What to look for in a bike frame

General Discussion about electric bicycles.
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Deepkimchi   1 kW

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Re: What to look for in a bike frame

Post by Deepkimchi » Apr 05 2008 8:19am

Watch out - the 5 series motors are offset and a tight fit. I have less than a 1/4 inch clearance on the left. On the right you can see how close the rightmost gear is to the stays, had to adjust the shifter not to shift into this gear.

I said before - really recommend the 5 speed freewheel. The 7 is too tight..

Would advise taking a ruler to Walmart and measuring clearance between stays where the perimeter of the motor would be..
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Bike: Cheap Korean Alton
Motor: 5304 Crystalyte rear mount
Controller: Crystalyte 72V 40A
36V (10ah) Lifebatt - the last from Gary G before Apr 08
36 V (10 ah) cells from AndyH - assembled, tested and ready to ride
Tires: Maxxis Holy Rollers
Down to 19 cells..

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TylerDurden   100 GW

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Re: What to look for in a bike frame

Post by TylerDurden » Apr 05 2008 10:13am

DK's rack flexes with the swingarm... the swingarm has half the weight of the rack/cargo.

My setup has the rack & baskets riding entirely on the swingarm, but I don't have a hubmotor's weight:
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JeffD   10 W

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Re: What to look for in a bike frame

Post by JeffD » Apr 05 2008 11:50am

How 'torque-arm-compatible' are these rear dropouts? That is about the only unanswered question for me on this bike.
Q: Would these dropouts prevent you from getting this bike?
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I'm no welder so would need something half-made that I could tweak to fit.
something like these from getadirtbike:
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The sale is over Sunday. Looking for some quick forum wisdom.
Bike: 26" old-CroMoly Mongoose
Batt: 48v12Ah NiMH
Motor: 408 rear
Controller: 24-72V 20A pedal first with IRFB4110s
Dashboard : Cycle Anaylyst
eODO: 2975 miles

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Lenk42602   10 kW

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Re: What to look for in a bike frame

Post by Lenk42602 » Apr 05 2008 12:17pm

keep looking!

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CGameProgrammer   10 kW

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Re: What to look for in a bike frame

Post by CGameProgrammer » Apr 05 2008 5:22pm

If the axle is long enough, you could in theory using washers to fill that recess and thus have the torque arm far enough out that it gets around those raised areas... but that's a big if and it's much easier to just look for a better frame.

I have verified that my 5303 does fit in a Voodoo Canzo full-suspension frame, and the rear dropouts are not recessed. I did have to remove the little white plastic cap on the wire side of the motor, and file down the cylindrical plastic sleeve so the dropouts can press directly against the metal, but once I did that, it fit well. This frame is more conducive to triangle-mounted batteries though, since the rear swingarm is pretty big but the triangle is very open.

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JeffD   10 W

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Re: What to look for in a bike frame

Post by JeffD » Apr 06 2008 12:29am

Thanks Lenk and CGameProgrammer for your input. Just the confirmation I needed.

I've been back and forth with various bike frames but I think I'm going to use my 15+ year old Cro-moly Mongoose Mountain bike. Dropouts are perfect and there is no aluminum on the bike. I'll need to get some front suspension and at some point I'd like to upgrade to disc brakes but the brakes are good. All old school Shimano Deore components. The best part is it's free since I already own it.

This thread has really helped me out and I hope it helped other newbie's too.
Bike: 26" old-CroMoly Mongoose
Batt: 48v12Ah NiMH
Motor: 408 rear
Controller: 24-72V 20A pedal first with IRFB4110s
Dashboard : Cycle Anaylyst
eODO: 2975 miles

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CGameProgrammer   10 kW

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Re: What to look for in a bike frame

Post by CGameProgrammer » Apr 06 2008 1:16am

There are indeed tons of options for hardtail bikes -- I've been using a $250 Trek 820 and despite regularly going 40-45 mph with up to 55 lbs of batteries, I've had no problems with it and it needed no torque arm. But there are plenty of bikes just as good.

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monster   100 kW

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Re: What to look for in a bike frame

Post by monster » Apr 06 2008 11:26am

i would say the frame is the most important component because it will always stay with you

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Lenk42602   10 kW

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Re: What to look for in a bike frame

Post by Lenk42602 » Apr 06 2008 7:21pm

hardtail, full suspension, cruiser, mtb..... your choice to configure a kit to what you already own is a wise one. invariably, if you get bitten by the e bike bug, the first build is the beta test - after it is complete, your experiential knowledge will automatically begin generating a new vision for the perfect ebike conversion. enjoy the process, anticipate finding the ultimate platform for your needs once you feel what it means to enjoy electric bicycling!

len

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BiGH   100 kW

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Re: What to look for in a bike frame

Post by BiGH » Apr 09 2008 9:56pm

JeffD wrote:Thanks Lenk and CGameProgrammer for your input. Just the confirmation I needed..
you want to look for a bike that has a flat dropout - as opposed to those ones that have hollow formed tubes like the one pictured. You want a nice deep dropout. preferably made of steel.
http://www.surlybikes.com/instigator.html

that had fat dropouts, but doesn't have lots of places to mount a torqur arm. you'd be able to mount a torque arm on the disk side fairly easily.

the best dropouts i have seen so far on a frame in person are those on the ezip (cheap version). as they ahve room for a rack, on both sides, are thick and flat and suit dual torque arms :)

for the perfect frame, sadly you'll have to custom build it.

and to what is said above: first build is def a beta test.:) hence i went throuh a frame!
Bike / Motor: Electric specalized rock hopper with Crystalyte 504 / 26"
Batt: Yesa 72v (36v*2) (getting 6.7ah) LiFEPO4 in a Topeak bag. OR 1x eMTB 48v 20ah pack (straps to frame) -depending on range requirements.
Controller: Unmodified 48a digital with 4110 Fets
Current Prob: Bike is in parts getting painted / drying / testing replacement BMS
Trail of Dead Parts:Avanti Frame, 408 motor *melted*, 35a controller - i broke by trying to mod it 2nd controller - blew it up.
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EVnewbie   100 W

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Re: What to look for in a bike frame

Post by EVnewbie » Apr 13 2008 10:44am

I picked up an Ironhorse Maverick Elite (2007) and it seems to have a great frame for electric conversion. The derailluer hanger is 3/8ths inch thick steel on the drive side, on the disc side the dropout is 3/8ths of an inch thick also. :mrgreen: On the aluminum dropout side, I can bolt steel plates as there is plenty of room. No problem mounting torque arms either...the raised swing arm gives a ton of space to play around with.

The full suspension frame reminds me of downhill bikes (what Ironhorse builds mostly) Although the beast is 6061 aluminum, the bike bends the scales at 36 pounds! The swingarm looks like the truss off a bridge so I think it will work well as an electric conversion. The front fork works well (Rockshox J4) using steel stantion tubes and steel steerer for durability. The adjustable suspension travel (80 to 125mm or 3.2 to 5 inches) allows slight changes in handling. My plan is 24" wheels for extra strength, would love a "stroke monkey" arrangement by tucking in a hub motor in front of the rear shock. The rear wheel will be a Fallbrook Technologies continously variable hub so I can ride up mountains and get some speed on the flats. LiFePO4 batteries with maybe 48V 20Ah rating should do it. Hope I can get those PHET automotive 12.8V batteries and use four of them.

At this point, I am converting the bike over to 24" disc brake wheels to check the durability and handling. Anyone use a 26" front wheel with a 24" rear? That is how mine is at this point and it handles very well. The dual 24" wheel project will be complete in two weeks as my son likes using that size for a "jump bike". The best way to check for durability is to use a teenager. :twisted:

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shinyballs   1 kW

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Re: What to look for in a bike frame

Post by shinyballs » Apr 13 2008 5:19pm

If given the choice for a custom-made swingarm made for a 40+mph ebike, what's your ideal thickness for drop-outs and width between them?

Maybe 10mm thickness(steel) and 170mm spacing, this way you can easily fit disk-brakes, torque arm and whatever is needed... :o
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