Bike frames suitable for frame mounted batteries and speed.

[dogman dan]

Another good example of the nice 4 bar suspension finally filtering down to cheaper bikes. Perfect for a 30mph bike, but faster, or loaded real heavy it will tend to have a flexy frame. Good for 95% of ebikes for sure.

For what its worth, I looked this morning at the bike at walmart again. The cheapest one. It has a pogo stick shock cleverly designed with a cover to make it look like an air shock. The frame though, did seem to feel stronger than the more common Y frame mogoose and pacific bikes. One thing I did overlook, was that the rear dropouts are aluminum.

So it's still the Blackcomb for the win, for a great bike to take a rear motor. Assuming the drops are still steel on that one, that is.

 

[auraslip]

Hey I have an interesting thought.

I know DH frames are good because they are designed with slack geometry for high speed. However the frame is usually slanted at an angle that cuts off room for a battery space in the triangle.

Would it be desirable to use a normal frame with plenty of room, and then run a smaller wheel in the rear to achieve a more stable geometry? I'm thinking 24 in the rear and a 26 in the front. Or a 26 in the rear and a 29 in the front...

Of course the surly puglsey brings me to another unrelated thought. With 3.7 inch tires running at 20 psi, is a rear suspension even necessary for asphalt? Are there any other bikes that allow for such huge tires (in the rear at least?)

 

[amberwolf]

Would it be desirable to use a normal frame with plenty of room, and then run a smaller wheel in the rear to achieve a more stable geometry? I'm thinking 24 in the rear and a 26 in the front.

Like this?

http://endless-sphere.com/forums/viewtopic.php?p=291768#p291768

 

[Grizzlybear]

Hi guys, just thought I'd re-post my one for you to look at, battery in alloy box in frame. 24" rear wheel 26" front.


Griz

 

[dogman dan]

That's Da Kine. Finding those bikes cheap, that's Da Problem. But the hunt is fun. 8)

 

[torker]

If I had the money I was going to pick up a K2 Sidewinder. Not real high quality but better than anything I've ever had There was one on Craigslist but he wanted 275. I figured if I could get it for 200 - it was listed for 2 weeks- it would be an OK deal. It had 4 inches front and rear and a lot of room in the triangle.http://www.singletracks.com/mountain-bike/photo.php?photoID=16768&tag=k2+sidewinder+ds

 

[tycreek]

I've been on the "hunt" ... I've seen and tried so many out (fun) ... and was determined to find something other than a Giant brand after my 2nd one (the Trance) but gave in and got another Giant. I came very close to getting a Specialized with ok triangle space and my draw to it was a longer wheelbase than most. Many a DH look'see but none quite met what I was looking for and I don't need more than 4" of travel 99.9% of the time! Rear of the seat post shock mount type frames that I tried all felt wrong (to me) for ride and handling with one exception being a Specialized.

IMO having the batteries center and in the triangle is a huge benefit to handling when pushing it to the edge and maybe more important is the advantage in avoiding obstacles that happen along the way! Choices in CL and other places increase greatly above the $1000 mark but with a bit of timing and patients good bikes can be had for less. My target was $500.

Early this spring I found a Giant Trance

Recently was a Giant Anthem and exceeded my target by a couple bills

Both of these have a good bit of space in the triangle but have aluminum dropouts to consider. The Trance has been working great as an eBike and very solid up to 45mph though I usually don't go over 35mph. I don't know how the Anthem will handle electrified yet, but it's so much like the Trance I expect it to be similar.

 

[auraslip]

Nice bikes guys! Although after reading up, I gotta say a good quality FS bike is hard to find under $1000.

I've discovered another benefit of running a smaller wheel in the back; easier fitment of large tires and fenders. For example at 13 inches from the axle the space between the chain stays on my hard rock is 2.6 inches. At 12 inches from the chain stays (as in a 24" wheel) the spacing is 3 inches.

My new search for a frame is as follows:

Straight tubes for easier box building
classic mtn. bike frame style
disc brake tabs
23" or 22" size
chromo

This 2000 hardrock meets all the requirements except the disc brake option

 

[auraslip]

http://endless-sphere.com/forums/viewtopic.php?f=31&t=20321

 

[auraslip]

In my quest for bikes that have a good rear suspension I found these:

http://www.choppersus.com/store/category/2/75/Frames-for-26%22-Wheels/

They are soooooo cheap! And best of all can fit HUGE rear tires. I'm talking 4 inch tires in the back. That should give plenty of suspension at 20 psi.

My only problem with them is they look hard to pedal. I love to pedal. It feels natural. They look like it would be awkward to pedal.

On the other hand the amount of trail they provide means they would be VERY stable at high speeds.

 

[dogman dan]

Neat frames. The head tube geometry on them will be for straight forks most likely on the cruisers, not suspension forks. But it may not matter that much for street riding.

No flea market where you live? I find lots of great old MTB's at the one in my town for cheap. Also junk stores and garage sales. gotta wade through a few zillion wallbikes to find the gems though, and maybe put three bikes together into one that has all good parts.

 

[GrayKard]

Just an FYI. The IBEX bike company updated their website recently with the following:

IBEX IS COMING BACK.

Look for IBEX to re-open FALL 2010.
Email Sales@IBEXBIKES.COM for Additional Information.

This is where I got my full suspension bike I used in my dual hub build. The model I bought has no room in the frame for batteries but they have other models. Well worth a look once they are back in business.

I have over 4000 miles on that frame. About 2000 of that motorized. Only problem I had was user error when I accidentally ran with the rear shock locked out and blew out the seal. Frame feels very solid when I ran it at 35mph using my GM rear hub.

Gary

 

[auraslip]

Hey derby,
The tire clearance is listed as 26x2.5 with fenders for the big dummy.

I'm building a high speed e-bike 40mph+ and would like to have the largest tires possible for suspension. If I ran a 24 inch wheel could I install a larger motorcycle tire in the back?

Hello Freak,
We’ve used some 24” x 3.45 cruiser tires on the Big Dummy. That’s about as big as will fit – even then you might be sawing off the cantilever mounts.
Don’t kill yourself out there.

Thanks,
Eric Sovern
Surly Bikes

Awesome. Gotta love surly support . A 24" x 3+ rear wheel would be plenty of suspension. And because of the weight distribution the front suspension fork would get more weight than on a normal bicycle. This would mean less weight on the non-suspension rear wheel and a smoother, safer, ride.

Also this bike is MADE to haul, so fifty pounds of batteries would be nothing in the frame triangles would be nothing.

Also I had to walk my bike home from a party with my girlfriend on saturday because her car is broken down. With a long bike she could ride on the back.

Did I mention this is a long bike?…=-) You sit at about the middle of the bike. This means you don’t get thrown up by bumps the way you would on a normal bike where you are sitting over the rear wheel. Combine that with some vertical flex from the steel frame and you’ve got a uber plush Cadillac ride. The long wheelbase gives the bike a lot of stability when you get up to speed. I’ve put miles on my Big Dummy on the highway, in the city, crappy rough dirt roads, muddy roads, off road entirely and on snow/ice. The best way I can describe the ride is easy. This bike makes everything a bit less challenging and a bit more fun.

This custom made frame by banjo bicycles is a cross between a surly pugsley and a surly big dummy. However pricing starts at $1300, which is twice as much as the big dummy frame.

 

[Microbatman]

I'm onto my third full suspension frame for E-bikes, and there is more to it than just frame space (although that is key).


I've broken the swingarm on one bike, a Jamis.


My second, a Kona Dawg, had way too much wobble through the pivot joints (if you whack the bottom bracket area, it wobbles back and forth). And the main swingarm connection to the frame was too light weight for me to dare fitting a rear motor to this frame.


My third dually, the Giant DH team, is solid as a rock, has good space for the batteries..but stock it has a though-hole rear axle. It needed significant mods to fit a hub motor (Kurt did it).


The best stock frame I have seen for an e-bike is a Kona Bass. Removable dropouts (you can make custom hub motor suitable ones), huge swingarm pivot that goes around the bottom bracket.

What is your opinion on the Kona Stinky? Do you see it having more or less wobble than the Kona Dawg?
I am looking for a full suspension frame for a rear hub 9c with 5inches plus of travel.
I checked out the Kona Bass and it only has 120mm of travel.

 

[Mark_A_W]

120mm is close enough to 5".

I've never seen a Stinky in person, but I believe the pivots are chunky.

 

[auraslip]

I'm thinking about getting this bike

What do you think it would ride like with a 100mm travel suspension fork on the front?

 

[auraslip]

Uhg I googled GT KARAKORAM TIRE CLEARANCE.

It only fits 2" tires

 

[dogman dan]

Yeah, most of the vintage frames like that were made before anybody made 2.5" mtb tires. So they have very tight clearance with a wider tire.

Solid frame though, I wouldn't hesitate to haul ass on it with smooth road.

 

[auraslip]

You don't think I could spread the frame do you?

 

[Drunkskunk]

Might work. I did it with my beach cruiser and it worked fine. I put about an inch in it.

Steel only though, the cheaper the steel the better it will work.

 

[auraslip]

Alright this took some google skillz but it payed off:

The 1995 GT Karakokoram is made with double butted tange mtb chromoly.

I read an article from Reynolds about their steels. It indicated that the "old" steels, such as Reynolds 531, had good tolerance for "cold settings". But, the lighter "heat treated" steel tubing can NOT be safely cold set, because the heat treatments make the steel "brittle", like aluminum, and cold setting increases the chances of a frame failure.

AVR was their non heat-treated butted chromoly tubing. AVR would basically be equivalent to Tange MTB,

Alright so I can Cold set the frame.

Sheldon Brown Says I can safely spread the frame to the next hub spacing size up.

But that's like what? 5mm extra? That is .2 inches at the hub. I'm not familiar with the math to calculate how much that extra space that would provide at spot where the tire meets the frame.

 

[amberwolf]

Don't have to calculate it. Lay down two pieces of wood or string or whatever, the length of the stays you're going to bend outward, at the positions/angles the stays are at. Easy to do by laying them under the stays on the floor and then lifting the frame off once aligned.

Pivot each one outward half the total distance you're spreading the frame, ensuring the BB end of them stays at the original point.

Measure the new distance between the stays at the tire point.

Probably it won't be enough to even hardly notice. To get even 2" tire clearance on the old ten-speed style Schwinn frame I used for CB2's rear, I had to hammer and clamp and squish the tubing on the inside of the stays on either side of the tire clearance point, and even then it was such a close thing that any failure of rim trueness or misalignment of the axle at the dropouts would cause tire rub, and that was using a 24" wheel rather than a 26", when the frame was a 700C (I think), so that the 24" tire already had more clearance due to stay angles than a 26" would have.

 

[auraslip]

I went to the LBS to ask for help. Sent I have student aid money coming in my budget for my new bike is in the $600 range.

They suggested the origin8 cyclocross bike. Huge triangle for batteries, chromo frame, and only 200! But alas.....with 700c tires the clearance in the rear is only 2.10. Hopefully with 26" tires it will take hookworms.

http://www.origin-8.com/product_detail.php?short_code=Origin+8+CX700+Cross+frameset&cl1=FRAMES

 

[Doctorbass]

Giant are making great frame with dual suspension and STILL ENOUG ROOM IN THE FRAME

I searched for month to find the best DH bike to convert into ebike to be able to store up to 1.3kWh of lipo.
The very unique rear suspension desing keep the triangle room intact with the rear shock located like that.


Giant DH comp 2003!!! We are in business now!!

 

[tycreek]

This thread took a bit of a turn... started as Full Suspension with triangle and now ? well, ok ... I guess that's the ol auraslip TaleSpin trick ... :lol:
The only non-FS frame I'd consider these days is the Pugsley or something similar that would fit large tires. I've seriously thought about one of these for a winter 2wd crawler! But speed is much better with suspension IMO.