agattu 11 tooth sprocket
- Thread starter carpetbagger
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C
Cyclezee
Guest
I bought one of these sprockets and fitted it with no problems, perfect fit.
I can't vouch for the durability of this non Panasonic part yet, but with regard to performance, assistance continues to over 18 mph before tailing off.
If you do fit one of these or any other drive sprocket, check the distance between the spindle centre of the motor and idler sprocket is between 60 and 65 mm. If it isn't then follow the advice given by Flecc here repairsnew.
J
hn
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Thanks John. However, the larger the motor sprocket fitted, the less critical this measurement becomes. It's really critical normally because the small 9 tooth sprocket only has a maximum of four teeth engaging the chain at any one time so can be very prone to chain jumping over the teeth, only the setting of the idler preventing this. It must be even more critical with the 8 tooth sprocket option.I bought one of these sprockets and fitted it with no problems, perfect fit.
I can't vouch for the durability of this non Panasonic part yet, but with regard to performance, assistance continues to over 18 mph before tailing off.
If you do fit one of these or any other drive sprocket, check the distance between the spindle centre of the motor and idler sprocket is between 60 and 65 mm. If it isn't then follow the advice given by Flecc here repairsnew.
J
The earlier version of the Panasonic unit used a lower speed 14 tooth sprocket and that needed no specific recommendation for the idler setting since the number of teeth engaging the chain was greater.
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C
Cyclezee
Guest
Thank you for that Tony,
After fitting to my Technium, I measured the distance to be 68 mm, so didn't bother to make any adjustments. I didn't measure the original, but it must have been more than 68 mm with the smaller drive sprocket.
J hn
After fitting to my Technium, I measured the distance to be 68 mm, so didn't bother to make any adjustments. I didn't measure the original, but it must have been more than 68 mm with the smaller drive sprocket.
J
hn
I will be replacing all the sprockets and chain on my bike in the not too distant future. By far, the greates wear is on the smaller sprockets, motor followed by 18 tooth rear.
I'm thinking that to achieve a greater life from the parts, would it be better to fit one of these 12 tooth motor sprockets, and reverting back to the larger rear sprocket. With something like the original 23 tooth rear sprocket and a 12tooth motor sprocket, would I achieve power assistance up to a similar speed as I do with my current set up? I anticipate that I would have to pedal at a greater rate due to the large rear sprocket.
I'm thinking that to achieve a greater life from the parts, would it be better to fit one of these 12 tooth motor sprockets, and reverting back to the larger rear sprocket. With something like the original 23 tooth rear sprocket and a 12tooth motor sprocket, would I achieve power assistance up to a similar speed as I do with my current set up? I anticipate that I would have to pedal at a greater rate due to the large rear sprocket.
C
Cyclezee
Guest
I agree Tillson, larger sprocket = less wear. Also, using the 12 tooth sprocket with a 7 speed Nexus hub, more use is made of the lower gears.
Personally, I have not had any problems with the the Nexus 7 speed in over 6000 miles on my Agattu and hopefully the Technium will be the same.
I have read lots of praise for the 8 speed version, but I guess it is a case of not missing what I have never had.
J hn
Personally, I have not had any problems with the the Nexus 7 speed in over 6000 miles on my Agattu and hopefully the Technium will be the same.
I have read lots of praise for the 8 speed version, but I guess it is a case of not missing what I have never had.
J
hn
I've also always been happy with the old established 7 speed, probably because I'm so familiar with pausing to change gear. It's the derailleur generation of the last 30 years who aren't used to pausing who tend to have the greatest difficulty.
Tillson, if you are using the 9 tooth sprocket, compensating with a 22 tooth rear sprocket in place of the 18 will give the equivalent to what you have at present.
If you are using the 11 tooth, you only need to change to a 20 tooth rear sprocket for the same result with a 12 tooth.
It's just a matter of applying thr same percentage change at each end, for example 11 tooth to 12 tooth is 9% change, so adding 9% to the 18 tooth rear gives 19.62, rounded to 20 teeth.
.
Tillson, if you are using the 9 tooth sprocket, compensating with a 22 tooth rear sprocket in place of the 18 will give the equivalent to what you have at present.
If you are using the 11 tooth, you only need to change to a 20 tooth rear sprocket for the same result with a 12 tooth.
It's just a matter of applying thr same percentage change at each end, for example 11 tooth to 12 tooth is 9% change, so adding 9% to the 18 tooth rear gives 19.62, rounded to 20 teeth.
.
I just oredered a 12T sprocket. Quite expensive for what it is - £23.91. I hope it is worth it. I suspect that my 18T hub sprocket may be a bit extreme with this.
How long did it take to arrive Aldby?
My 7 speed hub needs looking at again tonight - cannot get into 6 or 7 - I am guessing that the something has come out of alignment yet again. This sort of thing is extremely rare with the 8 speed hub - I think I had about 2-3 problems in 15,000 miles.
How long did it take to arrive Aldby?
My 7 speed hub needs looking at again tonight - cannot get into 6 or 7 - I am guessing that the something has come out of alignment yet again. This sort of thing is extremely rare with the 8 speed hub - I think I had about 2-3 problems in 15,000 miles.
Like Flecc, I have not always used derailleurs and I am happy to pause a little between gears.
However, there is no question in my mind that the 8 speed is a much nicer piece of work. I believe there are 2 versions, a green and red band or something like that.
That is not to say there is anything wrong with the 7 speed, mind you. I was happy with mine apart from the cable jumping which 50Cycles told me the known 'cures' for but which my LBS tell me is common and pretty much endemic.
However, there is no question in my mind that the 8 speed is a much nicer piece of work. I believe there are 2 versions, a green and red band or something like that.
That is not to say there is anything wrong with the 7 speed, mind you. I was happy with mine apart from the cable jumping which 50Cycles told me the known 'cures' for but which my LBS tell me is common and pretty much endemic.
C
Cyclezee
Guest
Hi Tangent,
The sprocket arrived in 3 or 4 days.
As for your 7 speed hub, are the yellow dots lined up when the in 4th gear? If not then the cable needs adjustment.
The 7 speed has not given any problems and my son uses that bike daily, he is not renowned for being kind to mechanical things, therefore I think the hub must be fairly sturdy
J
hnIs there any chain length adjustment, addition of links, necessary when changing from 9 to 11t drive sprocket?
Quite possibly you will need to add one link into the chain - depends how far back into the dropout slot your wheel is at present.
If it is right back into the closed end, you will be fine.
If it is already half way towards the open end, you will need another link.
Flecc's page here shows the 60-65 mm distance for the tension sprocket. If the distance is greater than 65 mm, you have some slack available here and may not need an extra link.
James
If it is right back into the closed end, you will be fine.
If it is already half way towards the open end, you will need another link.
Flecc's page here shows the 60-65 mm distance for the tension sprocket. If the distance is greater than 65 mm, you have some slack available here and may not need an extra link.
James
i swopped mine with no problems...i didn't even take the rear wheel off or slacken it. I pulled back the chain tensioner which gave me room to put the sprocket on and get the chain over the new one
Replaced my 11T sprocket with the unofficial 12T at the weekend and shortened the chain again. It is very difficult to tell the difference. The change is nowhere near as dramatic as the change from the 9T to the 11T.
The change to 12T motor sprocket and 18T hub sprocket has meant that I am now spending most of my time cruising between 18 and 20mph in gears 5 and 6 on flat ground. This is much more satisfactory than the original 15-17mph I was doing with the 9T/21T combination. It also means that I can step up the speed when I need to. For instance, yesterday I could see a light change ahead of me that I managed to get to by changing up to 7 and standing on the pedals. I got up to about 25mph, overtaking a couple of lycra clads and through the lights just as they went to amber.
The change to 12T motor sprocket and 18T hub sprocket has meant that I am now spending most of my time cruising between 18 and 20mph in gears 5 and 6 on flat ground. This is much more satisfactory than the original 15-17mph I was doing with the 9T/21T combination. It also means that I can step up the speed when I need to. For instance, yesterday I could see a light change ahead of me that I managed to get to by changing up to 7 and standing on the pedals. I got up to about 25mph, overtaking a couple of lycra clads and through the lights just as they went to amber.
I am sure that the range must be reduced, but I usually only do 15 miles per day and charge up every evening, so any reduction in range is not a problem for me. I have not noticed any difference in the battery discharge rate, having always had 3 LEDs lit on the battery after getting home.
I went for a 41mile trek from Blackburn to Lytham St Annes last week with the 11t, it was relatively flat after Preston but there was a strong head wind.
I wasn't sure how the battery would last so i used it sparingly going mostly on low power but when i got home two lights on the bars had gone so thats probably 3 on the battery...to think i could have used a bit more battery.......damn.....
I wasn't sure how the battery would last so i used it sparingly going mostly on low power but when i got home two lights on the bars had gone so thats probably 3 on the battery...to think i could have used a bit more battery.......damn.....
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I have been using a 12T motor sprocket for some time now and absolutely love it. I have been trying to figure out precisely what is going on, re-reading Flecc's excelent posting here:
http://www.pedelecs.co.uk/forum/technical/1957-panasonic-system-power-delivery-explanation.html
With the standard 9T the power starts to be reduced with a cadence above 39. But I am sure I am still getting high power with a higher cadence than this. With my 12T does the power reduction now not commence until the cadence reaches 52 (39 times 12 divided by 9)? If so, why?
Also, what is the effect on the level of power assistance? Is this reduced by a factor of 9/12?
I am not sure what measures the cadence - is this measured by the motor speed or the pedals?
http://www.pedelecs.co.uk/forum/technical/1957-panasonic-system-power-delivery-explanation.html
With the standard 9T the power starts to be reduced with a cadence above 39. But I am sure I am still getting high power with a higher cadence than this. With my 12T does the power reduction now not commence until the cadence reaches 52 (39 times 12 divided by 9)? If so, why?
Also, what is the effect on the level of power assistance? Is this reduced by a factor of 9/12?
I am not sure what measures the cadence - is this measured by the motor speed or the pedals?
You are getting the higher cadence since the cadence power reduction is indirectly measured by the motor/output gear speed. Since your 11 tooth sprocket spins the chain around the chainwheel at 12/9ths times the previous speed as you indicate, your cadence before power reduction has increased by one third.
The current Panasonic unit takes the motor speed from the feedback of it's Hall sensors, the previous unit used a Hall sensor to measure the passing speed of a ring of magnets on the output gear, arrowed here
:
.
This section in my Panasonic site explains all.
.
The current Panasonic unit takes the motor speed from the feedback of it's Hall sensors, the previous unit used a Hall sensor to measure the passing speed of a ring of magnets on the output gear, arrowed here
:
This section in my Panasonic site explains all.
.
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