I just reshoed the Trek 520 with a pair of 700x32 Marathons. What is the correct tire pressure? THX!

Which Marathon? The min and max pressure is stated on the sidewalls. I have 700x32 Marathon Plus HS348, min is 55 psi and max is 95 psi, I run mine at 80psi. I arrived at this number by trying. Higher and the ride is too hard, lower and it's too soft. Sometimes you need to try what suits you best within the specs.

I just checked my "regular" Marathons and the max and min pressures are the same as AdamDZ Plus's. I also ran mine in the neighborhood of 80-85 (they are off the bike right now). I think the correct pressure depends on the gross weight of the bike, rider, and gear. My uderstanding is --the heavier, the more pressure.

There is no need to exceed 75psi if bike + rider is less than 200 lbs. Maxing out the pressure may net an extra 0.5 mph at the expense of a much harsher ride on smooth road. If the road is bumpy, then your speed may go down because the bike is bouncing like a ping pong ball...loss of traction.

varies according to load, front has less than rear. 150lb rider doesn't need as much as 200lb rider so asking what is correct is like asking what is the right size of pants to buy. 10psi difference front to rear is reasonable.

THX for the help. I put them up to 80 pound figuring that would be in the ball park. By the way, the regular Marathons, not one of the heavier plus tires. I'l see how thes work as they are replacing a great pair of Conti TT2000s. One flat with those tires! great tires!

Oh, and there is nothing on the sidewall of the Marathons that makes sence to me. Something like 3.5 bars to 6.5 bars.

I weigh in at 220, so I'm going to run them at 80 and see how it goes.

and of course not all tubes hold pressure for the same length of time. Some tubes might hold 80psi for a week and some might go down to 65psi in a couple of days. I got used to thumping the tire for a particular tone after pumping it up with the floor pump to a particular psi. After a few months doing this you get familiar with the sound the tire makes and it becomes second nature to hit the front and back tire before riding as a rough check.

tom: bar is a measure of atmospheric pressure--roughly 14.7psi at sea level. That makes the 3.5-6.5 bar rating roughly 50-95 psi. Using the 15% drop suggested, this would be right about 80 psi, so you should be fine. Ride it for a time to see how they feel unloaded, and you can always adjust up or down as necessary.

FYI: I'm 190lbs, the bike is 35lbs and I carried about 60lbs of gear and supplies and 80psi worked for me.

Another POI - I run Marathon Supremes (85PSI tires) at 90-92#. The difference in roll is amazing - though higher pressures don't improve it any more.

I'm 190#, bike is 42# as normally loaded.

I run a 35 on the front, and a 40 on the rear.

Good stuff!!! Now I know what bar means.

I rode the bike, unloaded, at 80 pounds and the ride was smooth. This is my first time back on this bike in two years as i prepare to do some touring. Compared to the bike I've been riding, a Lemond Zurich, the 520 was slow. Which is exactly what I expected. By the way, for anyone here looking for a comfy fast road bike, a Lemond Zurich spine bike is highly recommended, if you can find one.

On with the rest of the pre- tour prep. next up, a final decision on new bags or a trailer?

THX for the help!

tom: I like my trailer for local and domestic tours, but would probably opt for the racks/panniers if I were planning any tours where I had to box and ship my rig.

Try out different pressure front/back. I could see with 220lbs and another 30lbs on the rear that it would be worth bumping up the rear to 85-90 and the front to 75-80. Can't help on the trailer/bags issue but it would help to specify the size of your total load before deciding.

THX guys.

The bags/trailer - never ending debate around here. Unfortunately no way to demo ride both options. Probably buy both and use a combo on different trips. Those trips are starting with some short local stuff around south jersey and the jersey shore and then ranging out to the delmarva. if things go well, there's NJ to Key West. We'll see!

I'll play with the pressures to see how it affects the ride. Anyone know of an accurate bike tire gauge for Presta valves?