Ripple in the tubing to increase weld contact area. Stronger, and looks good.
Flat crowns demand more welding and aggressive angles for the tubes, so it’s a bit of a compromise.
I wouldn’t recommend a carbon frame if you plan to mass-release it without getting problems in the long run. I just wouldn’t trust a plasticky-feeling piece of tube with carbon weaves ‘bonded’ (i.e. glued in with some strong liquid) into aluminium collars. It would just make me personally feel my frame is a disposable glued together job. Getting high quality carbon tubes is very expensive, and there are many different types, some with glass cores and then some also have thin aluminium tubes pressured into them to help increase strength/stiffness.
That being said, going for a chromoly frame as a first prototype to just get the basic shape is fine.
for street i use a round crown, the frame that impact makes is great because its light and since its wide you can actually get your feet on there pretty good if you ever wanted to do tricks that require such things. Its still not the same as having a flat crown but much better than the older nimbus frames. Also i like round crown frames because i dont bust my knees and legs on them near as bad
Soooo maybe think about making the frame wide at the top if your going to do a round crown design and then taper it down to a smaller size at the bottom.
thats just my 2 cents
For trial, street and flatland…
something like the triton disign
Or Like the carbon concept frame from koxx If you take a good look at the round crown, you see on the crown little things to make it stronger I think, but it makes also a little platfrom, so maby If you do something like that with bigger ‘things’ for a bigger platform it can be nice… idk (if you don’t understand, I made a little thing in paint ^^) It is just an idea…
and maby combine a seatclamp and frame
This design is good for trial and street: no pain for knees and it is ok for flatland
if you scroll down there are some concept web frame designs from koxx one…
i think the red 20" street one would be an awesome idea. sorta like tims design or somiliar to the triton spong. slanted but not completely round, so its good from traisl, street AND FLAT. Also maybe an integrated seat clamp like tim said and some quick release bearing holders
Your image gave me an idea. Would it be possible to design a round / angled crown frame that has removable blocks / steps that could transform it into a square crown?
I’m thinking the round section of the frame would be a little thicker and have a couple keyholes on each side. The removable blocks would have pegs that would slot into those holes. I don’t know how you’d get the blocks to stay in place (maybe a leaf spring inside the frame?) but that might not be an issue if the holes are keyed well enough.
Great ideas guys! So far people want a rounded crown frame with the capabilities of it transforming into a square crown, quick release bearing caps, a light built in seat clamp, and over all a light and strong design.
I have noticed on the kh frames, the bearing housing is quite a lot wider and hugs the crank than the standard bearing housing on frames such as nimbus’s and impact’s that just go over the bearing itself. From what I can understand is that this is so the frame forks don’t have to be sqoshed to be thin enough to be welded on the thin bearing housing. Any way does it help rolls or does anybody even notice if there is slightly more surface area to put your foot on when using the smaller bearing housed frames?
That round to bolt-on square idea suggested earlier in this thread is awesome in terms of pushing the envelope of design. It’s not the cleanest look, but for sure it’s nice in the sense that you get the simplicity, lighter weight, and stronger join to the seattube as well as a bolt-on option if ever you feel like a bit of flat.
I have some ideas that might help it work in harmony with a frame better like having a tough yet unmarking nylon layer between the bolt-on square crown and the actual frame’s tubing. Kinda like what mod bikes’ bashplates have sat between the plate and the frame to absorb shock whilst saving the frame from being harmed.
Re. the second point I quoted, I think Spencer once mentioned how the extra wideness of the KH bearing holders interfered with the comfort of a lot of flatland tricks. It’s important from a frame strengthening perspective to have a wider oval tube at the bottom. Who knows, maybe we’ll see it for the 2011 KHs, if not in a couple years.
I wouldn’t say that the KH bearing holders interfere with flat tricks, but I do think they’re wider than they need to be. The nimbus eclipse has nice machined aluminum bearing holders that are slimmer. I think the extra space on the cranks is noticeable.
It’s gonna be tough to make an “adaptor step/riser” that’ll fit neatly onto a rounded crown.
How about making the crown angled, then weld on two inserts per side, like heavy duty water bottle bosses, these would serve to anchor the steps and make removal easier. You could even make the steps out of nylon…
I’d skip on steel, aluminum is lighter, won’t rust, stiffer, and easier to work with, assuming you’re comfortable welding it. Don’t use bends, just cut and weld.
Make something for your own riding enjoyment, don’t get ahead of yourself and start dreaming about making money. There is no money in building uni frames
Here’s an idea for making drop out that I got from Josh at UDC:
Buy tubular Al that has a 42mm ID, then get some Al plate, now the idea is to have the tubular Al cut to the width of the bearing with pieces of plate welded as caps, then drill out the plates for the spindle, weld clamps to the the sides, then cut in half. A quick drop out with minimal machining.
When you weld up the frame, be sure and set the drop outs at the correct width and keep the drop outs square, otherwise they’ll place side load on the bearings and you’ll go through bearings fast!
Personally I really like the look of the new Qu-Ax QX series frames for a street/flat frame but would like to see more round crown semi-longnecks in the larger sizes for MUni and distance riding.
Longneak. You can always turn a neak into a beak but not the other way around. Besides they have a classier look and allow more seatpost adjustment if you are tall.
I did notice a big difference of space when I switched from my KH to my Triton frame. I never knew why the KH bearing holders where that wide. It’s not a big problem, but it could maybe help a little bit for rolls, I dont really know about flat though
I really like the Triton sponge design, I think it’s pretty good for trials and I had no troubles for the few crown tricks I do.
Ahh yeah that frame. I’m sorry to say but that’s the fugliest frame I’ve ever seen (>o<)
The ‘ripple’ on the Gravity is ridiculously wide, as is the leg in general. It looks a bit too overbuilt which ruins it aesthetically. However, I would like to see the same design on the Trialtech/Viz forks which works out fine and is lighter.
Don’t the Impact frames have QR holders? I think I heard snippets of that somewhere but to be fair, is it really necessary? I think bolts are fine and do the job better as a proven design. QRs on seatclamps and MTB hubs are notorious for loosening up and= easy meat for thieves.
With regards to someone’s post about which material, I think alu would be desirable but realistically if this topic’s theoretical ends up being made small-time or as one unit then steel is the easiest and cheapest realistic option. If only alu were easy to work with and as readily/cheaply available as steel tubes then I’d love to get someone to make me a custom one-off design similar to some biketrials forks.
