Hills near me...

[Bogmonster666]

Found a fun little website when researching gradients and hills near me. I'm on a TSDZ2 mid drive with stock firmware, stock 42t chainring, 11t to 28t cassette and 26" wheels.

I live in a hill and to go almost anywhere worth going (well, not quite true, my local is excluded) involves going down hill and if I want to get home, back up hill. There clearly are steeper hills in the UK and indeed in the SouthWest, but there are still some good hills. Here are a few of the options on a nice website I found:

Draycott Steep : https://climbfinder.com/en/climbs/draycott-steep-draycott

I cycled up this years ago but not recently and not on my ebike conversion. I am not convinced my gearing is low enough at the moment to want to tackle it. Going down is probably worse with rim brakes. I think I may be able to have a go with when I swap to a 32t rear cassette although I suspect 34t would be more comfortable (but not ideal on my 7 speed).

Dears Leap:

https://climbfinder.com/en/climbs/deerleap-wookey-hole

I have done this a few times. Can manage at a reasonable pace on fresh legs on 'tour' mode. Will be easier when I swap from 28t to 32t cassette but quite doable at the moment. The road is covered in loose gravel and is narrow and twisty so a great deal of care is needed descending this route - although I find myself often going this way.

Cheddar Gorge:

https://climbfinder.com/en/climbs/cheddar-gorge-cheddar

This one is easy enough, but often very busy so I try to avoid.

Shipham Hill:

https://climbfinder.com/en/climbs/callow-rock-shipham-road

The roads up the top from here are lovely. This tends to be my preferred route down off the hill for a leisure ride. Not tried cycling up yet but sure it will be fine.

Old Bristol Road:

https://climbfinder.com/en/climbs/old-bristol-road-wells

This is my I'm tired route back up the hill. It is also a reasonably direct route from the supermarket - so often lugging a few bottles of wine up.

Westbury Hill:

https://climbfinder.com/en/climbs/westbury-hill-westbury

Tend to go down this way but ok'ish going up.

Lots of fit lycra types flock to the Mendips because of the hills, but you have to be quite cycling fit to tackle them, especially if you want to incorporate into a longer ride. If you live in the hill then the big hill is allays at the end of the ride. I'm sure I'm being a wuss but the ebike has made this hills much less daunting and got me over a barrier to cycling.

 

[soundwave]

 

[Bogmonster666]

The tsdz2 is definitely NOT the strongest hill climber, certainly with stock firmware and no throttle. The Bosch bikes I'm sure will do better and the mid drive Bafangs certainly will. I suspect some of the more powerful hubs would also do fine.

The tsdz2 works well for me as it makes me work and even with a small battery I get good range.

I'm sure if I had the Bafang mid then the 1st hill on my list would be easy enough.

 

[matthewslack]

Your 26" wheels and 42T cancel each other out compared to my 700c and 38T. The lower couple of modes might not be too different to my 40Nm e5000, so I think you are doing pretty well with a 28T bottom gear!

I started with 11-36 9 speed, but for proper hills I now use 11-51 11 speed which is a transformation!

 

[AndyBike]

Ride to the top of a small grassy hill, for the analogue riders to collapse on from sheer exhaustion

 

[soundwave]

they have all got ebikes now bar 1 lol

 

[Bogmonster666]

I would love 11-51t. That would get me up proper hills.

I did some calculations using the motor simulator ( based on 28t getting me up 16%). I think 36t rear will get me up 25% inclines which is about the steepest I'll need to tackle. That would require 9 speed which isn't that expensive a change.

My guess is my swap to 32t will probably get me up a 25% but probably with more motor effort and wear and tear than I would like.

However, for the time being I can largely limit myself to 16% anyway by picking my route. I can do that on 28t easily enough so the swap to 32t will give me plenty of leeway and it's a very cheap swap.

My guess is that if I switch to 9 speed I'll swap out my 25+ year old bike and get something with disc breaks because stopping going down is likely to become a more serious problem then getting up the hills!

 

[soundwave]

i have 10-50 at the rear and a 52t equivalent on the front and electric shifter never going back to cable

 

[Sturmey]

........ I'm on a TSDZ2 mid drive with stock firmware, stock 42t chainring, 11t to 28t cassette and 26" wheels........

You could do better. At the moment, your lowest gear ratio is 42:28 which means only two thirds of the motor torque gets to the back wheel.
I have mine (36v version) set up with dual 44/34 front and 14-34 rear which give me at lowest gear (34:34) full motor torque to the rear wheel.
I think this is necessary for hills. Without the lower gears, the TSDZ2 is no better (and possibly worst) than my other (250w hub motor) ebike at hill climbing.

 

[I893469365902345609348566]

your lowest gear ratio is 42:28 which means only two thirds of the motor torque gets to the back wheel.

Please could you tell me how you calculated that?

 

[Sturmey]

Please could you tell me how you calculated that?

42:28 = 3:2 (when divided by 14) = 1: 2/3 or one in two thirds. (when divided by 3).
On a bike, the ratio of the front chain ring to the rear sprocket multiplies (increases) the speed but divides (reduces) the torque proportionally for a set cadence.

 

[I893469365902345609348566]

42:28 = 3:2 (when divided by 14) = 1: 2/3 or one in two thirds. (when divided by 3).
On a bike, the ratio of the front chain ring to the rear sprocket multiplies (increases) the speed but divides (reduces) the torque proportionally for a set cadence.

Thank you very much! (100/42) X 28 = 66.6667 = 2 thirds

 

[Nealh]

The tsdz out of the box is a bit like the bbs, the programming is a bit tame.
With the bbs one downloads the programme and orders a prog cable to change settings.
The tsdz isn't much different but the OSF programming is a bit more involved .
One has the option of increasing the % levels on the modes , the max being 500% assist which would likely be in Turbo mode for max power.
Typically the modes will be set starting at 40 /60% in eco, tour approx. 100%, sport 160% and maybe 200% or so in turbo.

 

[AndyBike]

For all the bike info you could ever want, and a great deal more, always refer to the great Sheldon Brown

Sheldon Brown-Bicycle Technical Information

A go-to source of information about bicycle maintenance, repair and customization

www.sheldonbrown.com

eg Gear stuff.

Articles about Gears and Drivetrains

Articles about bicycle gears, including gear shifting, derailer adjustment, chain maintenance, 7-speed internal geared hubs, Shimano cassettes, fixed gears.

www.sheldonbrown.com

Enough info to keep even the most fervent geek more than satisfied.

 

[I893469365902345609348566]

The tsdz out of the box is a bit like the bbs, the programming is a bit tame.
With the bbs one downloads the programme and orders a prog cable to change settings.
The tsdz isn't much different but the OSF programming is a bit more involved .
One has the option of increasing the % levels on the modes , the max being 500% assist which would likely be in Turbo mode for max power.
Typically the modes will be set starting at 40 /60% in eco, tour approx. 100%, sport 160% and maybe 200% or so in turbo.

Perhaps you know the answer to this question? How many amps is the tsdz2 using when assisting 500%?

 

[matthewslack]

Depends what the rider is putting in.

Two examples:

1. Typical 100W rider input I.e. rider working reasonably hard, but not killing themselves. Climbing a hill, for example.

500% of that is 500W, which strictly speaking is motor output at the crank, not electrical input, so need to allow for efficiency of say 80%, so electrical input will be 500 / 0.8 = 625W.

At nominal 36V, 17.4 amps.

2. Taking it easy on the flat, range not an issue. Homeward bound loaded with shopping say. Rider might be 50W only.

Halve everything, giving a tad under 9 amps.

For 48V the equivalent currents are 13 and 6.5 amps.

Very reasonable!

 

[Bogmonster666]

Perhaps you know the answer to this question? How many amps is the tsdz2 using when assisting 500%?

Not sure anybody can answer that, rather depends on how hard you are pushing on the pedals it being torque assist. However, assuming 48v 15a controller (can't remember if the 48v is 15a or 16a), then I imagine that most riders could pedal hard enough to hit the controller limit.

As for increasing the assistance from the motor, I would rather tackle by reducing gearing. I think as long as you can keep a reasonable cadence then a blas up a steep hill on speed and probably turbo as configured in stock firmware does not cause excessive heat build up. Ideally, I want to be able to get up my most frequently climbed hills in tour or at a pinch speed ( based on stock firmware). This should deliver reduced heat, reduced wear and perhaps more importantly increased range. My main gripe with the stock firmware is the rapid falloff of assist above 80rpm cadence - osf would deliver this via field weakening feature. On hills I often find myself losing assistance through spinning too fast and needing to change up a gear.

Before the conversion I think my granny chainring was 24t (can easily check). I could get up a sustained 16% climb with that and leg power on the 28t cassette but I found it very hard work, like sucking all the fun out hard work. So that's 100/24x28 = 116.

On my current setup, assuming 100% assist: 100/42x28x2 = 133.

With a 32t cassette and 160% assist in getting 100/42x32x2.6 = 198. That should be ample to breeze up my usual hills but they should still be quite managable on 80% assist (and I am getting up them on tour and 28t now).

25% inclines are a different ballgame. Ideally I think I want a minimum of 36t at the back if I am to avoid the cadence falling too low and risking too much heat and strain.

Not keen to go below 12t on smallest cog. Keen to avoid 2 X chainrings as the 1 X simplicity is nice. Ideally don't want the ongoing expense of 11 speed at the rear. By my calculations a 1 X 9 with a 12-36t is about the best compromise and tbh, I'm not that desperate to go up the 25% slogs anyway when there are nice 16% options that get me to the same place.

In the short term I'll experiment with the 7 speed 12-32t cassette that is in the post. And anyway, as I get fitter, the hills should get flatter.

At the moment I'm getting maybe 50 to 65 miles range on my 10ah battery including some ascents of these hills.

 

[Bonzo Banana]

Largest 7 speed cassette I've seen is 11-36T which is this one;

https://www.amazon.co.uk/gp/product/B07C82YGJ1/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Out of stock at the moment. The image shown is not 7 speed which must be a stock image for the range but you do get a 7 speed cassette as I bought a few when they were on offer on amazon warehouse.

I think ETC does a 11-34T 7 speed cassette apart from that most I've seen top out at 32T.

I think the Tongsheng can be configured to a maximum 18A continuous for hill climbing although peak momentary or a few seconds current may be higher perhaps somewhere around 20-22A. Anyway 48V at 18A (if that is possible) is 864W which seems too high to me. Maybe 18A is reserved for 36V which is 648W. 80Nm at the crank means if you have a 48T chainring and a 28T cassette you are down to high performance hub motor territory. You lose about 2Nm through the chain anyway so that is 78Nm and then 78x(28/48) is 45.5Nm max torque which is easily beaten by many hub motor ebikes. To really benefit from mid-drive motor torque you need e-mountain bike gearing. If for example you had a 36T front chainring and a 48T maximum rear cog. That is 78x(48/36) which is 104Nm of torque. Of course the speed of the bike will drop accordingly and the wear rate of the Tongsheng internal gearing will increase with more early failures.

 

[georgehenry]

I am sure the 11 speed matthewslack changed to with a 51 tooth bottom gear cog in the cassette is very nice but he could have gone the cheapskate route and put a wide range 9 speed cassette on with a 50 tooth bottom gear, all be it with wide gaps between the gears.

 

[guerney]

I am sure the 11 speed matthewslack changed to with a 51 tooth bottom gear cog in the cassette is very nice but he could have gone the cheapskate route and put a wide range 9 speed cassette on with a 50 tooth bottom gear, all be it with wide gaps between the gears.

I was looking at a 7 speed 11-36T freewheel with huge gaps between cogs last week. I reasoned I could dismount and move the chain up using a biro. (Didn't buy, still mulling over options for the Espresso).