Criticism isn’t always easy to hear, but I think it’s worth keeping it constructive.
Though I’m late to the pile-on, I see that building this design accurately would be extremely difficult. Especially chainring between split bb setup.
OP, what tube to tube fabrication experience do you have?
I know everyone here is trying to help, but as a friendly reminder: The Education forum is a safe space to explore new ideas. Let’s create a supportive environment to encourage people to learn or try new things.
Also, let’s keep in mind, building bikes is about having fun. All our bikes are more expensive, heavier, less efficient, lower tolerances than a $300 carbon frame, outright performance metrics are not why we build bikes.
Getting this topic back on track:
I think the CAD, aesthetics, and concept is great. IMO, packing the drivetrain is the crux of this challenge and might take a few iterations to get right. But I don’t see why it wouldn’t work.
I’ll push back a little here. He asked for us to poke holes in his design. That is what we are doing and none of the comments I’ve see here are nasty or hurtful or rude.
Happy to sit this one out.
I agree with @anon91558591 that gearbox systems largely solve the problems you’re concerned with. The big issue with those systems, is the inability to shift under any load. If you can solve that then you’ll have something really valuable.
I think the deleted comments are the ones that @Daniel_Y are referring to, not so much your constructive feedback.
Got it.
Stealth deleting by a lone moderator is not a good situation.
Agreed. Maybe it’s time to be done here.
Let me draw the line here: talking about genitalia, even as a joke, is not acceptable on this site.
The back-and-forth teasing and genitalia references were deleted.
I left all the posts containing technical information, feedback, and criticism. I have no problems with the posts left on this thread. While I encourage positive, supportive learning environments, I also appreciate other people’s knowledge, experience, teaching, and learning styles.
Even though I was the one who deleted the posts, there are several other moderators on this forum who I know will agree with me. Trust me, this is not a power trip, I would have much rather stayed out of this.
Finally, I understand it’s easy to get carried away poking fun, but context is important here: this is the Education Forum, the OP is a new member, and this is their first post. We know nothing about their age, gender, or background. So let’s be more welcoming and not pile on against new people or new ideas, feasible or not.
If anyone disagrees with how this is handled, feel free to message me in private and we can discuss it.
I have stitches in my scrotum from a seat post failure.
I have also raced in HPVs with a jack shaft between my knees to drive the front wheel. It was very sketchy.
I tried to deliver this concern using some humor.
However, deleting posts with no communication or warning is unacceptable in my opinion. I no longer will contribute my knowledge here.
To everyone commenting, please give me a few days. Making significant revisions to the design and will be back with some changes based on feedback given here.
Moderator here. I have seen the deleted content and agree it should have been deleted. If I had seen it first, I would have deleted it too. The community guidelines very clearly state that forum moderation can and will happen at any time especially in instance of gross and unnecessary commentary.
On a personal note, content as such is othering to people who are not part of ye old boys club. This forum is meant to be a space that is educational, inclusive, welcoming to newcomers to this community. This is a classic example of ~it’s just a joke~ ~we’re just kidding around~ but I would ask you to really just take five seconds to objectively think about it from a perspective other than your own and understand why moderation of this type is important.
I’m not going to comment on this further in this thread or respond to any commentary on the policies here. Carry on.
Chain angle appears to almost double on utilisation of that space. I modeled a 200mm chainstay which only offers 23mm of clearance on the ring+ cassette + not enough clearance on the tire so I’d have to resize things, change geo etc. In any case, I think based on what I’ve heard about 12 speed drivetrains being difficult to adjust, i’m pretty sure getting this close is a non-starter for shifting performance.
Did a few short revisions today, and nothing else really made sense so I’m back to the OP design, but with some modifications to move cassette lower (still on 395mm fake chainstay axis). Based on the feedback above, I took to heart the idea of knee/calf/thigh interference, and moved the cassette as far forward as possible. Did some mockups of tubes on the bike I modeled this geo after, design after and in this new position it seems to be much more clear that no impacts to pedalling will occur.
I had to make some bad rounded tubes to shoot out the struts, but I assume the the final design will look much more organic and polished.
So, at this point, I’ve checked 12 speed drivetrain clearance and I think it’s ready for moe barbequing on the forums. I don’t think anything is really different here, so no need for anyone to provide any additional feedback. I think it’s time for me to learn some proper CAD and get some lug/joints designed.
What about using a pinion and ditch all the cassette, rear mech and double chains. You could still have the range and eliminate the complexity? Yeah the cost of a pinion is a big pill to swallow but not sure I see the benefit of moving everything to the center of the frame. What about an internally geared hub instead of a derailleur setup? Single speed would help all this out also. Lol
Pinion is a higher cost, heavy, unable to shift under load alternative. I bought a pinion second hand thinking i wanted to go that route and as soon as i held it in my hands i decided to sell it. Internal geared hubs are also heavy.
This is an evolution of a 1x drivetrain location. The goal is to keep using existing drivetrains but change the location to solve aforementioned problems.
Yes a single speed is simpler. I’ve owned a single speed mountain bike. Is it the solution to some problems? Yes. Does it create other problems? Yes. Engineering seems to be balancing tradeoffs?
Let’s see the fixtures you intend to use to build this.
That’s a bit cart before the horse, it doesn’t make sense that a proprietary fixture would be designed or in place if the design is still up in the air. It’s a typical process to get a drawing finalized and then backwards-engineer a fixture as needed, ask any builder who does full suspension design/fabrication and has to build linkages, shock mounts, and a bunch of sub-assemblies.
This design is cart before horse
If you don’t like it, you are free to not comment or interact with it. There is no purpose in making snide remarks that offer no value, insight, problem solving, etc.
I’m saying this with a moderator hat on and you can consider this a strong friendly reminder of how to politely engage with other users here.
I’m definitely going to be backwards designing these to work.
@Nick
Just wrapped up a teardrop trailer build with my wife and father in law. Built it from scratch square tubing, we even built the base. We were able to cut square tubes and bend them to from radiii for the doors, frame and hatch, so I’m sure I can figure out how to line up some steel tubes.
