I use schrader valves
(car style) in preference to Presta as they're a much better fit in the larger GM valve holes.
![](https://howirollsports.com/wp-content/uploads/2019/02/Presta-vs-schrader-wheelchair-tube-valve.png)
A schrader valve also allows you to easily remove the valve core to enable
slime sealant to be pumped into the tube to give better long-term protection against punctures and slow air leakage.
With the deep "V" GM rims, a longer stem is always preferable to a short one, as it is better to have too much valve protruding from the rim than too little.
![Wink ;)](https://goldenmotor.com/SMF/Smileys/default/wink.gif)
I have used shorter 40mm schrader valves but they can be very difficult to inflate from flat as they will easily push back into the rim.
I would always use a screw on extension to prevent this from happening and then remove it once the tyre had been properly inflated to hold the valve in its correct position.
![](https://ae01.alicdn.com/kf/H4810ed53d39347f9bd9595e8f2cdc1f2z.jpg)
Check out
this video for more information on inner tubes.
Alan