so this is a second occurrance,

I ride tow ork, with no problems, park, outside, and when i come to ride home at 4, my front tire is flat.

The first time there was a very tiny hole facing the rim side, the second, most recent flat was a very long cut.

The most recent occurrence was a very hot day, and I pumped my front to what i rememmebered to be 5 psi over the max.

Does anyone have any ideas of why this is occurring?

I think someone is screwing with your bike.

A long cut? If it happened on your ride, you would have known within a minute.

A long cut on the inner tube, not on the tire

1. Check the tube side of your rim for any sharp protrusions and file/sand them if necessary,

2. make sure the spoke ends are in good condition and not poking the tube,

3. make sure the rim tape is of good quality and installed properly,

4. and make sure to reinstall the tube correctly or else it can pinch between the tire bead and rim, and thus tear in such a fashion so as to appear as a long, deliberate cut.

As for #4, it won't necessarily pop right away...

My last 2 flats also occured while parked at work, each time I suspected sabotage but both time the holes were on the rim side of the tube. My rim tape was in bad shape so I changed it. No other flat while parked since then.

The thing is that, as Ubergeek said, both time I wondered why It didn't go flat Under my weight while I was on the bike.

What kind of rim tape should I buy if I ride on 700 28c

You will find rim tape at any LBS, almost every tire manufacturer make rim tape.

I can't recommend you a specific brand as I'm a cheap ba****d and use electrical tape and put some baby powder in my tires when I put it on the Wheel.

If it works, it works.

I prefer the adhesive cotton type like Velox since it tends to stay put where the elastic type can slip out of place when reinstalling a stubborn tire. Really though, either are fine if installed properly.

You could use strips of duct tape or electrical tape (as mentioned), or even a strip of old innertube, but proper tape is cheap.

I never looked for it, I just thought that electrical tape would be cheaper. So how much for good rim tape? approx.

I've had people deflate my tires while working before but never puncture them.. the damage is all on the rim side of the tubes?!?!

Is your bike sitting in the sun? That's going to raise the air pressure in the tube by at least 5-10psi. Too much pressure = pop.

I dunno, maybe five to seven bucks for enough for both wheels. Not as cheap as electrical tape which most of us probably have on hand anyway, but IME electrical tape's adhesive gets gummy and loose and just sorta gets to be a hassle after a while. I say this as someone who has had to fix way more than my fair share of flats due to once living in goathead-ville -- when pulling the tube the elec. tape would often come with it, and that's just adding a minor insult to injury...

If you only have to fix a flat once in a blue moon then electrical tape probably won't ever be a problem as long as it stays lined up right when reinstalling the tire, but good tape is something that requires no further consideration unless you need to get under it to fix a spoke or something.

That's why I alway put a bit of baby powder in the tires.

Could be your rim tape. Easy and cheap fix at about 5-7 bucks. How old are your tires? Are beads still in good condition? Mine were not. One flat due to the lack of rim tape in one area and the next flat was because the bead started to fall apart.

My bike is almost 5 months old

Time to get a new one !!!

Two other things to consider.

1) If you feel the need to inflate the tire over its recommended max, you will be better off with a wider tire.
2) It might be due to poor quality tubes that are failing when getting baked in the summer sun. If you start the morning, with an over pressure tire, it is possible that the temperature increase during the day is causing enough increase in pressure to rupture the tube (the slit you noticed)...

Personally, I like schwalbe tubes and velox rim tape... both of which I get from Amazon.com

I went through a period last fall where I had half a dozen flats in about 3 weeks. All but one while the bike was parked at home. Started to wonder if the cats were puncturing them. Since then, no problem. Sometimes, they just run in streaks.

Sounds like a combo of cheap tubes and bad rim strips. Pull off your tire/tube and check to see that all the holes for the spoke nipples and spoke nipples themselves are deburred, if not, go ahead and care care of that. Then get a quality rim strip of the appropriate width. I see a lot of "split tubes" that are a result of bad rimstrips and poor factory QC.

piece of glass stuck in tire?

Too much air and heat make it expand.

+1
Velox is the only stuff I use. $5/wheel,but you only have to do it once and I've never had a failure.