Trek / CST motor / Hydraulic Disc Brakes / Cassette

[103Alex1]

Just given the Trek 8500 its 1st proper test ride. All I can say is WOW IT's FAST !!!!!!! Flew up 1st moderate short hill without a motor even with big knobbly 2.2 tyres and stock Bontrager race rims !!!! I can definitely see me keeping this bike - I'm starting to love it now.

Definitely want to try to keep this bike convertible back to regular wheelset with disconnectable controller, swappable rear wheel etc. if I use it for conversion project. No messing with dropouts etc. which would alter the underlying frame.

The bike has Shimano XT hydraulic disc brakes and a 9-speed cassette.

So a few more issues to weigh up :

1) How do I work out if the existing dropouts would take a CST hub motor without filing so the original setup can be restored in future.

2) Are controllers usually bolted to the frame or can they sit in a triangle bag with the battery so they can be unplugged and removed at will to remove the weight ?

3) I want to make wheel-swapping as easy as possible. If I want to keep the original rear wheel intact so I can just fit it back on in place of the hub motor wheel as an interchangeable set would I need to get a second cassette and brake disc to fit to the rear hub motor wheel ?

4) Where am I supposed to put a rear reflector (the bike doesn't have one at the moment) which despite them being legally required I don;t see the point of if you have a bright rear light (!) ? There's a crudcatcher mudguard with a steep upward angle and the seatpost will struggle to house this, a rear light, seatpost bag (in the absence of rack). Am I missing something totally basic ?

5) The seatpost clamp is rigged up to take a rack fitting (just swapped over). I can fit a Topeak Super Tourist Rack with MTX built for disc brake wheels which will be compatible with the wheels on the bike at the moment. Will fitting a wheel with built-in CST hub be compatible with that sort of rack if I wanted it on when using the bike in "eBike mode" ?

All help welcome. Thx !

 

[Jeremy]

My experience has been that it's rare to need to do anything to the frame on a standard bike to fit a hub motor. There can be clearance problems occasionally, but these can nearly always be fixed by just springing the drop outs out slightly and adding a washer, with no permanent harm to the frame done. The only slightly tricky bit might be the rear disc alignment, this may need the calliper spacing a bit. I've had one frame where this was a problem.

Not a good idea to fit the controller inside a bag, it needs to be out in the cool air. Fitted to the outside of a bag would be OK.

I fit reflectors/lights on the rear of the saddlebag/rear rack, works well and is easy to do.

Yes, you'd need a second cassette and disc unless you want to swap them over to the other wheel each time.

No reason why the rack should have any effect on the rear wheel, I'd have thought.

 

[103Alex1]

Thanks Jeremy.

No reason why the rack should have any effect on the rear wheel, I'd have thought.

If I swap out the wheels to run the bike in 'non-eBike mode' chances are I'll want the weight down as far as possible and remove any rack fitted (which is how it is at the moment). Do people only use these bikes off-road / in daylight without reflectors ?

Here's a pic of the current setup with no rack yet (seatpost bag would usually be on but it was on my other bike and I hadn't yet fitted the rear light when I took the pic). I can't see anywhere else to fit the reflector

 

[Old_Dave]

Fit a 'reflective' strip to the bag, or fit it to the rack when you have one.


Sent from my iPhone using Tapatalk

 

[Fordulike]

2) Are controllers usually bolted to the frame or can they sit in a triangle bag with the battery so they can be unplugged and removed at will to remove the weight ?

My 30A 9 fet controller sits inside my triangle frame bag alongside a 48v 15Ah Ping.
There is around 1cm air space along the top and sides of the controller.
I always have the bag fully closed. No fresh air can get in.
I'm constantly drawing the full 30A for periods of time, so I can imagine the controller getting quite warm.
I also WOT most of the time too.
To date, with over 1000 miles, I've had no problem whatsoever with the controller overheating.

 

[amigafan2003]

You'll also need to adjust the rear brake and the rear gears each time you swap the wheel as well as it's very unlikely they'll be in the same position for both wheels.

 

[Deleted member 4366]

which would alter the underlying frame.

1) How do I work out if the existing dropouts would take a CST hub motor without filing so the original setup can be restored in future.

2) Are controllers usually bolted to the frame or can they sit in a triangle bag with the battery so they can be unplugged and removed at will to remove the weight ?

3) I want to make wheel-swapping as easy as possible. If I want to keep the original rear wheel intact so I can just fit it back on in place of the hub motor wheel as an interchangeable set would I need to get a second cassette and brake disc to fit to the rear hub motor wheel ?

4) Where am I supposed to put a rear reflector (the bike doesn't have one at the moment) which despite them being legally required I don;t see the point of if you have a bright rear light (!) ? There's a crudcatcher mudguard with a steep upward angle and the seatpost will struggle to house this, a rear light, seatpost bag (in the absence of rack). Am I missing something totally basic ?

5) The seatpost clamp is rigged up to take a rack fitting (just swapped over). I can fit a Topeak Super Tourist Rack with MTX built for disc brake wheels which will be compatible with the wheels on the bike at the moment. Will fitting a wheel with built-in CST hub be compatible with that sort of rack if I wanted it on when using the bike in "eBike mode" ?

All help welcome. Thx !

Whenever I get a new bike to convert, it always seems to be too good to spoil, and I also get that idea about being able to convert it back easily, but a bike that's good before conversion usually makes a brilliant converted one, so I never went back.

You can test the width of the drop-outs with anything that's exactl 10mm diameter. With a powerful motor, you need some metal around the axle, and you often find that the axle doesn't go in deep enough because of the diameter and shape of the new axle shifts the centre by about 2.5mm. I usually dremmel mine to make the shape match the new axle and recentralise it. If you then want to swap back to a normal wheel, it'l be OK with a couple of washers at the bottom of the caliper bolts. Don't forget a good torque arm, which would be essential if you don't deepen and advisable if you do.

Both Saneagle and I have had KU123 controllers in bags without air flw on several 500w bikes, and they never got hot. It would be more of a problem with a high speed motor.

That rack sounds perfect, but you might want to adjust the legs to get the battery just above the wheel and tight against the seat-post for best handling. Look at Saneagle's Kraken.

 

[103Alex1]

Fit a 'reflective' strip to the bag, or fit it to the rack when you have one.

No bag at the moment Dave - this is "stripped down for racing spec" right now ! I can put one on the rack/bag if they are on as you say but if no rack there won't be a bag either.

I think the mudguards are going to have to go if a rack is fitted too ... unless there is some other way of getting them to fix under the rack. The frame doesn't have fixing points to bolt into. Asked the LBS and they just looked blank !

2)
I always have the bag fully closed. No fresh air can get in.
I'm constantly drawing the full 30A for periods of time, so I can imagine the controller getting quite warm.
I also WOT most of the time too.
To date, with over 1000 miles, I've had no problem whatsoever with the controller overheating.

Good to hear. That's some motor you have on there ... is it my imagination or are you running a 700c wheel at the rear and a 26" at the front ?

Btw ... What's WOT ?

You'll also need to adjust the rear brake and the rear gears each time you swap the wheel as well as it's very unlikely they'll be in the same position for both wheels.

Heck - it's never a walk in the park is it ? To be fair adjusting the rear brake and rear gears isn't such a big deal but in reality it's likely enough to mean I can't be bothered to swap them over for a day or two at a time (which is what it would likely be).

Whenever I get a new bike to convert, it always seems to be too good to spoil, and I also get that idea about being able to convert it back easily, but a bike that's good before conversion usually makes a brilliant converted one, so I never went back.

I never imagined a hardtail mountain bike could be that fast. It felt like riding like a racing bike with a bit of tyre drag from the knobbly bits ! Really made me stop and think. If I was riding that round here (or having a bash at off-road racing) rather than it being destined for the gruelling Devon Alps, I'd just leave it as it is. Losing all that weight (on the bike that is !), penny dropped I'm a lot fitter than I realized after 4 months racing lycras on my Kalkhoff !

Would definitely have no shortage of buyers - LBS reckoned I got it £150 less than it should have been let go for even with a cheeky cash offer and private sale. If I can keep the frame intact and in reasonable nick the bike will easily hold it's value for a good year. Always good to achieve if you can.

You can test the width of the drop-outs with anything that's exactl 10mm diameter.

Took a tape measure to them - they are exactly 10mm so hopefully that bodes well.

With a powerful motor, you need some metal around the axle, and you often find that the axle doesn't go in deep enough because of the diameter and shape of the new axle shifts the centre by about 2.5mm. I usually dremmel mine to make the shape match the new axle and recentralise it. If you then want to swap back to a normal wheel, it'll be OK with a couple of washers at the bottom of the caliper bolts.

I guess the only real way is to wait and try the axle in the dropouts from a motor unit ? I took these photos having removed the quick-release skewer and also pulling the dropouts away from the wheel. Don't know if it's possible to tell from that whether dremelling likely but there they are in case :

Don't forget a good torque arm, which would be essential if you don't deepen and advisable if you do.

Will these do or are there any others I should consider choosing instead ? ...

PS - just seen reference to 12mm axle there ... does that mean the CST is 12mm too as it says all their motors bar MagicPie3 are 12mm ?

EBike Torque Arm

That rack sounds perfect, but you might want to adjust the legs to get the battery just above the wheel and tight against the seat-post for best handling. Look at Saneagle's Kraken.

I'm still erring on the side of trying to get the battery in the frame triangle to leave the rack clear for either a slid-on MTX bag for stuff like a D-lock or bungeeing a duffel bag full of wetsuits and freediving kit onto .. I'm a very slim build and whilst I can wear rucksacks for gear they don't like to stay put on my shoulders and wind up being ... well ... a total PITA . It's something that's not an issue if you're not built that way - but if I can avoid rack-mounting I would really like to try mainly for that reason.

The "sea gear" is bulky. Also considered putting that stuff in a triangle bag but it would likely be a squeeze or cause it to bulge excessively so best option is a drysac on the rack if I can manage it.

.... mind is still going round & round over the mudguard thing !

 

[Deleted member 4366]

The axle is 12mm diameter, which is milled to 10mm accross the flats, so 12mm torque arm not 14mm.
I carry al my stuff in a large hold-all with shoulder strap. It doesn't hinder pedalling at all, I can get masses of stuff in it, quick to load and unload, and it leaves the bike unhindered.

 

[Fordulike]

Good to hear. That's some motor you have on there ... is it my imagination or are you running a 700c wheel at the rear and a 26" at the front ?

Btw ... What's WOT ?

Both are 26" wheels. Must be the angle the picture was shot.

The motor is a MAC 10T from Cellman and is a torquey beast

WOT = Wide Open Throttle (basically full beans on the throttle)

As for you fitting the battery inside a triangle bag in the frame.
On a quality bike like yours, I would definitely fit it inside the frame.
A battery inside the frame provides much better balance and handling, especially on wet or loose ground.
You'll ruin the feel of the bike by mounting the battery on a rack in my opinion.

Look forward to seeing your completed project

 

[103Alex1]

The axle is 12mm diameter, which is milled to 10mm accross the flats, so 12mm torque arm not 14mm.

Understood. M12 then.

Both are 26" wheels. Must be the angle the picture was shot.

The motor is a MAC 10T from Cellman and is a torquey beast

WOT = Wide Open Throttle (basically full beans on the throttle)

As for you fitting the battery inside a triangle bag in the frame.
On a quality bike like yours, I would definitely fit it inside the frame.
A battery inside the frame provides much better balance and handling, especially on wet or loose ground.
You'll ruin the feel of the bike by mounting the battery on a rack in my opinion.

Look forward to seeing your completed project

Right - don't read about many of those on here. I know what you mean about the handling - even when I load the Agattu up very heavily on the back you really do notice a difference. Well, I do anyway.

Still keep looking at the frame thinking it's too nice to cover up though .. really must get a grip - it's a bike and not a glamour model !

.....................................................................................................................................


Day of highlights and lowlights today ..

I have, in the meantime, had a day of highs and lows. There was a broken spoke on both wheels (vendor did tell me to be fair) ... I managed to replace the spoke on the front wheel and it's running fine after having the brake disc, tyre and tube off to fit it. So another new experience.

However, I did manage to break the presta valve on the front tube trying to get it out with those enormous 2.2 tyres on - so it was down the bike shop !

My efforts with the rear wheel spoke replacement have been less successful. I got the replacement tube ready (just as well because - yes- broke another Presta valve ... total rubbish compared to Schraders but the race rims won't take 'em !!!!!! )

Not having thought the job through I then realized I'd have to remove the blooming cassette to get at the hub as the spoke was on that side. Rolled over and bought a 20% off Halfords essential bike tools pack this evening in order to be able to get on with the job ... but have been completely defeated by the cassette removal exercise.

I am either so exhausted from going to the gym earlier that I haven't the strength left to get the cassette off - or someone has exceeded the 40nm torque and over-tightened the central (or it has seized). I just can't get enough purchase with the chain whip to unlock it. It's also really hard to get the wheel level because of the hub on the other side. Don't have a vice so have hit a brick wall on ideas.

May end up back at the bike shop with tail between legs having failed to DIY .... on account of a jammed cassette (very frustrating and not what I had envisaged !!!!!!!). If anyone has any readily do'able tips for dealing with this would be grateful !

I have none of the following up here where I am working on the bike :

- Drills
- Files
- Vices (well, not of the metal kind anyway !)
- Blocks of wood

- so any solutions involving same will require more dosh outlay

 

[oigoi]

What you need is a tool called a hypercracker. However these are no longer made so a tool called the next best thing 2 or NBT2 is available from spa cycles:

NBT2 (next best thing) Cassette lockring remover :: £17.00 :: PARTS & ACCESSORIES :: Tools :: Spa Cycles, Harrogate - The touring cyclists specialist.

 

[103Alex1]

What you need is a tool called a hypercracker. However these are no longer made so a tool called the next best thing 2 or NBT2 is available from spa cycles:

NBT2 (next best thing) Cassette lockring remover :: £17.00 :: PARTS & ACCESSORIES :: Tools :: Spa Cycles, Harrogate - The touring cyclists specialist.

Aha ... thanks. £17 ?! .. it's enough to encourage you to set up in business unlocking seized cassettes !

I'll have to look for another supplier tho' ... I am banned from buying anything from Spa Cycles. Owner is the nastiest man I've ever come across in retail and the only person to tell me to "f*ck off" (literally) over the phone when I queried where an order was. I kicked up a stink about his abuse asking for an apology and his response was to petulantly protest that he didn't want my business and would make a note never to deal with me again. Great way to run a shop !!!!

It does say on the item description "Prior to first time use it is recomended to check with conventional tools that the lockring hasn't been tightened way over the recommended torque by some hamfisted mechanic, to prevent overloading the dropout."

I think that probably sums up exactly what the problem is here !

 

[Deleted member 4366]

I wouldn't bother doing anything to the back wheel. It works as it is, and it should last until you get your hub-motor in. Then you'll have all the time in the world to fix it.

 

[banbury frank]

Hi youtube video on how to remove both types off free wheels screw on and cassette


How-to remove a bicycle freewheel or cassette - YouTube

Frank

 

[RobF]

I am banned from buying anything from Spa Cycles. Owner is the nastiest man I've ever come across in retail and the only person to tell me to "f*ck off" (literally) over the phone when I queried where an order was. I kicked up a stink about his abuse asking for an apology and his response was to petulantly protest that he didn't want my business and would make a note never to deal with me again. Great way to run a shop !!!!!

The bloke at Spa is certainly a character, you either, er, hate him or don't like him very much.

Having said that, he gave me a discount on my Brompton.

Brompton got wind of that - not sure how - and he fell out with them bigstyle.

Told me he'd dealt with them for 20 or 30 years and they'd always been difficult.

Other dealers have told me the same, so there's fault on both sides.

He dropped Brompton - or they refused to supply him - soon after my order was filled, so I think I may own the last Brompton sold by Spa.

 

[Electrifying Cycles]

Very interesting re Brompton have to be very careful. A number of companies have got in trouble for telling people you must sell something for a set price as this is illegal. Although nothing to stop companies refusing to supply companies. Have never sold Brompton bikes but have to admit they are very neat folders. However when we started we sold Mezzo which is a great brand but realtively unknown/low profile.

 

[103Alex1]

I wouldn't bother doing anything to the back wheel. It works as it is, and it should last until you get your hub-motor in. Then you'll have all the time in the world to fix it.

Was just a bit worried about about wrecking the rim doing any significant riding on it, but if that's not likely, pressure off !

I did think about not bothering to remove - then thoughts were that if I want to swap over the cassette so as not to have to immediately buy another one (at least initially) then one way or another it's going to have to come off so might as well get it able to be removed and replaced sooner rather than later.

Hi youtube video on how to remove both types off free wheels screw on and cassette

How-to remove a bicycle freewheel or cassette - YouTube

Frank

Thanks Frank. It's definitely a cassette and I reckon the tool I'm missing is Bikeman's huge wrench ! The Halfords pack works by inserting a long alum key into the top of the tool to provide required leverage, which is no way enough. The chain whip is also attached to a lightweight spanner which isn't ideal. It's like trying to use an adjustable spanner instead of a pedal wrench when the pedals have been over-tightened .. you're onto a losing battle from the start !

This is always the problem when bikes are serviced in workshops (as this one is claimed to have been).. you need workshop tools to get things undone again as in about 6 out of 10 cases someone has over-tightened !

I am tempted to return Halfords' kit and take some time selecting and buying some proper heavy duty tools which are up to the job and will last me a few years. It's a lot less frustrating doing jobs when you have a decent set of tools to work with.

He dropped Brompton - or they refused to supply him - soon after my order was filled, so I think I may own the last Brompton sold by Spa.

Perhaps it's a case of "ye reap as ye sow" ?!

 

[RobF]

Very interesting re Brompton have to be very careful. A number of companies have got in trouble for telling people you must sell something for a set price as this is illegal. Although nothing to stop companies refusing to supply companies. Have never sold Brompton bikes but have to admit they are very neat folders. However when we started we sold Mezzo which is a great brand but realtively unknown/low profile.

Out of favour dealers might find their orders take a long time to fill, or mess up in some other way.

Brompton also refuse to allow their bikes to be despatched to the customer by a courier - even Evans abide by that.

Daft really because the Brompton - packed in its box - must be be the easiest bike to send.


Alex,

As you know, the bloke from Spa could have a fall out in an empty room, so it was only a matter of time.

This quote from the Spa website gives an indication of the general attitude:

"If you bought it here, we fix it here.
"Repairs to quality lightweight or touring bikes and repairs to bikes belonging to good customers are likely to be accepted.
"We don't deal with BMX, full suspension or cheap poor quality bikes of any description."

Apologies for drifting your thread.

Rob.

 

[catsnapper]

A cheap, solid wrecking bar like thisRoughneck Wrecking Bar 18" : Tooled-Up.com plus a scrap length of chain wrapped round the cassette and hooked into the end of the wrecking bar makes an indestructable chainwhip.

Combine this with a cassette removing tool with a 1/2" drive to take a 12" (or thereabouts!) bar to defeat most stubborn cassettes.
Total cost is about £12.

Alan