Headset fitting instructions
Your Sturdy Cycles frame normally arrives with the headset fitted, the brake hoses routed and the steerer cut to suit your spacers. This page explains how the headset goes together, how to check and adjust it, and how to service or rebuild it. This revision covers frames fitted with an ENVE fork.
Before you start
Important
The headset holds the fork in the frame and lets it steer. If you are not confident working on it, have it done by a qualified bicycle mechanic.
ENVE’s own instructions come first for the fork, the steerer, the compression plug and spacer limits.
Both brake hoses run through the headset. Replacing the bearings, removing the fork or cutting the steerer means disconnecting both hoses and bleeding the brakes afterwards. If you are not comfortable doing that, take your bike to a bike shop.
Fits: integrated headset with a 52 mm bearing at the top and bottom, for a 1.5 in tapered steerer. Drawings and videos are shown with our UK setup: front brake on the right lever.
Headset parts
| Part | Qty | Notes |
|---|---|---|
| Upper bearing: Enduro ACB 4545 150 SS | 1 | 40 × 52 × 7 mm, 45° × 45°, stainless |
| Upper taper ring, rear section | 1 | |
| Upper taper ring, front section | 1 | Sits between the brake hoses |
| O-ring | 1 | Holds both sections together |
| Top cover | 1 | Hoses pass through the front opening |
| Spacers, 5 mm and 10 mm | As ordered | |
| Lower bearing: Enduro ACB 4545 150 SS | 1 | 40 × 52 × 7 mm, 45° × 45°, stainless |
| Crown race: Enduro HDC-0019 | 1 | 1.5 in, 45° |
From ENVE, with your fork: the compression plug. Use the Enduro crown race we supply, unless your fork came with its own 1.5 in, 45° race.
With your stem: the top cap and preload bolt (see our stem instructions).
The upper taper ring is made in two sections. The O-ring clips into a groove in both, holding them together so they are easier to fit. The brake hoses pass either side of the front section, and the O-ring passes over them so they can’t rattle.
How the hoses are routed
Both brake hoses enter the headset through the opening at the front of the top cover and through the front pocket of each spacer, then pass down through the upper bearing, one either side of the taper ring’s front section.
- Rear brake hose: runs down the head tube and back into the down tube.
- Front brake hose: runs down the front of the head tube and enters the steerer through a port low down, near the fork crown. The exact position of the port depends on the fork.
Labelled cutaway drawing
Tools and materials
- Torque wrench covering 1–8 Nm
- T25 Torx bit (stem bolts and preload bolt); 6 mm hex bit (ENVE compression plug)
- Good quality marine grease (or anti-seize)
- Anti-seize for the stem bolts, and carbon assembly (grip) paste for the carbon steerer
- For a rebuild: a crown race setting tool, and the tools and bleed kit your brake maker specifies
- For cutting the steerer: a steerer cutting guide, a fine-tooth carbon saw blade, 320–400 grit abrasive paper and a dust mask
Stem height and spacers
- The top of the steerer, or the top of the compression plug if that is higher, must be 4 mm below the top face of the stem. This leaves a small gap under the top cap, so the preload bolt can pull the stem down onto the headset.
- Spacers are 5 mm and 10 mm, fitted to suit your order.
- Don’t fit spacers above the stem. Your steerer is cut to suit the spacers fitted, so spacers can’t be added.
- To lower the stem, spacers can be removed, but the steerer must then be cut so it is still 4 mm below the top of the stem. See Cutting the steerer, or ask a bike shop or us.
ENVE forks: maximum 30 mm of spacers
ENVE limits the stack from the top of the upper bearing to the bottom of the stem to 40 mm, including the headset parts above the bearing. On our headset those parts take about 7 mm, which leaves room for 30 mm of our 5 and 10 mm spacers. Never fit more than 30 mm of spacers with an ENVE fork.
Checking and adjusting
Check for play
- Apply the front brake and rock the bike firmly back and forth, with your other hand around the joint between the top cover and the frame. You should feel no knock or movement.
- Lift the front wheel and turn the handlebar from lock to lock. It should turn smoothly, with no notchy or tight spots, and neither hose should pull tight at full lock.
Adjust the preload
- Loosen the two stem pinch bolts (T25).
- Tighten the preload bolt in the top cap just enough to remove the play: 1–2 Nm. The steering must still turn freely.
- Line the stem up with the front wheel and tighten the pinch bolts evenly to 5 Nm.
- Check again for play and free steering.
If you can’t remove the play, check that the steerer and compression plug are still 4 mm below the top of the stem, that the compression plug is tight, and that the spacers are seated properly. Otherwise, contact us.
Strip and rebuild
Both brake hoses must be disconnected
The hoses pass through the upper bearing, and the front hose runs inside the fork. To remove the fork or the bearings, disconnect both hoses following your brake maker’s instructions, and bleed the brakes when you reconnect them. If you are not comfortable doing this, take your bike to a bike shop.
Use this order for a bearing service, or if you are building up a frame yourself. Grease every bearing seat and the crown race with good quality marine grease.
Which way round the bearings go
Each bearing has two 45° edges: one on the outside and one on the inside. Both bearings fit the same way relative to the frame: the outer 45° edge leads into the frame’s seat, and the inner 45° edge faces out of the frame, towards the crown race at the bottom and the taper ring at the top.
- Crown race. Fit the Enduro HDC-0019 crown race, or your fork’s own race if it has one; it must be a 1.5 in, 45° race. Seat it fully with a crown race setting tool, holding the fork by one leg, never on the dropouts or the crown.
- Front hose. Route the front hose through the fork and out of the port in the steerer, following ENVE’s instructions.
- Rear hose. Feed the rear hose from the back of the bike up through the empty head tube.
- Lower bearing. Drop the lower bearing into the lower seat with its outer 45° edge leading into the frame. Its inner 45° edge then faces down, towards the crown race.
- Fork. Slide the fork up through the frame, bringing the front hose up through the head tube.
- Upper bearing. Slide the upper bearing over the steerer and both hoses and drop it into the upper seat with its outer 45° edge leading into the frame. Its inner 45° edge then faces up, ready for the taper ring.
- Upper taper ring. With the O-ring fitted around both sections, slide the rear section down the steerer into the bearing, with the front section at the front and one hose either side of it.
- Top cover. Fit the top cover with the hoses through its front opening.
- Spacers. Fit your spacers with the hoses through their front pockets.
- Steerer length. If the steerer is new, cut it to length now; see Cutting the steerer.
- Compression plug. Fit the ENVE compression plug into the top of the steerer following ENVE’s instructions: maximum 7 Nm. Never use a star nut in a carbon steerer. Fitting it now, before the stem, is easier than reaching it through the stem.
- Stem. Fit the stem (stem instructions, step 1), feeding the hoses up into the stem.
- Top cap and preload. Fit the top cap and preload bolt, set the preload and tighten the stem (stem instructions, steps 2–4).
- Brakes. Reconnect and bleed both brakes following your brake maker’s instructions, and check they work properly before you ride.
Cutting the steerer
Carbon steerer: a bike shop job unless you are confident
Follow ENVE’s instructions; a steerer cut too short can’t be repaired. Measure twice before cutting.
- Fit the headset, the spacers you want and the stem, without the compression plug, and mark the steerer level with the top of the stem. Then take the stem off to cut.
- The ENVE compression plug sits 1 mm above the steerer, so cut the steerer 5 mm below your mark. That puts the top of the plug 4 mm below the top of the stem.
- Cut squarely using a cutting guide and a fine-tooth carbon blade. Smooth the cut edge with 320–400 grit paper, and don’t scratch the steerer.
- Wear a dust mask and clean up the carbon dust.
Looking after your headset
- Check for play and smooth steering after your first few rides, and regularly after that.
- Don’t aim a pressure washer at the headset.
- Don’t remove the seals from the bearings: Enduro advises against it for these bearings.
- Replacement parts: bearings Enduro ACB 4545 150 SS (2 needed); crown race Enduro HDC-0019. Contact us for spare taper rings, O-rings, top covers and spacers.
- Replacing a bearing means disconnecting the brake hoses: see Strip and rebuild.
Questions? Contact us.
Warranty
Everything we make is guaranteed for the lifetime of the original owner against defects in design, materials and workmanship. On the headset that is the taper ring, top cover and spacers. If a part we made fails because of a defect, we will repair or replace it.
Bearings: the Enduro stainless headset bearings carry Enduro’s limited lifetime warranty for the original owner, with proof of purchase. It doesn’t cover damage from dirt or contamination, damage during fitting, or normal wear. Contact us or Enduro directly to make a claim.
Other parts we buy in, such as the crown race, are covered by their makers’ warranties. Your ENVE fork and compression plug are covered by ENVE.
Not covered:
- crash or impact damage
- damage from fitting or use that doesn’t follow these instructions
- modified parts
- normal wear and cosmetic marks
To make a claim, contact us with your order number (your order confirmation email is your proof of purchase) and photos of the problem. Stop riding a part you think is damaged.
This guarantee is given by Sturdy Cycles Ltd, The Old Tannery, Lower Keyford, Frome, BA11 4AR, United Kingdom. It applies worldwide to products bought from us or an authorised dealer. It is in addition to your legal rights as a consumer and does not affect them. See also our terms of service.
Revision history
| Rev | Date | Change |
|---|---|---|
| A | October 2026 | First issue (ENVE forks) |
This page is document SC-IP-FR-001 revision A. The PDF version has the same content.