17 August, 2017

Stack Em Up!

By Scott

Headsets don't get a lot of love. They are the 12th man of a cricket team, the pinch runner for a baseball squad, or the back up goalie for a hockey team. They tend to get forgotten until servicing or replacement is needed.


When the time comes to pick a headset, you need to do a bit of research and measuring. For the purposes of this post, I'm going to delve into the concept of stack height and how it relates to fitting a headset to a frame. While the discussion is directed at threaded headsets, threadless headsets use some similar math. So if you are swapping out a threadless headset, you have to allow for the stack height of the stem in addition to the headset.


So lets start out with our Campeur frame and fork. I'd like to install the 1 inch threaded Grand Cru headset. Now I have to figure out if it will fit (spoiler alert - all VO frames are designed to be 100% compatible with our headsets). To help determine this, I'll need a metric tape measure. If you don't have a tape measure marked in both metric and imperial, pop down to your local hardware store and grab one. It makes it so much easier for this project and for future ones as well.

I need three measurements to determine if my chosen headset will fit: 1) the stack height of the intended headset, 2) the length of the head tube, and 3) the length of the steerer tube. The stack height of the headset is the overall height of the headset once installed and should be found on the manufacturer's documentation. The head tube length can be measured with your tape measure. Simply measure the length of the head tube - don't include the existing cups or anything, just the head tube. To measure the steerer tube, you will need to remove the fork and measure from the top of the crown to the top of the steerer.


So I go to the web page for the headset and it says the stack height is 42 mm. This means that the top cup, lower cup, crown race, and lock nut take up 42 mm of vertical space. When I measure the steerer tube, I get a measurement of 207 mm.


The next measurement to take is the length of the head tube. In this case, it comes out to 155 mm.

So here is where the math comes in. The steerer tube is 207 mm. The head tube is 155 mm. Subtracting the head tube (155) from the steerer tube (207) equals 52 mm. This number is greater then 42 mm, so I can fit the headset and have room for a cable stop (about 3 mm thick) plus some spacers between the cable stop and the lock nut.

(Lots of room for a cable stop and some spacers)

We've always made the steerer tube on our bikes long enough to ensure there is room for a cable stop and differing heights of headsets. Some older racing bikes from the 70's had really low stack heights that means adding a modern headset with sealed cartridge bearings impossible. Is anyone interested in a low stack height headset with cartridge sealed bearings for those older bikes?

9 comments:

Richard Freeman said...

Yes, low stack headsets would be appreciated. A side benefit is that a low stack headset on a normal stack frame will gain room for brake cable hangers and such.

It's not so much a 70's race bike thing as an 80's Shimano proprietary-part thing. Campy was the de facto standard at around 41mm for years, although the track model was shorter. Shimano started making their road headsets at the track height of 38mm so the bike makers started cutting their steerers to fit. Now the owners of those bikes have no choice but to use Shimano headsets. Does Shimano even make headsets any more? Anyway, alternate choices would be good.

While you're on the subject, what happened to needle bearing headsets? Yours disappeared, along with most of the others on the market.

Rich

Don said...

When I transformed an old Bianchi cross frame, I used a Miche headset with needle bearings. Don't know if they still offer them.

Anonymous said...

@Don

I just got a new Miche 1" threadless headset with needle bearings for my wife's bike. It was brushed aluminum and I spent hours polishing them to a mirror finish in order to coordinate with the polished metal on the rest of the build.

Greg

Unknown said...

Oh man low stack cartridge would be so appreciated! I think some of the lowest cage bearing I've found have been Tange Levin? I've had 3+ bikes come through my hands with steerers cut down for old Shimano 600 headsets too. Love the finish on the Grand Cru parts.

Anonymous said...

+ 1 for a needle bearing headset--I don't think Miche makes 1" threaded anymore, and there are plenty of folks on low-trail rando rigs complaining about shimmy!

Ron

David Schensted said...

Scott, Thanks for the tips. This info will be useful as I put together my new Campeur.

Anonymous said...

A nice synopsis of stack basics but no mention of crown race fitting. Although it does not effect stack height anyone installing a headset has to know the diameter cut onto the fork crown race - either JIS (27.0mm) or ISO (26.4mm). Speaking of which, can you guys get your 'Rinko' headset supplied with an ISO/26.4 lower race? In fitting that headset to a custom frame with a 26.4 mm fork crown race I had to buy two of your Grand Cru headsets ('Standard' ISO and 'Rinko') and mix the upper and lower parts; it turned out great but I now have extra unused parts...

Keep up the good work!

Bruce in Montana

VeloOrange said...

@ Bruce in Montana

Thanks for the comment about crown race fitting. Your right that the crown race size is something to check on before buying/installing a headset. We did a post about headset basics
http://velo-orange.blogspot.com/2009/12/threaded-headset-basics.html
that covered the different sizes etc. This article was more about stack height and pitfalls to keep in mind when swapping a new headset into place.

As to Rinko, we did have both ISO and JIS when we first made them back in 2013. JIS outsold ISO by a long ways, so we only restocked the JIS. You could use the split crown race 26.4 that we sell individually in the headset parts section with the JIS Rinko headset to create a hybrid.

WE LIKE IKE! said...

+1 low stack cartridge. This is super timely as I recently learned much of the above the hard way after attempting to swap out the existing headset for a new Grand Cru and having no steerer tube to work with. Learned a ton in the process and refurbed the old headset, but would love more options in future.