Headset size and stack height

[Percy]

I've decided I might as well put a new headset on this re-build I'm doing, as I'm replacing everything else. Thankfully I seem to have a Peugeot frame that isn't awkward French sizes - the the heaset has '22.2' stamped on the top, which, from my investigation, seems to mean that I have a standard size and can replace it with a 1 1/8" headset.

First question - is this correct? The 22.2 refers to the mm size of the stem, right? And the 1 1/8" refers to the size of the frame tube? And they're mixing imperial with metric just to confuse me?

Secondly, I've fallen foul of buying the wrong stack height headset before - I fixed it that time with some creative sawing of an old cable-stopper washer, but I'd rather not do that this time (not that I have a cable-stopper washer on this bike, as it will have dual pivot brakes). How do I make sure I get the right stack height? All the ones I've looked at so far, on online shops, don't determine stack height - so I'm assuming they're only available in one size. Or do they come with a number of washers, allowing you to add/remove as suits your bike?

Thanks

 

[accountantpete]

Are you talking about a threaded headset or the A-Head type?

 

[Percy]

Sorry, threaded.

 

[swee'pea99]

I'm always totally baffled when people replace things that don't need replacing. I replace things when they go wrong/break/wear out, otherwise I leave them where they are and go about my business.

Having said that, it looks to me like you're muddling two distinct bits of kit: your Peugeot has a quill stem - all bikes of that era did - but all your queries about stack height relate to A-head stems. AFAIK you can't fit an A-head to an old bike like that - the tubing that takes the headset is too narrow. I could be wrong. But I think I'm right in saying that what you need is an old-style headset, to take your old-style quill stem. In which case, you needn't worry about stack-heights and spacers, 'cos those quill stems never had any.

 

[Percy]

Hi swee'pea99

My decision to replace the headset is based largely on the condition of the current headset. It's an old bike - the headset is worn and I'm replacing everything else, as well as touchng up paintwork, so sticking a new headset on now, while it's thoroughly stripped, makes sense.

Anyway - it looks to me like you've misread my post or are muddling two distinct bits of kit - my question relates mainly to the headset, not the stem. I am aware that the bike has a quill stem, and of the difference between and threaded and threadless headset.

Stack height is not just an issue for threadless headsets - with a threaded one, like I have on this bike... well, Sheldon has already gone to the trouble of explaining it so I'll take his words:

"With a conventional threaded fork, the steerer tube is longer than the head tube by some amount. If a headset is chosen with a stack height greater than this difference, there may not be enough of the steerer free above the upper bearing race for the keyed washer and lock nut to be installed."

My question therefore is how do I determine the stack height of the current headset, to make sure I buy the right size? I was also looking to clarify that the "22.2mm" stamp on my surrent headset (not stem) meant I was able to buy a standard 1 1/8" headset.

 

[RecordAceFromNew]

Most threaded forks require the 1" ISO Standard threaded headset in Sheldon's list here. If yours is different you will have to take special care sourcing replacement.

Indeed you do need to make sure a replacement threaded headset has a stack height that is not so high compared to the original one that the top nut runs out of thread on the forks - that nearly happened to me once. Generally it is possible to find out what headset stack heights are. Such as this and this, e.g., precisely because of the problem one could encounter otherwise. The stack height of your existing headset is the total height of all the headset components you can see - essentially it is the distance from the bottom of the crown race on the forks to the top of the headset minus the length of the headtube. If you have your headset including all races stack up on the table you need to subtract the bits that would have gone inside the headtube from the total height.

Perhaps your reference to 1 1/8" headset is potentially confusing others. Most modern bikes don't have threaded fork and threaded headset and quill stem but have 1 1/8" aheadsets and corresponding stems. If you have threaded forks and 1" threaded headset and you wish to use a modern 1 1/8" stem, you could use a stem converter. But they look a bit weird on a traditional bike.

 

[Percy]

Thanks RAFN

It was the '22.2' stamped on the current headset that led me to think I needed a 1 1/8" threaded headset. I have no interest in switching to a modern stem - I'd just like to replace the old threaded headset with a new one. 1 1/8" threaded don't seem too hard to come by - for example:

http://www.sjscycles.co.uk/headsets-1-1-8-threaded-dept584/

As you say though, I will have to be careful with stack height.

 

[brockers]

Don't know if this might be of any help.

Here followeth some thoughts on headsets. Apparently the Misuras are pretty good, and I've had a needle roller bearing Stronglight A9 on one bike (an old Peugeot 531) for over ten years which is still as smooth as. They look lovely too. I'd never touch a Campag headset again as a Record one I had on a fast bike only lasted a couple of years before becoming notchy. I've recently removed a 105 from my twenty year old project fixie frame and there doesn't seem to be any wear, so that's going back on after I've sprayed the frame.

 

[asterix]

think[/i] I'm right in saying that what you need is an old-style headset, to take your old-style quill stem. In which case, you needn't worry about stack-heights and spacers, 'cos those quill stems never had any.

a) stack height is most certainly an issue for quill stems, if not WRT to spacers. On my restoration jobs the headset was the main thing I sought professional advice on. As the OP demonstrates, it's not the easiest thing source these days.
b) it is possible to fit A-head to narrower tubing as I have 2 bikes where this was done from new. They are easier to adjust but don't look so good.