Bikeshop reamed away too much from my headtube

I bought a brand new Soma Smoothie frameset and brought it to the local framebuilder/bikeshop to get the headtube reamed and faced. I just picked it up and they reamed so much that I can press in the Chris King headset by hand and still twist it around. Does this mean they fucked up the frame? What can I do now? Thanks for all the input!

Chris King publish the tolerance they use for frames.

Depending on what you asked the shop to do it could be they have over reamed the frame so the blame would fall on them.

However King Headsets are often on the smaller side ( used to be issues with some specialized frames) so another headset might work.

a) yes
b) take it back, show the damage, hope to hell the bike shop is half decent or the workshop manager values their good name

I think reaming too much out is actually quite a hard thing to do.

I thought I’d done it to a frame I’d just spent months building but it turned out I just had a shit, undersized headset. Obviously that’s not the case here but I spent a while contemplating it.

The reamer is (presuming they used a pucker head tube reamer and not an adjustable hand reader or something) a set size. It’s not like it’s tapered and you could go too far along the taper.

There’s also guide bushings and stuff to keep the cutter centred in the headtube so it’d be hard to use the tool incorrectly.

Is your headset new or has it been fitted previously?

I’d guess the shop maybe doesn’t use the cutter much so it’s reaming out to the larger end of the ‘tolerance range’ and your headset is on the smaller end of the range. I was the first person to use the 1” reamer we have so I think that was part of my problem.

You might find another headset (even another King, though I imagine their tolerance would be pretty consistent) fits more tightly.

Worst comes to the worst King supposedly will make you a slightly oversized cup so it’s definitely not going to be a case of throwing the frame in the bin.

Thanks for all the help! I'll try a different headset and see how that goes.

You could try an expanding epoxy. We had a NOS Casati in the shop about 10 years ago and a king headset just slid in with no real force. It seemed to have worked, though the last time I saw the owner was 5 years ago.

I think once you’ve checked the size of both the head tube and the headset cups, if it is the head tube, a better option than epoxy is to have it reamed oversize and put in a 0.1mm shim all round. I forget if headset cups are a press fit into 30.0mm or 30.2mm - get it reamed to 0.2mm oversize and press it in with a 10mm wide 0.1mm thick shim all the way round. It’ll ensure it’s concentric, parallel and it won’t move.

Had you checked the headset before and did you discuss with the shop that you planned to use that particular headset or was there any discussion how much would be taking off ,

was there any discussion how much would be taking off

There isn't really an option of "how much".

The reamer will have looked something like this,

The bevel on the shoulder will centre the tool and then you just ream till the whole thing is inside the headtube.

The only option is which headset standard you are working with 1", 1 1/8" etc and if you used the wrong reamer you'd have bigger problems than the cup being loose push fit.

Yes @M_V very well explained

I tried and measured a few things. I took a Stronglight headset cup out of my mtb and tried it on the reamed Soma frame. I couldn't push it in by hand so atleast that is good sign.
I measured the Stronglight cup diameter and it is 34,1, I also measured the Chris king cup and that one is 34,0
When I dropped off my frame I told the bikeshop I was going to use a Chris king headset. According to the Chris king website headtubes should be reamed at 33,9 which means they reamed 0,1mm too much... It's not much... not sure what to do now, I feel temped to fit it with some bearing retainer and just start riding the bloody thing.

Annoying, but salvageable.

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F263851756171

[stupid link sharing convoluted hyperlink - sorry]

Buy that, which is 0.05mm. Cut a strip with some good sharp scissors, a little longer than the depth of the cup and just under one complete turn. Press the cups in with the shim.

Do you know what tool they used?

If it was the Park one, the spec on the reamer is 33.9mm

https://www.parktool.com/product/33-9mm-head-tube-reamer-for-1-1-8-headset-standard-754-2

The spec on the Var reamer is 33.8mm

https://www.vartools.com/en/1-1-8-head-tube-reaming-cutter-var-p40.php

It looks like the Cyclo reamer is 34mm going by this image of it,

I'm pretty surprised that there's a 0.2mm variance in these things that are all sold as "1 1/8" head tube reamers".

It's not something I'd have known to check, would have thought that an 1 1/8" reamer was an 1 1/8" reamer.

Have you measured the frame?

It's probably worth talking to the shop to find out what reamer they have actually used and to see how aware they are of the variance in sizes. I know it won't help you but you might stop them from doing the same thing to someone else's frame.

Liability would be difficult to pin down I'd imagine (everyone will want to say it's someone/something else at fault) but if the shop were to tell you they'd used a Cyclo reamer then I'd say you had grounds to be asking them to cover the cost of a King oversize cup. Conversely, if they tell you they had a cyteched mech (ie can prove their level of competence) do the work with a Var or Park cutter (should have left the frame compatible with a King headset) then you'd have to look at taking it up with the tool maker which might be more hassle than it's worth.

Annoying, but salvageable.

It's definitely salvageable but you know, buying a King headset and paying a shop to ream the headtube means this is not a job that @kjlem is looking to bodge.

Given the discrepancy in sizes of the cutters that are being sold as "1 1/8" reamers" I think finding out exactly what was used on the frame is a worthwhile step.

Might also be worthwhile checking the size of the cup with a couple different sets of calipers and/or micrometers. Like I said before, I expect quality control and tolerances at King to be pretty tight but you never know...

In case like this i usually use teflon tape. Wrap it aroud headset cup and push it into the frame. It always worked for me, and it's pretty cheap too.

It's definitely salvageable but you know, buying a King headset and paying a shop to ream the headtube means this is not a job that @kjlem is looking to bodge.

Shimming is not a bodge.

I’m more concerned, like you, that there are different sized reamers for what should be the same size hole. 0.2mm is the difference between absolutely won’t press in and rattling around loose - what’s going on there? I’m also massively surprised the King headset has cups apparently 0.1mm smaller than standard. That’s completely bonkers, why even have a size standard if it’s not going to be used?

0.2mm is the difference between absolutely won’t press in and rattling around loose - what’s going on there?

According to this article, 0.0007” or 0.017mm is the difference between press fit and slip fit.

It also mentions that the parts need to be trying to occupy the same space, so King probably don’t suggest a 33.9mm headtube id because their headset cup od is 33.9mm but rather because their headset cup od is 40mm and they want 0.1mm of interference.

@kjlem sorry if I’m missing seeing it but did you tell us if the headset was brand new or not?

It's a new Chris King that I bought especially for this frame.
I just spoke to the bikeshop and they said they reamed it 34,0mm and that's what they always do. I said to them that I told them I was gonna use a CK and that it needs to be 33,9, he said; then you should've brought your headset with you... So it was going to be an endless discussion...
So I'll just bodge and start riding the bike, should've known not to trust a shop that build bikes like this;

Use some bearing fit and don't use the shop again

Yes that's the plan. Thanks for all the help guys!!!

That’s completely bonkers, why even have a size standard if it’s not going to be used?

In my point of view you pretty much summed up the whole bike industry nonsense regarding standards

Or sell the CK and get a Cane Creek 110

Out of interest: how would you go about fitting this? I'm guessing it'd need to be bonded in place somehow. But the bonding would presumably add more material, so would it have to be reamed again?

My soviet-era Russian bike is shimmed so it can use a standard headset. I forget the exact sizes but I think it had a 30.4mm headtube ID instead of the usual 30.2mm. I just held the strip of shim in place to get it started, then the shoulder on the headset cup did the rest.

Plus plenty of grease according to my build thread, but the pics are dead, unfortunately: https://www.lfgss.com/conversations/275811/

I haven’t had to touch it since. That bike is my daily and it’s probably got around 6000 miles on it since fitting.

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