Total confusion on replacement headset

[septuagenarian]

I'm doing up a 2001 Trek 6700 and have all the parts bar the headset and as the one in it was a bodgie job and I'm doing a total replacement.

I've found the original 2001 Trek specs and they state that the headset was a Dia-Compe STR, 1 1/8" Sealed, and in a 2002 spec sheet (the frame specs were unchanged so I'm assuming all else was pretty much the same) with specs 25.4/34.0/30.0, Stack height 23.0mm.

What do I need to get? I've knocked out both bearing cups and they appear identical and measure around 34mm where they slide into the head tube. The head stem has an OD of 28mm.

[queequeg]

I'm doing up a 2001 Trek 6700 and have all the parts bar the headset and as the one in it was a bodgie job and I'm doing a total replacement.

I've found the original 2001 Trek specs and they state that the headset was a Dia-Compe STR, 1 1/8" Sealed, and in a 2002 spec sheet (the frame specs were unchanged so I'm assuming all else was pretty much the same) with specs 25.4/34.0/30.0, Stack height 23.0mm.

What do I need to get? I've knocked out both bearing cups and they appear identical and measure around 34mm where they slide into the head tube. The head stem has an OD of 28mm.

Try this little helper:- https://blue.canecreek.com/headset-fit-finder

[septuagenarian]

Cheers queequeg

The Murphy factor has kicked in as I've already tried that tool with no joy.

[septuagenarian]

I believe Dia-Compe were acquired by Cane Creek so perhaps I should ask them.

[queequeg]

Cheers queequeg

The Murphy factor has kicked in as I've already tried that tool with no joy.

Did you go through the "I don't know my bike". It shows you how to measure your existing headset and bike and tell you what you need

[septuagenarian]

Cheers queequeg

The Murphy factor has kicked in as I've already tried that tool with no joy.

Did you go through the "I don't know my bike". It shows you how to measure your existing headset and bike and tell you what you need

0

Thanks, I've just sent that off.

[septuagenarian]

Cheers queequeg

The Murphy factor has kicked in as I've already tried that tool with no joy.

Did you go through the "I don't know my bike". It shows you how to measure your existing headset and bike and tell you what you need

0

Thanks, I've just sent that off.

Already had a reply from Cane Creek and ordered a BrandX unit with sealed bearings. Fingers crossed it fits.

[Duck!]

What do I need to get? I've knocked out both bearing cups and they appear identical and measure around 34mm where they slide into the head tube. The head stem has an OD of 28mm.

I'm suspecting there's a typo there somewhere, because that combination of dimensions doesn't add up. Or the terminology is being misinterpreted...

I've found the original 2001 Trek specs and they state that the headset was a Dia-Compe STR, 1 1/8" Sealed, and in a 2002 spec sheet (the frame specs were unchanged so I'm assuming all else was pretty much the same) with specs 25.4/34.0/30.0, Stack height 23.0mm

Those specs don't align with a 1 1/8" steerer; the first figure, 25.4 shouts out 1" steerer tube. So what you need to determine are: a) the diameter of the steerer tube (the top bit of the fork that goes up through the frame) - it will be either 1" (25.4mm) or 1 1/8" (28.6mm); b) whether the headset is i) an external cup (EC) type, where the cups containing the bearings sit outsside the head tube with a spigot to fit into the frame; ii) a semi-integrated/internal type with the bearing cups located inside the head tube, then the bearings fitted in the cups; iii) an integrated type, with the bearings directly fitted in the frame. Slightly confusingly, both integrated and semi-integrated headsets will be described as "zero stack", meaning the headset assembly doesn't meaningfully exceed the frame's head tube length, although an internal/semi-integrated type will do so by 2-3mm; c) the bore of the head tube - this can be anywhere between 30.something mm for an EC headset to 44mm for a ZS semi-integrated model.

[septuagenarian]

The 25.4 reference confused me too (it doesn't take much) but the steerer tube OD is def 28.6mm so go figure.

The headset I've ordered is an EC type and the specs match those Cane Creek sent me, ie EC 34.00/28.6 and EC 34.00/30.00 and the ID of my head tube is 34mm and the OD of the head stem is 28.6mm