Cargo
Bike Design Documentation |
Updated
2-12-06 by Aaron Goss |
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Requirements |
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Gross Vehicle Weight |
800lbs
max |
Cargo Room |
2'
wide, 3' long behind rider's heels |
Overall Length |
not
important |
Standover Height |
699mm We need to allow for the lowest seat
height (BB center to top of saddle) to be 700mm as a minimum (Gypsie's seat
height). |
Rider Size Range |
5'6"
to 6''8" |
Accessory Accommodations |
Fenders
(with 2.35 tires), StokeMonkey (3/4" tube), front rack on downtube
extension |
Ground Clearance |
Ability
to climb/descend 6" or higher square curb |
Maximum Lean Angle |
TBD
(width and height of cargo area frame rails are design variables) |
Standard Cargo Loads |
Unloaded;
Hay; Chicken Feed; Couch; Toolbox; Drill Press; Passengers; Loose Dirt |
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Specifications Decided Upon |
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Two Wheels |
Because
we don't want to build a Trike |
20" Wheels |
21"
actual wheel size with large tire. |
Clearance for 2.7" actual tire width with
fenders |
West
Coast Chopper fenders? |
Integrated Center-Stand |
with
handlebar brake lever actuation (like Val's bike) Val to design. |
Side kickstand |
Why
not have both? Will need special
bracket on boom tube and a custom tube extension for a Greenfield 305mm
stand. |
Plastic rails on cargo area frame rails |
To
prevent hanging-up on curbs and driveways (Skate Board type, Nylatron?) |
Tube Dimensons |
DT
2" Seat Tube 1-1/4" TT 1-1/4" SS 3/4"
2-1/2" Boom Rack
3/4" Tandem Chainstays HT 1-1/2 x .083 machined to external butt. Steerer 1-1/8" |
Albatross Handlebars |
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Vertical Drop-outs |
Will
need to cut our own, solid. Rohloff specific with
dearilleur hanger |
Mid-chain double wheel tensioner |
Double
pully type, location and design to be determined. Singulator style mounted to
a 10x 1mm hole could be easy. |
Frame Material: 4130 Steel |
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American BB Shell |
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Rohloff Hub |
40
x 16 Gear (actual tire diameter is 21" for gear calculations) OTHER OPTIONS? |
Bed Deck |
Lenghtwise
Spruce slats coated with water-proof clear coat, mounted to bed supports with
"J"-brackets and carridge bolts with nylok nuts. Brackets could be
made out of L-Alumunim. |
Design of Bed Framework |
Welded-on
cross members. Square corners. Front "fence" framework to support
top rails. Also perhaps wood (spuce?)
slats should be installed as well and design side pannels to be able to carry
loose loads like sand/dirt/yard waste.
Perhaps we should use marine grade plywood instead of slats? |
Rear Rack design |
See
new drawing |
Removable bed upper rails |
Aluminum
tubes or square stock with M8 x 1.25 stainless bolts (same as a standard
seatpost bolt!) Rails should bolt-on
(stash) to the bottom of the deck when not in use. Stainless nuts could be
brazed on to the bed supports. Deck
side grind rails should be thicker than the stashed rails. |
Chain Routing and Tensioning |
Top
run of chain is straight with a 2-pully style tensioner on bottom run. |
Boom Tube |
2
1/2" boom tube STAINLESS (because it is available in the diameter and
wall thickness we need) DENNY- do we need that large? |
Brake |
Hayes
Hydraulic with 8" rotors.
Someone is making a 9" rotor, need to find who. As the front fork
drop-outs are drawn, hydraulic hose routing should NOT be a problem with a
Hayes brake! |
Fork |
Existing
fork dimesions are agreed. No
prototype. First fork will have
Maxle. Chalo to machine fork ends. |
Basket mount |
Large
tube stub welded to head tube. Basket
frame support to slide over telescopically with a clamp like a seat collar. |
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Stoke Monkey |
Rear
triangle to be built with room for motor and plate welded on for motor
mount. Mount should be inline with BB
and motor axle to eliminate tension cable system. KMC PT710-NP Half Link
(Pintle) Chain 1/8" would be a good choice for the chain to allow small
chain length adjustments. 1/8" freewheel and chainwheel would increase
durability. BMX Left Side Drive crankarm makes it easy, except the larges
chainring is only 48 teeth. Maybe Chalo can find larger? Todd recommended 60T
with the more powerful motor. Remember 1/8" thick is nice, but not
absolutly necessary.The "dry zone" just in front of the rear wheel
would be a good place for the SM battery and controller. Will require much longer wires. |
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Performance Targets |
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Descending |
Queen
Anne Counterbalance, without brake fading / failure, fully loaded on a hot
day |
Climbing |
TBD
(400watts fully loaded, minimum Rohloff gearing, minimum balance speed) |
Frame Stiffness |
TBD
(bounce mode, torsion mode, lateral mode) |
Safety Factors |
TBD
(yield and fatigue) |
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Progress |
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Drawing is now metric!
1mm = .03937" |
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Aaron has built the front wheel with Schwalbe Big Apple 20 x
2.35" tire, 48 spoke Diatech "Swinger" hub (convertible from
20mm Thru-axle or standard QR) and Alex Supra E rim (according to Chalo, the
strongest rim of any size made!). The hub will allow us to make a prototype
fork with long horizontal dropouts to experiment with trail, then build a
thru-axle fork once determined and use the same wheel. The hub comes with
different end caps. |
Next Meeting: Monday, February, 27th, 2006 @ 7:30 PM (Meet at
David's Shop then move to Stellar) |
Stellar Pizza , Ale & Cocktails 5513 Airport Way S, Seattle,
WA 98108 (206) 763-1660 |
Chalo to update existing drawing and create top
view. Denny to report on boom tube
size required, even if he cannot attend? Please! Order tubing! David
will need some money. So far we have
paid around $250 David? Also from David, can we get an estimate
for building the frameset (unpainted with minimal braze-ons at this point)?
Aaron will work on a parts package price.
Val, price of kickstand? |
Misc. Notes: |
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Denny can do 3D modeling. Chalo can print life
size drawings |
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