Zero (or low) stack 1-1/8 headsets

[stien]

I was doing some research on headset stack, marginal gains for lowering cockpit I know, but still.

Coming from an external cup Cane Creek 110, I'm eyeing this:

https://www.performancebike.com/cane-creek-zs-zerostack-threadless-headset-1-1-8-ahdzs286ak/p313975

https://images.amain.com/images/large/bikes/aheadset/ahdzs286ak_1.jpg?width=950

Or the Extralite Utra set:

http://www.extralite.com/Products/UltraTop-Bottom.htm


I have a few questions:

1) Wouldn't lowering the stack of the lower headset cup change the geometry of the bike?

2) Has anyone tried these? It says 1-1/8", but does zero stack mean it doesn't work with external cup (zero stack I think is a standard, as well as a descriptor).

[Lionel]

I think the lowest stack HS with external cups is the Tune one.

[Blown Reek]

Check out the King DropSet or the Cane Creek Slamset. Running these with your existing headset lower won't change your bike's geometry, and it'll lower your upper stack height.

[quickfeet]

I just ordered a slamset myself in a zs upper. It’s only 2mm stack height.

[false_Aest]

1) Wouldn't lowering the stack of the lower headset cup change the geometry of the bike?

2) Has anyone tried these? It says 1-1/8", but does zero stack mean it doesn't work with external cup (zero stack I think is a standard, as well as a descriptor).


1. yes but not massively. you're probably looking at 9-13mm stack height for an external bearing. I think at most that's 0.5 degree change in HTA.

2. This looks like a ZS44/28.6 - ZS 44/30

ZS = zero stack
44 = head tube internal diameter
28.6 = steerer tube diameter
30 = crown race diameter.

If you don't have a head tube with 44mm ID then you can't use this.

[stien]

Thanks for that, looks like I need EC34 for external cup which you can get the Extralite in. That would get me 8mm lower.

What would be the benefit to lowering the lower headset stack? It would get you closer to the front wheel, but not any lower from seat-bar drop perspective.

[false_Aest]

What would be the benefit to lowering the lower headset stack?

None. All it does is make the HTA and STA steeper. That might require you to adjust your position but I doubt it. Steering input will change but thats pretty minimal too. I think most people wouldn't notice it and, if they did, they'd adapt pretty quickly.

[KarlC]

Or the Extralite Utra set:

http://www.extralite.com/Products/UltraTop-Bottom.htm

I have a few questions:

1) Wouldn't lowering the stack of the lower headset cup change the geometry of the bike?

2) Has anyone tried these? It says 1-1/8", but does zero stack mean it doesn't work with external cup (zero stack I think is a standard, as well as a descriptor).

I just did this with the Extralite UltraTop-Bottom 34 (1 1/8") and I used a low stack stem to help lower my stack a bit more.

This was one of the goals I had for my project to lower the front end stack so I installed a Extralite UltraTop Headset. The UltraTop 34 dropped it about 10mm vs the Chris King, then I used a Deda Superleggero Stem 120 -8 stem that has a 34mm stack. The 2 together dropped the front about 16mm for me.

Note im using UltraBottom with its lower stack also and the bike does not feel any different to me. I dont think its and different that changing your tire sizes (28R 25F) or lowering your front tire PSI.

Also note that the Extralite Headset is not a smooth look as it has groves cut in it, you can see close up photos in the link below.

I'm trying this out to see how I like it, and if not the Chris King can go back on at any time.

If the Extralite UltraTop Headset stays I have some thoughts on how to smooth out the look.

Link Extralite UltraTop-Bottom on my Seven, scroll down a bit

https://forums.thepaceline.net/showthread.php?t=231447&page=7

.

[Mark McM]

As noted, there is little room to change handlebar height with headset stack height, and besides which, it produces other geometry changes on the bike. Handlebar height adjustments are usually made with fork spacers (minor adjustments) and stem angle (major adjustment). Stems are made with a variety of different angles that offer many centimeters of height adjustment.

It sounds like you want to lower the handlebar, below the level of the top of the headset. While the most common stem angles result in handlebars at or above the headset, there are some stems which will locate the handlebars below the headset. The most common types of bikes that use these stems are track bikes, so these stems are often called "pista" stems. They are made by several companies, including Cinelli (https://www.cinelli-usa.com/cinelli-pista-bicycle-stem-black-ano/) and Deda (http://www.dedaelementi.com/en/pista-2/). Compared to a "standard" 73 stem, a Cinelle 65 degree 120mm stem will place the handlebar about 17mm lower.

https://cdn11.bigcommerce.com/s-1hf4tfjzyx/images/stencil/600x1200/products/1473/658/ST8647__68395.1498508565.jpg?c=2
http://www.dedaelementi.com/wp-content/uploads/2018/03/STEM_PISTA_BLACK_FINISH_1000.jpg

[David Tollefson]

FSA makes a SL-K series of low-stack stems that put the bars below the standard -17 degree stem.

[stien]

I'm at the bottom of the spacer stack with a 130mm -17 right now. I didn't see any Deda Pistas in that length, good lead on other brands though, thanks.

[false_Aest]

custom