What to look for in a bike frame

I'm starting from scratch building my first electric bike. I've read many threads on batteries and motors but I need advice on buying a standard mountain bike to build upon. I have a 16 mile commute with mostly flat but includes one substantial hill. I don't mind pedalling - I'm looking for exercise too.

1. Do most folks recommend hardtails or full suspension?
2. Disc brakes seem like a good idea. Can I remove the disc brakes from the stock wheel and put then on the motorized hub?
3. I'm no welder so I need the frame to basically "work" with minimal machine work. Is there anything to look for?
4. Anything to avoid when choosing a frame? (Can I learn from your mistakes? :lol: )

I'm looking for something around $400 with disc brakes so any opinions on these?
Costco's 26” Schwinn Delta Full Suspension. Can you even mount a rear rack on these for the batteries?
Target's Forge Sawback Hard-Tail 5xx Mountain Bike
Performance Bike's Iron Horse Maverick 5.5 Mountain Bike
Performance Bike's 2007 Mongoose Tyax Elite Mountain Bike

I'm open for ideas?

JeffD said:

1. Do most folks recommend hardtails or full suspension?

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Suspension. No contest.

JeffD said:

2. Disc brakes seem like a good idea. Can I remove the disc brakes from the stock wheel and put then on the motorized hub?

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Not usually. I think most people have to modify their hubs to take a disc. However, if you get a rear hub, it won't really matter; most of your braking power comes from the front. My Schwinn S40 (similar to that Delta you listed) has a front disc and a rear caliper, which would be perfect for a rear.

JeffD said:

3. I'm no welder so I need the frame to basically "work" with minimal machine work. Is there anything to look for?

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Either big, beefy drops or a place to mount torque arms. Preferably both. My S40 has 8mm rear drops, but they're aluminum. Lazarus screwed his up just the other day, so definitely use torque arms with aluminum drops.

JeffD said:

4. Anything to avoid when choosing a frame? (Can I learn from your mistakes? :lol: )

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Like I've ever made a mistake .

Aluminum drops aren't a good thing. If you run torque arms, though, it's not a problem. Other than that, make sure you have a way to mount the batteries, unless you want to be carrying them in a backpack like me. :wink:

JeffD said:

I'm looking for something around $400 with disc brakes so any opinions on these?
Costco's 26” Schwinn Delta Full Suspension. Can you even mount a rear rack on these for the batteries?
Target's Forge Sawback Hard-Tail 5xx Mountain Bike
Performance Bike's Iron Horse Maverick 5.5 Mountain Bike
Performance Bike's 2007 Mongoose Tyax Elite Mountain Bike

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I don't really like the last three for their lack of rear suspension. It's not all that critical, but it's a nice thing to have.

The Schwinn S-series bikes (my S40 is one of them) are very popular. I think the S40 and S60 come with front discs. The frames are aluminum, but the front drops are steel. You'll have to use panniers or a rear rack (most of the frame is taken up by the rear suspension), but otherwise they're great bikes to use. They're also well under your budget. Mine cost me $250 from Target. :wink:

1. Hardtail bikes allow you to mount sturdy rear racks, with supports going from the rack to the rear axle. This is good if you are using heavy high-amp-hour (long range) or high-voltage (high speed) battery packs. But high-speed bikes often fare better going over bumps with a full suspension -- but it's (nearly) impossible to mount a full-support rear rack on a full suspension bike. It's easier to put a seat-post mounted rear-rack on them. There are many work-arounds and compromises to these problems, if you're interested.

2. Disc brakes are indeed a good idea, with the added weight and speed of electric bikes. But because of limited width between the American bike dropouts, and the extra width of Chinese hub motors, it can be dificult to mount a disc brake (and the freewheel sprocket cluster if rear) onto a hub motor wheel. Some solutions are to accept rim-pinchers for the rear brakes as the front wheel does most of the braking anyway, or use a single- or five-speed sprocket cluster on a rear hub motor wheel, instead of a 6- or 7-speed. When the bike & motor arrive, be sure to test-fit them right away, so you can return one or the other.

3 & 4. A steel frame with big thick dropouts is good to find, however some aluminum frames can work also. A steel frame can be stretched if the hub motor doesn't quite fit, aluminum cannot. Avoid road racing bikes with tiny dropouts; a bike good for pedaling usually isn't a good bike for electrifying. Beach Cruisers and Mountain Bikes seem to always make great electric bikes.

Get a good idea what the torque arm for the motor looks like, and when shopping for a bike consider how you will mount it on potential candidates -- otherwise you may have to machine your own version of this very important part. Make sure the brakes and deraileurs are quality components; you don't want to struggle with them while riding fast.

The bikes you posted look good, but I don't have specific experience with any of them. I have enough bikes around the house as it is. :lol:

I invite you to look at the ebike galleries here: http://endless-sphere.com/forums/viewforum.php?f=6
Oh, and be sure to check out my ride: http://endless-sphere.com/forums/viewtopic.php?f=6&t=3672

Good luck with your build! Astound us all with a sweet ride!

I quite like the Schwinn Dually.

But you have to be prepared to either:

- build a cantilever rack from the seat post. They always fail in the end...

- get a long format battery, and tape it under the down tube - there's plenty of clearance to the front wheel. This will be ideal, with good weight distribution and therefore better handling. Getadirtbike has this setup, and with an x5 rear motor it goes really well


If you just want it simple, get a hardtail and a sturdy rear rack.

Go with the 5 speed freewheel. 7 is too much. I had to adjust my 7 speed so it wouldn't engage on the outer smallest gear.

Also had a really hard time getting the hub motor and 7 speed between the drops.

If you think you're going to use a cycleanalyst meter, then get the CA and matching controller both from ebikes.ca.

Definitely use a torque arm..

Go with 5 series Clyte motor & 72V higher amp controller- once you ride that 36V ebike you want more speed.

Again, no contest between a hardtail and a full suspension. >30mph you just want that comfort.

As Link and disadvantage have mentioned, the Schwinn S-series from Target are great bikes for electrifying. Unless you're really planning on doing offroad, I'd say save $200 on the donor bike by getting a S-40 or something and then putting that money towards better/bigger batteries.

As for the aluminum frames, they're great, except the dropouts. With my S-25, I didn't have any problem fitting a 5303 with a 7-speed freewheel. Though, after two weeks, the motor made the drops into nice round ones, letting the axle spin free. Other expensive bad things followed. So get, or make, or have made a torque arm before powering up that motor.

For the brakes, front discs are a good idea. You can also use your motor to brake, regeneratively and non-regeneratively, but really, really make sure you have torque arms for that.

Thanks for the many great replies. My confidence is building.
I've been convinced to go with full-suspension (I wanted that anyways but thought it would be impossible to work with)
The Target Schwinn S-40 sounds good (full suspension, front disc brake, others have used it).
It's currently listed at $207 so it could allow me to shift my $$ to the other needed components.

IF I went with this bike - being aluminum I need the Torque arms (anyone got a picture?).
It has 8mm dropouts which are deep enough I assume?

How does the hubs fit on these guys? Is it a tight squeeze?

Nah, mine had plenty of clearance Not a problem. No wedging or prying required.

As for torque arms, we're just having a discussion on them! I'm designing a set for my bike, based off of disadvantage's torque arm design. Yup, pictures too. Check them out for ideas:

disadvantage's build thread: http://endless-sphere.com/forums/viewtopic.php?f=6&t=3672
my torque arm discussion thread: http://endless-sphere.com/forums/viewtopic.php?f=2&t=3733

the S40 is a great pick, but mounting batteries can be tricky on a full suspension bike. If you don't have fabricating skills, you may want to consider a hardtail with a suspension seat. 90% of the time, you go over a hard enough bump to use the rear suslension, you'll be standing up on the pedals, so the use of the rear suspension will be minimal.

The other thing to consider is getting a bike with conventional brakes, and the ability to upgrade to disk. Disk is nice, but not all hubs will work with it, so having a frame that can handle notmal brakes on the rear is a real help. Bikes like this one :http://www.target.com/Schwinn-26-Mens-Ranger-Bike/dp/B0000BXHPC/ref=pd_ecc_rvi_2/602-0073549-7367034
can have disk added, but come with normal brakes.


Aluminum frames are fine, but use a torque arm for anything over 500 watts or voltage 48V and higher. Really that should read, Use torque arms, period. But you can get away with not using them on smaller set ups.

I've run as much as 4000 watts through a rear 5303 in a 100% steel hardtail bike (a Trek 820) with no problems at all, with no torque arm. But there aren't many bikes that can handle that, and certainly not any aluminum ones. Also, if using a front hub motor, a torque arm is always needed regardless of how strong you think the fork is or how little power you're using. Front fork dropouts are very thin and thus even steel ones can be pushed out easily.

But even small bumps are very annoying and downright dangerous, so I'm looking at full-suspension bikes now. But a torque arm is required for all of them so I have to make one.

I went window-shopping at Target, Dick's, and Wallyworld. Dick's had overpriced or overkill. Target had the s25 and s60... both not bad. Wallyworld had a Mongoose xr250, that has potential @ ~$200usd:


It has lugs for a rear disc, but not the threaded hub. Might have a decent shock, too.

http://www.walmart.com/catalog/product.do?product_id=3610588

Only available with 26" wheels.

s60.. only pic of current model:slightly beefier than s40/s25.

I've just gone and ordered a Voodoo Canzo frame for $600.



Tons of triangle space, and as you can see by the hinges, that shock does not rotate forward; it only compresses. That swingarm shouldn't be hard to attach a torque arm to, and the mtbr.com reviews say the frame is very durable, tracks like a hard-tail, but is plush. So it sounds good... I'll see how it is when it arrives and I have time to migrate all components over to it.

I love the S40 (great price and lots of others have electrified them so support is good) but for my situation I actually need to heed the advice of many of you and look for a hardtail. You guys are awesome. Thanks again for your direction.

disadvantage said:

Hardtail bikes allow you to mount sturdy rear racks, with supports going from the rack to the rear axle. This is good if you are using heavy high-amp-hour (long range) or high-voltage (high speed) battery packs.

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Mark_A_W said:

build a cantilever rack from the seat post. They always fail in the end...If you just want it simple, get a hardtail and a sturdy rear rack.

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Drunkskunk said:

If you don't have fabricating skills, you may want to consider a hardtail with a suspension seat.

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Other factors:
* My commute is 16 miles each way I'll need larger/heavier batteries than the average guy and seatpost racks are likely not beefy enough for me.
* Living in the Seattle area - i'll need some good fenders which mount better on hardtails.
* I may also need to pack work stuff back and forth and would prefer to use panniers rather than a backpack.

I'm now keeping my eyes pealed for a hardtail with front disc brakes for less than $300 if possible. Drunkskunk suggested this one:

Drunkskunk said:

...http://www.target.com/Schwinn-26-Mens-Ranger-Bike/dp/B0000BXHPC/ref=pd_ecc_rvi_2/602-0073549-7367034
can have disk added, but come with normal brakes.

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That is looking better to me now.

JeffD said:

I'm now keeping my eyes pealed for a hardtail with front disc brakes for less than $300 if possible.

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Looking for a hardtail? Here's a possibility Micargi SM600 Mountain Bike Suspension 26 Sale price: $189.99 http://www.2wheelbikes.com/fsuspension-mountainbikes/sm600-mountain-bike.html

If you are worried about a rough ride you could also you could get a shock absorber in the seat post like one of these (I'm sure that you could find others searching the web).

http://xoomgear.com/mountainbike/seatposts/suspension_seatposts/2/

Hi Guys,

This is an interesting discussion - I've been trying to work out the best bike to use for a conversion, and its a dilemma.

To go fast the normal route would be lightweight racing style bike with drop handlebars and no suspension. That would give the lowest air resistance; its what the lycras would do on a road and surely all the same arguments and benefits would apply to an electric bike.

On the other hand, the roads I ride on are not actually perfect. On my current ebike (eZee Torq, front hub motor with no suspension) there are downhill stretches where I chicken out at 25mph because the shaking has got to the point where I think its affecting the control. That argues for a suspension bike. But is that not heavier and more difficult to ride unassisted?

My worry is that if I go for suspension and comfort, I end up with something that doesn't really work in non electric mode. It starts becoming a cruiser, gets heavier and more reliant on the electrics, so it needs bigger motor. Then it really doesn't work in non electric mode, so I need a bigger battery, etc, etc.

What's the answer? To concentrate on weight and air resistance, or just throw more horsepower at it?

Nick

Everyone will tell you to keep your e-bike and regular bike separate, and everyone is right. For the e-bike, it's best to use something cheap if you don't know what you want, so you can replace it later without having wasted much money, once you ride it and learn of any shortcomings.

Everyone will tell you to keep your e-bike and regular bike separate, and everyone is right.

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Indeed.

The requirements of fast electric bikes are so far from fast muscle-powered bikes, most specifically weight. Extra weight is not an issue for a battery and motor setup that weighs 50lbs, while racing bikes cost thousands because they shaved off a few ounces here and there. For ebikes, that weight would better spent as structure, to be sturdy at speed.

So, in short, "just throw more horsepower at it" is the inelegantly phrased answer. The power output of your legs is nothing compared to mildly-powerful motors. besides, the tradeoff isn't so severe. Do mountain bikes not really work around town? You can pedal them easily, can you not?

Not to say wind resistance isn't an issue. A nice aero tuck on a mountain bike can make a big difference.

Thanks guys,

Point taken. My Cycle Analyst says I add about 100 W to the 400 W from the battery; the machine in the gym says I produce 150 W, but its probably lying . Either way, I want to be looking at >750W on the next ebike, so my own contribution will be a tiny fraction.

I can't help feeling though that this is like the different American and European approach to automobiles in the 1970s. So what about handling? I want to build something that handles like a bike, not an oil tanker. You can be pretty agile on a well sorted bike, but the first time I tried to dodge an oncoming car on the ebike I fell off.

Nick

The biggest thing you can do to to improve your bike's handling is locate your battery in the front triangle. Also weight of course is important, so if you're concerned about handling, lithium batteries are a wise investment. If you're riding with 50+lbs of SLAs, your bike will in fact handle somewhere in-between a truck and an oil tanker.

I found a GT Avalanche 3.0 with disc brakes in a bike shop on sale for ~$330.
I like it but I have 2 concerns:
1. If I were to add a Clyte 408 rear hub - do these generally fit within the stock axel width between the rear stays? I dont want to have to bend them to get the 408 hub to fit.
2. I plan to use some sort of torque arm but the dropouts on this bike look to be less than ideal for mounting a torque arm. I am I right?

Here is the bike:


Here are the dropouts:



Is this bike suitable for a rear 408 with torque arms or should I keep looking?

for <300 you might consider the mongoose blackcomb:



http://www.walmart.com/catalog/product.do?product_id=4698935

I like it, but the XR250 might be a better deal... no rear disc (lugs tho), but aero rims and $100 less.

http://www.walmart.com/catalog/product.do?product_id=3610588

:?

Having symbolic pedals on your motorcycle and being too lame to register it does not make it an ebike. Hence you get people claiming dual suspension/disk brakes are required for an "ebike" to be used on roads... Gimmie a break, that's one of the very least practical choices you could make. They don't have fender/rack mounts, are a neon sign that yells "steal me", suck your eff way down and feel terribly sloppy to ride around on road. Awesome!

Somehow, for summer use something in a touring bike style seems wiser.

TylerDurden said:

for <300 you might consider the mongoose blackcomb:

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Thanks Tyler for the suggestion. Looks good but being from Washington I need something to work well with fenders and a sturdy rack mounted on the back - thus I'm looking for a hardtail (no rear suspension).

JeffD said:

I need something to work well with fenders and a sturdy rack mounted on the back .

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Me too.

I use racks/baskets on the front and rear. The Blackcomb has parallel sides that would permit attachment of plates that extend rearward, like Mark_A_W's rack. Fenders are cake once the rack is on.