WTB Serra hub service User Guide
- June 4, 2024
- WTB
Table of Contents
WTB Serra hub service
Before you start
WARNING
All WTB products should be installed and serviced by a qualified bicycle
mechanic using appropriate professional tools. WTB assumes no liability for
products which are improperly installed, removed, assembled, disassembled or
configured. Improper installation, adjustment or service may result in damage
to the component or component failure. Use only genuine WTB replacement parts.
DANGER
After any installation, adjustment or repair, test your work by taking a
test ride in a controlled environment, away from cars, fellow cyclists,
obstacles or other hazards.
Failure to follow these instructions can result in component failure.
Component failure can cause the rider to lose control of the bicycle and fall,
leading to serious injury or death.
- Identify your hub. The best way to determine if your hub is a WTB Serra hub is by the circular 6-bolt disc mount area. Serra hubs are not machined out in between the threaded holes like they are on other WTB hubs. Looking at the hub from the non-drive side, the disc mount area of a Serra hub is round, without any machining done to remove material. If your hubs do not have a circular disc mount area, find the correct service manual for your WTB hub model on the following webpage, www.wtb.com/pages/resources.
- Make sure you have read the WTB hub instructions which are available in this document as well as the WTB website at www.wtb.com/pages/resources.
- Follow each step of these service instructions.
Tools and Equipment
To disassemble and reassemble your hubs, you will need the following tools:
- Two 17mm cone/hub wrenches
- 14mm hex key
- 2mm hex key (not required in all instances)
Serviceable Parts: High resolution schematics available at www.wtb.com/pages/resources
PRODUCT DESCRIPTION
WTB Serra
12 x 100 Front Hub
- W135-0633 Serra 12×100 (28 hole)
- W135-0642 Serra 15×100 (28 hole)
- W135-0710 Serra 12×100 (32 hole)
| No. | Description | Qty |
|---|---|---|
| 1 | M12 End Cap (L) | 1 |
| 2 | 23×1.5 o-ring | 4 |
| 3 | 30×2.0 o-ring | 4 |
| 4 | 20x32x7 Bearing, 1 pcs | 2 |
| 5 | Hub Shell | 1 |
| 6 | Axle | 1 |
| 7 | M12 End Cap (R) | 1 |
| 8 | M15 End Cap (L) | 1 |
| 9 | M15 End Cap (R) | 1 |
W TB P a r ts / Se rvic e Kits
Part Number| Description| No.
W035-0130| 20x32x7 Bearing, 1 pcs| 4
W035-0143| Serra Axle for 100mm hub| 6
W035-0135| Serra End Cap Kit for 15×100/110 hub| 10
W035-0142| Serra End Cap Kit for 12×100 hub| 11
WTB Serra
15 x 110 Front Hub
- W135-0631 Serra 15×110 (32 hole)
| No. | Description | Qty |
|---|---|---|
| 1 | M15 End Cap (L) | 1 |
| 2 | 23×1.5 o-ring | 2 |
| 3 | 30×2.0 o-ring | 2 |
| 4 | 20x32x7 Bearing, 1 pcs | 2 |
| 5 | Hub Shell | 1 |
| 6 | Axle | 1 |
| 7 | M15 End Cap (R) | 1 |
W TB P a r ts / Se rvic e Kits
Part Number| Description| No.
W035-0130| 20x32x7 Bearing, 1 pcs| 4
W035-0136| Serra Axle for 110mm hub| 6
W035-0135| Serra End Cap Kit for 15×100/110 hub| 8
WTB Serra
12 x 142 Rear Hub
- W135-0711 Serra 12×142 (28 hole) Shimano HGR mtn/road
| No | Description | Qty |
|---|---|---|
| 1 | M12 End Cap | 2 |
| 2 | Left Bearing Nut | 1 |
| 3 | 15x28x7 Bearing, 1 Pcs | 1 |
| 4 | Hub Shell | 1 |
| 5 | Axle | 1 |
| 6 | Right Bearing Nut | 1 |
| 7 | Freehub Nut | 1 |
| 8 | Freehub Carrier | 1 |
| 9 | Freehub Seal | 1 |
| 10 | 1/8″ x 25pcs loose ball bearing | 2 |
| 11 | Pawl | 3 |
| 12 | Spring | 1 |
| 13 | Large Spacer | 1 |
| 14 | Small Spacer | 1 |
| 15 | 11spd Freehub Body | 1 |
| 16 | Cassette Spacer | 1 |
| 17 | Bearing Race | 1 |
| 18 | 15x26x7 Bearing | 1 |
| 19 | Freehub Dust Seal | 1 |
W TB P a r ts / S e rvic e K its
Part Number| Description| No.
W035-0133| 15x28x7 Bearing, 1 Pcs| 3
W035-0145| Serra Shimano HGR mtn/road Axle for 12×142 hub| 5
W035-0148| Serra Shimano HGR mtn/road Freehub Kit for 12×142/148 hub| 20
W035-0156| Serra Shimano Freehub Nut| 7
W035-0147| Serra Shimano HGR mtn/road End Cap Kit for 12×142/148 hub| 21
WTB Serra
12 x 148 Rear Hub
W135-0712 Serra 12×148 (32 hole) Shimano HGR mtn/road
| No | Description | Qty |
|---|---|---|
| 1 | M12 End Cap | 2 |
| 2 | Left Bearing Nut | 1 |
| 3 | 15x28x7 Bearing, 1 Pcs | 1 |
| 4 | Hub Shell | 1 |
| 5 | Axle | 1 |
| 6 | Right Bearing Nut | 1 |
| 7 | Freehub Nut | 1 |
| 8 | Freehub Carrier | 1 |
| 9 | Freehub Seal | 1 |
| 10 | 1/8″ x 25pcs loose ball bearing | 2 |
| 11 | Pawl | 3 |
| 12 | Spring | 1 |
| 13 | Large Spacer | 1 |
| 14 | Small Spacer | 1 |
| 15 | 11spd Freehub Body | 1 |
| 16 | Cassette Spacer | 1 |
| 17 | Bearing Race | 1 |
| 18 | 15x26x7 Bearing | 1 |
| 19 | Freehub Dust Seal | 1 |
W TB P a r ts / Se rvic e Kits
Part Number| Description| No
W035-0133| 15x28x7 Bearing, 1 Pcs| 3
W035-0146| Serra Shimano HGR mtn/road Axle for 12×148 hub| 5
W035-0148| Serra Shimano HGR mtn/road Freehub Kit for 12×142/148 hub| 20
W035-0156| Serra Shimano Freehub Nut| 7
W035-0147| Serra Shimano HGR mtn/road End Cap Kit for 12×142/148 hub| 21
WTB Serra
12 x 157 Rear Hub
W135-0635 Serra 12×157 (32 hole) Shimano HG mtn
| No | Description | Qty |
|---|---|---|
| 1 | M12 End Cap | 2 |
| 2 | Left Bearing Nut | 1 |
| 3 | 15x28x7 Bearing, 1 Pcs | 1 |
| 4 | Hub shell | 1 |
| 5 | Axle | 1 |
| 6 | Right Bearing Nut | 1 |
| 7 | Freehub Nut | 1 |
| 8 | Freehub Carrier | 1 |
| 9 | Freehub Seal | 1 |
| 10 | 1/8″ x 25pcs loose ball bearing | 2 |
| 11 | Pawl | 3 |
| 12 | Spring | 1 |
| 13 | Large Spacer | 1 |
| 14 | Small Spacer | 1 |
| 15 | Shimano Freehub | 1 |
| 16 | Bearing Race | 1 |
| 17 | 15x26x7 Bearing | 1 |
| 18 | Freehub Dust Seal | 1 |
W TB P a r ts / Se rvic e Kits
Part Number| Description| No
W035-0133| 15x28x7 Bearing, 1 Pcs| 3
W035-0150| Serra Shimano HG mtn Axle for 12×157 hub| 5
W035-0134| Serra Shimano HG mtn Freehub Kit for 12×157 hub| 19
W035-0156| Serra Shimano Freehub Nut| 7
W035-0131| Serra Shimano HG mtn 12×142/148/157 End Cap Kit| 20
WTB Serra
QR x 135 Rear Hub
W135-0709 Serra QR x 135 (32 hole) Shimano HGR mtn/road
| No | Description | Qty |
|---|---|---|
| 1 | Grip Ring | 2 |
| 2 | Left End Cap | 1 |
| 3 | 10x26x8 Bearing | 2 |
| 4 | Hub Shell | 1 |
| 5 | Axle | 1 |
| 6 | Drive Side End Cap | 1 |
| 7 | Freehub Spacer | 1 |
| 8 | Freehub Carrier | 1 |
| 9 | Freehub Seal | 1 |
| 10 | 1/8″ x 25pcs loose ball bearing | 2 |
| 11 | Pawl | 3 |
| 12 | Spring | 1 |
| 13 | Large Spacer | 1 |
| 14 | Shimano Freehub | 1 |
| 15 | Cassette Spacer | 1 |
| 16 | Bearing Race | 1 |
| 17 | Freehub Dust Seal | 1 |
W TB P a r ts / S e rvic e K its
Part Number| Description| No
W035-0161| 10x26x8 Bearing, 1 pcs| 3
W035-0160| Serra Shimano HGR mtn/road Axle for QRx135 hub| 5
W035-0159| Serra End Cap Kit for QRx135 hub| 18
W035-0158| Serra Shimano HGR mtn/road Freehub Kit for QRx135 hub| 19
WTB Serra
QR x 141 Rear Hub
W135-0638 Serra QR x 141 (32 hole) Shimano HG mtn
| No | Description | Qty |
|---|---|---|
| 1 | Locknut | 2 |
| 2 | 1.5mm x 19mm Spacer | 1 |
| 3 | Steel Dust Guard | 1 |
| 4 | Bearing Nut | 2 |
| 5 | Rubber Dust Seal | 1 |
| 6 | Bearing retaining ring | 1 |
| 7 | 1/4″ x 9pcs loose ball bearing | 2 |
| 8 | Bearing Race | 1 |
| 9 | Hub Shell | 1 |
| 10 | Axle | 1 |
| 11 | Freehub Bearing Seal | 1 |
| 12 | 1.0mm x 19mm Spacer | 1 |
| 13 | Freehub Spacer | 1 |
| 14 | Freehub Carrier | 1 |
| 15 | Freehub Seal | 1 |
| 16 | 1/8″ x 25pcs loose ball bearing | 2 |
| 17 | Pawl | 3 |
| 18 | Spring | 1 |
| 19 | Large Spacer | 1 |
| 20 | Shimano Freehub | 1 |
| 21 | Bearing Race | 1 |
| 22 | Freehub bearing retaining ring | 1 |
W TB P a r ts / S e r vic e K its
Part Number| Description| No.
W035-0138| Serra Axle and Small Parts Kit for QRx141 hub| 23
W035-0139| Serra Axle for QRx141 hub| 10
W035-0153| Serra Hub Bearing and Retaining Ring Kit for QRx141 hub| 24
W035-0141| Serra Shimano HG mtn Freehub Kit for QRx141 hub| 25
Adjusting the bearings
Serra front hubs do not require bearing adjustment. There will be a small
amount of play in each hub when it is not tightened down in a frame or fork,
which is normal. When an axle tightens down on the hub, the components will
compress slightly and eliminate any play.
Serra rear hubs utilize bearing nuts and end caps on each of the axle in order
to achieve proper adjustment. The inner bearing nuts should be tightened down
using 17mm cone wrenches until they barely touch the bearing. There is no need
to tighten past this point. Poor performance and increased wear will result if
the adjustment is too tight (or too loose). The end cap is then tightened
against the bearing nut with a 17mm cone wrench until it is snug against the
bearing nut. It is important to hold the bearing nut in place while tightening
down the end cap in order to prevent the bearing nut from spinning and putting
too much pressure on the bearings. Serra freehubs come pre-adjusted; do not
attempt to adjust the bearing load within the freehub body.
Disassembling the hubs
Front hub:
To simplify their removal and installation, end caps (1,7,8,9) are held on the
hub shell (5) using a slip fit and O-rings (2,3). To remove the end caps,
securely hold the hub shell with one hand (do not clamp in a vise) and pull
them from the hub using your other hand. An alternating side-to-side motion
often aids in end cap removal. Once the end caps have been removed, the
O-rings can also be removed and cleaned. The bearings (4) in the hub shell
should now be exposed, allowing you to thoroughly clean the area. The bearings
are not serviceable and therefore must be replaced if they exhibit signs of
wear. Removal and installation of the bearings requires specific/expensive
tools in order to prevent damage to the hub shell or bearings. WTB strongly
suggests taking your hub(s) to a local bike shop to have the bearings replaced
if they are worn or creaking. To reinstall the end caps, reinstall the O-rings
on the end caps and slide the end caps onto the hub’s axle (6) until they
bottom out.
Rear hub:
The axle (5) is retained within the hub shell using bearing nuts and end caps
(1,2,6) which accept 17mm cone wrenches. The end caps (1) are the outermost
components/nuts on axle of the hub. To remove them, it is important to always
hold the bearing nut (2,6) in place with one cone wrench and loosen the end
cap from the bearing nut with another cone wrench. The first step is removing
the drive side end cap. Access to the bearing nut (6) is protected by the
freehub body (15) on the drive side and therefore you must hold the bearing
nut (2) on the non-drive side using a 17mm cone wrench while loosening the end
cap on the drive side with another 17mm cone wrench. Remove the drive side end
cap and remove the bearing nut on the same side. Once the bearing nuts have
been removed, the dust seal (18) can also be removed, thereby exposing the
bearings (3,17) in the hub shell (4) and freehub (19).
The freehub is removed from the hub using a 14mm hex key once both the bearing nut and end cap are removed from the drive side. Insert the 14mm hex key into the non-drive side of the hub and slide it through until it engages with the freehub body carrier (8) on the drive side. Looking at the non-drive side of the shell, rotate the 14mm hex key clockwise to remove it from the hub shell. Removal and installation of the bearings require specific/expensive tools in order to prevent damage to the hub shell or bearings themselves. WTB strongly suggests taking your hub(s) to a local bike shop to have the bearings replaced if they are worn or creaking. To reinstall the freehub, bearing nuts, and end caps, follow the above steps, but in reverse order. When installing a freehub, the pawls (11) may interfere with inserting the freehub into the hub shell. To aid in the reinstallation of the freehub, spin it around the axle while using a small hex key (~2mm) to push the pawls in as the freehub is rotated and pressed onto the hub shell.
Contact Information
If you have any questions or problems with any WTB product, please contact WTB
through wtb.com or info@wtb.com.
Disclaimer
The original English language version/meaning of these instructions supersedes
all translations. WTB is not responsible for any errors in the translation of
these or any other product instructions.