My road bike has a BB86 which turns out to be only approximately circular on one side. One way to fix it is retaining compound (glue) and another is various kinds of screw-together PF bottom bracket (aka "bodge"). Another fix is ear plugs. At the moment it's sat in bits making me feel guilty.
But a friend of mine suggested that he could build me a nice steel frame with a screw-in 68mm BB. Columbus Zona was mentioned.
He doesn't really know much about bike building, having built only two somewhat iffy bikes - a fixie with more flop than a floppy thing, and a super-slack MTB which is great on smooth downhills and (IMO) terrible anywhere else.
However, it would mean that pretty much any kind of geometry would be possible.
The actual fit on my road bike (TCR Alliance from 2011) is pretty good, but it feels to me very twitchy. Cycling around Cambridgeshire it's fine, but anywhere steeper, faster and rougher, it always feels quite nervous.
I'm wondering - how much longer, lower and slacker can I go on a road bike? It works for my FlareMax, why shouldn't it also work for a road bike?
Ha, I posted some very similar thoughts recently when I jumped back on the road bike after 18 months on the FlareMax. Having ridden the road bike a few more times I’m starting to appreciate the advantages of road bike geometry on the road. I think I’d still go a bit slacker, say 70-71 but not FlareMax slack.
I’d look at the gravel/adventure/touring bikes as a guide. Some stick with 72-73 degree HA but others go down to 70-71.
If I were getting a frame built I’d also want dropper post routing, but maybe that’s just me 😀
Google giant defy geometry. A little bit more stable than the TCR. I’m assuming that the TCR does fit you. Bigger bikes with shorter stems can feel more twitchy. There is a lot of choice in road frames. But I’d say why not?
Normally you want the 500th frame from a builder rather than the third 😉 . But I would, just because it’s a nice touch.
So a screw together bb is a bodge while a bike built by someone who twice has proved themselves incapable of building a good bike is a solution.:-)
Go for it, at the very worst you'll have the bike that proves your friend inept.
Take a look at the hambini you tube video about oval cervelo BB. Maybe he can help?
I had a press fit BB on a Carbon fatbike. When it (inevitably) started to creak I replaced it with a Wheels Manufacturing screw together unit. I must admit, I never thought of that as a bodge, just a much better system than the original press fit unit. Ran creak-free for many months until I sold the bike.
Funnily enough, unlike the OP, the experience made me worry less about having a press fit BB in the future. As long as Wheels Manufacturing make a unit to fit it doesn't seem any better or worse than an external threaded unit in practice.
Go for it, look at old bikes from <1930's, they had massively slack angles with short stems and big offsets on the forks yet presumably still handled fine.
30mm stem, 68 HA, and an offset that keeps the trail and flop numbers consistent with 'normal', add the ~90mm lost in the stem onto the reach, add 30mm to the stays, and fit the most compact drops you can find. Could be awesome, might be rubbish. Will probably be a bit of a pig to ride in a group owing to the wheelbase.
I'm not sure there's much to gain though, the roads round here are caked in mud and gravel at the moment and aside from a few squirrely moments braking into corners my racey road bike handles just fine. In fact the handling issues feel more like the frame is flexing under erratic/oscillating braking effect (from the poor road surface) putting the wheels out of alignment and causing it to wobble rather than the geometry itself.
Thank you for your suggestions!
In the end I couldn't resist the temptation of a shiny new Aluminium frame delivered overnight from the nice people at Kinesis.
68mm screw-in BB. Yes, I know I can fit pressfit BBs if I have to, but it seems I don't have to.
If you are going to play around with geometry it's worth have a tinker on Bike Cad.
30mm stem, 68 HA, and an offset that keeps the trail and flop numbers consistent with ‘normal’, add the ~90mm lost in the stem onto the reach, add 30mm to the stays, and fit the most compact drops you can find. Could be awesome, might be rubbish.
Fairly rubbish ime.. I should post a pic of the bike I got made a while back, close to those numbers inc the longer front and rear. It was both a bad MTB and a bad road bike, ok on mostly straight tracks, awful on road corners. Fast on the Ridgeway but so is my 29er. Learned a fair bit from it though, certainly not a waste of time. Some may have liked it.