Shimano Ultegra ST-6510: 2/3x9 STI levers - repair and reconditioning

Shimano Ultegra ST-6510 STI 9-speed

Shimano Ultegra ST-6510 are road STI levers integrating braking and shifting. They belong to the 9-speed Ultegra generation and can be found on double or triple chainring setups depending on the version. They remain sought after for road bikes from the late 1990s and early 2000s, especially for restorations and bikes still in regular use.

Common problems with ST-6510

Over time, the original grease can harden, trap dust, and slow down the internal pawls. The lever may then no longer engage correctly, become stiff, not return to normal, or only work in one direction. A clicking failure does not necessarily mean that a part is broken.

Disassembly and reassembly of Shimano Ultegra ST-6500 / ST-6501 / ST-6510

The mechanisms of Shimano Ultegra ST-6500, ST-6501, and ST-6510 are more delicate to disassemble and reassemble than some older models. A large part of the mechanism is free once opened, which requires more precision and care to avoid displacing small parts from their original position.

One of the most important points for the proper functioning of the lever is the correct positioning of the return spring. This spring allows the toothed part of the mechanism to return to its initial position. It must be correctly positioned and tensioned, without excessive pre-tension.

The part I most often find damaged in this mechanism is a thin washer located directly above this spring. When it is deformed, even slightly, it can prevent the mechanism from working properly and block shifting.

Another delicate step involves reassembling the black washer located between the toothed elements. It must be correctly engaged on its support point while maintaining the spring tension. This operation requires working progressively to maintain the alignment of the different parts.

Reassembling the brake lever is also particular. To properly re-tension the spring and position it on the lug that maintains this tension, I use a string, which allows me to pull the spring with enough control during assembly.

On these models, the difficulty therefore comes not only from cleaning the mechanism, but especially from respecting the exact position of the washers, gears, and springs during reassembly. A single misplaced or slightly deformed part can be enough to prevent shifting.

Repair and reconditioning

Reconditioning consists of disassembling the necessary elements of the mechanism, removing old grease and deposits, checking the pawls, springs, pivots, and contact surfaces, lubricating correctly, then reassembling and testing the shifting.

When the essential parts are intact, this type of intervention often allows an ST-6510 to be restored to reliable operation without replacing the entire lever.

Shimano Ultegra ST-6510 Features

Series: Shimano Ultegra 6500
Reference: ST-6510
Type: Integrated brake/shifter STI levers
Drivetrain: 9-speed rear
Front: 2 or 3 chainring versions depending on configuration
Usage: Road bike
System: Flight Deck depending on version

Buy reconditioned Shimano ST-6510

Availability changes depending on the levers I acquire, repair, and recondition.

See currently available Shimano Ultegra ST-6510

Have ST-6510 levers repaired

If your Shimano Ultegra ST-6510 levers are no longer shifting correctly, send the exact reference and a short description of the defect. Problems with hardened grease, seized pawls, or dirty mechanisms are often repairable.

Frequently asked questions

Are Shimano ST-6510 9-speed?

Yes. The ST-6510 is part of the 9-speed Ultegra road generation.

Are there ST-6510 for triple chainring?

Yes, depending on the version and configuration. It is important to check the exact reference and compatibility of the left lever before purchase or replacement.

What is the difference between ST-6500 and ST-6510?

Both belong to the same 9-speed Ultegra generation, but there are differences in version, configuration, and finish. The ST-6510 is often associated with Flight Deck variants and double or triple configurations depending on the lever.