I really fancy designing my own frame (to see if I can do it as much as anything else). Can anyone recommend a free software package to do it?
BikeCad is 2D, but very good. That’s what I used initially to check everything. Then gave it to my mate who re-drew it in 3D on Autodesk360 with all the correct tube profiles etc.
Pictures but no figures, this place is going downhill, how will all the armchair experts be able to froth properly?
😆
Perhaps it’s the way you’ve written it or it’s the reference to the smaller tyre but it sounds already like a tyre compromise.
Shirley ( ) if you are considering a HD you’d want more than a few mm clearance especially as it would be likely run in winter.
Probably how I wrote it… The “tyre” in the drawing is 70mm wide and there’s clearance. A Hans Dampf on a 28mm internal rim is 62.5mm to the outside of the knob edges, so it would fit with mud room… Personally I’m not a fan of the Hans Dampf though so won’t be using one (but others may hence designing clearance for one), would likely be using a 2.3″ Maxxis Minion or a Rock Razor (which is actually a couple of mm less across the knobs than a Hans Dampf despite same casing size) as the biggest tyre in there. With no seat or chain stay braces, and a kink in the seat tube, forward tyre clearance is never less than 20mm and no mud traps, so hopefully be a good uk winter trail bike.
A ubiquitous man in a shed. 😉
A nice touch on saw on Guerrilla Gravity’s recent frames is a double bend in the seat tube to steepen the actual seat tube angle so the effective seat tube able doesn’t get slacker the longer your legs are. But now I think about it I’m not sure how you’d fit a long dropper post in, so please ignore that!
Yeah longer dropper would scupper that. Also I’m after as clean lines as possible, a small bend near the BB allows that and doesn’t mess up the geometry too much.
Speaking of which… Have designed it to have a 73.5deg effective seat angle at my saddle height. I’ve got relatively long legs and a short torso for my height, and the actual seat angle isn’t that slack at 72deg anyway, so for anyone shorter legged wanting to ride it the effective seat angle would be somewhere nearer 74deg, and anyone taller would likely want the next size up anyway as though the reach is roomy, it’s not as ultra long as many modern in vogue frames (the next size up I’ve designed having an effective seat angle of 73.5deg at a taller saddle height of course, so actual saddle angle is slightly steeper, around 72.2deg or so). I’ll agree that some of the more extreme kinked seat tube designs don’t work for those with freakishly long legs, but done right, they can still work for the 95th percentile most bikes are designed to fit anyway.
Geometry is static, so with a sagged fork, these figures will steepen around a degree or so anyway (based on a 120mm fork).
