Brainstorming, 20” FWD, Cargo Fork, Sleeper Build

[Niner63]

Happy New Year all


I have a 29er steel all road, gravel bike that has been unused for several years that I’m planning to convert to a 20” cargo fork fwd hub motor.

To be completed by the fall.

The EBB and rear dropouts of this frame make a mid drive or rear hub build a challenge, other than a Grin All Axle or GMAC, without modding the frame which I don’t want to do.

I already have an rear All Axle build that is my current daily driver, grocery getter, gravel, do it all ride, in conjunction with a Burley COHO trailer.

I’d like to have a second Ebike that would become my primary daily driver, grocery getter, do it all ride.

I’ve sourced a CrMo cargo fork that look as though they would be suitable for a front hub build and would appreciate your thoughts and input about my current conversion plans.



Essentially my current plan would involve fitting a 20” hub motor and a shallow, lidded, Euro Crate to the cargo forks with the battery inside a partition within the crate and possibly fitting the Baserunner/Phaserunner controller inside or outside the crate. With additional room for waterproofs, tool roll, pump etc.





A second, deeper, Euro crate can then be mated/stacked on top of the Battery/Controller crate, held tight with a strong coupling system on both short sides. Additional couplings could be added to the long sides of the crate, if needs be, and or straps etc.





I’m aware that this could effect the handling and that the battery weight would be better behind the steering axis but I would like to keep as “clean” as possible look to the build, without a battery fitted within the triangle or a rear rack battery.

I’ve also carried much heavier loads on top of the rear rack of this bike frame,in the past, such as full 5 gal heating fuel bottles and panniers full of groceries, before purchasing my COHO trailer.

***Worst case scenario I would/could fit a downtube battery.


Cargo Fork:

The fork dropouts look, to me, as though they’re suitable to file fit either 12mm or 14mm axles and a decent size for fitting custom or store bought torque arms/plates, such as the Grin V7 and V5







The rack has plenty of threaded inserts to help securely attach the Euro crate



Fit a fender and mount a front light.

Motor:

#1 At this time, despite its weight, is a NC Grin FH212 which is easily available within the EU.

#2 Grin eZee regen, only available as an import to the EU.

*I love regen braking on my Grin AA

Controller:

*Baserunner L10 or possibly my AA Phaserunner

as I am considering using a baserunner in my EM3ev case to give my AA build a cleaner look.

*Either fitted within the Euro case or externally.

Battery:

At this time, I’m looking at an Amorge 13S4P 20AH*** because of its rectangular design, which fits within the Euro crate nicely.

9.5*10*31cm (3.75*4*12”)

ANT Bluetooth BMS

XT60 Discharge port

XT30 custom Charge port ?

which would allow me to use a XT30 to ST3 charge port that could be mounted inside the Euro crate allowing for easy external charging.






Advice needed to fit an isolating switch/on off switch that could be fitted to the back, or preferably to the underside of the Euro crate.

Sticky foam tape for extra protection within it’s dedicated partition ?

***A lower AH rectangular battery may be considered before completing the build.


Display:

CA V3

Torque sensing BB

Back peddle regen braking


Euro Crate/Battery Box:

I’m assuming that attaching sticky back foam tape to either the cargo rack rails and or the underside of the Euro crate would be advised before using screws to attach the crate to the cargo rack ?

I’m considering using L aluminum profile to create a foam limed, rear battery partition and possibly U section to create a lid to this partition.

Centering the battery and using low profile L aluminum to prevent any sideways movement, roughly creating two 10cm, 5”, pockets either side of the battery for the controller, cables, ST3 charge port mounting and externally accessible cutoff switch.

The remaining approx 31*27*10cm 12”*11*4” space can be used for waterproofs, tool roll, pump etc etc and could be partitioned to keep everything organized.

Epoxy bonding the aluminum to the plastic crate and or pop rivets ?

Summery:

If you’ve made it this far, thank you and I’m looking forward to hearing your thoughts, advice and/or suggestions about this build.

Cheers

 

[gromike]

I like that front cargo fork you pictured, though the price on what I found approaches $400.
I want one but I'm too cheap to buy one.

 

[99t4]

I’m aware that this could effect the handling and that the battery weight would be better behind the steering axis but I would like to keep as “clean” as possible look to the build, without a battery fitted within the triangle or a rear rack battery.

What is the projected weight you are planning to carry on the front fork rack?

 

[neptronix]

Can you do a 22" wheel?
It'll have way better bump compliance.. and you kind of need that with no suspension

 

[Apartunis]

I've done a small number of conversions using the Crust Clydesdale fork, and usually everything lives right on the fork and underneath the load platform. Battery on one side, controller on the other, motor in front. Only the throttle and display reach away to the handlebars, no cable has to articulate. The load bed stays available for loads.

I'd use a wide 20" ISO 406 rim and fatter 20" tire before trying a bigger diameter wheel. The fork crown sets the terms.

 

[Niner63]

What is the projected weight you are planning to carry on the front fork rack?

Nothing too crazy, I will use my COHO trailer for heavier loads

 

[Niner63]

Can you do a 22" wheel?
It'll have way better bump compliance.. and you kind of need that with no suspension

The fork crown to race is optimized for 20" wheels, max width being 2.1"

I'll be riding mostly on pavement and shared cycle paths all of which are in great condition

 

[Niner63]

I've done a small number of conversions using the Crust Clydesdale fork, and usually everything lives right on the fork and underneath the load platform. Battery on one side, controller on the other, motor in front. Only the throttle and display reach away to the handlebars, no cable has to articulate. The load bed stays available for loads.

I'd use a wide 20" ISO 406 rim and fatter 20" tire before trying a bigger diameter wheel. The fork crown sets the terms.

Love to see some pictures of your builds, if you don't mind sharing.

1 x Rim20_JUMBO_36h Sapim E-Strong 2.6/2.3mm
2.1" tire

 

[Niner63]

With regards to a Power switch.............

The Amorge 13S4P 20AHbattery that I'm considering using on this build does not have a Power switch like most battery cases have.

After some searching I found a post suggesting using an anti spark power switch and then found this

FLIPSKY Anti Spark Switch Pro V3.0

Which, to me, looks suitable for my requirements to mount a discrete power switch, preferably to the underside of the battery crate.

What do you guys think, would this type of switch be suitable ?

 

[99t4]

What do you guys think, would this type of switch be suitable ?

Judging by its rating specs, looks like a good choice.

I’m assuming that attaching sticky back foam tape to either the cargo rack rails and or the underside of the Euro crate would be advised before using screws to attach the crate to the cargo rack ?

Something like camper tape:

30 ft. Gray Foam Tape Camper Seal for Camper Shells

The M-D Foam Tape Camper Seal seals gaps between camper and truck panels to protect against drafts, noise and vibrations. Can also be used on residential doors and windows. Easy peel and stick installation. Before installation, cut to desired length by using scissors.

mdbuildingproducts.com

 

[Zambam]

Judging by its rating specs, looks like a good choice.


Something like camper tape:

30 ft. Gray Foam Tape Camper Seal for Camper Shells

The M-D Foam Tape Camper Seal seals gaps between camper and truck panels to protect against drafts, noise and vibrations. Can also be used on residential doors and windows. Easy peel and stick installation. Before installation, cut to desired length by using scissors.

mdbuildingproducts.com

Another possibility, no adhesive, tough, provides lot's of friction:

Amazon.com

 

[Apartunis]

Love to see some pictures of your builds, if you don't mind sharing.

The conversions were for others, but if I run across one soon, I'll try to take a picture and post it.

1 x Rim20_JUMBO_36h Sapim E-Strong 2.6/2.3mm
2.1" tire

View attachment 383065

2.0mm-1.8mm butted spokes or even 2.0mm straight gauge spokes will make a stronger and more reliable wheel than thicker spokes. Put 2mm washers under the spoke heads if the hub drillings are excessively large.

The heavier you load a wheel, the more the rim deflects under the load, so it becomes increasingly important to use thin spokes that can stretch enough to track rim deflection without losing all tension during force peaks. Use a heavier, stiffer rim for more strength. But to make a given rim carry greater load without problems, use thinner spokes, not thicker.

 

[Papa]

@Niner63​

I personally, would never place any unnecessary loads on the steering axis. If you're dead-set on mounting weight that far forward, then I would suggest mounting rigidly off the head tube instead, so the added weight becomes static and not swinging side-to-side. You'd also be wise to confirm how much mechanical 'trail' the fork swap will produce. If the swap produces much over about 25mm, I would think twice before proceeding. JMO.

 

[neptronix]

^-- these are good points.

I get a lot of cross winds in my area and a very small bag ( 1ft wide ) with 2lb in it on the handlbars is enough to induce an unnerving wobbliness on the front end, the more wind, the worse the problem.
This becomes and issue above 25mph with wind, usually causing me to slow down in response to the uncertainty.

If you do not plan to go too fast then it might be a non problem.

I don't even like how a front hub motor feels >750w, it can tend to twist the handlebars a bit when you kick on the power suddenly.

 

[Papa]

I should also add...
Mounting the cargo platform rigidly off the head tube instead of the fork, also opens up the door to installing a front suspension fork, if you so choose.

 

[Niner63]

I personally, would never place any unnecessary loads on the steering axis. If you're dead-set on mounting weight that far forward, then I would suggest mounting rigidly off the head tube instead, so the added weight becomes static and not swinging side-to-side. You'd also be wise to confirm how much mechanical 'trail' the fork swap will produce. If the swap produces much over about 25mm, I would think twice before proceeding. JMO.

I should also add...
Mounting the cargo platform rigidly off the head tube instead of the fork, also opens up the door to installing a front suspension fork, if you so choose.

Different strokes for different folks

I have a long history with my 2008 Singular Cycles Peregrine and will not be modifying the frame in any way shape or form, other than fitting the Clydesdale Cargo Fork, which are rated at 50lbs load capacity.
I have no intention of overloading the cargo forks and intend my bike to be my daily driver, grocery getter and general run around town bike and will ride it within both my own and the bikes handling capabilities.

I also have no concerns regarding the geometry of fitting the Clydesdale forks to my Peregrine

Quote = Crust Cycles

"Turn whatever frame you want into an ultra-utility cycle-truck. The Clydesdale fork utilizes a 20" front wheel allowing the cargo platform to sit much lower. This lowers the center of gravity making large or heavy loads much easier to manage while riding. Great for courier work, carrying your pets around, or touring with the kitchen sink.


Each fork has a set of canti brake mounts and a disc tab. Get wild, run a duplex lever hooked up to a disc brake and a v-brake.


The platform features 6 bolt holes on the top of it so you can bolt your preferred containment method to it. It could be a basket, a big plastic tub, a milk crate, a post office bin, a sheet of plywood, or whatever. It also has two braze-on's on the front of it to hang a dynamo light. The fork offers all of the necessary braze-ons and bolt holes for a fender as well.


The Clydesdale fork is designed to replace a fork with an axle to crown of ~400mm with about a 72° HT angle and have a level platform. That means any old mountain bike with a non suspension corrected fork, your Crosscheck or Long Haul Trucker, even an Evasion would make for a good match. Basically all of the bikes that seem like a logical choice for a cargo bike usually are. No hard standards here though. If your axle to crown or head tube angle is a little different, not a huge deal, it just means the platform may be slightly out of level.


For those of you looking to throw one on your early 2000's Big Hit:


Ok, so what if your axle-crown measurement is far off from 400mm? Then your head tube angle, seat tube angle, and bottom bracket height are going to change. Generally, frame angles will all change by about 1 degree per 10mm of axle-crown length difference, and your bottom bracket height will change by about 5mm per 10mm axle to crown. If your original fork is longer than 400mm, then the resulting angles with The Cargo Fork installed will be steeper and the bottom bracket will be lower. If your original fork is shorter than 400mm, then the resultant angles with The Cargo Fork installed will be slacker and the bottom bracket will be higher." end Quote.

^-- these are good points.

I get a lot of cross winds in my area and a very small bag ( 1ft wide ) with 2lb in it on the handlbars is enough to induce an unnerving wobbliness on the front end, the more wind, the worse the problem.
This becomes and issue above 25mph with wind, usually causing me to slow down in response to the uncertainty.

If you do not plan to go too fast then it might be a non problem.

I don't even like how a front hub motor feels >750w, it can tend to twist the handlebars a bit when you kick on the power suddenly.

None of your points are really a concern for me.
Other than short sprints between mini roundabouts, clearing intersections etc
I'll be cruising about at +- 33 kph and only running PAS without a throttle fitted.

My Ti All Axle will be used for more spirited riding.

I have in the past carried heavy loads in none optimal positions, though these days I tend to use my COHO trailer for hauling heavy and awkward cargo.

 

[Niner63]

Came across this Temper Soma Wolverine, E-Cargo Fork, FWD build and love its clean lines.

350W geared hub and a small 36V 10Ah battery with Samsung 21700 cells

 

[HardWaterATX]

I’ve been curious about these cargo forks, I used to carry a 40lb water jug on each cargo rack (yes, that’s a front pizza style rack modified to fit the rear) until I switched over to a trailer to carry 30 gallons in a trailer. It was a bit squirrelly but totally doable if you are experienced and I can only imagine how much better these forks handle.

 

[Niner63]

I’ve been curious about these cargo forks, I used to carry a 40lb water jug on each cargo rack (yes, that’s a front pizza style rack modified to fit the rear) until I switched over to a trailer to carry 30 gallons in a trailer. It was a bit squirrelly but totally doable if you are experienced and I can only imagine how much better these forks handle.

Wow 80lbs total and with 40lbs out front

Love it

I totally get the rational regarding placing "weight" behind the steering axis and as low as feasible possible.
While also understanding that those rationals go out of the window when needs arise.

I have close to 60 years of cycling experience, have carried heavy loads and done plenty of dumb shit on bikes and my intention is not to carry heavy loads on these cargo forks.

Though I can visualize occasionally wanting to carry a heavy load such as a 5 gal bottle of fuel but that would be far and few between and if I felt it was unsafe I'd not do it again and be sure to use my trailer.

After much research regarding this style of cargo forks the general consensus appears to be that most folk love them and the rider quickly becomes accustomed to any handling quirks.

The Temper cycles Soma Wolverine, pictured above, with its small FWD 350W hub motor is reputed to handle well.

My own, proposed build, could have a heavier, more powerful, front hub motor but I'm confident that it would still be a fun ride with or without my typical grocery shop, runs to the recycling center and general run around town bike.

I'd also have less anxiety leaving this cargo bike locked up in town than I currently have with my Ti All Axle build.

I've started a second revised design and have even built some cardboard mock ups of the crates, battery etc which has helped me better visualize my plans.

Watch this space for updates

 

[Papa]

At age 16, I delivered 35lbs of newspapers via Schwinn springer for two years - with bags dangling off the handle bars. Suffice it to say, I'm genuinely surprised I'm still alive today. No internet, no forum to turn to, and no one to warn me just how dangerous the bicycle's handling would suffer because of it. The 3 pound Sunday Times was much worse, and I ultimately landed in the hospital after dumping the rig in a busy intersection.

 

[Niner63]

Onward and upwards, "consider yourself(s) warned..."

I'm moving forward with my Clydesdale (clone) cargo fork FWD build plans.

I'm now at version 2.1 and skipping straight past version V2.0

V2.1 thoughts (not set in stone, except the forks)

Clydesdale (clone) cargo fork, FWD + fender.

Grin eZee fast, 350rpm motor, laced to a 20" rim, the regen version.

Plastic crate, attached to the cargo fork, size to be determined and or more than one crate to be used, swapped out, as required. Elasticated water resistant cover (rucksack cover) and cargo net.

Battery, mounted vertically, inside the crate, central to the steering axis with a Custom ABS battery enclosure.
(thank you CC)

Size to be determined based upon my current usage of a em3ev 48V 20Ah battery, Grins "Trip/Motor Simulator" and suitability to use the battery as a "range extender" on my other builds.

Controller, mounted to the outside of the crate, ideally central to the steering axis, possibly within a custom ABS cover, including "soft start" power switch and ST3 charge port.

CAV3 Display, mounted externally to the crate, viewable from the cockpit and helping to keep the cockpit "clean"

PAS level controlled from lhs handlebar, keeping the cockpit uncluttered and clean.

PAS Sensor 12/24 pole crank sensor, torque sensor BB to be fitted when funds allow.

Brakes/Disks, service and fit my old BB7 clones, for testing.
If I find them to be inadequate there are plenty of other options.
Which can be explored and implemented, such as fitting, stand alone, front Magura HS hydro rim brakes
and or using a duel pull, lockable, levers to control both front and rear cable operated disk calipers.
Back pedal regen braking will aslo be used regardless of disk/rim brakes.

Rear wheel, using my old Alfine 8 igh 29er, for "testing", most likely to re-laced to 27.5" which will enable me to fit larger volume tires with a full fender. Burley-Ballz axle mounts for attaching my COHO trailer.

Tires

Front, 20" Schwalbe Pick-Up
Rear, 27.5" Panaracer Gravel

Double kickstand

Rear Rack

Front and Rear lights + reflectors


V2.2

Have a custom crate bag made, to include battery straps/elasticated pocket. Additional internal pockets for tool roll, pump, waterproofs etc.



Vertical 10Ah 2.8Kg battery inside crate
(thank you CC)

 

[Papa]

I’m looking forward to hearing your thoughts, advice and/or suggestions about this build.

I responded... at your request.
I did us both a favor... and initiated the "Ignore" option - you too have that same option.

 

[Acme Anvil Corp]

My current daily rider is a truck bike with 20-inch front and 26-inch rear. The initial build used an old Grin 9c 2810 front hub in a 20-inch wheel. The idea was to make a bike that could haul just about anything in my hilly town by running a lot of power through a very small wheel. It worked. That thing could climb a wall but at 3kw the torque was way more than I wanted in a front hub. And that was after years of running a powerful front hub in a 26-inch beach cruiser frame.

I reconfigured the bike with a rear hub 9c at 3kw (80v/40amps) and it handles much better in that configuration. For a while I placed the battery in the plastic bin on the front rack (which attaches to the frame rather than the fork). However having that much weight out over the small front wheel was not ideal. The bike handled okay. I never felt unsafe cruising at 28 mph (45 kph). But when I moved the battery to the center the bike immediately became more stable and a real joy to ride.

At the power you plan to run you shouldn't have any problems with the front drive. But the weight distribution is something to consider, especially since you will have more space and weight capacity for cargo on the front rack if you put the battery in the frame. Now, if you value stealth, putting the battery in a box on the front rack is a great option. You'll find that with the box on the front rack, most people won't be able to see that you have a hub motor on your tiny front wheel.

Just some thoughts as you start a somewhat similar build.

 

[Niner63]

I reconfigured the bike with a rear hub 9c at 3kw (80v/40amps) and it handles much better in that configuration. For a while I placed the battery in the plastic bin on the front rack (which attaches to the frame rather than the fork). However having that much weight out over the small front wheel was not ideal. The bike handled okay. I never felt unsafe cruising at 28 mph (45 kph). But when I moved the battery to the center the bike immediately became more stable and a real joy to ride.

At the power you plan to run you shouldn't have any problems with the front drive. But the weight distribution is something to consider, especially since you will have more space and weight capacity for cargo on the front rack if you put the battery in the frame. Now, if you value stealth, putting the battery in a box on the front rack is a great option. You'll find that with the box on the front rack, most people won't be able to see that you have a hub motor on your tiny front wheel.

Just some thoughts as you start a somewhat similar build.

Thank you, a stealth build vs weight distribution/handling are all key points to this build using a much smaller 13S battery than the 80V battery that you once had on your front rack. More details to follow in my next post.

 

[Niner63]

Beta Testing​

Handling vs Battery weight(s) + positioning considerations vs Stealth/Clean build.


Once the cargo forks are fitted, I can begin Beta Testing the handling of the bike using an old BMX front wheel and my old Alfine 8 rear wheel, unassisted as a regular bike.

At which point, my plan will be to initially, temporally, mount my 4.5Kg 48V 20Ah battery to the rack, vertically, horizontally and or any configuration that it will fit.

These cargo forks are load rated at 25kg with a lot of empirical internet evidence of folk hauling heavier loads and bikepacking/touring with these forks.

These "tests" will give me a reference point to how the handling will be affected by the "max" weight battery I "might" consider using. While also considering the additional weight of a hub motor, Max 6.5kg 9C DD, Min 3.8kg eZee GH.

In reality, I currently plan to be using a 10/15Ah (2.8/3.4Kg) battery mounted within a crate or possibly, space depending, behind the steering axis while still being attached, discretely, to the cargo forks.

If the initial Beta testing is a "disaster", handling wise, a down tube Bottle style battery, see post #17, would be an option while still keeping the build stealth and clean.

Examples, below, of just some of the batteries I've recently researched:


48V 14.5Ah 40A BMS (TP29HE cells need researching) for the Serval 1200W 48V electric dirt bike from Nitro Motors





NEXUM custom battery kit, the cells being welded "in shop" and their "Assembly service"
Though with more research I believe I could assemble the pack myself saving 95 euros.