Presta vs Shrader Valves - Fit both!
The old Shrader valve versus Presta Valve debate. You don't know which type to fit. Maybe you are sick of getting punctures? Getting a puncture on the rear wheel can be really annoying because you have to drop the rear wheel and play around disengaging the chain from the gear clusters. This always results in your hands getting oily.
In this project we look at fitting dual tubes to a bicycle wheel. This allows you to run with one tube pumped up and the other left flat. Then if you get a puncture, you pump up the spare tube and keep riding. It also allows you to fit one Presta valve tube and one Shrader valve tube.
Unfortunately all rims do not come with another hole for the second tube's valve so we will have to drill one. On aluminium rims, this is not a major problem. The hole has to be directly opposite the current valve hole.
In order to fit another tube, we need to mark where the hole will be drilled, which is directly opposite the current valve hole.
Marking a hole so we can drill a hole for our second tube.
After the hole has been drilled for the second valve
Once the hole has been drilled a small hole will also need to made into the spoke protection liner which covers the spoke heads. This is necessary to allow the second tube's valve to fit. Once this is done the tyre can be placed back onto the rim.
View showing the two tubes in the tyre.
Inserting the tubes is rather tricky as both tubes need to cross each other twice. The point that they cross is halfway between the two valve holes on both sides of the rim. This is at 90 degrees to the valve holes.
View showing both tubes in the tyre,
It was a bit of a squeeze trying to fit two thorn resistant tubes so we fitted a standard tube and a thorn resistant tube. You then need to pump up only one tube as the other will remain deflated until it is needed. Because we only had Shrader valve tubes in stock, we couldn't show the end result of a Presta and a Shrader valve.
Having the tubes cross each other also has the added benefit of the deflated tube acting as a tyre liner and giving protection to the inflated tube on half of the wheel.
You would only puncture both tubes if you took a large nail through the tyre that went through both tubes. We tested this, but the mountain bike tyre stopped the nail reaching the tubes. We did discover after some experimenting that it is possible to puncture the deflated tube and not the inflated one. This is because on half of the wheel, the deflated tube is on the outside of the inflated tube thus acting as a tyre liner.
Having this set up on a mountain bike wheel it was hard to tell if there was any bump at the point where the tubes crossed. This may be noticeable on a racing tyre but we haven't experimented with this as the second tube would add unnecessary weight.
We have successfully tested this dual tube wheel and have not had any problems with it. We were unable to actually puncture a tube in normal riding conditions, so we went for a ride and deliberately punctured the tyre with a rather large nail.
After the tyre went flat, we just pumped up the second tube and kept riding. This is another world first, brought to you by the team at BicycleWA. Patents Pending!
It also allows you to use one Shrader valve tube and one Presta valve tube if you can't decide which one to use, and solves that long running argument over which one is better. Play it safe and use one of each.
