i Filled my back tire cause it was low, back to 40 psi two days ago. i just i checked it and its at 30 psi.
Should i replace the tire? or just patch it? a friend told me that with its better to just replace it and if i patch it i shouldnt go over 80mph with that tire..... its stil got alot of tread on it.... what should i do?

 

We had a big discussion about this recently. I recommend just putting on a new tire but you can get away with a patch depending on where it's punctured. Have a shop put in a good quality plug if you do that.

 

THis has been discussed alot. I personally have had two plugs in my back tire for almost a year.
There are plenty of people that have had no problems. Many people will say not to, but have no evidence to say there is a problem.
They make bike specific plugs also. I plugged my tire myself and have lost no air. They are safe, and if they "fail"
air just leaks out. The plug basicy become part of the tire after one good ride.

 

If it were me, I'd replace it.

 

Again, tons of people say to replace it, but have no evidence to show that a plug is unwise. If you have money to burn, buy a new tire and I'll take the one you are going to throw out and put a couple thousand miles on it.

 

it depends on how bad the leak is and where the leak is. personally i would patch it only if it was a very small leak in the center of the tread. if it was on the lean area, i wouldn't bother. i'd replace. they do make tubeless tire repair patch kits, but i'd only also use that as a temporary solution (again, depending on how bad the leak was)

 

Depends on how much money you have. If you can afford a new tire, thats the best way to go. If your on a budget, plug it and drive safe. As Michellin says it, the only thing between you and the ground is your tires, they're alot riding on it.