Every bicycle has a head set. Head sets wear out over time. The head set is the part of the bike where the fork attaches to the stem. Bearings in the head set allow you to turn the handle bars. The parts of the head set that hold the bearings are called the 'cups'. An integrated headset means that the 'cups' are part of your expensive new frame and cannot be replaced unless you replace the frame. Wow! What a great idea huh?
Now, since the 'cups' are part of your frame and cannot be replaced, you have to use the specific bearings that were designed for your make, model and production year of your bicycle. Because there's no real standard, there are over 250 different specifications to choose from.
Picture yourself on an extended tour, and in need of new headset bearings for your bicycle. Do you think any shop in the entire world is going to stock 250 sizes of headset bearings? You'll be stuck for days or weeks waiting for parts. Any shop in the world should be able to install a headset or bottom bracket in your bike right away if your bike is using an ISO compliant part.
Think I'm exaggerating?Check this out: Below is a sample from just one company. It takes six pages of their technical manual to list the 250+ so called 'standard' integrated headset dimensions. I'm showing the actual pages that we have to use to determine what bearing to order (taking into account O.D., I.D., cup depth and bearing race angle) for a bike that has one of their integrated headsets. This, to me, is an unacceptable nuisance for my Rodriguez customers. Why set them up with a bike that cannot possibly be serviced easily? There's absolutely no benefit to the customer by using an integrated headset. Nothing but drawbacks and chaos on this one. The really sad part is that a bike with an integrated headset cannot be converted to ISO.
How long do you think that companies will make all of these sizes? Wouldn't it be sad if your bike's bearings were on the 'discontinued' list?
This first picture shows the tools required to determine which of the 'standards' the integrated headset falls into.
Should a bicycle headset require this much complexity to repair?
Page 138 ~ 143 of the technical manual shows the current integrated head set sizes available in 2011: