Muc-Off has worked with the Big Bore Hybrid Valves a real block at the start. The brightly coloured anodised valves work in a completely new way. Instead of a core that prevents the flow of air, the British use a ball valve as we know it from taps.
This has several advantages: There are no internals that could get in the way of the air, and no insert needs to be removed to fill with sealing milk. The Hybrid Valves also have a special feature: they fit through classic Presta rim bores, but use Schrader dimensions for the valve head, which should further improve the air flow. This also makes it easy to top up at the petrol station - practical.
Disadvantage of the design: The weight is relatively high at almost 10 grams. The Big Bore Hybrid Tubeless Valves are available in four lengths and six colours. The scope of delivery also includes sealing rubbers for different rim shapes. An Allen key insert in the valve base helps with fitting.
Muc-Off Big Bore: The most important information
- Price: 45 Euro >> at Bike Components or Rose available at a reduced price
- Weight: 9,89 gram
- Valve length: 45 millimetres
- Available lengths: 30/35/45/60 millimetres
- Valve head: Schrader
- Outlet openings / insert-compatible: 5 / yes
- Special features: No valve core, ball valve, wide opening for filling with sealing milk, assembly tool, various sealing rubbers for different types of valve. sealing rubbers for various rim designs. rim designs
How the valve works
Fitting the Muc-Off valves is really easy. The slightly higher knurled nut runs smoothly over its thread, and you simply use a 4mm Allen key to tighten it. The conical rubber seal also fits most common rims - if not, other rubber options are included in the scope of delivery.
Unlike most tubeless valves, Muc-Off uses a Schrader head, which increases the air flow even further. The ball valve opens smoothly and also allows precise adjustment of the pressure - the wider you open the valve, the more air flows. Just like a water tap. If the valve opens accidentally off-road or in the event of contact with an obstacle, the seal in the dust cap prevents you from rolling on the rim a short time later.
It says Big Bore on the tyre and it's definitely high flow! The air flows into the tyre with almost no resistance - of course, there is no core to get in the way. Sealing milk can be easily filled through the wide opening, and if the ball valve needs to be removed, it can simply be unscrewed by hand.
Incidentally, no other valve offered more airflow in the test. After just 5 seconds, we could no longer measure any pressure in our 29 x 2.4 test tyre!
Our conclusion - Muc-Off Big Bore Hybrid Tubeless Valve
| Category | Grade |
| Weight (20%) | 4,0 |
| Handling (20%) | 1,1 |
| Airflow (30%) | 0,5 |
| Protection against clogging (30%) | 1,0 |
| Overall grade | 1,5 |
Conclusion: Muc-Off Big Bore Hybrid Tubeless Valve
By dispensing with a core, the Muc-Off achieves maximum airflow. The ball valve is also easy to operate and effectively prevents clogging. The wide knurled nut and a 4-piece Allen insert in the valve base make installation easier. Sealing milk can be easily filled in via the wide opening. Please note: only suitable for Schrader pump heads, but can also be used for the initial fitting of tubeless tyres.
The air flow - how we measure
To find out which valve offers the best airflow, we carried out extensive series of measurements. However, the effect can be most clearly demonstrated directly on the wheel. The basis is a 29 x 2.4 inch wide MTB tyre, which is inflated to 2.0 bar using a digital pressure gauge. In several runs, we measured how much air escapes in five seconds when each valve is fully open.
While all Presta valves - with deviations of +/- 2 per cent - are in the range of 34.1 per cent, twice the amount of air flows through the Topeak valve in the same time. With Stan's Exo-Core we measured an air loss of 78 per cent, with Reserve 87.4 per cent. The coreless Muc-Off Big Bore Hybrid achieves 100 percent air flow, which means that after five seconds there was no measurable pressure left in the tyre. This makes it by far the best tyre in this comparison.
Stefan Frey
Editor
