Tubeless valve test - Stan's Exo Core: Cleverly designed high-flow tubeless valve
Stefan Frey
· 14.03.2026
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Sealant for tubeless systems - this is Stan's real hobbyhorse. Stan's launched the original tubeless sealant back in 2001. Since then, the formula has been continuously developed further. To match this, there are now also special tubeless valves that make the inflation process easier and prevent clogging. Their special design should also allow significantly more air to flow into the tyre.
To achieve this, Stan's uses a voluminous core that is screwed onto the outside of the valve stem. This should also make it easier to adjust the air pressure. Instead of pressing the core downwards, as is usual with Presta valves, the air flow is opened by turning the valve top.
The valve base has a total of 5 openings through which the sealing milk can flow into the tyre and also past tubeless inserts.
Stan's Tubeless Exo-Core Valve - Info
- Price: 54,95 Euro >> available here at a reduced price
- Weight: 6,84 gram
- Valve length: 49.15 millimetres
- Available lengths: Regular / Medium / Tall / Extra Tall
- Valve head: Own system, Presta-compatible
- Outlet openings / insert-compatible: 5 / yes
- Special features: Air release via twist function, special valve core with enlarged diameter, twist and pull cap, colour-customisable
Assembly & handling
The elongated rubber seal does not fit all rim profiles perfectly. In our test with a Newmen rim, we sometimes experienced slight air loss. The small nut has a slippery grip and is difficult to screw on with the integrated rubber seal. The valve base does not have an Allen key hole that could help when screwing in the valve.
On the other hand, we liked the way the tyre deflates. The external valve core is easy to screw on and can be finely adjusted. The further you open the valve, the more air flows through the valve.
Thanks to the special design, the tyre can also be filled with sealing milk without having to remove the core. If you want to maximise the air flow when fitting the tyre for the first time, the valve core can easily be unscrewed by hand. However, even with the core, we were only able to press all tubeless tyres in the test into the rim well with pressure from the floor pump.
Rating & Conclusion - Stan's Tubeless Exo-Core Valve
| Category | Grade |
| Weight (20%) | 2,5 |
| Handling (20%) | 2,3 |
| Airflow (30%) | 1,5 |
| Protection against clogging (30%) | 2,0 |
| Overall grade | 2,0 |
Conclusion: Stan's Tubeless Exo-Core Valve
The assembly of the Stan is a little more complicated because the knurled screw with integrated sealing ring runs slowly and there is no Allen insert in the base. However, the elaborate design with an external core pays off. Significantly more air flows through the valve and the handling when adjusting the air pressure is also pleasing. Milk can also be filled with the core in place and yet the Stan's is less prone to clogging. Coloured valve caps offer the option of customisation. Unfortunately quite expensive.
This is how we measured the air flow
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. At Stan's we measured an air loss of 78 per cent, at Reserve 87.4 per cent. The coreless Muc-Off 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
