Converting Carrera Subway 2

[perpetualbrian]

I've had this bicycle unridden sitting in the garage for over 5 years. This is my first conversion experience.

I bought the sutto 36v 250 watt rear hub motor from varstrom a batangas subsidiary. I believe I made a mistake as to the compatability.

I installed the tyre had to widen the dropouts with a metal file. Then noticed that the disc brake rotor was scraping against the IS adapter that the hydraulic break needed to attach to the bike frame. So I tried filing down the side of the caliper adapter.

I then thought buying narrower rear break may suffice so I went for a cabled rear brake because it seems that I may have to replace both hydraulic breaks with mechanical.

The kit came with a 7s freewheel. I wanted to keep the 9s so I bought a 9s freewheel which I think hasn't helped with the brake caliper so I would like some advice please on what I've mentioned already and my bike has 27 gears 9s 3 settings. How do I make the 7s freewheel compatible with a 3x9s gear shifter?

I believe I need to buy a torque arm which I will invest in. The caliper is part of Clarks brake set. Any help would be great! Thanks

 

[Saracen]

Welcome to a great forum

Would it not have been better to have the job done by a proper retail outlet

 

[saneagle]

I've had this bicycle unridden sitting in the garage for over 5 years. This is my first conversion experience.

I bought the sutto 36v 250 watt rear hub motor from varstrom a batangas subsidiary. I believe I made a mistake as to the compatability.

I installed the tyre had to widen the dropouts with a metal file. Then noticed that the disc brake rotor was scraping against the IS adapter that the hydraulic break needed to attach to the bike frame. So I tried filing down the side of the caliper adapter.

I then thought buying narrower rear break may suffice so I went for a cabled rear brake because it seems that I may have to replace both hydraulic breaks with mechanical.

The kit came with a 7s freewheel. I wanted to keep the 9s so I bought a 9s freewheel which I think hasn't helped with the brake caliper so I would like some advice please on what I've mentioned already and my bike has 27 gears 9s 3 settings. How do I make the 7s freewheel compatible with a 3x9s gear shifter?

I believe I need to buy a torque arm which I will invest in. The caliper is part of Clarks brake set. Any help would be great! Thanks

What you're saying is quite normal and there's a simple solution, which you have to do on nearly every hub-motor conversion.

When you install the wheel into the drop-outs, you have to get the spacing right on the brake side before anything else. For just about every one I've ever done, that has a disc brake you have to install a standard 12mm washer on the axle somewhere between the drop-out and the motor. The extra 2mm will shift the motor and disc away from the caliper. There's nearly always a pair of 12mm washers provided with the kit.

 

[perpetualbrian]

What you're saying is quite normal and there's a simple solution, which you have to do on nearly every hub-motor conversion.

When you install the wheel into the drop-outs, you have to get the spacing right on the brake side before anything else. For just about every one I've ever done, that has a disc brake you have to install a standard 12mm washer on the axle somewhere between the drop-out and the motor. The extra 2mm will shift the motor and disc away from the caliper. There's nearly always a pair of 12mm washers provided with the kit.

Thanks for your replies. Yes, it did come with two washers. I placed the washer with the lip into the dropout space then place the washer and tighten the bolt on the axle. Is that the correct way. The kit didn't come with instructions. I've been using YouTube videos to install the right side pas which is magnetic. I haven't specifically found a good one on installing a rear hun motor as yet. The search is ongoing .

 

[Waspy]

Thanks for your replies. Yes, it did come with two washers. I placed the washer with the lip into the dropout space then place the washer and tighten the bolt on the axle. Is that the correct way. The kit didn't come with instructions. I've been using YouTube videos to install the right side pas which is magnetic. I haven't specifically found a good one on installing a rear hun motor as yet. The search is ongoing .

It should look something like this, you can experiment with washers until you get it set up right. Ideally, both sides should be the same

When I installed my kit I removed the chain and brake caliper so I could try different washer set-ups more easily, then I refitted the caliper with loose mounting bolts to check I could get it all aligned, then when I was happy, tightened up and replaced the chain. But having said that, most people don't feel the need to remove the chain and caliper.

 

[perpetualbrian]

Cool thanks much appreciated. I have to get to work for a 12 hour shift but plan to sort this tomorrow. I've also ordered two torque arms which should be arriving tomorrow as well.

 

[saneagle]

Cool thanks much appreciated. I have to get to work for a 12 hour shift but plan to sort this tomorrow. I've also ordered two torque arms which should be arriving tomorrow as well.

There's no exact way to fit all the washers and spacers. Even if there were an instruction, it wouldn't work because every bike is different. Here's how I fit a motor:

First, file the drop-outs first to get the motor into the drop-outs. I normally file the drop-outs about 2.5mm deeper to re-centralise the axle otherwise the tab washer doesn't engage with the slot and your brake pads might not line up with the friction area of the disc, though every bike is different, so I have to make a judgement on each one.

Next job is to get the disc to line up with the caliper, so I put the caliper in the middle of its sideways adjustment slots and put arrange any washers or spacers to position the disc so that it lines up with the gap between the pads.

Then I move to the other side and arrange any spacers and washers so that the cassette is just far enough from the drop-out to stop the chain touching the frame. That adjustment is vital to prevent the rim being off-centre. The clearance needs to be as small as possible.

Finally, check how central the rim is in line with the frame, then dish the wheel, if necessary, to make it central.

When arranging the washers and spacers, it helps to have a box of old 12mm washers and spacers of different sizes and thicknesses. The tab washers can go on either the inside or outside of the drop-out to suit, and you often need a non-standard 20mm O/D washer on the cassette side to go into the cassette without rubbing, though the Bafang type anti-rotation washers can be used for that when placed on the inside of the drop-out as long as it let's the chain close to the frame. It depends where the axle nut is inside the cassette. Some are nearly flush, others are deeper inside.

 

[sjpt]

You may not really need the torque arms, but make sure the torque washer engages properly in the dropout; can be an issue with shallow dropouts.

 

[saneagle]

The rule I use for torque arms is multiply the nominal battery voltage by the maximum controller current. If it's less than 650, no TA required. Between 650 and 1000, one TA required. Greater than 1000, 2 TAs. That's assuming an aluminium frame. It's not an exact rule, but it's the starting point for judgement. It depends on the thickness, size and shape of the drop-outs and how well the tab washers fit, etc.

For front forks, it's different. I'd always fit at least one TA. After that it depends on judging how strong the drop-outs are.

 

[perpetualbrian]

There's no exact way to fit all the washers and spacers. Even if there were an instruction, it wouldn't work because every bike is different. Here's how I fit a motor:

First, file the drop-outs first to get the motor into the drop-outs. I normally file the drop-outs about 2.5mm deeper to re-centralise the axle otherwise the tab washer doesn't engage with the slot and your brake pads might not line up with the friction area of the disc, though every bike is different, so I have to make a judgement on each one.

Next job is to get the disc to line up with the caliper, so I put the caliper in the middle of its sideways adjustment slots and put arrange any washers or spacers to position the disc so that it lines up with the gap between the pads.

Then I move to the other side and arrange any spacers and washers so that the cassette is just far enough from the drop-out to stop the chain touching the frame. That adjustment is vital to prevent the rim being off-centre. The clearance needs to be as small as possible.

Finally, check how central the rim is in line with the frame, then dish the wheel, if necessary, to make it central.

When arranging the washers and spacers, it helps to have a box of old 12mm washers and spacers of different sizes and thicknesses. The tab washers can go on either the inside or outside of the drop-out to suit, and you often need a non-standard 20mm O/D washer on the cassette side to go into the cassette without rubbing, though the Bafang type anti-rotation washers can be used for that when placed on the inside of the drop-out as long as it let's the chain close to the frame. It depends where the axle nut is inside the cassette. Some are nearly flush, others are deeper inside.

Thanks that is helpful!

 

[RollingChunder]

There's no exact way to fit all the washers and spacers. Even if there were an instruction, it wouldn't work because every bike is different. Here's how I fit a motor:

First, file the drop-outs first to get the motor into the drop-outs. I normally file the drop-outs about 2.5mm deeper to re-centralise the axle otherwise the tab washer doesn't engage with the slot and your brake pads might not line up with the friction area of the disc, though every bike is different, so I have to make a judgement on each one.

Next job is to get the disc to line up with the caliper, so I put the caliper in the middle of its sideways adjustment slots and put arrange any washers or spacers to position the disc so that it lines up with the gap between the pads.

Then I move to the other side and arrange any spacers and washers so that the cassette is just far enough from the drop-out to stop the chain touching the frame. That adjustment is vital to prevent the rim being off-centre. The clearance needs to be as small as possible.

Finally, check how central the rim is in line with the frame, then dish the wheel, if necessary, to make it central.

When arranging the washers and spacers, it helps to have a box of old 12mm washers and spacers of different sizes and thicknesses. The tab washers can go on either the inside or outside of the drop-out to suit, and you often need a non-standard 20mm O/D washer on the cassette side to go into the cassette without rubbing, though the Bafang type anti-rotation washers can be used for that when placed on the inside of the drop-out as long as it let's the chain close to the frame. It depends where the axle nut is inside the cassette. Some are nearly flush, others are deeper inside.

With my kit; on the freewheel side, the washers supplied fit inside the freeewheel which meant I had to stack about three of them before the washers became flush with the smallest gear. I then put an extra one to stop it rubbing on the frame. However I notice there is a lot more resistance (although still spins for a short while) to turn the wheel when I torque down the axle nuts.

Could it be these washers in the freewheel interfering? So in my case, the supplied washers OD is smaller than freewheel ID. How about you?

 

[Woosh]

could you post some pictures?

 

[RollingChunder]

could you post some pictures?

Not with the bike unfortunately. I think I was exaggerating with "a lot more resistance". It's very slightly increased. But I don't know how much resistance a hub motor should have. It's certainly massively more compared to the front wheel.

 

[Woosh]

There is a very slight increase in friction with a geared hub motor because the motor has an internal hub but you should get 5 revolutions or more of freewheeling when you spin your geared hub motor by hand.

 

[RollingChunder]

There is a very slight increase in friction with a geared hub motor because the motor has an internal hub but you should get 5 revolutions or more of freewheeling when you spin your geared hub motor by hand.

Okay, I get 1 revolution with a firm spin. 2 if I give it my all. I will have to investigate where it's rubbing, I'm quite sure it's not the brake.

 

[Woosh]

Remove the brake rotor. Sometimes people re-use their old rotor bolts which may be too long. The second place where binding may happen is on the ball-bearing chain side. You have two M10 nuts that limit the dropout. Loosen them a little to see if the binding goes away.

 

[saneagle]

With my kit; on the freewheel side, the washers supplied fit inside the freeewheel which meant I had to stack about three of them before the washers became flush with the smallest gear. I then put an extra one to stop it rubbing on the frame. However I notice there is a lot more resistance (although still spins for a short while) to turn the wheel when I torque down the axle nuts.

Could it be these washers in the freewheel interfering? So in my case, the supplied washers OD is smaller than freewheel ID. How about you?

If the resistance increases when your tighten the axle nuts, something is rubbing, so check your washer and spacer arrangement carefully. Common causes are the washer that's nearest the cassette or freewheel, whatever is resting against the motor bearing on the brake side, and the freewheel rubbing against the motor (resistance only when freewheeling).

 

[perpetualbrian]

So the bike originally had a cassette but the hub is threaded so I thought I would buy a 9s freewheel. A 7s freewheel came with the kit. I didn't really want to downgrade but I've got the brake side working now thanks to all your suggestions just that now the freewheel is too big and the spacer I do have is quite small and doesn't seem to be much room after the brake caliper is aligned. So I'm contemplating downgrading to 7s do I need to swap gear switchers or can I keep the gears I have an just never go past 7 or 6 which ever one it is?

 

[Woosh]

You should use a 9-speed shifter with 9-speed freewheel, 7-speed shifter with 7-speed freewheel. The spacing is not the same

 

[saneagle]

So the bike originally had a cassette but the hub is threaded so I thought I would buy a 9s freewheel. A 7s freewheel came with the kit. I didn't really want to downgrade but I've got the brake side working now thanks to all your suggestions just that now the freewheel is too big and the spacer I do have is quite small and doesn't seem to be much room after the brake caliper is aligned. So I'm contemplating downgrading to 7s do I need to swap gear switchers or can I keep the gears I have an just never go past 7 or 6 which ever one it is?

You can use your 9 speed shifter and derailleur. It'll work, but your indexing won't be accurate. Sometimes when you want to shift one gear up, you have to go two up and one back. It's not too much problem because the main gears you use are top and bottom, and they will be accurate because you set them with the end-stops.

You could get an old style non-indexed shifter, like we used to uson before there were indexed shifters. With that, top and bottom gears will be fixed and accurate, and for the rest, you just pull the lever until the derailleur is in the right position for the gear. It doesn't take long to get the hang of accurate shifting.

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