Burton

Just thought I`d post the question for general discussion.

I`m not a frame builder myself but have built a number of bikes up for a small Canadian company that had some titanium frames custom made to their specs using a mix of round and oval tubing and specific geometry specs.

The supplier is a Chinese company that interestingly enough, apparently also supplies titanium frames for a number of well none companies in the USA that claim to be marketing their own frames but I guess are just rebranding them.

The reason for the post is that three frames were ordered with a BB30 configuration and NONE of those three met the tolerance specs for BB30 bearings. The possible issues were discussed at length with the `supplier` ahead of time who assured us that they had done this previously and it wouldn`t be an issue. Supsequently, of course, the claim was that had been no previous complaints.

Understandably, titanium can be a little tricky to machine, but in my opinion any frame should be QC`d for quality control before being shipped. Also understandably - the group is currently negotiating with a Canadian supplier.

So I`m curious - anyone else making and/or having difficulties with BB30 dimemsioning? This is being pushed as a `new and better system`, but it`ll only be new and better if built to spec.

The threaded bottom brackets weren`t an issue, although there were some other details (again tolerance related) that I would personally consider unacceptable on a frame that a supplier is charging about $1,000 to put together.

Cheap labor obviously isn`t the answer to everything. Particularly if you don`t get what was specified.

Thoughts? Experiences? Is this the right forum to post this kind of thing?

unterhausen

I don't know if there really is a forum to discuss this, this is probably the best choice.

I only build in steel, and BB30 does not seem like a good match with steel. However, it is assumed that on a welded/brazed frame, bb30 requires post weld machining/reaming. This is the kind of operation that isn't all that trivial, particularly in a production environment where the frame alignment probably isn't perfect.

And if you read the forums, users are having problems with BB30, at least to the extent of having squeaking.

Burton

Actually I kinda figured that a BB30 configuration would be less work. Sure, it needs to be concentric bored, but a conventional threaded BB needs to be threaded along the same axis too.

The actual issue was that the BB shell diameters were all oversize. It was adjusted, but was a lot more complicated than it might have been if they were undersized. And no squeaking anywhere.

The real issue is cost control.Re-engineering things that are out of spec takes time, which not only means additional costs, it also impacts delivery dates. Costs need to be predictable on anything being sold for a fixed price so threw the question out there just to see if it was an issue that people just weren`t talking about.

unterhausen

Threaded bb's come threaded, and it's easy to fix any distortion with a bb tap/facing tool. The same can't be said for a bb30 absent easy access to reamers. With a production frame that might not be particularly straight, fixturing to ream on a machine could be interesting. The bb shell could be made significantly undersized, but that would mean more tool wear.

I've never had a BB30 bike, so I wouldn't know. But if you ask owners of bikes with BB30, a significant number of them report squeaking after some period of use. Never heard of a brand new bb squeaking, that would probably lead to significant problems.


Anthony Maietta is offering BB30 reamers, so it will be a little easier for hand builders to offer this in the future

Scooper

It looks like Adam is doing BB30.

https://www.bikeforums.net/showthread...1#post11822610

ftwelder

$1,000 is waaaay too much money for a chinese Ti frame. It should be around $250.00

I built a BB-30 frame last week.

The shell is heavy
less weld area
less room for chainstays
bearing are closer together (more leverage/greater wear)
less overlap of tubes, weaker BB junction.

stanridgespeed 

BB30! Ask any and all questions. The shell warped during brazing. had to be machined post build (nearly impossible, no way to secure in mill/lathe) @FT would love to see what you came up with.


highstreet2 by stanridgespeed bicycles, on Flickr

stanridgespeed 

@unter I used a 1 5/8 reamer. and turned it into a paperweight - when one of the reamer fingers popped away from the shaft because the plunger maxed out. It was given to me with the understanding it would probably break.

erik c

PF30 is not BB30, it's yet another "better" standard.

unterhausen

thanks, I got mixed up on what bb reamer he was making.

erik c

No worries, should have been something other than PF30 when BB30 is already out there.

I'm thinking about bringing the BFH30 standard to market. No need for post braze/weld reaming.:2cents:

unterhausen

the great thing about standards is that everyone can have their own. I'm sticking with threads until there is something that is actually better.

erik c

yup