HEL Performance have pulled out all the stops when developing their carbon fibre brake pad shims for BMW 1 Series F20, F21 all models including M135i and M140i with Brembo 4 piston calipers 2010-on. They've used the finest carbon fibre, combined with an exclusive resin which is non-combustible and thermally resistant to temperatures over 400°C (752°F). This special resin cures an attractive yellow or orange depending on the batch.
These don't just look the part though: initial testing carried out by a professional racing driver in various road and track conditions showed a huge average temperature drop of 49°C (120.2°F) on the front calipers.
HEL carbon fibre shims come in at a super-lightweight 3.5 grams per shim, compared to weighty titanium which are a typical 17 grams per shim. That's a dramatic 79% weight saving.
That's not the only comparison which makes titanium inferior though: carbon fibre also has a much lower heat conduction compared to titanium (1W/mK compared to 22W/mK for titanium and 65W/mK for steel). Anything that helps reduce the temperature and increase efficiency of brake components is a good thing, especially as caliper seals are at risk of being damaged when they get too hot.
Installing these carbon fibre brake pad shims will certainly inspire confidence that when you brake aggressively, all the components are being kept cool and working at their best.
You can also re-use the shims when changing pads, as long as they're in a good condition.
| Standard | HEL Carbon Fibre Shims | Difference | |
| Front Right | 217.8°C | 165.6°C | ↓ 52.2°C (24%) |
| Front Left | 224.8°C | 178.9°C | ↓ 45.9°C (20.4%) |
| Rear Right | 138.9°C | 116.6°C | ↓ 22.3°C (16.1%) |
| Rear Left | 131.1°C | 113.3°C | ↓ 17.8°C (13.6%) |
