KTM Terramo Rohloff Bafang 36v500w BBS02 Complete

[robwalley]

The beast is done bar the magnetic brake cutoffs for hydraulics, stripped to the frame, powder coated and rebuilt including rear wheel. 14.5 amp battery and 14 speed rohloff.
I've set to 9 assists with a 17 inch wheel in kph which gives mph on a 700c, the chainwheel is a Bafang 52t which gives the exact measurements (on a vertical dropout) to require no chain tensioner. Specs on the stand are crazy level 1 in gear 1 is 3.57mph rising to 50.8mph in level 9 in gear 14. This of course will not equate with 11 stone and the bike weight underneath, but should equate to 30+. Full test on the flat tomorrow. I also have a USB programming lead, so any suggestions for parameters welcome(variable throttle is a given), mixed flat and steep hills with the odd family leisure ride.

 

[Kinninvie]

You can set your wheel size correctly and set max speed to 50kph as I have on my 29er and it pulls happily to 34Mph which I think will be faster than yours will go being a 500w as opposed to my 750w.
To be honest,with those brakes, I think 30Mph will be plenty!

 

[Kenny]

I don't want to start the disc v rim brake debate but I'm also 11st and find my Magura hydraulic rim brakes more than adequate at any speed.

Very nice bike Rob!

 

[robwalley]

You can set your wheel size correctly and set max speed to 50kph as I have on my 29er and it pulls happily to 34Mph which I think will be faster than yours will go being a 500w as opposed to my 750w.
To be honest,with those brakes, I think 30Mph will be plenty!

I think they may both go a little quicker, work out your top gear ratio and wheel circumference and the max rpm which I counted at about 130rpm, this should give your theoretical no load speed, you may find your gearing to be the limiting factor, the rohloff range is 526% 1-14 and I have a 52t on the front. Beside the point though, I'm would be happy with 30mph with better torque, range and longer controller lifespan.

Curious how you go 34mph when the max is set 50kph, shouldn't it cut out at 30mph(50kph) That's why I set 17inch wheel and kph, so the max is close to 50mph not kph. Not sure you can up this in the advance programming.

The magura hs11 hydraulic rim brakes have huge stopping power, some downhillers prefer them. I'm just not sure I want to install the brake cutout sensors, you can adjust the cutout time (in milliseconds) when you stop pedalling to very virtually zero in the advanced programming, which would be as quick. I guess in an emergency which comes first, stop pedaling or brake.

Quick test this morning got to 28mph in level 6 in 14th gear. Theoretical no load is 40mph with these settings, so I can probably reduce some higher settings in the advanced programming, I know I can reduce gears, but the rpm is too high to feel comfortable, so far ambling along in level 2 in top gear at 19mph is just right and closer in percentage terms to the theoretical of 23mph.

 

[Kinninvie]

Didn't realise they were hydraulic.
I think when you set max speed to maximum it maybe doesn't regulate it.
Fastest I have been on this is 49.9mph(on gps and Strava) but I think going down a 25% hill helped there!

 

[mfj197]

I think when you set max speed to maximum it maybe doesn't regulate it.

Correct.

I'm just not sure I want to install the brake cutout sensors, you can adjust the cutout time (in milliseconds) when you stop pedalling to very virtually zero in the advanced programming, which would be as quick. I guess in an emergency which comes first, stop pedaling or brake.

I find the brake cutoffs essential myself for the following reasons:

• Downshifting as I slow down for a junction (I still need to turn the crank as mine's a derailleur setup - don't want the drive kicking in!)
• Coming to a halt a car or two back from a junction and needing to move forwards slowly when each car in front moves off without being fired into oncoming traffic by the motor
• Half-turning the cranks to keep the inside pedal high when leaning hard over and switching from one side to the other as for a roundabout
• Generally creeping forward in stop-start traffic (as opposed to filtering).

Some of these may not be applicable for you but it's amazing how much I use the cutoff functionality, and it's also surprised me how quickly it has become second nature.

Quick test this morning got to 28mph in level 6 in 14th gear. Theoretical no load is 40mph with these settings, so I can probably reduce some higher settings in the advanced programming, I know I can reduce gears, but the rpm is too high to feel comfortable, so far ambling along in level 2 in top gear at 19mph is just right and closer in percentage terms to the theoretical of 23mph.

What do you want to achieve with the programming? What would you like the motor to do in the different levels?

Michael

 

[robwalley]

Correct.

I find the brake cutoffs essential myself for the following reasons:

• Downshifting as I slow down for a junction (I still need to turn the crank as mine's a derailleur setup - don't want the drive kicking in!)
• Coming to a halt a car or two back from a junction and needing to move forwards slowly when each car in front moves off without being fired into oncoming traffic by the motor
• Half-turning the cranks to keep the inside pedal high when leaning hard over and switching from one side to the other as for a roundabout
• Generally creeping forward in stop-start traffic (as opposed to filtering).

Some of these may not be applicable for you but it's amazing how much I use the cutoff functionality, and it's also surprised me how quickly it has become second nature.

What do you want to achieve with the programming? What would you like the motor to do in the different levels?

Michael

The creeping forward bit is a good point, I have nearly come a cropper on other bikes at asymmetric metal posts usually at the end of cycle paths to slow you down, I can usually drift through, but if I get it wrong then a bit of pedal pushes you straight into the posts. On the programming, I'll do a couple more test runs and normal basic programming that others tend to agree on and come back to you.

 

[Kinninvie]

I use a horn button connected to a brake cutout plug then it works like a clutch to disconnect the motor power.
EM3EV sell them as do Emax and others

 

[robwalley]

Just thought of an idea. You can buy brake lights for bicycles that work on inertia like the devices inside iphones. I have used one and they are instant. Investigations underway.

 

[mfj197]

Just thought of an idea. You can buy brake lights for bicycles that work on inertia like the devices inside iphones. I have used one and they are instant. Investigations underway.

That would unfortunately only work when actually slowing down, not when for example creeping forward.

I use a horn button connected to a brake cutout plug then it works like a clutch to disconnect the motor power.
EM3EV sell them as do Emax and others

Why not just use a brake cutoff switch? That way you don't need to find extra handlebar space or think about another control. They are also available in the UK.

If it helps, here are my brake cutoff switches on the Shimano M355 hydraulic brakes I have. Installation was dead easy actually.

 

[robwalley]

I have the hydraulic cutoff switches, just haven't fitted them and am trying to be clever regarding other ideas. But as usual re-inventing the wheel doesn't work so I think this is next, looks like a small job, not sure about self adhesive though?

 

[mfj197]

The adhesive backing works fine. I cut off the two protruding tabs so the sensor would fit within metal gussets on my brake levers and made a smooth chamfer out of epoxy putty for a completely flat surface.

By the way, if you got the sensors from Eclipse they had a batch of faulty ones. I've just updated an earlier thread detailing the issue and how to diagnose.

 

[robwalley]

Ta, I found the other thread, I'll try them out in the next couple of days, I'll have to stick them on underneath I think, the magura rims have no room within the hinge.

 

[Kinninvie]

Why not just use a brake cutoff switch? That way you don't need to find extra handlebar space or think about another control. They are also available in the UK.

Because I dont want to be pulling the brake lever when changing down gears on uphills.

 

[mfj197]

Because I dont want to be pulling the brake lever when changing down gears on uphills.

You can set the sensors up so they cut power well before the brake pads make contact with the brake discs, so no problem there. I'm not hugely keen on using the cutoffs when changing down going uphill anyway, whether activated by a brake lever or other switch plugged in to the brake cutoff connector. The pause in power is a bit too long and is not adjustable via programming. It is possible to send a "low throttle" signal instead which brings power back instantaneously once released, but it's rather more complicated. Myself I just use lower power levels and not worry about cutting the power at all for shifting in these circumstances.

Michael

 

[anotherkiwi]

My PAS cuts off the motor in under a second. I don't have a throttle so no risk it will stick open. I am on a bicycle going bicycle speeds, not in a F1 car where half a second delay is death or grievous bodily harm. I also have a Magura hydraulic on the front and in a panic situation pulling hard on it will cause a stoppie (yes I have already tried). No brake cutout = two less wires on the handlebars, no throttle makes three less wires! Win, win, win as far as I can see it.

 

[robwalley]

My PAS cuts off the motor in under a second. I don't have a throttle so no risk it will stick open. I am on a bicycle going bicycle speeds, not in a F1 car where half a second delay is death or grievous bodily harm. I also have a Magura hydraulic on the front and in a panic situation pulling hard on it will cause a stoppie (yes I have already tried). No brake cutout = two less wires on the handlebars, no throttle makes three less wires! Win, win, win as far as I can see it.

I'm trying the programmer soon and I know in that I can reduce the milliseconds between cutout when stopping pedalling and the 25 miles so far with no brake cutouts and default delay has been no issue, also tried emergency stop with the hydraulic rims and the motor has no chance, it's only adding similar watts to a pro racer, although watching the TDF they seem to struggle stopping, think that is rubbish brakes by design.

 

[robwalley]

My PAS cuts off the motor in under a second. I don't have a throttle so no risk it will stick open. I am on a bicycle going bicycle speeds, not in a F1 car where half a second delay is death or grievous bodily harm. I also have a Magura hydraulic on the front and in a panic situation pulling hard on it will cause a stoppie (yes I have already tried). No brake cutout = two less wires on the handlebars, no throttle makes three less wires! Win, win, win as far as I can see it.

Posted my BBS02 programming settings on another thread and I have motor cutoff set to 100ms, works fine, definitely do not need the brake cutoffs, did want to creep forward now and again without lurching, but some less agressive starting amps and a longer ramp up in the programming solves this too. So I have for sale.........