Help! PSW conversion kit on Carrera Subway 2?

Bonzo Banana

Esteemed Pedelecer
Sep 29, 2019
740
432
Thanks for all your responses. Lot of very useful info for me to consider!
I didn't even realise that 27.5" rim was different from 700 rim! That's confusing and a bit limiting!
I did look at the various Woosh kits and I really like the look of them but they are maybe a bit more expensive than I was wanting to pay for my first attempt into the world of ebikes. But they do seem the simplest design with the best support so I definitely won't discount the option..
The point Woosh makes about the rigid front forks being unpleasant to ride makes me wonder if I'd be better going for a used Carrera Crossfire 2 as I've seen a few of them for sale for around £100 as well in recent weeks. I believe these are a bit heavier than the Subway, but I don't have any stairs to carry it up so that wouldn't be a problem. They also have standard disk breaks rather than hydraulic which might simplify things a little. Any thoughts on that being a better option than the Subway?

My original thinking was that a front motor would be easier to fit but I might now consider a rear hub motor as I'm getting the sense that most people prefer them.

Thanks again for all your comments and help, very much appreciated
Other benefits of the front hub motor are;

You aren't messing with rear gearing at all so whatever you have at the moment is fine.

By having a front hub motor your rear spokes are full length to give more spring in the rear wheel and comfort

Steel forks and a low power hub motor means you you shouldn't need a torque arm to secure the hub motor

Your bike becomes two wheel drive as you have traction on both wheels which can help on loose surfaces

It can be a pain to remove rear hub motors to deal with punctures which becomes much easier on front hub motors as there is no gearing to get in the way

Tyres wear at a similar rate front and back

Some people like the heavier steering of a front hub motor it can feel more stable

The motor is simpler without a freehub or freewheel thread so less maintenance issues and things to go wrong

You can return it to a normal bike easily just by swopping back the original wheel and removing the battery

You don't have to compromise the rear dropouts of the main frame to get a rear hub motor in

The bearings of the hub motor get an easier life at the front as much more of the riders weight is at the rear typically 60-70%


As for the disadvantages I don't think hill climbing traction is a problem on low power front hub motors. A huge amount of pre-built ebikes have front hub motors and its not a widely reported problem and a large percentage of those have smaller wheels which are more torquey (if that is a word). The Subway is basically a hardtail mountain bike with rigid steel forks instead of suspension, being a mountain bike you can fit big tyres on it for comfort like Schwalbe fat franks or similar (and these will also give you more grip), comfort grips and of course a sprung saddle or even suspension seat post. Lots of ways to improve comfort without the additional expense, weight and maintenance requirements of front suspension.

I personally wouldn't choose a Subway for a rear hub motor conversion. I think if you are going the rear hub conversion route there are better options. On some of the recent Subways they have perforated rear dropouts rather than solid rear dropouts so removing material is more risky. You will definitely need a torque arm, maybe 2 which are a pain to work with and time consuming plus extra money.

A Subway with a front hub motor is convenient and easy to live with I think. It's almost fit and forget. I'm a heavy rider so I actually get much more punctures on the rear than the front but I realise you aren't so heavy so that probably isn't an issue for you so I haven't put that as an advantage of front hub motors but for a lot of people that is especially those that overload the rear with shopping or have a rear child carrier.
 

Peter.Bridge

Esteemed Pedelecer
Apr 19, 2023
666
302
Thanks Peter. Just so I'm clear, what do you mean by a 'normal' bottom bracket and can I tell which types of bike have a normal bracket and those that don't?
I try and avoid the press fit bottom brackets on more "top end" bikes and stick with the BSA threaded bracket

1) if you are fitting a bottom bracket torque sensor or want to keep this as an option for later (or buying mid drive)
2) for a cadence sensor, the LHS pas sensor fits onto the square taper bottom bracket
See instructions here


Go to what's new/new.lhs pedal sensor
 
  • Like
Reactions: unknown quantity

Peter.Bridge

Esteemed Pedelecer
Apr 19, 2023
666
302
.. The Subway is basically a hardtail mountain bike with rigid steel forks instead of suspension, being a mountain bike you can fit big tyres on it for comfort like Schwalbe fat franks or similar (and these will also give you more grip), comfort grips and of course a sprung saddle or even suspension seat post. Lots of ways to improve comfort without the additional expense, weight and maintenance requirements of front suspension.
...
Yes, I think rather than the relatively heavy oil filled front suspension forks (that I have on my Vulcan), that rigid forks / bigger tyres / suspension seat post might be a better option for comfort, certainly on road
 
Last edited:
  • Like
Reactions: unknown quantity

Waspy

Esteemed Pedelecer
Sep 8, 2012
298
85
Thanks Peter. Just so I'm clear, what do you mean by a 'normal' bottom bracket and can I tell which types of bike have a normal bracket and those that don't?
This video shows a guy removing and installing a 'normal' or square taper bottom bracket, also called a sealed cartridge bottom bracket. These were the standard for many years on bikes.
A lot of modern bikes now have bottom brackets where the bearings are in cups outside the frame.

<iframe width="560" height="315" src="
" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe>
 
Last edited:
  • Like
Reactions: unknown quantity

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,130
8,230
60
West Sx RH
Front suspension became all the rage with MTB's and off road use, they simply aren't needed on roads or local car free cycle routes . They add unnecassary weight and are imv a fad that aren't really needed for the op's intended usage.

Which ever system one plumps for just make sure it isn't a crappy speed control system.
 
  • Like
Reactions: unknown quantity

Cadence

Pedelecer
Feb 23, 2023
178
143
I have a 1992 Giant rigid mountain bike that cost me the princely sum of £35.00, which I converted with a Yosepower rear kit:-
WP_20230625_18_36_07_Pro_LI.jpg

With a steel frame It's a heavy old thing but is my "go to" bike for road, cycle path and canal towpath riding. I use it much more than my other conversion, which has 700c wheels. With 26" x 1.95 tyres it's very comfortable and gets up hills with ease. I fitted a 350w. kit and as it's unrestricted I can sustain 20mph on level or slightly rising gradients and it is very stable, although in practice I rarely need to go that fast.
The only real downside is the v-brakes which get through brake pads quickly and need regular adjusting, but for the fairly sedate riding I do they stop adequately. I tend to use softer brake pads to try and minimise the inevitable rim wear. I wish I could find a replacement front fork with disc mounts, but it's not a pressing issue.
If I started again from scratch I would definitely be on the look out for an older Carrera Subway with disc brakes. Very similar geometry to my Giant but with a lighter aluminium frame and rigid steel forks.
 
Last edited:

saneagle

Esteemed Pedelecer
Oct 10, 2010
4,163
2,066
Telford
Thanks Peter. Just so I'm clear, what do you mean by a 'normal' bottom bracket and can I tell which types of bike have a normal bracket and those that don't?
Traditionally, most bottom brackets were 68mm long with a 1.370" dia x 24 this thread. You'll find that on all catalogue type bikes and most bikes before about 10 years ago. Today, bikes have become more technical. MTBs have wider tyres and they want stiffer and stronger BBs, and road bikes have become lighter and stiffer. That has brought a whole range of new BB designs - different lengths, different shafts, different threads and the press-fit unthreated ones.

When you buy a conversion kit, the pedal sensors are mainly designed to fit only the BSA type BB. The important things are how much gap you have between the BB and either the chainring or left crank to fit a sensor, or the width when you want to fit a crank- drive motor. There are a range of more special parts that can often overcome whatever difficulties the bike has in those areas, but they normally require some understanding and imagination on the part of the installer.

A motor makes a big difference to a bicycle. A lot of features that are advantageous on a normal bike become less significant when you add the motor. You don't need fancy gears on a bike for riding to work anymore, nor are fancy bottom brackets going to do much for you. What you want are nice brakes, suspension and a strong frame. Light weight can still give an advantage if you're not heavy yourself.

Some of the modern MTBs have wide BBs and rear frames that encroach on the chainwheel, so that there's only room for a small chainwheel. That makes them mainly unsuitable for ebike conversion as a general purpose bike apart from the cost of replacing the very expensive service parts.
 

unknown quantity

Finding my (electric) wheels
Feb 2, 2024
11
7
Lots more helpful replies and info, so thank you all for that!

On reading bonzo Banana's and other comments on the benefits of front hubs along with alternative suspension options for rigid front forks, I am thinking this might still be the best option for me.

However, as was mentioned earlier, the Subway has 27.5/650C wheels, but there don't seem to be many (or any?) conversion kits around that offer front hub kits in that wheel size? An I missing something here?

I've read that you can make your own motor wheel but I'd rather not have to do that ideally and would probably think about an alternative donor bike with a wheel size that has more readily available kits (with matching wheel sizes).

Any input welcome!
 
  • Like
Reactions: Waspy

Waspy

Esteemed Pedelecer
Sep 8, 2012
298
85
However, as was mentioned earlier, the Subway has 27.5/650C wheels, but there don't seem to be many (or any?) conversion kits around that offer front hub kits in that wheel size? An I missing something here?
Yes you are missing something!

Woosh already said earlier in this thread he does a 27.5 XF07 Front Wheel kit LOL

For anyone living in the UK, Woosh is a great choice, great advice pre-purchase, great after sales service, great warranty.

What are you waiting for? Get your hand in your pocket!

/fanboy
 
  • Like
Reactions: unknown quantity

Bonzo Banana

Esteemed Pedelecer
Sep 29, 2019
740
432
I have a 1992 Giant rigid mountain bike that cost me the princely sum of £35.00, which I converted with a Yosepower rear kit:-
View attachment 56429

With a steel frame It's a heavy old thing but is my "go to" bike for road, cycle path and canal towpath riding. I use it much more than my other conversion, which has 700c wheels. With 26" x 1.95 tyres it's very comfortable and gets up hills with ease. I fitted a 350w. kit and as it's unrestricted I can sustain 20mph on level or slightly rising gradients and it is very stable, although in practice I rarely need to go that fast.
The only real downside is the v-brakes which get through brake pads quickly and need regular adjusting, but for the fairly sedate riding I do they stop adequately. I tend to use softer brake pads to try and minimise the inevitable rim wear. I wish I could find a replacement front fork with disc mounts, but it's not a pressing issue.
If I started again from scratch I would definitely be on the look out for an older Carrera Subway with disc brakes. Very similar geometry to my Giant but with a lighter aluminium frame and rigid steel forks.
That is a really nice looking conversion, so neatly done almost like a pre-built commercial ebike, the cable management is excellent. I can see why you are not totally happy with the brakes though. I think V brakes are fine when combined with a direct drive hub motor with regen or a very low power ebike kit like the Swytch kit but they seem a little underpowered for your setup. Stick it on facebook marketplace for £700-900 and if anyone bites you have your budget for your mk2 build with disc brakes.
 
  • Like
Reactions: unknown quantity

scbk

Pedelecer
Feb 25, 2019
51
16
Highlands
Hydraulic disc brakes are great, much better than mechanical disc, which are better than rim/V brakes.

But my first electric conversion was on a 26" wheel bike with V brakes, that old thing has done almost 5,000 miles now. More powerful motor than you're wanting, plenty of hills, and I didn't die......the brakes were fine.

You could convert your existing bike into a reasonable electric bike, see how you get on using that, and plan your next conversion.


I'm not keen on 2nd hand gumtree/facebook bikes, too many stolen. You can buy new for not much more, there's deals to be had.
 
  • Like
Reactions: unknown quantity

Bogmonster666

Esteemed Pedelecer
Jun 6, 2022
263
139
I did think about that - it's a claud butler trailridge mountain bike. However, it's got off-road knobbly tyres with v brakes so I'm not sure it's up to the task.
I thought a newer bike (like the Subway or crossfire) with relatively standard fittings might be better if people were able to confirm that they had already been able to convert these.
I have been keeping an eye out for older mountain/hybrid bikes that I thought might be suitable though..
My bike is a ~30 year old Claud Butler MTB. I upgraded to vee brakes from cantilever.... However, you may find that so much is worn out on your bike that getting something newer would be more cost effective.

I have a tsdz2 mid drive and thought I might source a newer bike at some point and move the kit. Really have not felt the need though as my bike suits me.

The great think about my bike is it looks like a heap of dung so nobody gives it a second glance when I leave it places and I take the bag battery (mine is actually in a waterproof box) with me.

Whilst disc brakes would be better (and I do live on a steep and dangerous hill), properly adjusted rim brakes are feasible. I find I do need to take a bit of extra care in the wet and anticipate the steepest parts of the dangerous hill. On relatively flat terrain the rim brakes cause me absolutely zero concerns.

If I were to build another bike I think I would try a rear hub with a BB torque sensor.

A very long time ago I had a front hub bike and didn't like it much. Things have moved on I'm sure but it would not be my choice.
 
  • Like
Reactions: unknown quantity

Cadence

Pedelecer
Feb 23, 2023
178
143
That is a really nice looking conversion, so neatly done almost like a pre-built commercial ebike, the cable management is excellent. I can see why you are not totally happy with the brakes though. I think V brakes are fine when combined with a direct drive hub motor with regen or a very low power ebike kit like the Swytch kit but they seem a little underpowered for your setup. Stick it on facebook marketplace for £700-900 and if anyone bites you have your budget for your mk2 build with disc brakes.
Many thanks for the compliments. Not easy to see in the photo, but the cables to the handlebars are contained in a length of black D-Line half-round trunking (from B & Q and elsewhere) fixed underneath the downtube. The over-long Yose motor cable goes up the rear leg of the pannier rack, fixed with spiral wrap.
I like the Giant so much now that I wouldn't want to part with it. It's very comfortable and the v-brakes are OK for my kind of cycling. If a cheap Subway came up locally though....hmmm?
A fourth ebike might take some explaining to the domestic authorities! :(