Two consecutive rides, two flats. The first was in the back, the second in the front.

I weight 183 lb.

Redstone tires,,, psi range 90 to 110.

Ive been riding them at 90 psi.

Roads are covered with scattered gravel, but smooth.

First flat seemed like a puncture. Second was a pinch.

I have just ordered some kevlar reinforced tires. What can I do to prevent these constant flats?

Could just be coincidence. At your weight, more pressure might help prevent pinch flats. I'm not familiar with the tires; what size are you using?

What Kevlar-belted tires did you order?

RichC

the tires are 700x25.

I just bought a pair of Serfas Seca, in the same size.

You ought to check your rim strips too just to rule that possibility out as well. If the tape isn't covering the nipple holes completely, you'll flat after only a few miles.

It sounds like you know what caused the puncture (glass? nail?) and sometimes there's nothing you can do. A pinch flat would come from an installation error (tube caught between rim and bead) or from hitting something hard enought to compress the sidewall and tube against the rim. More pressure, bigger tires, stiffer sidewalls.

It really is possible that you would have had the same flats with any tire under the same circumstance. And it really is possible to go thousands of miles with no flats and then have a cluster of them, all for reasons that can be diagnosed but not avoided, with any tire.

I didn't even know Serfas made tires. I couldn't find any review on them, but the look like they have potential.

RichC