Necessity for Headtube Reaming & Facing on Bikes that have Existing Headsets
 

I need to do some pressed headset work and have been contemplating acquiring some tools for that. One of the things that is holding me back is the necessity for reaming and facing headtubes as part of the headset installation process and the cost of the tools that I'd want for that.

Is reaming and facing something that is only required on new frames that haven't yet had headsets installed? Or is it it something that should be anticipated for the replacement of existing headsets as well?

Thanks for your help.

Basically, any frame that has not has it done will benefit. Not all new bikes have had the reaming and facing done properly. That said, buying the tools for one or two bikes is usually not worth the cost if there is a bike shop nearby. They have the tools and the job takes minutes.

I’ve never, ever, had to have a head tube faced and that’s counting easily over a hundred bike frames.
Based on the quality of bikes in your sig, not likely that anything in that league would require such work.
Unless you were trying to install a different sized crown race or cups than the frame was previously prepped for.

Reaming and facing is a one and done job. Once a frame has been cut to spec. there's nothing to be gained by doing it again, and may even be counter-productive.

The ONLY reasons I consider repeating the job, if I suspected it wasn't done the first time, or if I were changing to a different headset with different specs. ie. changing from an JIS 30.0 headset to an ISO 30.2mm headset.

Aren't those less commonly needed with cartridge headsets?

Actually more important, but generally done by the builder, or pre-machined into the head tube.

As I said earlier reaming/facing is one and done, so no need to consider unless there was a searing problem with the prior headset.

Those are tools I wouldn't buy there are so many other tools I would rather have. As others have said it is a one and done situation and I would have my local frame builder or shop do it if it wasn't already done. If you are getting a custom frame it is likely already done and probably most modern production frames are set up already or are carbon and not something you want to face and ream.

I've built bikes both with and without the face and ream job and one before and after. It can definitely make it easier to get the cups fully and squarely seated. I'd say rarely necessary but often beneficial it only needs to be done once, it's just good practice.
Unless something makes it impractical, just do it.
Supports and helps build a relationship with you local shop for not a lot of money.

I'm even more strongly in favor of chase and face for the bottom bracket. That's another topic.

If I had a bike where the headset wore out prematurely, I would face the head tube before I put a new one in. Otherwise, I would not.

But on a virgin steel frame, I would definitely ream and face. Like a new Surly. I have never encountered an aluminum frame that needed it, and you can't ream or face Ti.

Why can’t you ream and face Ti?

The metal is too difficult to correctly machine with standard hand tools. All of that work is done by the manufacturer with CNC machines.

It should have been done before the headset was installed, but if your headset shows signs of needing it (unable to adjust without binding and/or slop), it may benefit from having it done. The proper tools are too expensive to consider buying for a one-off job (several hundred dollars), so it's best to pay a properly equipped shop to do the work.

About the only time a headset replacement would need reaming and facing is if you are replacing a JIS-spec headset with an ISO-spec headset.

It's been my unfortunate experience that lbs seldom have the tools OR someone who actually knows how to use them. And as was already mentioned it is a one and done thing and if it is screwed up it is not un-screwable

It should only take a phone call to determine if a shop has the tools and people to do the work. Generally there is at least one shop around that is known for being able to do this kind of stuff. Google, yelp, etc.

And you can re-face bad work. You generally only remove half a mm. I'm not sure how you could screw up reaming bad enough to matter.