As more modern mountain bikes get slacker trail bike geometry, do you wonder if your existing bike might need a geometry update? Wolf Tooth’s new Headset Extender lower cups might just be the ticket to a more aggressive setup on your current bike (maybe paired with a modern offset fork?) Or you might use it to keep the same geometry on the bike if you want to decrease from travel or even swap to a rigid fork. In any case, adjustability means more options…

Wolf Tooth Lower Headset Cup Extenders adjust your geometry

Wolf Tooth Lower Headset Cup Extenders, 10mm extended internal headset cups, adjustable trail mountain bike geometry
c. Wolf Tooth

Beyond their solid chainring offerings, dropper remotes & a cool set of chain pliers, Wolf Tooth often produces some great little tidbits to give more options on the bike – think: the Road & Goat Links or the Boostinator, via their Lindarets relationship. This new extended lower headset cup falls into that latter category.

By adding an extra extension to the lower headset cup, you lift the bottom bracket a bit and slightly slacken your headtube angle. That should give your current bike improved stability when descending and at high-speed. But be aware that getting slacker without changing fork offset will also affect Trail. That will impact handling at low-speed (as much as stability increases at high-speed), which is why modern trail bikes get modern offset forks. It is essentially the same thing we’ve seen from a number of companies that make bikes that can be converted from 29″ to 27.5+ wheels. Now you can just use it to experiment on your own bike.

Wolf Tooth also notes that it could help maintain your current geometry if you are changing forks. Putting a rigid fork onto a suspension corrected frame might need some extra axle-to-crown, as may changing from various road, cross, gravel, or bikepacking forks.

Tech details

Wolf Tooth Lower Headset Cup Extenders, 10mm extended internal headset cups, adjustable trail mountain bike geometry

The Lower Headset Cup Extenders add 10mm of axle-to-crown height to your existing fork. That’s generally not going to have a huge impact on your bike’s geometry – probably a bit less than 0.5° at the headtube and <5mm at the bottom bracket. But that might be just the small change you need to tweak your ride.

Wolf Tooth Lower Headset Cup Extenders, 10mm extended internal headset cups, adjustable trail mountain bike geometry

The extended lower cups are machined from 6061 alloy in the USA and weight 62-68g. They are sold on their own (you need to buy an accompanying upper headset cup if you need a complete headset setup) and include Enduro stainless steel sealed bearings.

Wolf Tooth makes a complete family of precision machined headsets, made in Minnesota to fit any bike.

Pricing & availability

Wolf Tooth Lower Headset Cup Extenders, 10mm extended internal headset cups, adjustable trail mountain bike geometry
EC or ZS lower cups

Available now, they come in two versions – EC to fit 1.5″ lower headsets with external cups that press into a 49mm ID or ZS to fit 1.5″ lower headsets with internal Zero Stack cups that press entirely into a 56mm ID headtube.

Wolf Tooth Lower Headset Cup Extenders, 10mm extended internal headset cups, adjustable trail mountain bike geometry

For now the EC version is available in red, blue, or black ano & the ZS is black-only.

WolfToothComponents.com

7 COMMENTS

  1. Another option to accomplish the same result is MTB Tools extended crown race. It is available in 5mm increments up to a maximum of 25mm. I installed one with a 20mm extension on the Chromag Aperture that I built for my daughter to mimic the geometry that I would have gotten if I had built it with a 120mm fork (I used a 100mm Fox Float that I had laying around). To make sure that the extended crown race wouldn’t skew under load, I pressed on a crown race ring (purchased from Nova Cycle Supply) to support the extended crown race at the top lip. Note that you will have to machine the race ring with a Park crown race cutting tool or the equivalent after you press it to the right place on the steerer tube. Your friendly local bike co-op should have that tool. It took a little bit of effort, but I think it was worth it. The extended crown race is as stable as a regular crown race, and the bike rides great.

    • I used a custom canecreek race for the same effect as well in the past (just call them on the phone they have custom stuff)

      I like the wolftooth product though, it seems easier to get and probably cheaper

  2. It’s a lot easier to just press in a new lower bearing race than what you went thru. that said, I am surprised that WT is only offering the new parts in 10mm extension.I wonder how f’d up it would be to use a WT extended lower cup WITH a MTB Tools extended crown race? Unstable? or not… Not sure why Wolf Tooth hasn’t started making angle changing headset cups like Works Components does in the UK. You want a NOTABLE change, change the freakin fork angle. I have put a few Works Components headsets on my bikes over the years, and aside from dealing with an overseas company, it’s an easy project.

  3. I actually do have a use for this. Frame designed around a 120mm fork, I’d like to run rigid without making it steeper, and I haven’t found a rigid fork long enough. Like pretty much all Wolf tooth products, it’s simple; not revolutionary (or particularly clever), just enough to make a practical, small change.

    this gem: “But be aware that getting slacker without changing fork offset will also yield more Trail. That will slow handling at low-speed (as much as stability increases at high-speed), which is why modern trail bikes get modern offset forks. ”
    is typical ‘why it’s getting hard to read Bikerumor’…
    1: yes, more trail is why we all want slacker head angles. The comment about slow low-speed handling is just repeating long-discredited 70s-80s road bike handling mythology.

    2: what do reduced offsets do? They increase trail even more. Cory, either you don’t know what trail is or you’ve never drawn a picture and thought about how changes affect it, because your explanation is not only wrong, it’s the exact opposite of correct.

    • @i You are for the most part very much correct.

      The trick there is that additional Trail is a good reason to get reduced fork offset, while keeping the same head angle. Slacker head angles can also be fun, when you are keeping Trail in check, unchanged by modifying fork offset also.

      It is a bit more risky to get more Trail and a slacker head angle at the same time (like this could do in a small increment). That is the same thing you would do by putting a long travel fork (with the same offset) onto a bike designed for shorter travel. That can be fun, but can also do wacky stuff to your slow speed handling.

      I definitely am aware of what Trail is, and can surely draw you a diagram.
      I also have not been afraid to put a longer travel fork onto a bike not quite designed for it. It can be a lot of fun. But you should be cautious doing it to extremes (and it is not the same as getting a modern offset fork, or a bike with modern slack geometry.)

      • Slacker head angles increase trail. Period. It doesn’t “keep trail in check, unchanged.” There is simply no way to change head angle without changing trail. I say again: if you don’t understand this, you don’t understand what trail is.

        Changing geometry of a bike is ‘risky’, just by nature – you’re making the bike handle differently than it was designed. Unless you’re an utter ‘princess and the pea’ type, a 10mm increase in a2c (that’s easily reversable) is not a big risk, because it’s not going to be a big change.

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