Back in the Saddle: Going to California: 2011

[REdiculous]

If it was me I'd take the trailer (unpowered) anyway. Even if it'll only hold 50lbs, it's that much less weight and bulk on the bike....easier on the tires at least.

[Kingfish]

If it was me I'd take the trailer (unpowered) anyway. Even if it'll only hold 50lbs, it's that much less weight and bulk on the bike....easier on the tires at least.

Strangely – I have been reconsidering the option for that reason. The primary issue with restoring the trailer is that I only have one 24” wheel strung up, and that’s now mounted on the eBike rear. (The frame can only accept 24" wheels). That given, I do have another 24” Kris Holm Rim, 24” Hookworm, and 24” DH Tube (3 in fact) – just no hub or spokes. It would likely take a week to get spokes unless I can rob Peter to pay Paul; buy a 24” rim locally that’s already spoked-out. The problem there is that those spokes are likely to be not as strong. Though it is definitely an intriguing thought. The trailer needs to have at least 30 lbs. on it to prevent it from bouncing: With clothes, tools, and spares – that about completes the equation.

• I have done another weight calculation. It is remotely possible to put 18 batteries forward. This would reduce the aft section to 21 batteries on each side; totals are 36 fore and 42 aft or 46 lbs. fore and 53 lbs. aft. I like those numbers and shall try to shoot for that.
• Alternatively I do have these Timbuktu bags that I bought last year; they hold 6 batteries each, and can be modified tonight to sling across the front. Also just did an assay on my APP connectors; it will be close but I think I have enough to do the job.
• It’s been raining pretty hard outside and I’m not keen of getting wet, but will do shortly for the weight tests. Just trying to figure out how to hang the weight.
• Also I have a DNP Epoch 8 Speed Freewheel 11T Small Cog 11-32. I was thinking of pulling the 11T ring off and putting that onto the Shimano (being that it’s a better quality freewheel).
• Lastly, I want to check and see if my custom Front Torque Arm can fit on the rear, and if so then have the Machinist crank me out two more.

All easy tasks for a wet Sunday. At least it’s a warm rain.
River Deep, Mountain High. KF

[REdiculous]

Even a really old junker wheel missing a few spokes would work if you're only loading 50lbs or so. I can usually trip over those at the junk shop.

[Kingfish]

Noon Update
I just got off the phone with Gregg’s Cycles in Bellevue; I forgot that they have a spoke thread rolling machine- and that have single-butted spokes, not the 2.1 Sapim – but they do have 2.0 and that might be strong enough. AND – I have a spare Hope Pro II hub. Instead of using the Problem-Solvers rear axle, I use the custom axle I has made up for the hitch instead. Now the challenge is how to mount the hitch to the hub motor…

Late Afternoon Weight Test Results
There were four incremental tests given before I left for Gregg’s, each adding a bit more weight to the front and then to the back. Legend:

Num = Test number. The first test has doesn’t count since the batteries are already in situ.
Where = Fore or Aft.
Type = Device used to add weight; batteries, frozen gallons of water, or lifting weights.
Amount = in pounds.
Total = Running total with each test.
F/R Total = Cumulative total for front and rear.
Goal = 1st figure is the total weight, and the second figure is the remainder.

Code: Select all

Num   Where   Type        Amount   Total   F/R Tot   Comments
0     Front   Batts, 18   22.86    16.6    22.9      Already on the eBike since January 1st, though included in the total weight.   
1     Rear    2 gallons   16.6     33.2    16.6      Hardly worth noting
2     Front   Batts, 12   15.24    48.44   38.1      Know it's there, minor lugging uphill
3     Rear    2 gallons   16.6     65.04   33.2      Just beginning to feel squirrely, though manageable
4     Front   3 lbs x 3   9.00     74.04   47.1      Struggles to start on steep incline - but climbs well enough.  Bounce in frame noticeable but does not "wobble".  Definitely harder to manage.  Not sure I would feel comfortable putting any more weight on.
Goal          99.06      25.02                       Conclusion: Means that 18 to 24 batts must go to trailer.


EDIT: Formatting.

Test #4 had me worried; I did not want to add more weight because it would take the fun out of riding. In fact – I was a little fearful after Test #3 which is where I could still enjoy the drive without much effort.

Return of the Trailer
Whether it’s “Return of…” or “Son of…” or “Version II” ~ I think we need to resurrect the Trailer. The weight test did prove one thing crystal-clear: The rickety wobble is gonzo. I could not make it klink about like it did before and that is a good sign.

About 5 PM I bolted off to Bellevue – enjoying every hill climb I found – and dropped off the goods at Gregg’s to fabricate a 24” wheel; they said they could get this ready for me by tomorrow; they are planning on having it deal with a 50 lb load, and I asked them to armor the shit out of the thing too. We also discussed a special type of hand brake that has two cable-pulls for like one-armed people or BMX tricksters that want just one hand on the control. The idea is to run a second “Tandem” type brake line all the way back to the rear disc. Anyways – the concept is being explored. I am not going to wait for mail-order stuff though; if it’s not local – it’s not going on the frame.

That leave’s one sticky wicket left and that’s how to mount the hitch to the hub motor. I could to it the “Bob” way but I think that’s kinda low-strength. Anyways, it needs sorting out. Tomorrow is a big day then for me; Seattle, then Bellevue, then Machinist. If it comes together I’d like to leave on Tuesday – but that’s not realistic, so it looks like Wednesday at the soonest – weight being the biggest issue.

Note to Self: Self – the front wheel spins too much so let’s reduce the current. Also we need to dial back a bit more on both power-hungry controllers for long distance thrift.

Summery for those jumping into the middle
Last year I went to California on a hardtail and broke 5 spokes on the last day cos the bike was too heavy. Resolved to build a trailer for this year and put most of the weight on it. Decided early on to make the trailer a pusher. Trailer ended up having a weird and yet dangerous axial twisting motion when under full load. Hub motor from trailer was removed and then added to the eBike – making it a full-suspension 2WD light “Enduro” type urban assault vehicle; it tears arse as a hill climber! The majority of the entire weight will now go on the ebike with the trailer in tow carrying < 40%; this should greatly reduce the nasty axial twisting problem. This is the last best hope to reach California this year by ebike.

Cheers, KF

[mobybike]

Thanks for posting all this KF! I can't help but armchair engineer along with you as you go, and I just wanted to mention a couple of things that "seem" like it might help.

• Mounting Hookworms... when you wrap the rim a lot of times with tape or liner, it make the tire harder to mount. Prove this by mounting the tire without any liner = easy.
• 2.1 Sapim spokes you use, are thicker at the "j" bend. This is useful for hubs with larger holes (hub motors, but actually bigger would be still better... see next bullit), but on your regular hubs the 2.0 (14g) will be just as strong.
• Breaking spokes; the stress riser of note on e-bike hubs are the j end. The reason spokes break here is because they bend here, like when you bend a paper clip or wire over and over, it finally breaks. The e-bike hub has large holes in the flanges, the bicycle spokes typically used are too small and every revolution of the wheel bends the spoke here at the flange. Push down, pull up. push down pull up round and round it goes. Eliminate the extra space here and only the spoke body flexes not the "j" end. This is why even thin spokes can sometimes produce a stronger longer lasting wheel. There is less stress on the ends. The nipple end is another concern, because the large flange and cross pattern typically used on e-bike hubs produces a tight bend at the nipple, and if the wheel builder doesn't compensate and adjust this area, you have another stress riser that will cause spoke breakage here or the nipple will also fatigue and fail.
• Torsion from the trailer; When you place a load on either side of the wheel back there over your 24" wheel, you are using a large heavy lever that wants to stay static or move where it wants to. The bigger the loaded wheel, the greater the leverage twisting against your bikes frame and wheel/tire via the massive hitch you designed. Reducing leverage would probably include; no weight placed over the wheel at all, all weight forward of the tire. SMALLER lever = smaller wheel. 16" wheel smaller lighter tire. The center of gravity against the load would be shifted aft, and weight the tongue at the same time. This would allow the trailer to track you instead of attack you.
  
  

Keep up the great work, its fun to watch all this, thanks for logging it! It would be great to see you get to go after all!

[Kingfish]

Hi Moby
Many humble thanks on the feedback

• Broken spokes: Makes sense. Last year this occurred on the non-hub wheel; 19-yo original equipment! I had the rim replaced in Auburn.
• Torsion: Yes, I think that sounds reasonable. The Bob trailer design has the small wheel aft of the platform. In my case the rear wall of the battery box is about an inch forward of the axle. On that point…

Correction
I found a typo in the previous post. Evidently I had 6 more pounds on the ebike than indicated (which is good). Regardless, I think we have a good case for bringing the Trailer back because I really do not want to add more weight to the bike. Updated results are below.

Code: Select all

Num   Where   Type        Amount   Total   F/R Tot
0     Front   Batts, 18   22.86    22.9    22.9   
1     Rear    2 gallons   16.6     39.5    16.6
2     Front   Batts, 12   15.24    54.7    38.1
3     Rear    2 gallons   16.6     71.3    33.2
4     Front   3 lbs x 3   9.00     80.3    47.1
Goal          99.06       18.8


Seeking Balancing
This is still hypothetical – however I would like to remove the last 9 lbs added to the front (Test #4) and put that on the Trailer. New numbers would be:

Front = 18 (original) + 12 more (30 total) = 38.1 lbs. fore
Rear = about 24 batteries, 27 max = 33.2 lbs. aft
Trailer = about 24 batteries, 28 lbs.


• I will need to play around with the qualities between the Rear and Trailer cos I will want easy access to tools, food, and the Charger.
• Trailer batteries, if using 24, can be split as 12 on each side, and I can move those all the way forward within the box where the weight is over the Bottom Bracket. Airy cargo, such as clothes and jackets can go aft to make room for denser items to move forward.
• I will also try to trim the total weight down as well.

Daylights’ burning, KF

[SamTexas]

Is now a good time to change the thread tittle to something more appropriate?

[dbaker]

Try to be more positive, SamTexas Most of us are still pulling for KF to get on the road. We want ES positive energy to help get him there

[SamTexas]

OK, message edited.

[Kingfish]

Try to be more positive, SamTexas Most of us are still pulling for KF to get on the road. We want ES positive energy to help get him there

My Support Network: You guys rock!


The Day of Gremlins!

• Before I headed out, or tried to… I screwed around trying to figure out how I am going to get an 11T on the freewheel. Finally after fussing about I just went ahead and put the DNP Epoch 8 Speed Freewheel 11T Small Cog that I had laying about. The original plan was to rip off the 11T and put it on the Shimano, but they are made by different manufacturers and have zero-interchangeability. For all the times I’ve taken the rear hub off and played with eh disc rotors – I had a good idea how to fix the spacing problem and nailed it on the first try. The DNP Epoch 8 Speed Freewheel is now mounted and spins fine; we are good to go on gearing ~ not optimum, but good enough.
  
• Loaded the bike with the Hitch to take back to the Machinist for rework. Also loaded the charger so as to top off before heading out to Seattle Fabrics. Also took with me the Timbuk2 bags cos I think it’s faster to adapt them as 6-gun, er 6-battery holders; just needs a under-over sling and power cabling.
• Reprogrammed the Primary-Front controller to 14A Battery/35 Phase from 20A/50A. I’m ready to go.

At 1:30 PM - head out the door and on down the hill, then pull out onto the main road. I could tell the launch acceleration was way down. Not a bad thing cos economy settings are often underwhelming, though the top-end was still viable. Hit a bump and lost all Throttle; dead in the water. WTF? Well – when this happens it’s typically the eBrake – and it was, only now the eBrake microswitch had lifted off the mounting. Arrrg! I grabbed the little leaf-part of the micro-switched and squeezed: Throttle returns ~ yea! OK – one hand on the throttle and one finger on the leaf-switches and try to turn around AND engage mechanical brake with other fingers to fight my way back to the hidden urban Bat cave.

• It turns out there is more wrong than just a buggered eBike/Stop-light switch: My running light (aka Taillight) is also out. Now I have to tear into the whole belly of the beast to trace this out. Finally found the break right where the signals fork to go to the Trailer connector; broken solder joint.
• Also all auxiliary voltages were periodically going out during this time. Crapola: Traced that to a cold-solder joint that enabled Aux power on the DC-DC converter.
• Next – tried to superglue the microswitch pairs back onto the brake. Wouldn’t take, so I clamped it. This worked fine but now the switches were dead from compression. Grrrr. Pull the switches off. I have replacements as roller-leafs. This is about the 4th time the micro-switches have pulled off the brake lever. Resolved to use the two-hole mount – but I don’t have screws small enough. What to do? OK – mother of invention kicks in: I had some extra spokes and they fit the holes. Took the broken switch and using it as a template, drilled two holes into the brake lever. Next, took two good switches and as guides ran the spokes through them (butted ends up and threads down) and sorted out how they would integrate into the brake lever; it’s almost a tight fit mainly cos the drilling was slightly imprecise and creating tension – which is good. Pull this assembly out, apply superglue to the holes and surfaces, and reinsert the switches/spokes making sure the threads are in the holes; the mounting takes! Superglued the second switch down on top of the first. Took a cable-cutter and trimmed off the protruding spokes; it left a 1/8” high nub and I ground that off and filed it down nice. More superglue into the mounting holes; suck it up bugger! Now we have a firm fix on the little f@#ker. Tested the swithes – they are a little flakey. Grrrr. Test test and more test. OK, I think it will work so I solder them up, heat shrink, wrap tape, and test: nuttin. Arrrg! Test test and more test – finally they work.
• Hook up the bike, put everything back together except the front faring and go test. Nuttin works. More hair falls out – and I only have three skinny hairs on this pointy head. Fiddle about fiddle about fiddle about – finally switches work… some of the time. Go for road test, up the hill (economy-level kinda sucks compared to yesterday). Then the controller kinda figures out “Hey, I got an ebrake!” and begins to work consistently. I swear to all the sacrificial barleys that I have consumed in the past week that these controllers have two more brain cells than me and are conspiring to frustrate my process. I think we need to sacrifice more barleys tonight.
• Did the horseshoe loop up the hill and down and back up again (it really is a good torture test); everything seems back to normal… except the Time: It’s now 5:30 PM and I have lost the initiative of the afternoon.

D'is is da pesky critter after rework. The two "posts" that secure it to the brake casing are just beneath the electrical tape.

Da Plan

• The tentative plan is to try and leave on Thursday. Wheel wasn’t built today but should be ready after lunch. Regroup for tomorrow: Machinist, Seattle Fabrics, Gregg’s Cycles. Hopefully Machinist will take one day; we only need to replace the ghetto rear torque arms and fix the Hitch so we can mount it to the rear hub.
• Modify the Timbuk2 to accept a sling; maybe two hours.
• Build the rear battery bags; keep it basic. Just reviewed what I did last year; I had a metal framework made up to hold the batteries together inside the Ortlieb bags; these can be reused. I may even try to put them in the new Ortliebs – though if so then then need another strap to keep them from flopping around. I think I can make something work here without a lot of trouble.
• Trailer should go back together quickly now since it’s just pieces that I cut and marked as I went; assembly likely Wednesday. Load up with static weight and test test test.

Battery Wiring

Code: Select all

Location         Batts    Wyes   Status    Notes         
Front Triangle-L   9      3      Done            
Front Triangle-R   9      3      Done            
Front Saddle-L    6       2      covered   Trailer is strung for 36 batteries/side;          
Front Saddle-R    6       2      covered   That's 3x4 wyes x 2 = 24 wyes.         
Rear-L            12      4      covered   Trunk bag is strung for 2x3 wyes.         
Rear-R            12      4      covered   Conclusion: Prune the branches to make new harnesses.         
Trailer-L         12      4      covered   We have enough APPs to do this, though 2 short on 45A lugs.         
Trailer-R         12      4      covered   Note to Self: Self - stop at Vetco to see if they have 45A lugs.         
                        
Total             78                  


OK – that’s a good plan. I am still partly packed so time is saved there.

My two brain cells are in collusion to have me to: Relax, Don’t Worry – Have a Homebrew! I think I’ll go and do just that.
Gremlins be gone! KF
EDIT: Added photies

[Lemlux]

KF:

You've finally persuaded me not to make a trailer out of my 1993 Giant 770 AX 16" Chromoly frame. I wouldn't have the skill, patience, or funding to do all you've done.

giant_frame.jpg (9.32 KiB) Viewed 910 times

I do have an idea, though: I could give you this frame and you could weld it mounted parallel to the ground as a stabilizer platform for the bottom of your trailer. It's yours for free if you pay shipping.

You might even use one or both of the dropouts to reinforce the pivot for your front-leaning trailer arm.

[Kingfish]

KF:

You've finally persuaded me not to make a trailer out of my 1993 Giant 770 AX 16" Chromoly frame. I wouldn't have the skill, patience, or funding to do all you've done.

giant_frame.jpg

I do have an idea, though: I could give you this frame and you could weld it mounted parallel to the ground as a stabilizer platform for the bottom of your trailer. It's yours for free if you pay shipping.

You might even use one or both of the dropouts to reinforce the pivot for your front-leaning trailer arm.

Yeah, I like that idea

Tuesday July 19th: Git’r Done!
Today was a busy day; got some much needed rest after a night of chasing… I bet you were gonna say chasing skirts huh? Nope; I was chasing after sacrificial barleys! Anyways – slept well cos I’ve been stressed out lately.

• Called Gregg’s Cycle and they said that the 24” wheel would be ready near the end of the day.
• Finally got out the door at half-past Noon. Stopped at Radio Shack and bought four Submini Lever Switches as backups for my eBrake and Brake Light.
  
• Stopped at Ace Hardware and picked up two bronze bushings, ½ x 1” for $3 each, and a pair of matching washers.
  
• Went directly to the Machinist and dropped off my parts. We discussed the torque arms and he told me that the mills were tied up for a few days, so I axed that work as not optimum but also not essential. He did say though that the bushings could be finished by EOD. On the return trip I picked up the finished parts: The bushings were modified to match to a 14mm threaded axle and machined down to slip inside my hitch brackets. It took ¾ of an hour on the lathe. The parts are a tight fit inside the hitch but slip on over the threaded axle nicely. Gone is the Delrin. We’re after a firm tight fit. Here’s a picture of the left and right hitch brackets with the bushings mounted – flange facing out. I like this setup; mucho happy puppy.
  
• Topped off the charge at the Machinist and headed out to Seattle Fabrics in the Greenlake district. Got as far as I-405/116th in Kirkland when the chain locked up on the bike. WTF? Couldn’t find anything wrong so I kept going – only to be halted again 20 feet later; complete lockup now – can’t spin the crank forward or back. I figured that the freewheel was synched up next to the frame and that I required one more washer to space it out. Bummed, I drove on electricity all the way back to Redmond ruing the moment the entire way; it felt unmanly.
• Began to take the wheel off when I noticed that the reason the chain was locked up was because the rear derailleur Dropout mounting screw and lost the bolt-part and the flush “screw” part was jammed into the freewheel, locking the chain. That was easy to remove. Called Gregg’s and they assured me they had replacements. 2 points for Gregg’s.
• Since I had the left-side ghetto torque arm off, I replaced the soft cold rolled steel (CRS) with a ¾ x ¾ x 1/8 Aluminum 6061-T6 L-Angle which is vastly stronger. I think it makes a nice footrest don’t you? It requires flat black paint to hide the magpie effect, and maybe the clamp too.
  
• Topped off the charge and headed back to the Machinist at 5 PM. Picked up my nice parts and headed off to Gregg’s. It’s now 6 PM and John had finished building the wheel but not the tire, so Travis did that part and I guided him on how I wanted it armored: Layer of Stop-Flats 2 on the rim, covered with a layer of Velox tape, then tube, then Stop-Flats 2 on the perimeter, then tire. Done.
  
• Next, John had promised to fix my other bike issues but had to clock-out; Jimmy took over. Disc Brake Rotors Front and Back: Both Jimmy and Travis worked these discs over to true them up with me keenly observing their technique, and got the bike to where I had full-brake at 50% lever which was a vast improvement! I also bought the Park Tool Rotor Truing Fork DT-2.
  
  Then we paid attention to my derailleurs and Jimmy got them both in spec and tuned up, and finished with a lubed chain. Finished by 8 PM closing. My wheel build, tire-mounting, fixing the brakes and derailleurs, plus the Park Tool came to just over $100: What a deal! Oh and the Dropout screw was tossed in for free. Neat guys! The bike flies down the road!!

The only item I don’t care for on this new confirguration is the hard braking of the Regen. If I had more time, I’d like to tinker up a circuit that allows me to progressively add Regen through the Throttle like my old controller. Lyen says there’s a way to do it but we need to mod R12 – presumably in a dynamic manner.

What’s next:
Well, I really want to leave on Thursday. I thought about how to resolve the battery bag issue with materials on hand; maybe use the 1000 Denier Cordura instead. Going to Seattle Fabrics now would cost me ½ day there and back. I’d rather have that time for integration and testing. I think then that will be The Plan.

We’ll know for certain in the next 24 hours. KF

[Kingfish]

Wednesday, July 20, 2011
Close, very close… Optimistic Test Drive

Today I busied myself with getting the trailer assembled to a point where testing could be accomplished. This took a bit longer than anticipated.

• The Hitch Bracket – now with the bronze bearing is slightly wider due to the flange and washer, AND the hub axle in shorter than my custom axle (now mounted on the Trailer). Took a while to sort out the absolute minimum washers that could go on to the axle. As it turned out, I didn’t use washers. Instead I used the flat file and leveled the surfaces of the stamped-steel torque arms and put them on first, then the bronze washer, then the hitch bracket, and finally the nut; that’s all the room there was, and no threads left to spare. This was all tightened down and then I worked it over making sure the nut would not back out.
  
  
  Right side rear stamped steel torque arm, modified to miss the rear derailleur mounting.
  
• Also I removed the EBikeKit torque arm cos it was pointing in a direction that was not useful. Instead I used a modified stamped-steel torque arm, leveled on both sides, and then cut out a link from Aluminum angle and fabricated the clamp. These items were planted flat black and heat cured in the oven one the paint was dry.
• In parallel to this, I would alternate to the trailer and put the unit back together again sans the faring. Really – those are the two big ticket items other than mounting the trailer to the hitch which took time to set correctly.

Prepping for the Test Drive
About 4 PM I started calculating what I needed to do here. Much of my stuff is still packed, so choosing a load was easy. The Timbuk2 bags were stuffed with 6 batteries each and temporarily saddled over the front of the bike. The Ortliebs were loaded out with 12 batteries on each side just like I did last year using the same pieces of framework and paneling. Then I added a 3 lb. free weight to each side to mimic the charger and some food. Next the trailer was loaded with 12 batteries on each side – forward inside the boxes, and down some bags of clothes. Grabbed a yellow Ortlieb and stuffed two frozen gallons of water inside and strapped that in the forward section over the center and on top of the clothes to simulate the maximum about of crap that I could probably take. Here’s the weight chart:

Code: Select all

Where       Type        Amount      Total   F/R Tot   Comments      
Trailer     Batteries   12          15.24            
Trailer     Gallons     2           16.6            
Trailer     Clothes     2           4       35.84      Trailer Total      
L/R Rear    Batteries   24          30.48            
L/R Rear    Weights     2           6       36.48      Rear; Simulate charger and food      
L/R Front   Batteries   18          22.86             Already loaded in Triangle      
L/R Front   Batteries   12          15.24   38.1      Front      
                     
Total                  110.42
Bike only               74.58


The total weight is about 10 lbs. over what I expect. After strapping it all down temporarily I headed out for a test drive at 6:30 PM.



No faring; just a go-no-go test.



Toolboxes contain 12 batteries shoved all the way to the left (forward). Orange bags are heavy clothes. The yellow Ortlieb had two gallons of frozen water inside.

Test Drive
Decided to head up the hill. The bike lugged heavily. I fear that I must reprogram some current back into the controllers to get more horsepower. Once near the top the bike picked up speed just fine. Handling was good going up and down the hill. On the flat, wobbling can be induced by the rider.

I headed down the horseshoe – braking at first, then slowing allowing more speed then braking, several times before reaching the bottom. I was very satisfied with the brake work done yesterday; between the eBrake and the double-discs, stopped in not a challenge and the trailer does not swing around. Still unsure about flat and level riding, I gingerly drove into town, though taking right turns and eventually winding up climbing the backside ridge of Redmond also known as Education Hill. Very steep and winding rural roads had me on my toes keeping the bike stable at low speeds.

Eventually I wound up on the main route back into town and going faster and faster. Though I really had to watch it cos I could induce a wobble if distracted. Part of me wants to remove more batteries from the bike and place them on the trailer, though I fear this could exasperate the known problems. Another thought was to rearrange the battery packing so that they are closest to the front-to-rear centerline, reducing the lever (moment) and hopefully the wobble. The ride concluded with one of the hubs dropping out at a stop-light; I had to make a quick stop when the light changed suddenly. Acceleration was off, and I couldn’t climb the hill back home. Both wheels spin though with throttle, so I don’t know if it’s a controller issue yet (FET?). The total test drive was 5.8 miles with an elevation gain of 459 feet. On the whole I consider the ride an optimistic albeit limited success.

I am going to take one more day to evaluate whether I can use the trailer or not; more testing required.

What’s left to do:

• Fabricate the saddle bags connective link.
• Create battery bags for the trailer; just a simple sling where I can pull the whole lot out to make the trailer lighter. The plan is to pull the saddle bags and the Ortliebs off the ebike to make it lighter for stowing. The trailer could be unloaded quickly as well cos my clothes and stuff are already bagged; we just need to bag (or sling) the batteries as well.
• Finish up the batteries cabling; prune the existing cables and add connectors.

Summary
We are getting there. Just need a bit finer tuning. There is still a chance to make the trip. I am concerned about the power consumption; means I’ll need to go slower to save energy or break up the trip into more days. Moving the hub motor to the eBike offset some of the wobbling, but did not eliminate it. I don’t think there is a viable way to do that though with Aluminum frames.

Zonked out and tired after the ride. KF

[jonathanm]

You need to try and figure out if ALL the wobble is coming from the flex in the frame, or if there are other factors involved. Is there any slop anywhere in the hitch? If it IS purely due to flex in the frame, then the only solution is to increase stiffness with some more material....welded triangle ideally, but even bolting some thing with a lot of torsional stiffness might help as a "get you going" temp solution. You don't have any 80/20 aluminum extrusion lying around do you?

[Kingfish]

You need to try and figure out if ALL the wobble is coming from the flex in the frame, or if there are other factors involved. Is there any slop anywhere in the hitch? If it IS purely due to flex in the frame, then the only solution is to increase stiffness with some more material....welded triangle ideally, but even bolting some thing with a lot of torsional stiffness might help as a "get you going" temp solution. You don't have any 80/20 aluminum extrusion lying around do you?

The link between the two frames is tight. If I wobble the rear of the trailer, it will propagate through the entire length as one wave action very solidly. At least that part is good. The only extrusion that I have is the L-Angle Aluminum 6061-T6; ¾ x ¾ x 1/8 inch. It’s pretty sturdy.

The only part that doesn’t wobble per se is the front of the bike where I have the saddle bag; the steerer is the most stable part. It is definitely frame flex. The only way I could think to stiffen the trailer is with two channel plates that are wide enough to cover the top and bottom tube – but that defeats the weight reduction. A welded link between the two tubes would probably help quite a bit – but then we’re into TIG/MIG.
~KF

[jonathanm]

Yeah....any ally welding you do is gonna weaken the frame also......bolting something on could work short term though not ideal

The L angle extrusion does not have much torsional stiffness.....been there done that.

You need to add some material with very stiff torsional rigidity, or add some triangles in rotational plane somehow - ie from as high on the trailer steerer tube as possible to as low on the seat tube as possible....but I can't think of anything stiff enough that would work......

OR add something like the 8020 aluminum down the middle which has great torsional rigidity but is heavy...

[Kingfish]

I’ve had an epiphany: Structural Foam! Right down the middle. Lightweight, adds rigidity, inexpensive, DIY.

Whatcha think?
~KF

[jonathanm]

wow....i have no idea of the rigidity.....could possibly add a damping factor into the equation.......that's some outside the box thinking going on there - what brand of barley you been sacrificing tonight? I want some......

[Kingfish]

No barleys were sacrificed tonight; I'm on the wagon trying to leave. It popped into my pointy lil' head after watching an episode of "Doc Martin" on Netflix.

Technically it is referred to as Closed Cell Spray Foam, of which there are many types. High-density is preferred. I am familiar structural foam composites from previous projects, and in fact had considered a composite foam core for the base of the trailer: Lightweight – yet rigid, with laminated exterior.

I am trying to source some now. Home Despot doesn’t carry exactly what I am looking for; they have the “spray insulation” version. There’s a two-part version that is really strong, but I don’t want to drop $500 for my application. Figure 2-3 cans would be enough. Need to treat the top and down tubes of both bikes, and possibly the stays as well. And it will certainly add dampening!

~KF

[dbaker]

Is the spray foam going inside the tubes or are you going to clamp a skin on the outside and use it to glue a stressed skin to the frame tubes?

[Kingfish]

Is the spray foam going inside the tubes or are you going to clamp a skin on the outside and use it to glue a stressed skin to the frame tubes?

Goes inside the tubes

There's a thing called a skin-affect; when you have a rigid foam and a rigid skin, the two materials work together to create a very strong structural bond because the resonate frequency of the dissimilar materials can dampen audio-acoustic waves. The two frames connected have a low resonate frequency, and I suspect that the hub motor on the trailer was contributing which the slightly out-of-balance wheel. If I am not careful, I could also induce a resonate frequency at the handlebar that would have the waveform travel from the front to the back and front again without dampening. BTW - the Steering Dampener is set to a modest level; slight resistance but not stiff.

Volumetic Calculation

• 2009 Felt Compulsion 1 FS Frame: 7005 Double-Butted Aluminum
• 2011? Because Simple Frame: Aluminum 6061-T6

Code: Select all

Frame    Tube    Dia-in  Len-in  Qty  Vol-in  Vol-oz   Comments
----------------------------------------------------------------------------------------------
Because  Top     1.25      23     1    28.2    15.6    Consistent
         Down    1.75      23     1    55.3    30.7    Squashed to ovid at seat/stays
         Seat    1          4     1     3.1     1.7    Consistent
         Stays   1         13     4    40.8    22.6    Squashed to ovid, narrowing towards axle
Felt     Top     1.38      20     1    29.9    16.6    Hydroformed
         Down    2         24     1    75.4    41.8    Hydroformed
         Seat    1.38       7     1    10.5     5.8    2-part with shock mounting in the middle
         Stays   1         11     4    34.6    19.1    Round to Square; lengths averaged

Total                                 277.9   154.0   


We are interested in the total fluid ounces to know how many cans of foam to purschase. I sourced this stuff at Home Despot:

GREAT STUFF 16 oz. Big Gap Filler Insulating Foam Sealant

The Great Stuff 23 oz. Big Gap Filler Insulating Foam Sealant is designed to permanently fill gaps in many materials, including drywall, metal, masonry, glass and most plastics. It helps seal out drafts, insects and moisture.

• 1 Can equals up to 24 tubes of caulk
  
• For indoor/outdoor use on a variety of materials, including wood, drywall, metal, masonry, glass and most plastics
• Permanently fills gaps larger than 1 in., helping to block drafts and entry of insects and moisture
• Cures rigid in 8 hours

• Presume that 1 tube of caulk = 10 fluid ounces (U.S.), one can of this stuff expands to 240 fluid ounces. The total volume of the bike frames (discounting wall thickness) is 154.0 - therefore one can should do both bikes. There will need to be some dissassembly and I am uncertain if I can get foam into all the voids easily.
• For the Felt Frame, easiest access is through the Head Tube, although access through the Bottom Bracket might be required unless I can snake a filler tube down there. The stays would need to have the vent holes opened; not keen on that.
• The Because Frame can be access easily at both the Head Tube and the Bottom Bracket, and I think the Stays are opened at one end there as well. This is the frame that requires the foam more so than the Felt.

I think I'm going to break the two frames at the hitch and make a dash over and fetch this stuff this AM.
Rigidly, KF

[dbaker]

Buy 2 cans

[Kingfish]

Buy 2 cans

Yeah!

OK – I have disassembled the Trailer to where I have access to the top and down tubes. This was more work than I expected. I don’t think I’ll be able to squirt into the top stays though; the bottom stays have a large vent right behind the BB.

I am not going to shoot into the Felt frame; that’s just too much to do in one day – too much disassembly. We don’t know what the gain will be if any, so let’s stay with the largest target.

Anyways – I’m away to the store. KF

[dbaker]

KF, how is your cell phone working with Speedict?

[Green Machine]

I was also wondering how the speedict is working out.

Kf why are you running both speedict and CA?