Tune GumGum stem Expander 1 1/8" 7g

GumGum is our only part made out of silicone. It serves as expander in the steerer and spares the carbonsurface. With its only seven gram it undercuts naturally every standard expander. It fits into bore diameter from 24 upto 25.5 mm.
How does it work? Stick the GumGum with the nitril rubber, the separator sheet and the thread sheet together, put it into the shaft and tighten it, ready. Why it is so easy? As the silicone rubber gets pressed together and pressed towards the head tube and blocks when screwing on. Quasi like a brake pad. Just the same easy it gets removed. Suitable for carbon steerer.

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• Material: silicone, aluminium and nitrile rubber
• Head tube: from 24 to 25.5 mm
• Weight: 7 g

Functional principle: while justifying the head tube the silicone rubber gets pressed together towards the steerer. During the conversion process, the GumGum is easily removable.