Frame "prepping" - maybe daft question

[Sweep]

Saw some nice soma frames in a London shop earlier today.

Googled them (was maybe dimly aware)

and found this on their page:

Thanks for purchasing a Soma FrameNow that you have your frame, it needs to get built.And getting it built properly is supremely important in getting maximum enjoyment from your bicycle.Here is a list of procedures for prepping your frame prior to as-sembly: (Some of these require special tools)1) Face the headtube and bottom bracket shell to assure your headset and bottom bracket will install correctly.2) Chase the bottom bracket shell and all other threads. This al-lows the bottom bracket and bolts to insert smoothly. 3) Ream/hone the seat tube so it is clear of any burrs or obstruc-tions that may scratch your seatpost or prevent it from inserting smoothly.4) Check alignment of frame, including dropouts and fork tips. Slight misalignments can be corrected in a jig.5) Clean frame of metal shavings and all other loose debris.If you do not have the expertise or proper tools to get these procedures done correctly, have them done by a profession bicycle mechanic. Not every frame requires all of these procedures to be done. A trained mechanic will properly determine if your frame needs it or not. Soma Fabrications will not be held responsible if there is damage to your bicycle com-ponents resulting from these procedures being skipped or not being completed properly. Warranty is void if product is damaged by improper frame preparation. For more informa-tion, see our Frame Warranty online at http://www.somafab.com.



Now as a non techie bike person, this seems to me like they are chucking the "fabrications" out of the factory unfinished.

And telling me to pay someone else to do work they couldn't be bothered to do.

Why can't they do all this?

What am I missing?

Yes I have come across cautions to get frames "faced" before but thought it was mostly to do with external bearing BBs.

And never in truth understood why that couldn't be done before the frame left the factory.

[NickJP]

That's pretty standard for a factory-built frame. Only if I'd ordered a custom frame from a custom framebuilder would I expect that they should have done the frame prepping before sending the frame off. And even there it sometimes doesn't get done - here's an image I took of the BB shell of a very expensive Ti custom frame that I ordered about a decade ago from a well-known framebuilder. The BB shell had obviously been distorted by the welding of the frame, but nothing had been done post-welding to restore it to accuracy. The threads needed chasing, and on both sides, material needed to be removed from the front end of the shell to get the faces co-planar and square to the threads.

As I have all the tools needed for prepping frames I didn't harass the framebuilder about it, I just did the job myself. This image was towards the end of facing the shell, and I still hadn't quite removed enough material:

[Valbrona]

You needn't have worried about that last bit, and maybe needn't have taken so much material off.

Not that many UK framebuilders have ever built with titanium, if any at all. I mean in a TIG welding kind of way. One guy who used to TIG weld steel also pretended to weld titanium, but he was in fact just sending frame drawings to a framebuilder in Eastern Europe.

[Tiberius]

And never in truth understood why that couldn't be done before the frame left the factory.

FWIW....nor me....

[reohn2]

And never in truth understood why that couldn't be done before the frame left the factory.

FWIW....nor me....

+1

[peetee]

I believe that is the sort of work that should be carried out as part of the frame building process. In their favour, at least they make customers aware that there may be issues. I am certain there are lots of other brands that should be advising customers to do the same but don't bother.
Skimping is not new. 30 years ago I saw top of the range Basso SLX frames having the same work done in a retail workshop before being assembled as bikes.

[PH]

When you buy a Thorn frame it's an added extra
https://www.sjscycles.co.uk/frames/frame-workshop-prep/

I've mixed feelings, I think you could make a case for it either being part of the frame manufacture or the bike building, there's several ways in which the frame preparation might be different depending on the build specification.
Main thing IMO is that it's made clear in the buying process and at least SOMA and Thorn do that. I was a little taken aback the first time I bought a frame that it wasn't all ready to just bolt stuff together. I did pay the bit extra for my Thorn frame and I'm glad I did, it made for a very simple build.

[Sweep]

I must say I was particularly shocked by the apparent need to finish off the bb threading.
Would this sort of stuff be acceptable with any other product?
All in all this sounds like a very good argument for buying a ready built bike from the likes of ridgeback. And cheaper. Can always change a few bits.

[horizon]

Somewhere on this forum, colin531 wrote this (sorry, cannot find thread link):

Before assembling a new frame, there is quite a lot of preparation which "ought" to be done.
Ream seat tube
ream and face head tube for headset cups,
Face crown race seat,
face disc brake mountings
face bottom bracket (for external bearing cups)
chase all threads

The Touring and Audax frames are made in the same factory; most of the tourers go out with square taper brackets, most of the Audax go out with external cups.
Spa have been assembling and selling these frames for a while now, and whereas it isn't clear to me which processes are the responsibility of the frame manufacturer and which are the responsibility of the bike assembler, I think Spa will have arrived at a way of working by now.

Well put I think.

[axel_knutt]

When my frame was replaced under guarantee, the LBS ruined the fasteners by forcing them into threads choked with paint. So much for having things done by 'professionals'.

[Brucey]

I must say I was particularly shocked by the apparent need to finish off the bb threading.
Would this sort of stuff be acceptable with any other product?
All in all this sounds like a very good argument for buying a ready built bike from the likes of ridgeback. And cheaper. Can always change a few bits.

well, yes, if the frame on the ready built bike is definitely prepped.

However IME this is very rarely the case.

One the occasions when I (or a good friend) have ended up with a new bike, I have always taken it to bits and refitted/checked everything properly. It has never yet been time wasted.

cheers

[Sweep]

Somewhere on this forum, colin531 wrote this (sorry, cannot find thread link):

Before assembling a new frame, there is quite a lot of preparation which "ought" to be done.
Ream seat tube
ream and face head tube for headset cups,
Face crown race seat,
face disc brake mountings
face bottom bracket (for external bearing cups)
chase all threads

The Touring and Audax frames are made in the same factory; most of the tourers go out with square taper brackets, most of the Audax go out with external cups.
Spa have been assembling and selling these frames for a while now, and whereas it isn't clear to me which processes are the responsibility of the frame manufacturer and which are the responsibility of the bike assembler, I think Spa will have arrived at a way of working by now.

Well put I think.

That just confirms that Spa and Colin are responsible though doesn't it?

Doesn't address the question that faces simple minded buyers like me - why doesn't the factory do it?

I mean - the threads?

[ElCani]

It seems absurd to me that it isn't done at the factory, or at the very least by the vendor. When I bought a Surly Cross Check frame from Spa they charged extra to face the bottom bracket and head tube.

[Sweep]

One the occasions when I (or a good friend) have ended up with a new bike, I have always taken it to bits and refitted/checked everything properly. It has never yet been time wasted.

cheers

Yes, when I bought my new Ridgeback Expedition I did pretty sharpish take the (Octalink) BB out to check that it would come out OK and so I could slather it in antiseize, but with the factory regime I referred to I can see no amount of confidence that I could get a BB in in the first place, or not without wrecking something.

The Ridgeback BB came out like a dream I add - presumably because they had checked the threads in some way before screwing the BB in.

[Brucey]

or they might just have specified incredibly slack tolerances for the parts so that (despite distortion etc) 'anything fits in the hole'. Often this means that a large percentage of frames will have an unacceptably slack fit in the BB or headset.

You can tell something about the tolerances and/or if a frame has been prepped properly or not by looking at the paint; if there is still paint on the surfaces that should have been prepped, then there is almost certainly some kind of slack tolerance/insufficient prep evil at work.

cheers