05/09/2018
Sinter the Dragon: Addressing the H-D Street 750's Weakest Link
The Harley-Davidson Street 750, while lauded for its innovative 60-degree V-Twin engine and overall value, has consistently been criticised for a rather underwhelming front brake. Many riders and reviewers have noted a distinct lack of stopping power, often describing the feel as 'weak and wooden'. This is particularly disappointing on a motorcycle that otherwise offers an engaging riding experience. In an effort to address this common complaint, we looked to Scandinavian Brake Systems (SBS) for a solution, specifically their sinter pads, to see if they could transform the Street 750's weakest link into a strength.
Our journey began with the stock ceramic pads on the Harley-Davidson Street 750. While ceramic pads are generally known for their longevity, reduced rotor wear, and quieter operation, these benefits often come at the cost of outright stopping performance, especially under demanding conditions. For an entry-level motorcycle like the Street 750, Harley-Davidson might have opted for a less aggressive brake setup, perhaps to protect newer riders from accidentally locking up the front wheel. However, for those seeking more confidence and capability, the stock setup proved to be a significant letdown.
Initial Impressions of Stock and SBS Ceramic Pads
Upon installing the SBS 924H.HF Ceramic pads, a slight improvement in braking power was observed. However, the difference was marginal, barely noticeable for riders accustomed to more potent braking systems. Even with a firm two-finger squeeze, achieving significant tire squeal required a substantial effort, and locking the front wheel was still challenging. Furthermore, during repeated stops from higher speeds, both the stock ceramic pads and the SBS ceramics exhibited fade, indicating an inability to dissipate heat effectively. This lack of consistent performance highlighted the limitations of ceramic compounds in this application.
To illustrate the difference in heat management, consider the following:
| Pad Type | Initial Bite | Stopping Power (Two Fingers) | Fade Resistance | Rotor Wear (Est.) | Noise/Dust |
|---|---|---|---|---|---|
| Stock Ceramic | Moderate | Requires strong squeeze for chirp | Poor at higher speeds | Low | Low |
| SBS Ceramic H.HF | Slightly Better | Manly squeeze for chirp, 3 fingers for lock-up | Poor at higher speeds | Low | Low |
| SBS Sinter 924H.LS | Excellent | Good two-finger squeeze for squeal | Significantly Reduced | Moderate | Moderate |
The visual evidence after use also supported these findings. The pads that most efficiently converted kinetic energy into heat were clearly the sinter pads, as indicated by their wear patterns and composition.
The Sintered Solution: SBS 924H.LS
The real transformation occurred when we swapped the ceramic pads for the SBS 924H.LS sinter pads. After a proper bedding-in period, the results were immediately apparent. Even without addressing potential air in the brake lines, the sinter pads provided a much firmer brake lever feel. A good two-finger squeeze was now sufficient to induce a satisfying front tire squeal, a testament to the enhanced grip and stopping power.
The most significant improvement, however, was the drastic reduction in brake fade. Stopping from 80 mph became a far more confident experience, with substantial deceleration maintained right up to the final feet before a complete stop. We estimate that the SBS sinter pads provide at least a 20% increase in braking power and shorten stopping distances by 10-15% from speeds above 60 mph. While perhaps still considered marginal on a sportbike, on a 505-pound cruiser like the Street 750, these pads transform the braking performance from merely 'passable' to genuinely effective, especially when used in conjunction with the rear brake as intended for cruisers.
Why Sinter Pads Excel
Sintered brake pads are manufactured by fusing metallic powders together under high pressure and temperature. This process creates a dense, durable friction material with excellent thermal conductivity and a high coefficient of friction. Here’s a breakdown of why they are often superior for performance braking:
- High Friction Coefficient: Sintered pads generally offer a stronger initial bite and more consistent stopping power across a wider temperature range.
- Excellent Heat Dissipation: The metallic composition allows heat to transfer away from the braking surface more efficiently, significantly reducing the likelihood of fade.
- Durability: Sintered pads are typically more resistant to wear, especially under demanding conditions, leading to a longer service life.
- Consistent Performance: They provide reliable stopping power in both wet and dry conditions, offering greater rider confidence.
Potential Downsides of Sinter Pads
While sinter pads offer significant advantages, it's important to be aware of potential trade-offs:
- Rotor Wear: The harder, more aggressive nature of sintered materials can lead to increased wear on brake rotors compared to softer ceramic or organic pads.
- Noise: Sintered pads can sometimes be noisier, particularly during light braking, due to the metallic composition.
- Dust: They may produce more brake dust than ceramic pads, though this is often a minor concern for riders prioritising performance.
Bedding-In Sinter Pads
Properly bedding-in new brake pads is crucial for optimal performance and longevity. For SBS sinter pads, a typical procedure involves:
- Initial Gentle Stops: Make several moderate stops from around 25-30 mph, gradually increasing the pressure but avoiding full-on emergency stops. Allow the brakes to cool completely between stops.
- Moderate Stops: Progress to a few stops from 40-50 mph, applying moderate lever pressure. Again, allow for cooling periods.
- High-Speed Stops (Carefully): Perform a few harder stops from higher speeds (e.g., 60-70 mph), but do not lock the wheels. The goal is to transfer a thin layer of pad material to the rotor surface.
- Cool Down: After the final stops, ride for a few minutes without using the brakes excessively to allow them to cool down fully.
This process ensures that the pad material is properly married to the rotor surface, maximising friction and minimising the risk of glazing or uneven wear.
Frequently Asked Questions
Q1: Are SBS sinter pads suitable for all riding conditions?
SBS sinter pads are generally excellent for most road riding conditions, offering superior stopping power and fade resistance. However, for very light commuting or if absolute silence and minimal dust are paramount, other compounds might be considered. For performance-oriented riding, they are highly recommended.
Q2: Will SBS sinter pads damage my brake rotors?
While sinter pads are more aggressive than ceramic pads, the wear on rotors is generally manageable, especially with regular maintenance. The increased stopping power and safety often outweigh the slightly accelerated rotor wear for many riders.
Q3: How do SBS sinter pads compare to the stock Harley-Davidson pads?
SBS sinter pads offer a significant upgrade in terms of stopping power, lever feel, and fade resistance compared to the stock ceramic pads on the Street 750. They provide a much more confidence-inspiring braking experience.
Q4: Is it difficult to install new brake pads?
Brake pad replacement is a relatively straightforward maintenance task for those with basic mechanical aptitude. However, if you are unsure, it is always best to have a qualified mechanic perform the installation to ensure safety and correctness.
Conclusion
For owners of the Harley-Davidson Street 750 (and 500) seeking a tangible improvement in braking performance, the SBS 924H.LS sinter pads are a highly recommended upgrade. They effectively address the bike's notorious weak front brake, providing a firmer lever, significantly better stopping power, and greatly reduced fade. While the stock ceramic pads offer quiet and clean operation, they fall short when it comes to delivering the confidence and capability that many riders desire. The SBS sinter pads bridge this gap, transforming the Street 750 into a much more assured and enjoyable machine to ride, especially when the need to stop quickly arises.
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