Sourcing a mountain bike for a build

[dolby]

After reading through these forums it is now obvious that the best way to go with an ebike is to build one rather than buy one complete. I have a number of questions in relation to sourcing the base mountain bike.
Does the bike need a front suspension? Will v brakes be sufficient for travelling speeds up to 45km/hr? I plan to spend a maximum of $400 for this bike but am considering saving some money and just using my old existing Konya 21 speed Mountain bike with 26in wheels (weight 20 kgs). Only if it isn't too dangerous.
What are some reasonable brand mountain bikes to buy here in Australia for around $400 if my Konya is not suitable.

 

[neptronix]

Do they sell Trek bikes out there?
If so, i am a big fan of Trek 4300-4900's from the mid 2000's.

..because they are so damn easy to make torque plates for.

 

[dolby]

yes they do seem to have some Trek mountain bikes here, but nothing under $500 with disc brakes. Still not sure whether I really need the disc brakes though :?

 

[dolby]

Do they sell Trek bikes out there?
If so, i am a big fan of Trek 4300-4900's from the mid 2000's.

..because they are so damn easy to make torque plates for.

Do you have disc brakes on yours?

 

[neptronix]

Not on the back of the bike, but i do have them on the front. I run a 180mm front, vbrake in rear. Has been fine for my MAC trek bike ( runs about 45km-hr just like yours ).

These bikes came with a weird disc brake adapter that you had to buy separately. Coincidentally, the big fat mounting holes for that adapter are right next to the dropout, which is one of the reasons why these bikes are perfect for the job.

 

[Philistine]

Choosing the right bike will depend on how you intend to use it (are you intending to pedal and power, or will you be mainly "ghost pedaling" for the benefit of the boys in blue)?

Downhill, dual suspension bikes are awesome for powered use, but don't pedal that well (being designed for jumping mainly), rigid frame bikes pedal well but at speed aren't so good. Having said that if you are staying under 45kph rigid is fine.

I picked up a Giant DH Comp in Sydney on eBay for $560, and these have an open triangle frame for batteries and ES member Kiwi sells bolt on plug and play clamping dropouts for these which are awesome, but they don't pedal that well as a bike per se. Neptronix is right that if you are using a hub motor you should think about dropouts and torque arms when choosing a frame - that and battery placement.

Disc brakes are awesome, not only for braking power, but with a hub motor your wheel has a tendency to go out of true faster, but with disc brakes this doesn't matter, v-brakes will rub.

In Australia, you will be able to find a tidy Giant brand bike for $400 second hand easily

 

[dolby]

Choosing the right bike will depend on how you intend to use it (are you intending to pedal and power, or will you be mainly "ghost pedaling" for the benefit of the boys in blue)?

Downhill, dual suspension bikes are awesome for powered use, but don't pedal that well (being designed for jumping mainly), rigid frame bikes pedal well but at speed aren't so good. Having said that if you are staying under 45kph rigid is fine.

I picked up a Giant DH Comp in Sydney on eBay for $560, and these have an open triangle frame for batteries and ES member Kiwi sells bolt on plug and play clamping dropouts for these which are awesome, but they don't pedal that well as a bike per se. Neptronix is right that if you are using a hub motor you should think about dropouts and torque arms when choosing a frame - that and battery placement.

Disc brakes are awesome, not only for braking power, but with a hub motor your wheel has a tendency to go out of true faster, but with disc brakes this doesn't matter, v-brakes will rub.

In Australia, you will be able to find a tidy Giant brand bike for $400 second hand easily

I intend on ghost pedalling most of the time. Sorry for being such a noob but what is a dropout and what makes it important? Will I need to modify the rear wheel part of the frame to withstand the torque of the hub motor?
I have been checking out the Giant bikes and yes I can easily get one for under $400 but not with disc brakes.

 

[dogman dan]

You should be able to get a trek 820 for under $400. They retail for about $350 brand new in the USA. Not knocking the other trek, that's a nice dropout for applying a torque plate for sure.

Dropouts are the notch the wheel axle fits into. On a regular bike, the axle is round. On a hubmotor, the axle is flat on the sides, and needs to be held secuely to prevent a "spinout".
The bikes dropouts were not designed strong enough for this, regardless of brand or price, so you need a torque arm, or torque plate to hold the flats of the axle stationary. As the motor rolls forward, the axle tried very hard to roll backwards. This breaks the frame, cuts the wires to the motor, and the cut wires may short and burn up the controller, if you don't hold it secure with a good torque plate or torque arm.

In general, for noobs the best bet for the first try is a steel frame hardtail bike, like the trek 820. Usually cheaper, but look for a better quality one such as a trek, giant, specialized, etc. Not a bike that sells for under $100 new though, for gods sake. Equally good would be a better quality beach cruiser, with 7 speeds and two v brakes.

V brakes btw, are perfectly adequate if kept adjusted properly, up to at least 50kph/ 30 mph. So are the cheaper steel frames on bikes that retail for about $200 or more new. Such bikes make good commuters for riding about 25 mph. The front suspension helps some with handlebar fatigue on longer rides, but the big deal is that you can place the battery in the best possible location, in a box bolted into the front frame triangle. Battery on the rear rack is too high and heavy, and destabliizes the bike too much.

Since you will be running motorized, feel free to run big fat tires like beach cruisers have. You don't need skinny low rolling resistance road tires with a motor helping you.

 

[itchynackers]

I bought my Trek 3700 disc on sale for $450. http://www.trekbikes.com/us/en/bikes/mountain/sport/3_series/3700_disc/#

It's worked very well for me.

 

[Philistine]

Will I need to modify the rear wheel part of the frame to withstand the torque of the hub motor?

Exactly. Depending on how much power you intend to put through the thing (anything over say 1000W is going to start requiring something), you need to reinforce or clamp the axle of the hub motor, as it will want to spin in the opposite direction of the wheel.

It depends on the amount of watts that will be going through your system, and also on the type of hubmotor, but to give you an idea I have a Giant Talon that has shattered rear dropouts, because even though I used torque arms (admittedly pretty shitty off the shelf ones), the axle eventually bit through the torque arms and caused the (it is aluminium frame, which is very soft) drop outs to completely shatter. Basically I have now bolted heavy steel plates to the rear dropouts. If you run over 1000W or so, torque arms and damage from axles to the frame will quickly become your bugbear. The DH comp drop out adaptors I mentioned that Kiwi sells, basically bolt straight into the frame, and clamp the axle with a bolt, so it can never move. They are awesome.

Doing a quick search though looks like I got a pretty sweet deal on my DH comp.

If you can do a blaggin' you could spring for something like this (this is the type of DH comp I mentioned). They pedal like a wheelbarrow through glue, but when powered they go like a jason recliner with a heart full of hate:

http://www.gumtree.com.au/s-ad/brookvale/bicycles/2007-giant-downhill-comp-bike/1010904930

These are the drops I mentioned that Kiwi makes:

http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=33767&hilit=kiwi+drop+out

Kiwi is a genius and all round good man to deal with. My DH comp with Kiwi adaptors is the only ebike I own that has never had (and I can confidently say never will have) drop out/torque issues. It never ceases to amaze me how much force and damage is wreaked by hubmotor axles.

 

[wesnewell]

My only requirement is that it has steel dropouts. V brakes with decent pads work great. Like having 26" disc brakes, because that's basically what they are. A FS bike rides a lot better than a hardtail, but I used a non suspension bike for a year up to 70kph. I always replace tires with 2.4" tires. Also always replace seat and handlebars with wider ones for comfort and control respectively.

 

[melodious]

If your more apt to modify things from the start, this from the folks from el cheapo walmart: http://www.walmart.com/ip/Mongoose-XR-PRO-29-Men-s-Mountain-Bike/16913467

Its gotten startling reviews for being a big box store bike. Semi decent components, full suspension, disc brakes. Many have replaced the rear suspension when it finally gives out. Here is the forum discussing the pros/cons of it: http://www.bigboxbikes.com/viewtopic.php?f=2&t=499 75 pages of thread :wink:

However, it is an aluminum bike probably with aluminum dropouts. I believe the frame tubing is molded so it's not perfectly round which may rule out certain mid drive kits. I'm not sure if anyone has posted making it into an E-bike however. Just an idea to post your way. Good luck on your decision!

 

[Mesaman]

I chose the Genesis V1200 from Walmart as a platform and added a 48v 800w yesusacom rear hub kit and 15 ah lifepo4 battery, all for $800. Here are my observations:
Pros:
1. Low price
2. Full suspension works great
3. Looks stealthy. My neighbor saw me riding and knew it had to be electric as i was not pedaling up the incline on our street, but he could not see any motor, even with the large rear hub.
4 light weight
5 the rear dropouts are strong and precise. The kickstand is mounted on the axle and I was able to also use it as a torque arm.

Cons:
1. The front disc brake is not as good as expected. Linear pull would have been fine, maybe better.
2. There is little room for a battery or controller, except on a rear rack
3 . Due to the battery location and its 15 lb weight, plus the weight of the rear hub motor, the bike is not very well balanced front to rear, and the center of gravity is pretty high. Seems fine once moving, but a bit weird when stopped or when pushing it around to park it.

Overall, the bike is a hoot to ride and I think it will be pretty durable long term on the streets.

 

[Gordo]

The bike in my Avatar is a $250 CCM. Full suspension, disk brakes and 48V 12Ah battery in the 'V'. The kit is from Solarbike.com.au They have a very clever torque arm and other quality components. Well balanced lost cost solution. My second build with a Solarbike kit.

After reading through these forums it is now obvious that the best way to go with an ebike is to build one rather than buy one complete. I have a number of questions in relation to sourcing the base mountain bike.
Does the bike need a front suspension? Will v brakes be sufficient for travelling speeds up to 45km/hr? I plan to spend a maximum of $400 for this bike but am considering saving some money and just using my old existing Konya 21 speed Mountain bike with 26in wheels (weight 20 kgs). Only if it isn't too dangerous.
What are some reasonable brand mountain bikes to buy here in Australia for around $400 if my Konya is not suitable.

 

[Racer_X]

To all those suggesting wallmart bikes. There are no Walmart stores in Australia. They do have K-Mart don't know if those bikes are available in k-mart.

 

[dolby]

So it might be a safer bet going with a bike with a steel frame. I wonder if I should just consider just building my Konya. This is my cheapie Konya:




Does this bike have front/rear disc brake mounts if I wanted to upgrade later. Maybe I could use this torque arm on the Konya.
http://www.conhismotor.com/ProductShow.asp?id=166

Other bike options I am considering are:
http://www.gumtree.com.au/s-ad/burwood/bicycles/trek-mountain-bike/1010764966
and
http://www.ebay.com.au/itm/Mongoose-downhill-mountain-bike-/290837029552?pt=AU_Sport_Cycling_Bikes&hash=item43b73ce2b0&_uhb=1#ht_717wt_1186

Any thoughts?

 

[Sunder]

To all those suggesting wallmart bikes. There are no Walmart stores in Australia. They do have K-Mart don't know if those bikes are available in k-mart.

The other thing to remember is that prices and budgets in Australia are very different. I gave a mate of mine a 1992 Giant CFR2 so he could strip the group set off it for his bike. He sold what was left for $300... $300 for a 20 year old frame!

A basic K-mart bike might set you back $250-300 here, but the minimum I would ever recommend someone spending on a bike theyre intending to pedal (not a donor to an eBike) is $600 for a hybird or $800 for a suspension MTB or road.

But hey, this is the land where the median wage is 70k AUD (approx 75k usd) and a truck driver can earn 180k in the mines, and a labourer not much less.

 

[dolby]

How about this bike? Good choice for a 1000w conhismotor hub motor install? It is a Giant STP 2.

 

[Philistine]

Only downside to that bike is the frame triangle is somewhat limited for battery storage. A really nice and easy off the shelf solution for battery storage is a Falcon EV triangle bag. It is cheap, and keeps the weight of the batteries low and centred.

EDIT: have you seen Shorzas bike for sale? (http://www.endless-sphere.com/forums/viewtopic.php?f=9&t=46671).

The 9x7 is a great all round motor in my opinion. Worth having a look at in my opinion.

 

[TheBeastie]

If your more apt to modify things from the start, this from the folks from el cheapo walmart: http://www.walmart.com/ip/Mongoose-XR-PRO-29-Men-s-Mountain-Bike/16913467

Its gotten startling reviews for being a big box store bike. Semi decent components, full suspension, disc brakes.:

Yeah I have been doing research on the price of dual suspension 29ers and the price difference between USA and AUS is astounding.
In the USA a dual suspension 29er mongoose for $379, noticed other DS 29ers on that side for $219 but in the AU the CHEAPEST dual 29er is just under $1500 http://tinyurl.com/Au29ersrripoff
The above is a link to bikesexchange Australia's main eBay/amazon of all the bike stores in AU, with all 29ers with dual suspension sorted by cheapest first.

Considering the AU dollar has 5% more buying power then the USD there seems to a bit of a racket going on here. I mean in a lot of other things from large companies I have noticed things match up perfectly in price computer components like Intel CPU are sometimes just as cheap here. But when it comes to bikes seems like its a conspiracy.
While its the same old excuse of the power of the masses churning buying power sometimes it looks a bit beyond that, and I don't like it when the biggest international companies seem to be fair of price but other industries have the average x4 fold price difference.

 

[Ykick]

Keep these things in the "bicycle" realm of performance and little need for FS. I ride a quality FS Cannondale but leave the shock in lockout 99% of the time.

Same opinion about steel/Alu dropouts. A good torque arm or two, avoid regen and motorcycle power levels Aluminum dropouts work just fine in that dept, as well.

Quality brakes, headset, forks and location for batteries = the most "important" concerns to qualify IMO.

 

[hydro-one]

are you a breaker of parts? then you want a real mountain bike, not some walmart bike - with fake disc brakes that barely stop the bike. they are sold as toys. LMAO - understand the legal implications of that. ....they are ok for slow speeds or open fields,

When you pay $1500 or more in the bike store for is for a MACHINE that is designed to work and last and not break (with maintenance). If you are going 50km+ you need a dual suspension bike with a good strong swingarm, hydraulic damping front and rear. parts should be DH or bigger, for the loads your bike will see. if you have that , trails and road feel like butter no matter how rough, and you will have stability on any terrain.


hardtail is exactly that, hard on the tail. but thats how i started out, i had to learn the hard way.