I LOVE my secondhand Pro Connect!!!!!!

[Crooty78]

Hello to you all! After lots of research I decided to go electric, and while searching Ebay I found a 3 year old pro connect, in very good condition, for under £800. I am so happy with my new purchase, it literally puts a smile on my face every day!
Im already thinking about changing the gearing, and yes I know the legal guff and no I dont care. I really am hoping there is someone on here that can give me some advice on this, like do I buy standard cogs etc. Basically any info on improving speed will be very much appreciated.
I live in sunny Clacton on sea, the area is extremley flat so im looking for a few extra mph to eat up the long straight roads.

 

[flecc]

Easiest way with a derailleur gear if that's what you have is to change the motor sprocket from the 9 tooth to the 11 tooth one, though that might mean changing the chain as well if there's wear. That will increase the assist speed from 15 mph to 18 mph. The downsides are that you'll be pedalling that much faster as well and your range will drop since the motor will be working more of the riding time.

Otherwise it means changing the rear sprocket set of the cassette, but there's limit to how much smaller the top gear sprocket can be to give more speed.

50cycles usually stock the 11 tooth motor sprockets.

 

[Crooty78]

Thanks for your reply flecc. My bike has 8 gears, all enclosed by a chain guard with one sprocket on the back wheel. I hope from this you know which model I have.
Range is not too much of an issue. As long as I can get 10-15 miles on full assist thats more than adequate for me. I did read another thread on this site where someone changed 3 sprockets to achieve more speed?

 

[flecc]

Oh that's good, it's a hub gear model. That only means changing the rear sprocket for a smaller one, the lowest cost option. Just check how many teeth that rear sprocket has, decide on the percentage speed increase you need and reduce the rear sprocket by that percentage of teeth. The smallest one that can be used is 16 teeth. Any good bike dealer can obtain and if needed, fit the rear sprocket for you, it's a fiddly job.

Doing that will increase the assist speed without any increase in your normal pedalling rates.

 

[Crooty78]

Ive just ordered a sturmey archer 16 tooth sprocket, and found a youtube video showing how to fit. Yes it does look fiddly but I reckon ill get it done. I will post again when fitted thanks again for the info flecc.

 

[flecc]

If you have a look at this excellent post from member JamesC, there's a wealth of detail on changing the Pro Connect Nexus sprocket

 

[Crooty78]

That is just the post I was looking for, brilliant! Any idea how many chain links I will need to remove for a 16 tooth sprocket and as ive never done this before, any advice on how to do it will be great and very much appreciated.

 

[flecc]

I don't know how many sprocket teeth you have at present, but it's one link to remove for each two teeth reduction. Don't worry about any odd tooth, the derailleur rear mechanism can take care of that slight difference either way.

If you have the original Pro Connect setup with a 23 tooth rear sprocket, your change will take assistance up to 20 mph, but the range will drop considerably.

 

[Crooty78]

I reckon the sprocket is the standard 23 tooth one, so yes, perhaps a tad extreme going all the way down to 16 teeth in one go. But the way im thinking is I want maximum speed and as long as I can still get at least 12 or so miles range thats enough for my commute. Im just hoping I dont break anything in the process of sprocket swapping!

 

[flecc]

That should be ok, the lowest range I've had reported on a Pro Connect with that change to 16 teeth is 18 miles.

 

[Crooty78]

Received sprocket, its flat, is that right as the one on the bike is dished?

 

[flecc]

I'm not sure on the eight speed with a 16 tooth sprocket, hopefully someone else will have the answer. The chain alignment tiny error won't matter, it's more whether the chain on an flat sprocket will touch the hub or interfere with the change mechanism.

 

[Crooty78]

Rookie mistake eh! Think I will just get an offset one to be sure.

 

[flecc]

If there's any difficulty sourcing one, SJS have them on this link

 

[JamesC]

Received sprocket, its flat, is that right as the one on the bike is dished?

Hi Crooty
You might find it useful that most Shimano bike components are backed up with two technical documents available via Google on the internet; one is a parts list and the other is a service sheet.

For a hub gear, the main number is written on the casing of the hub and will start with WH-xxxxx (when it is a complete Shimano wheel with a hub eg WH-8R25) or SG-xxxxx (when it is a Shimano hub built into another makers wheel eg SG-8R36).

The parts list includes the list of alternative Shimano sprockets designed for that hub with its part number.

In actual fact, there are only 2 types of sprocket for 8 speed hubs; the most common does NOT include a chain guide (Nexus type) and the more recent does have a chain guide (Alfine type).

Here is the parts list for a Shimano SG-8R36 Nexus hub; the sprocket is item 28 with the various sizes listed. The 16 tooth (dished) is Shimano Part Number Y-322 03220.

I am guessing that you have the Nexus style of dished, unshielded sprocket because the other shielded type is available only with 18 or 20 teeth.

I can recommend Petra Cycles in Surrey as a good start place for Shimano parts when you know the part number - google Petra Cycles and then use their search 32203220 to get you to here.

(Edit - Petra have a typo for the Shimano part number - easier to search on "Nexus Sprocket" to see the ones that are available)

Hope this helps.

James

 

[JamesC]

One other word of caution, this time regarding chains.

Your bike uses a Shimano hub gear, but Kalkhoff also started to make ProConnect models with Shimano derailleur gears at around the date of your bike.

The motor/pedal unit complete with the chainwheel (probably 41 teeth) and tiny motor sprocket (9 teeth or 11 teeth) are made by Panasonic and are available from 50cycles or European suppliers.

The sprockets associated with the gears on the back wheel are made by Shimano, but hub gears often use a sprocket with thick teeth whereas derailleur gear cassettes use narrower teeth.

So, it is safest to use 1/2" x 1/8" cycle chain with your hub setup; with derailleur gears you have to use narrower chain, typically 1/2" x 3/32" or even narrower for 10/11 speed setups.

Panasonic have made "thick" and "thin" chainwheels and sprockets, but both sizes will work with the wider 1/8" chain.

 

[Crooty78]

Thanks for all your advice James, I really appreciate it. As you know im changing to a 16t hub sprocket. My question is if im running a 9t motor sprocket (havent actually checked this yet) will I gain a noticable speed increase changing to the 11t in combination with the 16t hub sprocket?

 

[flecc]

Pending James coming in, yes, and I think it's too much. The change from the 23 to the 16 tooth rear sprocket increases the final assist cutoff point from 15 mph to 21.5 mph. Adding to that the motor sprocket change from 9 to 11 teeth will further increase that 21.5 to 26.3 mph.

Virtually all riding will be powered with most of it in the maximum power area of speeds, so the range will suffer as current draw will almost always high. It might also compromise steep hill climb ability since the lowest gear is being considerably raised.

My preference would be to do one or the other rather than both.

 

[JamesC]

I have less experience than others when chosing the best sprockets for out and out speed.

There are 2 things that must also be taken into account - how much assistance do you want from the motor and what is your preferred rate of pedalling (cadence).

Well worth going out for a ride and counting your pedal rotations for 1 minute when you are at a comfortable speed.

I am 62 with less power in my legs than many of my age. As such, I am very comfortable cycling at 60-65 rotations per minute. This is slow - others will do 80-100 - and people will say that a slow cadence will damage your knees. For that very reason, it is good to use the crank style of motor assistance like your ProConnect to absorb half the pressure.

The choice of motor sprocket (coupled with big chainwheel) is closely related to your preferred pedal speed. I use the original 41 T chainwheel and 9 T motor sprocket with the level of assistance set to maximum with the standard 250 watt Panasonic motor.

This means that the assistance from the motor is diminished when I ride at 65 RPM, but builds up when my pedal speed slows.

If I fit an 11 T motor sprocket, I would still not pedal faster than 65 RPM because it is uncomfortable for me.


When chosing the rear sprocket, the consideration is more down to the type of terrain you ride on and the loads you carry. I live in a very flat area, but with frequent headwinds. However, I ride mainly for leisure and take the bike to some very hilly areas. I also get a lot of pleasure from pulling a couple of grandchildren in a Chariot trailer from time to time.

For these functions, I found that a change from 23 T to 19 T gave me nearly sufficient speed on the flat whilst still providing a low 1st gear for rides up and down the claypits of Cornwall.

In opting for the 16 T rear sprocket, I am guessing that you are a more powerful rider than I am and less likely to need a low first gear. If you enjoy a leisurely leg speed, then stick with the 9T motor sprocket. If you like a fast leg speed, then consider an 18T/19T rear sprocket with an 11T motor sprocket.

Guys with the 300 watt sports motor often find that the 11 T motor sprocket can still deliver good assistance for hills.

 

[Crooty78]

I live in East Anglia, lovingly known as the flatlands. Only some gentle inclines and no real hills to speak of. Ive only really used the top three gears, with fifth being more than comfortable to get me up the only real slope on my commute. Im pretty fit and can pedal at a reasonably fast rate, so the low gears dont get used. I would say my riding style is moderate to fast.
I will change the rear sprocket and see if the bike suits me better then. I was finding that even when I just wanted to gently ride along, my cadence would get faster and faster to keep up with the motor. Im thinkng this may be because im on full assist constantly?