TourCountryside

Greetings,

Wondering if you know the specs of the headset I would need for a 2007 Trek 520 Headset. If I measure the sizes myself it will most likely be unridable for a time (which I'm trying to avoid). My only bike. I've kept it on the road since 2007. About 40K+ miles (spent a few years running more than cycling). The last original part, other than the frame, was the headset and that has now developed a "notch". May have been there for some years, but I recently found it when I checked.

I searched everywhere for parts, and there's nothing around anymore for the Cane Creek SC1 except a store in England from which I've ordered bearings.

Taking the preload cap off, I can see the top of the fork is 1", but I wouldn't know the other specs (lower fork size, frame cup size and race size) without deconstructing it.

Even if you don't know the exact specs, if you've replaced the headset perhaps you could let me know the model and size you purchased and I could reverse engineer the specs from docs online.

Thanks!

mstateglfr 

https://www.rei.com/product/237415/r...aHACeQykzXVZy0

If your fork has a 1" steerer, then just buy a new threadless 1" headset.
Replace the headset in full instead of trying to find parts to keep your current headset going. Youve used it for 17 years and 40,000mi...you got your money's worth.

Removing and installing headsets is straight forward and made easy with youtube videos that walk you thru the process.

djb

get a bike store to install it, they will do it fast, and get everything aligned properly and its done.
they have the tools to do it and it will not cost much.

going forward, every x number of years, open up, clean and regrease the bearings and it will last for ages if greased and adjusted properly with no collisions into walls

and this is from a guy who does nearly all my own work on my bikes and isnt rich

TourCountryside

Thank you! Much appreciated. Really had no idea that 1" was standardized and not subject to the dizzying array of crown race sizes, etc., etc.

mstateglfr 

There are a couple crown race sizes, but

1" threadless headsets can have 26.4mm or 27.0mm crown races, that is true. I assumed you knew which you have. You can easily measure that with a vernier caliper.

Anyways, an '04 520 came with a 26.4mm crown race and that size is what I have seen used on every other threadless 1" steerer Ive owned/worked on(admittedly only 5 others).
The Ritchey headset linked earlier is 26.4 and a Cane Creek 40 headset is very good quality and also 26.4mm - https://crustbikes.com/products/cane...0-1-threadless

But if you cant figure out if yours is 26.4 or 27.0, then you can get a headset that comes with both crown races- https://www.bmxguru.com/products/ori...0mm-race-black

Tourist in MSN

Before you order the parts, double check the steerer tube outer diameter. if you remove your stem cap on the top, you can measure the steerer tube quite easily. It might be 1 1/8 inch outside diameter which is much more common on touring bikes.

Your stem would still be attached to the steerer tube to maintain the bearing pre-load, so there is nothing wrong with removing the stem cap to measure, then re-attach.

I agree with Djb, have a bike shop install it. Parts are pressed onto the fork and onto the frame. Labor charge likely is less than the cost of tools. I am a former bike mechanic, do my own work but the last time I had a headset install project was nine years ago and I had a bike shop press the parts into the frame and onto the fork.

mstateglfr 

The OP mentioned the cap was removed and steerer measured.

saddlesores

if you don't have a bike shop that can do the work, it is possible to remove and replace yourself.
no expensive headset press tools needed.
threaded rod, nuts, washers, rubber padding.
youtube videos will walk you through the process.

Tourist in MSN

I saw that but I would be surprised if that is 1 inch.

robow

I could see this being 1" in the photo.