Due to the material characteristics, the steer tubes of Brompton titanium forks are known to deform and/or fracture, particularly when the quill stem bolts are over tightened. Riding with a fractured steerer is dangerous.
We have developed reinforcement steel sleeves that fit over the steer tubes of the titanium forks. With minimum weight penalty, the added strength will provide positive feedbacks while tightening the quill bolts whether by hand or by torque wrench, thus prevents inadvertent overtightening that results in the cracking of steer tubes.
The sleeves are made from seamless mid-carbon steel tubing precisely machined to be within 1/10th of a millimeter of the Titanium steerer diameter. Due to this tight tolerance, if your steer tube is already deformed from over tightening, you may need the optional tool to press in the sleeve.
For different strength requirement, two versions of sleeves are available.
1.0mm wall thickness – 55g ± 1g, $12.5
2.0mm wall thickness – 105g ± 1g, $13.5
The installation of the steer tube sleeves are recommended during headset service or replacement. The procedure for undamaged/non-deformed forks are relatively straight forwarded, as followed:
1. Install the lower headset cup on to the head tube (frame) as normal. If you don’t have the tool to press in headset cup, the optional sleeve tool can be used for this purpose.
2. Install the bearing race, and bearing on to the fork steering tube as normal.
3. Insert the fork steerer through the head tube, and then insert the reinforcement sleeve from above.
4. Install the upper headset cup on to the head tube. If you don’t have the tool to press in headset cup, the optional sleeve tool can be used for this purpose. Install the remainder of headset assembly as normal.
If the forks steering tube is already deformed, such as having developed a bulge, then the lower section of the headset parts will need to be installed on to the fork first, and the reinforcement sleeve needs to be pressed in using the sleeve tool. Then the forks, together with the lower headset parts, is installed on the bike, followed by the upper portion of the headset.
In the future should you need to remove the reinforcement sleeve that was pressed in, a special tool will also be need. Please contact us in such case. If your fork steer tube was undamaged to start with, then when the stem is removed, the reinforcement sleeve will simply slide out.
Finally, please note that the reinforcement sleeves are meant to prevent the titanium steer from deformation and cracking, and not meant as a remedy for already cracked steer.