Hi! I hobbled through Daniel’s Fusion360 demo. It’s rough and needs some touch ups but between a bit more work and paper mock ups I’m ready to order some tubing. I’m looking for some advice on tubing mostly before I pull the trigger as my funds are limited. This style of bike kind of gets nerdy and splits genres so that’s why I’m posting for advice. Trying to balance novice brazing, lively feel and bikepacking durability.
Uses - my version of an ATB/go anywhere/all rounder bike. My goal is if a Rivendell Atlantis and a VO Piolet had a baby. Wide tires and “lively” tubing similar to the Atlantis. Something that doesn’t ride like a brick on pavement but that I would also take bikepacking on rough road routes like the Tour Divide, forest roads ect… Most of my rides are on mixed surfaces and I’m really not bikepacking enough to justify spending the time to build a 100% bikepacking tour divide focused rig. Most of my rides really don’t need a tire bigger than a 650b x 2.3 ish but if I’m building my own bike might as well add as much clearance as I can. Really the majority of my rides are paved with as much dirt and connector trails as I can find in MA.
Also I’d like to build my own disc fork as well. Yes, I know novice framebuilder + forks may not go well together but it’s what I’m inspired to do. I’d like to make a fork in a similar style to Mone bikes tri-plane with rake built into the straight blades by extending the plates outward.
I am 6’0" 175 lbs
Here’s my general thoughts:
TT 9/6/9 28.6
DT 9/6/9 31.7 or 35?
ST - Externally butted .8/.6/1.2. Or different tubing and use a sleeve?
HT 1mm 31.7 for 1" threaded
CS - 19mm x .9 aircraft spruce - I’m looking to build 485 ish stays and couldn’t find any stock tubing that appealed to me for these long stays
Fork plates - 6mm
Fork Blades - Columbus 25.4 1.2/.9 ? I have a set of Waltorks blades lying around too but those seem a bit too beefy for my applications
I’m a novice as well and I am terrified of bending tubes. (I also don’t have a tube bender) So for my first frames (2) I specifically designed my bikes around available tubing with the bends already made. I think I got most of my stuff from FramebuilderSupply.com. But if you’ve got the tools, I think your choices seem sound.
I really liked using the Bike Fab Supply dropper post seat tube made for 31.6 droppers. I didn’t want to deal with a welded/brazed on sleeve, so that could be a good option.
Are you planning on making the fork crown plates yourself or using Send Cut Send? I love the look of Moné fork crowns and have always wanted to try that.
I think you’ll have a fun bike on your hands.
Love the idea of this bike. For reference I am the same weight and height as you.
In 2017 I purchased a Large Crust Dreamer, a small batch bike built by Darren Larkin that replaced my Surly Long Haul Trucker I had put 40,000 km on. I’ve put about 30,000 on the Dreamer and I reckon it’s exactly the kind of bike you’ve described. A lightweight, all-weather touring bike. It clears a 27.5 x 2.2 out back and a 27.5 x 2.3 up front. 68mm shell, 142x12 rear, 100x12 front. Tubing is light for the intended use. 8/5/8 DT and TT. 35mm and 31.8(?) respectively. Not sure on the seat tube butting but chainstays are 19mm and the seat stays are tapered.
Geo wise I like the short rear end with drop bars when my weight is forward but whenever I run flat bars on it (and sit more upright) I feel like the chainstays could be longer for better balance. 485 might be longer than I’d go but there’s only one way to find that out. Pic below of the setup I ride the most like on this bike. Just enough stuff for a 2-3 day trip. Keen to see what you come up with!
I’d plan to fabricate some head tube rings, especially if you’ll be running disc. 36x1mm is thin for off roading, and having upper and lower head tube rings (1mm+ thick) will help the HT a lot.
Also, make sure that you have at least 12mm from joint end to tube end. IE, top tube terminates at head tube, that joint has to be at least 12mm from the closest face of the head tube. This will help keep distortion down, give you more room to lay a fat fillet, and put a HT ring. I’d recommend a ring of 10-15mm long.
Make sure your 1.2mm seat tube ends up at the seat cluster. I’ve welded one in upside down before.
I’d say you’re on track, and I second the questions and advice from others. I’d say either down tube diameter that you listed will work well. I use seat tubes with 0.9mm on the bottom end and I do recommend it. The thicker BB shell from Paragon helps with BB distortion. I also used 19mm-3/4" for chainstays and it does work very well especially if it is not dimpled. As others mentioned, take a close look at head tube diameter before building a frame for 1" steerer tube forks.
I don’t know much of anything about building forks and will be curious to see what others recommend.
Good luck with your build!
I’ll roughly draw them up and get some help from some other members at my makerspace who would be able to fab them for me using our laser cutter. They won’t look as nice as his but a similiar design. I plan on mostly getting tubes from framebuildersupply. But nothing really available for the long chainstays I want.
Good advice, I was worried about the headtube. Would just buying thicker aircraft spruce is the same diameter work instead of fabbing up reinforcement rings? Something like 31.7 x 1.2-1.3mm? I wasn’t able to find a HT labeled for a 1" from any of the typical frame supply sites online that seemed good enough for offroad touring. fork Just one less step for me to worry about. Most likely won’t be using lugs either. A threaded fork/quill stem makes it a bit more difficult. Headset compatibility and headtubes has always been confusing to me. I’m lucky I have the correct one on my current 1" threaded quill bike.
The lugs are essentially the reinforcement rings. They are typically 1mm thick (or a bit more). So I’d recommend making reinforcement rings that are at least 1mm thick.
For example, the ‘standard’ 1 1/8" head tube OD is 36mm. I just built a bike with 36.5mm HT OD and reinforced it with 1mm thick rings, bringing the OD of the reinforced portion to 37.5mm. This is on a gravel bike.
You could go with a very thick HT stock to achieve that wall thickness, but I think it’d become pretty heavy. Easier just to make reinforcement rings.
Someone with a better memory than me should chime in, I haven’t built something for 1" in a few years, but if I remember right, the EC30 is the general standard for 1" headsets. Someone correct me if I’m wrong!!
Edit: an addition I just thought of, a classic retro MTB story is that after a downhill run, they would have to tighten their headsets because they’d rattle loose, no matter how tight! They’d literally carry headset wrenches with them. Maybe the Chris King 1" headset fixes this (but I don’t think they make it any more?) but it may be a good idea to just go to 1 1/8" threadless, even though that’s something you don’t want.
One thing I’ve learned about bikes through framebuilding is that there is always a compromise. It’s a constant juggle of ‘this becomes better if I do that, but I lose out on this’. You just have to constantly judge pros vs cons to get the end point in your design.
@terraformbicycles brings up a good point. In the custom frame-building world you get some legacy standards that only make sense in that period of time. A 1" quill stem and its headtube pre-dated big knobby tires, 35mm downtubes, and disc brakes. It relies on lugs for reinforcement.
From an engineering perspective, I would recommend going with a 1 1/8 headtube, the 37mm OD headtube will give you more room to braze, and the whole system is stronger for off-road riding.
Thanks, all good points on the reinforcement rings. I’ll make some mock ups. I’ll go for a few rides and mull over how important a quill is for me. I can’t deny the pros of threadless. I have seen a few elegant threadless stems being built up, maybe I’ll go that route. I do have to admit, my 1" quill Lightning Bolt does need to be tightened every once in a while. Sounds like a PITA when bikepacking.