2013 Trek Cyclecross drop bar conversion assist for hills Scotland

[Mpgscott]

Hi Everyone,

First post so please be gentle

I have had a read through all the information on the site so hopefully this is ok to ask for everyone’s thoughts.

I have a 2013 Trek Cyclecross rip that i have enjoyed for a number of years. I have recently moved to a location on the west coast of Scotland that is very hilly, this is resulting in me not enjoying cycling in the same way as i have and i would like to convert to an ebike to give a small level of assistance for climbing all the hills.

I still wish to cycle but if i could just knock the edge off how difficult the hills are with some assistance from a motor then that would be great.

The bike has drop bars you can see the bike here: Trek Crossrip Elite (2013)

Trek Crossrip Elite (2013) Well put together, comfortable commu-tourer with solid spec and excellent brakes road.cc

What would be everyone’s thoughts on best way to go? Can you do cycle assist with a hub conversion or does it need to be a crank type?

As the bike has currently got a two chainring hub setup as 50T and 36T does a hub drive ditch both these or do you retain the larger 50T chainring?

Im not seeing kits specifically for drop bars that the cyclecross has, do any of the kits have this or since I’m only wanting assistance and don’t want the motor to drive the bike with no peddling then do I not need any motor speed so no lever?

Totally new to this e-bike hence the questions, however I’m simply looking for a level of cycling assistance to ease the hill climb element and to stop my heart rate getting as high as it currently does with no assistance.

Thanks
Mark

 

[amberwolf]

Because you have "very hilly" conditions, most likely some version of middrive will be what you are after, but how that affects your chainrings/etc and whether it will fit on your specific bike's frame shape (especialy downtube/chainstays) and BB shell depends on the specific middrive (and bike).

A hub drive might have to have a bigger battery, motor, and controller to do the same job without problems, depending on the specifics of the job you need it to do and conditions it has to do that job under.

Since we don't have specific information on your hills, or exactly what you expect from your riding experience, how far you need to go, how fast you really want to go up those hills, your total rider/bike/etc weight, etc., we can't know how much power it will take to do the job you want, and so we can't say which drive will do the job you need.

But you can use calculators and simulators like the motor / trip ones at ebikes.ca along with that information to guesstimate what power you need, both worst case and continuous minimum, and guesstimate the wh/mile (or km) power usage over the usual trip, so you can be sure to get a big enough capacity battery.

I'd recommend a battery at least 25-50% bigger than you need, so that as it ages it can still provide the needed range, and can also do so under unexpected adverse conditions such as significant detours or headwinds.

Once you know about how much power it takes, worst case and minimum, and about how many Wh the battery must be at minimum, then we can start working out what systems meet those needs, and which ones would fit on the bike itself.

 

[Mpgscott]

Many thanks for the information greatly appreciated.

So I’m currently 240lbs or 110kgs and the cycle I cover is around 20miles with around 500mtrs (1640foot) of elevation which is approx 10% inclines and around 30 of them on the ride.

There are a lot of climbs on the route and no getting around it.

Up until last year I was cycling every day, after moving to where we are and the amount of hills it put me off cycling. So I’ve been walking but it’s just not as good as cycling, so want to get back in the bike and try and get the weight down. Want to get back to my 100kg weight.. I’m 50yrs old and can maintain around 225watt

I will get a look at those simulators.

Thanks
Mark

 

[gromike]

I really love to ride my direct drive rear hub motor bike. It's a more bicycle feel than my mid-drive bike. Yeah, you'll need to pedal a bit more than a mid-drive, so you would want a full range of gears.
If I had the money, and didn't have five ebikes already, I would get the Grin all-axle hub motor kit. Torque sensing and regen braking makes a nice ebike.

 

[Mpgscott]

I will take a look at that, sounds ideal as it’s just assist that I want. Not looking for throttle so just assist for the plentiful hills where I stay.

 

[amberwolf]

Keep in mind most of the non-middrive PAS-controlled systems do not provide proportional assist using the pedals. (unless they use a torque sensor, which very few do or can; most just use a cadence-type sensor but they don't actually measure cadence, just detect if you are or are not pedalling and dont' care how fast).

Almost all of them provide only full-on assist of whatever assist level is chosen in the display, if they have assist levels. Some of them provide this assist as a speed limit, providing however much power is required to reach that speed (up to the full power of the system), and some of them provide it as a battery power or battery current limit (they don't know how much power is actually being made or used by the motor itself). Many of the ones that have a throttle use the throttle itself as the only variable-assist control on the whole system.

You can get proportional PAS on these systems using the Cycle Analyst (CAv3.x) from ebikes.ca even without a torque sensor, either as speed or battery power/current modulation, without even needing assist levels (but you can make those too if needed). AFAICR all of the ebikes.ca Grin kits can have this option (or you can have a torque sensor, though this isn't required for proportional assist as long as you can tune it for your cadence and gearing usages vs conditions vs required assist).

There are certain systems (KT Kunteng, LS Lishui, etc) that, if you're willing to do some significant DIY, can be reprogrammed with user-created Open Source Firmware OSFW to do these sorts of things without the CA, but I don't have direct experience with these.


If you use an FOC controller (Phaserunner/Baserunner, VESC, etc) then with the CA you can get proportional PAS control over the motor power/current...but FOC controllers require setup and tuning for the specific system and conditions they're used in, so they're more complicated (and expensive), and most likely not needed here.


Some middrives have proportional pedal assist control, usually via a built-in torque sensor. TSDZ2, Toseven, some of the newer Bafang (non-BBSxx) systems, "Lightest ebike" kit, etc. Most of these have threads here on the forum for various versions of them, discussing their good and bad (because nothing is perfect).



If you don't care whether the assist from the system matches your efforts, and instead just adapt your efforts to however much assist you get out of the system, then you can use any system that can sustain enough power for long enough to go up the hills you have at the speed you require.


As previously noted, a hubmotor system will almost certainly be bigger and heavier and more power-usage-intensive than a middrive for the same usage, since the middrive goes thru the bike gearing.

The main advantages to the hubmotor are that it itself has less maintenance in most conditions, and it doesn't wear out your chain and sprockets faster, doesn't usually change anything about your pedal drivetrain (front ones won't at all, rear ones won't if you can simply move your freewheel or cassette over to them from the wheel you're replacing, and the placement and spacing of the gears is the same so you don't have to adjust the derailer).

The worst disadvantage to most middrives aside from increased chain / sprocket wear is that almost all of them widen the pedal positions, and almost always move the right side one out farther than the left.

 

[Mpgscott]

Thanks for the details, some great points there so I will take a good look on the ebikes.ca and will get in touch to find out about there Grin kits.

Thanks

 

[neptronix]

You'd probably like a small-mid size geared motor.
Shengyi SX2 is the best small-mid size geared hub i know of, very efficient and nice weight for the power it outputs.

I'm not sure what the law is regarding ebikes in your area. ( or if you care to adhere to it ) You may have a 200w limit, look it up!