Lets face it, if your chain lets loose at 50+ mph, nothing is going to stop the damage that is about to occur. But at 50, there is much less stress on the chain then there is shifting from say 2-3 or 3-4, hard on the gas, bumping up and down in the woods.
Thats why I run as big of sprockets I can front and rear. I dont have to worry about boink-n rocks or logs in the rear, as I dont ride in the woods.
If I could make em work, Id run 18t front and 55t rear. There are several theories behind this.
1. The more teeth that engage with the chain at any given time cause less shock and stress on the chain and sprocket as your spreading the load across a broader area or links.
2. The more teeth that engage with the chain at any given time cause less shock and stress on the transmission and ultimately the clutch as their is less space between the teeth and chain links.
3. More links in the chain means a longer chain and larger sprockets means the chain bends less to circumvent the sprockets. Less bending = less energy to bend the chain = more HP to the rear wheels.
4. More links means the chain lasts longer as there are less links being engaged per revolution.
Take a look at your typical drag atv. They run as big of sprockets as they can find. The new billet banshee engine cases made by mattoon machine facilitate the use of 20t front sprockets now. Their HUGE. Not to mention it makes for an ever increasing options in final drive ratios.