Already 95% sure here, just looking to hear my opinion in different voices
I finished the welding on the park bike front triangle, but I have a feeling I’m getting the “slow no” from the guy who usually does my bottom bracket facing/chasing. Not sure yet, I’m just covering my bases.
I guess the question is, if I can easily thread both halves of the bottom bracket itself into the shell by hand, they sit flat against the edge and the axle slides right through, do I absolutely need to get this faced/chased? It’s not a trail bike so I’m not going to be doing a lot of epic pedaling days, it’s gonna get chucked on the chairlift and bombed down mountains.
Tell me what I wanna hear! Or that I’m a dummy and if I don’t get that BB shell faced and chased the whole thing is gonna explode. Or something…
Your BB is also nominally either .5mm or 1mm wider than desired in anticipation of facing / chasing. So if you don’t, your BB will be oversized. Might be hard to get some cranks to have proper pre-load if the BB shell is 1mm longer than necessary, or more I guess, since it isn’t a flat face.
Can you thread it in by hand now? That may change after you attach the chain stays.
Right. I see your use of the word “ideally” there. I get that. Nothing I do is ideal, it’s all a bit of a compromise. It is .5mm wide on both sides, but for my setup (gonna be really weird, left hand drive, jack shaft, 2 chains) I believe that to be a non issue. However, Noted and appreciated. Thank you.
Sure can. Easily. By hand. And they bottom out nicely and sit flat against the edge of the shell.
Also, no chianstays will be welded to the BB shell. It’ll look something like this
So the welding is done and everything assembles nicely.
Also worth mentioning, I’m gonna be using BMX 3 piece cranks that always require spacers and such to get the correct chain line, so the .5mm extra width shouldn’t be an issue there.
I’m seeing a theme developing, I’ll look into getting it done right. Maybe
Me either! And probably, but I think I have some wiggle roome there because I’m using BMX cranks. I also should have mentioned It’s gonna be single speed, so the “ideal” chain line isn’t an issue as long as I can get it straight-ish.
I wouldn’t bother. If the BB goes in easily and looks pretty flush it should be probably just work fine. You might wear out the bearings a little bit quicker (put not thát much quicker) and there would be a tiny chance your crankspindle might be a bit too short, but in my experience pretty much all systems have been designed to accomodate slighty varying BB shell widths.
Concerning chainlines: I have played with using both boost and non boost cranks on boost and non boost frames and there were no real issues. It can even be a nice way to move your chainline towards a lighter or heavier gear. (If you have a bike that mostly climbs, using a non boost crankset on a boost rear moves the chainline towards the bigger cogs, which might be nice, etc)
That’s what I’m talking about, my opinion, different voice
I’d considered accelerated bearing wear. If it was gonna be a real pedal focused bike I’d be more concerned but for bike park laps, even a slow ass like me doesn’t pedal much. I could also, theoretically, afford a few bearing replacements for what I usually spend on facing/chasing.
I also ordered the longest crank axle that Profile makes at 6 7/8", so I should have some room to play there too.
Lots of good information here. Thanks for that link too, those aren’t as un affordable as I thought.
Before I started this thread I reached out to a different frame builder here in town that I was unaware of previously, he already got back in touch and im gonna go use his stuff this afternoon.
Glad to have the information if things end up going a different way. Thanks everybody!
That’s the spirit! Turns out, that local framebuilder was none other than @StratoCycles! Good to meet a real framebuilder and nice making connections with people from this forum. Thanks so much for your help, dude!
I’m a novice/ignorant. I’m half way through my 2nd frame. And i really don’t want to water down the knowledge/experience of this forum. That being said.
My first frame I didn’t face or even need to chase. Its on a BMX frame so by no means a delicate piece of art. But like you i was able to thread in the cups by hand pretty easily, and right now i need to put $$$ other places before I put it to facing tools. (I think we just connected on IG btw so )
Me too! Water away! This is only my 3rd, so I don’t know what the hell I’m doing either. Funnily enough, I recognised your frame on IG from here
It probably would have been fine. It’s a little fine-er now.
All my junk is just hobby stuff. I’m neither skilled or inclined enough to want to do this for money. I’ve done stuff I enjoy for money before and it f**ks it up every. single. time. I also have certain feelings about customers that make doing this as a commercial endeavor impossible.
Thanks so much for all of the input! I truly appreciate everybody’s contribution!
Truer words and whatnot. I couldn’t agree more. I quit building cars for people because I got tired of building boring, 6/10 verisons of what I wanted, only to be insulted and usually underpaid. Done with that shit.
Does Ice Tools still sell they’re facing/reaming kit? I bought one probably five years ago for pretty cheap I think from Wiggle in the UK. Think I paid like $200. Yeah it’s no park stuff but the bits are still good and had it at a shop i used to manage and got some use there.
I was just tired of trying to find a shop to do the work and by the time to drive and then the labor I wasn’t that far from paying for the tool kit. With a quick search it’s a hit or miss on the Icetoolz kit but another company called Lifeline makes a similar kit for about the same kit.
you can just measure the BB shell with a Vernier caliper to see it was distorted in welding/brazing. usually the chainstay side has shrunk. I think having a facing tool is pretty useful if you plan to mount the frame on a BB post for truing. park bike with BMX crankset you say? I think the BB bearing is not going to break because the faces are not perfectly parallel (but because of other reasons)
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