someone to do it for me.

Regards Marina

 

[flecc]

Any bike shop can do that easily Marina, that it's an electric isn't an issue.
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