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  1. Q

    Approximate cost of materials to build a basic chromoly MTB bike frame?

    That is quite some skill if I might say so. I've never seen someone able to weld a bike frame without jig. If you find some time during your next build, maybe make a few videos showing how yo do it ? I'm pretty sure a lot of people would find that interesting!
  2. Q

    Approximate cost of materials to build a basic chromoly MTB bike frame?

    Congrats on your motivation to dig into framebuilding! I'm in the process of building a custom cwlb, and from my experience, welding is the least of your problems. A simple diamond shape frame should certainly be easier, yet it also comes with its own challenges. You need access to reliable...
  3. Q

    Tube failure Calculation ?

    Well my guts tell me it's too thin but I can't figure out a way to prove it theoretically. I guess my best option is to build a replica and attach weights to it until it deforms!
  4. Q

    Tube failure Calculation ?

    Tried Freecad + calculix today to simulate 3KN applied on the seat tube. Using a 45cm 36x1mm tube protruding by 250mm, I get a deflection of 3.21mm. But von Mises are super high If anyone wants to give it a try, I attached the freecad file.
  5. Q

    Tube failure Calculation ?

    Ineresting replies - thanks. Did some research, and was surprised that there is no exhaustive list of dynamic loads for something as simple as a bike frame: too many different scenarios. Nevertheless, the only relevant force in my case is the strongest one applied to my tube, which if I'm not...
  6. Q

    Tube failure Calculation ?

    No idea - the welder had it in stock. EDIT: 36x1.1mm is actually standart steering tube.
  7. Q

    Tube failure Calculation ?

    The angle of the top tube is around 6° so nearly horizontal; bike already full suspended - all I need for the seat tube is to take an adult weight without bending.
  8. Q

    Tube failure Calculation ?

    Hello, I'm working on a custom CLWB and could use some help figuring out the seat tube strength. If I bolt the seat on a 36x1mm horizontal insert tube, what's the max extension possible before it starts bending ? Thanks for your help; EDIT: Here my findings so far: Area Moment of inertia of...
  9. Q

    'lightest.bike' 1.7kg 1000w mid drive

    Interesting reply: You went for the friction issue, while I had rather weight and overall number of components in mind. My point is: if you already have the component, you might use it for gearing as well. Keeping system complexity as low as possible seems always a smart move. BTW $30 is also...
  10. Q

    'lightest.bike' 1.7kg 1000w mid drive

    If the mid drive is intented for the maxarya, an IGH would habe been redundant, since that bike requires a rear chain tensioner anyway. The true benefits of IGHs only makes sense if you have horizontal or sliding dropouts in my opinion, since a chain tensioner is basically a derailleur...
  11. Q

    'lightest.bike' 1.7kg 1000w mid drive

    This one's easy. You can find them in the dealer's manuals. Here a link to a dealer that listed some of the most common hubs. Though the values are way too conservative in my opinion, so it won't help you much. I'd put my two favorite shimanos the nexus 3 and the alfine 8 at 120 n.m-2 and 80...
  12. Q

    'lightest.bike' 1.7kg 1000w mid drive

    What data do you need ? I have plenty of shimano docs laying around...
  13. Q

    'lightest.bike' 1.7kg 1000w mid drive

    So it's the same study. Too bad Oehler did not include the best shimano ( 3 speed and alfine 8) and older sachs/sram hubs.
  14. Q

    'lightest.bike' 1.7kg 1000w mid drive

    Where did you get that from ? Here in Europe, there is a german study widely spread around. While it's true that under ideal conditions a new clean derailleur will beat any IGH, those conditions are very rarely met, so that in most everyday scenarios, efficiency between a good IGH and a...
  15. Q

    'lightest.bike' 1.7kg 1000w mid drive

    Chain wear depends little on quality and a lot on maintenance/use: a long chain rolling over large sprockets will distribute forces better and hence resist to wearing/elongation longer than a short chain on small cogs. But this becomes irrelevant is the chain is constantly full of dirt, as the...
  16. Q

    'lightest.bike' 1.7kg 1000w mid drive

    I have some experience with IGHs. Only one able to take full power of 1kw mid drives are 3 speeds, though shimano and legacy sachs / srams are way better then SA since the takeover by sunrace. The newer shimano 5 speed has supposedly been developped with middrives in mind and comes with an...
  17. Q

    Tire Concentricity

    Schwalbe advise to use lube all around the tire seat. Then slightly overpressure and the tire will jump right into the correct position. Only works with new tires and flanged rims.
  18. Q

    Spreadsheet of mid drives available in 2024

    Nice. Missing cyclone kits though, and a few others less known, like the yalu kit.
  19. Q

    Bms refitting info..

    Usually bms allow for some sort balanced charging, which means they try to avoid the explosion of one series group while the others are barely charged. Do do that, the board needs to be connected to each cells groups, as shown on this simple pic of 3 cells in series. On a sidenote: it's usually...
  20. Q

    New Fat Tire BBSHD Build From Scratch! Need HELP Selecting Components!

    This should probably go into the Ebike Build Threads subsection...
  21. Q

    6 Bolts or Splined adapter for Bottom Brackets ?

    Interesting reply. I'm not sure how I would fit a belt sprocket on a bmx crank, but the trial crank thread could work. Do you know if the threading is the same as for one of those 6 bolts adapters ?
  22. Q

    6 Bolts or Splined adapter for Bottom Brackets ?

    Good idea, but also not easy. Tandem chain usually go from crank to crank. Those using left side drive up front need freewheel adapters with much larger sprockets than mine. I guess machining is the only real option. Not that hard either: I just need a cheap crank with a sprocket pressed in that...
  23. Q

    BBS02 loud noise once per pinion rotation

    Can't see the vid.
  24. Q

    Rad Power Batteries are now UL certified and fully potted

    Why would anyone pot a battery ? In all batteries I've seen, repaired, corrosion problems occur wayyyy after one of the cells, the bms ... or just the plug holder failed!
  25. Q

    6 Bolts or Splined adapter for Bottom Brackets ?

    Thank you for your reply. Finding sprockets is no the issue - the tricky part is to mount them onto the BB:
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