(HUB users) What do you do when you break the dropouts?
- Thread starter swbluto
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John in CR
100 TW
1. Use the old dropouts for a xtracycle type extension.
2. Make some proper steel torque arms that bolt to the frame in a way that they are the new dropouts with the old ones just for alignment and transfer some of the impact forces to the frame.
BTW they tried to deliver the motor today, but the electricity was out and my doorbell isn't hooked to my back generator power. Hopefully tomorrow.
Since it's an RC motor, I figure it needs to go on a bike for the kids, or maybe a granny trike for the old lady across the street. :lol:
John
ps- The last comment was just for our Australian buddy. Don't worry I'll put it to good use. I've got a Lyen 18fet sensorless to test out anyway. 8)
2. Make some proper steel torque arms that bolt to the frame in a way that they are the new dropouts with the old ones just for alignment and transfer some of the impact forces to the frame.
BTW they tried to deliver the motor today, but the electricity was out and my doorbell isn't hooked to my back generator power. Hopefully tomorrow.
Since it's an RC motor, I figure it needs to go on a bike for the kids, or maybe a granny trike for the old lady across the street. :lol:
John
ps- The last comment was just for our Australian buddy. Don't worry I'll put it to good use. I've got a Lyen 18fet sensorless to test out anyway. 8)
vanilla ice
1 MW
Weld some tq arms on to the frame as the new drops.
swbluto said:
morph, what have u done with swbluto & how did u hack into his account???
Not all aluminum is weldable, but most aluminum bikes frames are. There's a catch, however - you'll lose approx 50% tensile strength in the immediate area surrounding the weld (normally referred to as the HAZ or heated affected zone). The only way to restore the strength after welding is to heat treat the entire frame again under carefully controlled conditions.swbluto said:
BTW... I hear someone is selling quality steel frame sets in the used classifieds section
AussieJester
1 TW
Toorbough ULL-Zeveigh said:
^^kekeke :lol:
J.J i thought you were popping one of your youngin's on the bike to race anyway
lightweight jockey with the rc motor he will be hard to beat for sure excellent plan
KiM
EDIT: oh..spreading dropouts had to do it on my frame actually, i used a 10mm threaded rod and nuts to push
out the width some, worked brilliantly.
Does anybody sell steel swing-arms? I have a dual suspension I was thinking about running a 9C on. I would love to try out running the torque limits of torque arms and whatnot, but I need to have a suitable "backup" plan if the dropouts fail. If there's no suitable backup plan, then I'm not going to get anywhere near the torque limit before dropout failure.
Hmmmm... I'm thinking. I wonder if I could transplant a cheapie y-frame mongoose or walmart dual-sus swing-arm? That way if it gets damaged, I'm not too worried about it as the original is still in tact.
Hmmmm... I'm thinking. I wonder if I could transplant a cheapie y-frame mongoose or walmart dual-sus swing-arm? That way if it gets damaged, I'm not too worried about it as the original is still in tact.
Toorbough ULL-Zeveigh said:
I don't get the reference, unless you're implying some level of ineptitude. It's true I have no experience with welding, but I recall references from touring pages about people who swore against aluminum bike racks because of their propensity to fatique and break, and how they were impossible to find a way to weld it back together, unlike chromoly or steel racks. I guess this was just due to "aluminum welders" being rarer instead of simply non-existent.
swbluto said:
only that it's a morph-worthy kind of question.
how did u imagine all those alu bike frames get assembled, ever notice the nice weld bead at the joints?
i'll cut u some slack tho, it sounds like what ur really asking is if u can re-weld aluminum.
there's been some discussion of that in the past, Papa pretty much recapped it.
i think it's not that it's rare per se but rather welding alu must require a special touch or a lot of experience as i am now the proud owner of a warped aluminum oil cooler after i took in for 'repair' of a new fitting & ended up costing me $250 for the privilege.
this was courtesy of a rad-shop which i thought knew what they were doing, got sucked in by their full page add in the phone book where in big bold beautiful letters claimed they routinely worked with aluminum cores.
u can actually see where the clamps began to crush in the frame as it started to soften & melt probably because (so i'm told) aluminum doesn't undergo any color change as it heats, unlike steel.
btw i'm one of those sworn off alu bike racks, gonna try SS next, Ti would be nice if anyone knows of any.
dogman dan
1 PW
Your dilemma is one of the reasons why this is such a great bike to make into an ebike. Of the cheap bikes that have alloy frames but still have steel rear swingarms, this is one of the best ever made. Start hunting. It took me two years to find mine.
You said don't tell me that, but sorry dude I can't change the world. Just saying keep the peeps open at the flea market in case one of these turns up. Meanwhile, start designing the best strongest torque plate you can. Hopefully your existing bike has nice big flat areas around the droupouts?
If you do ruin a swingarm, then you'd be also looking for the same frame on ebay to get another.
You said don't tell me that, but sorry dude I can't change the world. Just saying keep the peeps open at the flea market in case one of these turns up. Meanwhile, start designing the best strongest torque plate you can. Hopefully your existing bike has nice big flat areas around the droupouts?
If you do ruin a swingarm, then you'd be also looking for the same frame on ebay to get another.
docnjoj
1 GW
Hey Bluto
On my old trike I was regularly redesigning/rebuilding the rear suspension and regularly found steel swing arms on cheep bikes at thrift shops, some as low as $10. Good luck with your quest. Spinning Magnets thread has some cool suspension ideas.
otherDoc
On my old trike I was regularly redesigning/rebuilding the rear suspension and regularly found steel swing arms on cheep bikes at thrift shops, some as low as $10. Good luck with your quest. Spinning Magnets thread has some cool suspension ideas.
otherDoc
gtadmin
10 kW
If you rub bathroom soap on the aluminium, it turns brown just before it's about to melt. Well, for pure ali anyway, don't know about alloys.Toorbough ULL-Zeveigh said:
liveforphysics
100 TW
Before I even messed with putting a hubmotor in aluminum frame drop-outs, I would make a couple plates from 3/16th stainless steel (or 1/8" hardened high carbon steel if you are going to have it water-jet cut rather than doing it yourself.)
Put perhaps 4-6 1/8" holes in the drop-outs that line up with the holes in the plates, tap them, counter-sink the plates for the heads of the machine screws (i would use some flush socket-head machine screws.)
Then clean the aluminum drop-out surface as best as possible with some solvent, apply a thin layer good metal/metal bonding epoxy, place your plate on, a drip of red loctite on the thread of each of the machine screws, torque them down, wipe off the excess epoxy, wait 24hrs and have drop-outs that you will never need to worry about, or need torque-arms.
And don't try to say you don't have the tools etc etc needed... I know you've got time, which means you can go to a pawn-shop, buy a $10 drill, a $10 dremel and a $3 hacksaw, then go to a hardware store and buy $4 in screws, a $1 drill bit, and a $4 tap, and you've got all the tools required.
Put perhaps 4-6 1/8" holes in the drop-outs that line up with the holes in the plates, tap them, counter-sink the plates for the heads of the machine screws (i would use some flush socket-head machine screws.)
Then clean the aluminum drop-out surface as best as possible with some solvent, apply a thin layer good metal/metal bonding epoxy, place your plate on, a drip of red loctite on the thread of each of the machine screws, torque them down, wipe off the excess epoxy, wait 24hrs and have drop-outs that you will never need to worry about, or need torque-arms.
And don't try to say you don't have the tools etc etc needed... I know you've got time, which means you can go to a pawn-shop, buy a $10 drill, a $10 dremel and a $3 hacksaw, then go to a hardware store and buy $4 in screws, a $1 drill bit, and a $4 tap, and you've got all the tools required.
John in CR
100 TW
Luke,
After you did a double-take you wouldn't use 1/8" thick torque arms. They won't give, but they could easily cut into the axle. I did that in the first 10ft of my first hub motor ride ever. The SS torque arms were a bit less than 1/8th, but they cut grooves in the axle like it was butter. That was with a Grubee 500W motor, not my big ones. Thickness of torque arms can't be replaced with strength.
Toorbough ULL-Zeveigh,
Actually the original suggestion was at least as Morph-like. Welding more AL is a bad idea, unless you have long enough axles to make it really thick and/or you have a way to heat treat the result. Otherwise you're adding the same material back to what broke so easily before, but this time it has half the strength for the same thickness. Torque arms need to be nice thick steel or other strong material, not AL.
After you did a double-take you wouldn't use 1/8" thick torque arms. They won't give, but they could easily cut into the axle. I did that in the first 10ft of my first hub motor ride ever. The SS torque arms were a bit less than 1/8th, but they cut grooves in the axle like it was butter. That was with a Grubee 500W motor, not my big ones. Thickness of torque arms can't be replaced with strength.
Toorbough ULL-Zeveigh,
Actually the original suggestion was at least as Morph-like. Welding more AL is a bad idea, unless you have long enough axles to make it really thick and/or you have a way to heat treat the result. Otherwise you're adding the same material back to what broke so easily before, but this time it has half the strength for the same thickness. Torque arms need to be nice thick steel or other strong material, not AL.
vanilla ice
1 MW
swbluto said:
Actually I can!
Yea, I assumed the frame were steel.. reading is fundamental.
spinningmagnets
100 TW
Here's a thread with lots of pics of beefy DIY torque arms. Perhaps make one wide enough to sink bolts through the torque-arm and also through the drop-out?...
http://endless-sphere.com/forums/viewtopic.php?f=1&t=11570
http://endless-sphere.com/forums/viewtopic.php?f=1&t=11570
docnjoj
1 GW
Hey S/M! Doesn't that hole in picture 2 need to have a bolt in it? Or is my vision really poor (which it is)
otherDoc
otherDoc
spinningmagnets
100 TW
Of course!...without the bolt inserted (and an axle-nut), that torque arm is just like a 2WD Jeep, de-caffeinated coffee, and non-alcoholic beer...
dogman dan
1 PW
Notice the dropouts in the pics have nice big flat surfaces. Not all bikes are like that. The pics do show how it's done, even if they were taken with the nuts and bolts out of the way to show how it was made.
Here's some pictures. They don't seem that flat, so it seems like it'd be more difficult, and the existing hole you see if the eyelet where the rear rack is going to attach to. (Yes, a rear rack on a dual suspension on the swing arm - not the seat post. This should enable 80 pounds loads with a "Tubus cargo" rack.)
I don't think most of us count on the aluminum dropouts in these DS/DH bikes to resist major torque loads (9C on 18s Lipo). We count on the dropouts to hold the wheel in position and transfer wheel loads to the bike frame. Torque loads need to be managed with good torque arms and many of the earlier suggestions in the thread will work on this bike. The ability of that 9C to spread those dropouts without torque arms is much greater than the typical axle loads on that bike. Just make/buy some torque arms and enjoy the bike
Well, hmmm, good news. It appears that to sustain 30 mph on a 20 inch rim only requires 45 NM of torque or thereabouts. Since most hub failures seem to occur somewhere north of 60 NM with the appropriate setup, If I limit the phase current such that it peaks at 55 or somewhere around there, I should have no worries while still being able to travel ~30 mph up a "serious" hill. (Also, the heat output looks like it'd be quite manageable at ~250-300 watts)
Not a "wheelie" machine, but hey, at least a "I can go fast up hills" machine.
Now I just need to find a controller that does phase limiting. Do the "infineon controllers" really do phase limiting? I just wasn't aware that any ebike controllers actually did current sensing on the motor wires.
Not a "wheelie" machine, but hey, at least a "I can go fast up hills" machine.
Now I just need to find a controller that does phase limiting. Do the "infineon controllers" really do phase limiting? I just wasn't aware that any ebike controllers actually did current sensing on the motor wires.
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