Remember first reading about my project on Muniac.com when you first arrived on the scene? I know you read it, but not sure if you remember it.
I smiled as I saw the computer graphic representations. That’s almost identical to my first muni project. Except it didn’t have the truss under the crown.
Here is the link with photos on the building process.
Welding with the mitred corners is really tough as the builder had told me. I ended up having the frame pinched to accomodate the tire because I had a suzue hub with a 3.0 gazz. I think my tubing is greater in width than yours. My frame flexes, but that could be from a variety of reasons. When you look down the seat post tube, the whole frame is not aligned. After welding, the tubes had bent due to the heat, but he did his best to straighten it out. Also, the pinched sides to accomodate the tire may have weakened the fork legs. But the frame does flex under hard pedaling like when going up a steep hill which causes the brakes to hit the rim. So, the missalignment or the pinching could have contributed to the frame flex. Your design uses the truss, so that may mitigate the flex on my frame.
Additionally, the frame was designed around a Sun BFR rim, which is much narrower than the Alex DX32. We still got the brakes (Magura HS 33’s) to run with this narrower rim. Since the tubing was aerodynamic, the x- section was tear-drop shaped. Is yours? We reversed the tubing to put the fatter side tubing to the back and then the magura two hole brake mounts were welded inside the forklegs. We couldn’t weld on the very end, too narrow and pointy. He had to cut the braces from the stock mounts(available at uni.com) to match the taper on the inside of the fork legs.
I haven’t read your entire thread, yet, but responded only to your most recent posts. Maybe I missed some info.
Your using different materials and a different welder, so that may eliminate any of the issues I had with my frame. I mention them only because of the similarity in design. It’s fun designing and being involved in these custom projects isn’t it!
About 6 months ago, a chap in the UK sent me an email regarding making a “Coker” frame with aero dubing. I don’t know what happened if it ever got finished. I need to look up the old PM. I can get it to you later. His experience with aero tubing may be helpful.
Rod, a good welder should have been able to compensate for the heat distortion due to welding. If he chose to square up parts by bending the tubes after the fact, it means he wasn’t paying very close attention to the welding, and didn’t bother to create a good welding jig to do the welds in.
Andrew, 15mm of clearance is excessive. I have <5mm, and on the last SB ride with plenty of mud, I was fine. If the mud is so thick that you think you need 15mm of clearance, then no frame is going to work. You’ll need a wicked long crossover cable on your maggies if you go with clearances like that, aswell. Just because you didn’t have much clearance on your previous frames doesn’t mean you need excessive clearance on this frame. Also, have you accounted for the knee-knocking attributes of a sharp-crowned frame that is that wide? Right now you’ve got a crown about 130mm wide (>5"). Not to rag on you, but that’s obscene. Why sacrifice general ridability for the few times when you might need extra clearance.
And for your own sake, don’t use a 22.2mm seatpost. Do something, anything to get a 25.4 or larger. If not for any other reason, it looks 10x as cool. You will bend your post eventually, and life will suck when that happens.
Of course I remember your frame. I’ve always loved the design…in fact I was looking for it the other day. That link didn’t work (it must be from before the gallery update) but I found the correct one - http://www.unicyclist.com/gallery/?g2_view=core.ShowItem&g2_itemId=109198 . Thanks for letting me know about the issues you’ve had. I’m hoping all will be okay…my old frame was a very similar design and had very little flex. And yes, the tubing is teardrop-shaped.
I was never pretending that the 15mm was a rational decision, but I think you’ve convinced me to go to 10mm around a 3" Gazz. That will make the crown width about the same as my current frame and I don’t knock my knees on it, and don’t have to ride bow-legged. The tubing has already been bought and is about 25mm wide. The neck of the frame goes up very high and there will only be about 40mm of seatpost sticking through, 15-20mm of which will have some sort of brake lever mount attached to it. Do you still think 22.2mm is a bad move? I was originally hoping for a 25.4mm post but it won’t work with this tubing and we’re a bit restricted by availability.
Andrew, I’m glad I’ve convinced you to drop the clearance. 10mm seems much more reasonable.
I only have about 50mm of post showing on my uni, and I bent it recently on a bad rolling hop. I would reccomend going larger.
As for availability, I know New Zealand has at least some industry, so tubing must be somewhat available. Check the local yellowpages equivalent. You can always ream to proper size. There are also millions of thomson seatpost sizes, so you can be pretty confident you’ll find a seattube to fit.
Do you think there’s much chance of the neck of the frame breaking or just the seatpost? I really don’t see the seatpost bending very often at all and as long as the frame holds out it’s not too much of a drama. Even if it doesn’t it can be fixed…this is a bit of an experiment of how thin and small a frame can go without flexing too much or bending…in a way. As I said though, the tubing has already been bought so there’s not much of an alternative.
What’s with Quick Releases? I’ve never found them very useful. My seat clamp holds pretty tight, and in order to adjust it all you need is a $0.50 Allen Key. And it’s low profile with no risk of snagging your shorts. And lighter than a QR. And the allen key fits in your pocket.
I think Andrews’ from Brisbane. But yeah, there are quite a few bike builders over here in NZL too. I’m planning a custom 29’er next year- hoping to make something super light and stiff for racing with. Tubing wise- thinking of using those off-the shelf carbon stays that they glue onto the rear ends of road bikes.
I’m really excited about this colour scheme. I found out you can get annodised blue DT Swiss spokes! My only concern is that the two shades of blue (Jim Cielencki pedals and annodised blue) won’t match well. Do you think I should run chrome or black spokes? Is chrome the right word? Should I be saying silver instead? Here’s how it’s going to be…
Seat - Black KH Fusion
Seatpost - Chrome
Seatpost Clamp - Annodised Blue
Frame - White
Rim - Black, stickers removed
Tyre - Black
Cranks - Chrome
Hub - Chrome
Pedals - Blue
Spokes - Chrome or black (what do you think?)
Nipples - Annodised Blue
Good call, except I think I’ll stick to the chrome hub and cranks…partly to save money, partly because I prefer the hub that way and the hub and cranks must match.
I’m going for a kind of subtle colour scheme though so I really just want a hint of anything coloured. Notice that all the blue bits in the colour scheme are small parts.
Thanks for letting me know. I wonder, can you buy blue brass nipples? I never thought I’d hear myself saying this but if it comes down to blue nipples that may need replacing from time to time and plain strong ones, I’ll most likely go for the blue ones. Obviously, blue strong ones would be ideal. Replacing a nipple isn’t such a big deal anyway…I’ll just make sure I’m careful when tightening them. Do the threads actually strip in aluminium nipples? I’ve only ever seen or heard of nipples rounding off.
I may have to stop wearing my favourite red muni shirt.