Monster-cross Build (newbie)

[gmacmt]

Hey all,

I am a second year electrical engineering student looking to expand my horizons with some practical experience.

I currently ride a 29+ bike, which is kind of halfway between a fat bike and a standard 29er mountain bike if you aren't familiar. My current bike is a hard tail with pretty typical geometry (photo below) but my plan is to make a new commuter bike that will replace my car for most of my daily needs.

My favorite townie that I ever build was this one right here...

It had totally crazy seat to bar drop, but was super comfortable and really fast. The only problem it has was tire clearance.

My favorite "real" bike is this guy right here.

So the new bike is both of them put together... A road bike with 29+ mountain bike tires.

Currently building the frame with standard road tubing and geometry (a nearly square 72/73 road bike) under the tutelage of an experienced builder.

So that is the background, design considerations in the following post.

 

[gmacmt]

Desired max speed on level ground. mph or kph

Looking to have a pedal assist to enable cruising speed of 20-25 mph.

Desired max range at what cruising speed. mph or kph

Would like to be able to cover 30 miles at 20mph or 20 miles at 25mph. Ideal would be 30m@25mph but that sounds like it could get expensive. Would like to pedal wherever I am going, but don't want to show up sweating.

Preferred bike wheel size, or wheel size of bike you want to convert. Most common kits are for 26" wheels.

It is going to be a 29er wheel, and the tires are probably around 2.5-3" tall on the rim.

Brake type of motor wheel. Disc or not.

Disc Brake

Rider weight.

145#

Terrain.

Mostly flat if it makes life easier regarding the design, but I live in Montana and mountains are abundant.

Budget.

Would like to keep all electronics expenses under 1k.


OVERVIEW

Bike will be used as a commuter in montana. Commonly with front rack carrying groceries, book bag, etc. Payload not to typically exceed 30lb.

Our weather ranges from about -20*F to 105*F. I ride in everything, but would be willing to drive in really cold weather if it is too hard on the electronics.

I was hoping to do a discreet light build (I live on a 3rd floor walk up) that weighs in at less that 50 lb with everything. Bike will weigh about 25lb totally built.


QUESTIONS

1) Was thinking something like the qute q100h would be a good motor with the lower RPM wind? Any input?

2) Since I have the ability to do whatever I want with the dropouts, what is the preferred for a hub motor?

3) I was thinking that a rear motor would handle better, but is a front motor something to consider? Seems like it is easier to not have to deal with integrating the driveline into the electric system, and it could be very discreet with batteries on the front rack.

Open to any and all advice.

Thanks in advance,

Graeme

 

[MadRhino]

1) Was thinking something like the qute q100h would be a good motor...

I have a problem figuring together "qute q100h" and "Monster-cross"

 

[wesnewell]

Any of these will work, although I'd suggest the 1000W models because there isn't much cost difference for twice the power rating.
http://www.ebay.com/sch/i.html?_from=R40&ghostText=&_sacat=0&_nkw=48v+1000w+rear&rt=nc&LH_PrefLoc=1
http://www.ebay.com/sch/i.html?_from=R40&ghostText=&_sacat=0&_nkw=48v+500w+rear&rt=nc&LH_PrefLoc=1
1. See above.
2. Steel. 135-170mm wide. 10mm axle size. 16mm deep.
3. I would only consider a front motor on a delta trike.

The cold won't hurt the electronics or motor. Actually better for them. It will effect the battery though. They tend to lose capacity the colder it gets.

 

[Drunkskunk]

Unless you're trying to build a cute little monster, Q100 and Monster don't even belong on the same page. It's a great little motor. But lets not lose sight of that word "little". You would be hard pressed to find a weaker, wimpier motor for any ebike.

If you're just looking for a great motor for assist at normal human speeds on flat terrain, the Q100 is good. Forget the mountains, though. And snow. And dirt.

Your design looks like a road bike with off road tires stuck on it. That might be ok if you never plan to go off road, but if you do, you need more clearance between the top of the wheel and the frame. Look at the silver bike you showed a picture of. see all that space around the back wheel? You need that front and rear for an off road bike.

If you plan on a 3" tire, the 74 degree front may be a problem. fatter tires will roll on the rim more in cornering. you need more angle on the fork to help counter that. I think the Surly Krampus 29+ uses a 69 degree angle

If you're looking for all weather riding in Montana, I assume that also means snow? The 29+ aren't known for good performance in snow compared to the 26" Fat Bikes with their 4 and 5 inch wide tires.

 

[gmacmt]

I have a problem figuring together "qute q100h" and "Monster-cross"

Should specify that monster-cross refers to the genre of bike. It is a cyclocross bike with big tires, typically 45c or better.

Any of these will work, although I'd suggest the 1000W models because there isn't much cost difference for twice the power rating.
http://www.ebay.com/sch/i.html?_from=R40&ghostText=&_sacat=0&_nkw=48v+1000w+rear&rt=nc&LH_PrefLoc=1
http://www.ebay.com/sch/i.html?_from=R40&ghostText=&_sacat=0&_nkw=48v+500w+rear&rt=nc&LH_PrefLoc=1
1. See above.
2. Steel. 135-170mm wide. 10mm axle size. 16mm deep.
3. I would only consider a front motor on a delta trike.

The cold won't hurt the electronics or motor. Actually better for them. It will effect the battery though. They tend to lose capacity the colder it gets.

thanks for the beta. Looking to build up a kit that doesn't include a wheel though as I need to lace it up to a 29+ rim.

Unless you're trying to build a cute little monster, Q100 and Monster don't even belong on the same page. It's a great little motor. But lets not lose sight of that word "little". You would be hard pressed to find a weaker, wimpier motor for any ebike.

If you're just looking for a great motor for assist at normal human speeds on flat terrain, the Q100 is good. Forget the mountains, though. And snow. And dirt.

Your design looks like a road bike with off road tires stuck on it. That might be ok if you never plan to go off road, but if you do, you need more clearance between the top of the wheel and the frame. Look at the silver bike you showed a picture of. see all that space around the back wheel? You need that front and rear for an off road bike.

If you plan on a 3" tire, the 74 degree front may be a problem. fatter tires will roll on the rim more in cornering. you need more angle on the fork to help counter that. I think the Surly Krampus 29+ uses a 69 degree angle

If you're looking for all weather riding in Montana, I assume that also means snow? The 29+ aren't known for good performance in snow compared to the 26" Fat Bikes with their 4 and 5 inch wide tires.

Looking for a simple assist. I prefer pedaling being the number one source because I am sure there will be days that I push beyond my batteries range, want the bike to still be able to be ridden somewhat efficiently.

29+ is great in snow. Obviously compared to a fat bike, it isn't as good, but it is far preferable to a standard 29er. The bike pictured with the severed arm is my bike. The clearance it has with that suspension fork is actually around 5mm to the tire. It is a very tight fit.

The reason I am not so interested in a 26 fat is because they are so inefficient compared to the 29+. Much more difficult to maintain speed with that much tire, although they are very fun to ride.

Here is a bike in a similar genre to what I am planning. This looks to be a smaller rim size and has a sloping top tube. The only offroad use that I would anticipate seeing is conditions similar to that of a cyclocross course, which is typically pretty mellow compared to what you would think of when thinking about mountain bikes. And the only snow it would see would be snow on a road during a commute. Do not plan to go on XC ski trails or into "off-piste" untracked snow on this bike.

Regarding the q100h, it appears that the ku/63/65 250W is a preferred controller?

And how much power should I be expecting to need per mile if the motor is used as pedal assist.

Thanks so much,

graeme