Supposed to get my new bike next week. I will be putting these GP 4000s tires (120 psi Max) on it and wondered what tire pressure I should go for on the rear and front tire.

I'm 6' 2 3/4'' and 205 lbs. The bike is supposed to weigh about 20-21 lbs.

Also, is there a good pressure gauge out there for presta valves other than those already attached to a pump?

Thank you!

They are now finding high pressure is over rated, I never do 120, 110 rear 105 front works smoother for me with no feeling of roll reduction whatsoever. and I am 220 right now.

I just pump with pump gauge, why need another?

+2....for 2 correct answers.

I have a new set about 150 miles on Vred Tri Comps and I ran them today at 130 rear and 120 in the front. I am about 178 6'2 and I like them to be pretty high, the ride was smooth and better than my last tires with about 115 psi. I may try them someday at 140-45 but probably not neccessary.

There are all sorts of theories and formulae, but my tires are rated for 130# and I pump 'em up to 125-130. I'm 160 pounds on a 18 pound bike.

I've often wondered where anyone gets the idea that running 130 psi is the correct pressure to use. I've seen numerous articles giving tire pressure recommendations based on testing, such as this one from Frank Berto who used to equipment tests back when Bicycling magazine still did actual testing; and I've never seen 125 lbs recommended for a 178 lb bike/rider combination. I think the high pressure myth just gets passed around by word of mouth unfettered by all evidence to the contrary.

So using this chart the OP's 225 lb load means 112 lbs per wheel (the chart uses per wheel loading) that which indicates 120 psi for a 23mm tire.

At 225 lbs, and that will go up a few lbs with water, tools etc; you should be considering running the largest width tires your bike will fit. Like 28mm. Big men warrant big tires. Larger tires at lower pressure will give you a more comfortable and faster ride on any kind of pavement that is less than perfect.

I have been running mine at about 28psi, tubeless, but I've been thinking that I can get away with low 20's, because I didn't smack the rims all last summer...oh, wait, this is the Road Bike forum...well, then.

Sheldon wrote about it. The takeaway is that you can easily overinflate your tires and they'll start to bounce on little bumps (like seal coat) and you'll see a reduction in speed because you are constantly losing a little traction. A more detailed workup for you engineers can be found here and the most detailed CRR study can be found here. Keep in mind that the CRR data collected here were taken from a smooth roller so the real world issue of tire pressure never really comes up.

Oh, and unless you want to work on your French, you should select the English option when you are at rouesartisanales. Bottom line is, unless you are on 19s or are a really big boy (wooky class), then 120 psi is too high. 100 psi is probably too high for you lightweights.

FWIW, I agree. I'm a little heavier than you these days, but when I weighed about what you do, I tried everything, from 19mm tires at 120 (really high in those days) to 37mms at around 70, sometimes lower. Grant petersen at Rivendell has written about this, too, and as I recall (check it at www.rivbike.com) he doesn't recommend the standard 23mm tire for anybody over about 140 pounds. Several years ago I put 32mm or larger tires on both my road bikes (Atlantis and rambouillet; plenty of room), and I'm never going back. I do most of my riding these days on 35s at 75-80 pounds, and there's no consistent difference in time for a 12-mile commute I've done hundreds of times between those and 700x25s at 105. There are several advantages to larger tires at lower pressures, and no disadvantages that matter to me.

Check this:

https://www.vintagebicyclepress.com/images/TireDrop.pdf

I can add to this and say that on asphalt any pressure over 90 psi is detrimental to rolling resistance, so you need to choose a tire size that allows your weight to be carried with no more than 90 psi. Approximately 2/3 of the weight is on the rear tire, so the rear tire needs to be a larger diameter than the front tire. The reason for the 90 psi limit is that, believe it or not, higher pressures tend to deform the asphalt, which is not good for rolling resistance. Concrete surfaces can take a higher tire pressure. The use of 130 psi road tires is a practice that has already been proven wrong and I think the knowledge of this will seep down from the HPVA racers to the road racers in the next ten years.

I've recently gone to 90 psi (I weigh 161, bike 21) based on the above tiredrop article, and I like it. One additional advantage: It's faster and easier to pump up your tires.

I'm not looking for a free lunch or anything, but I've checked out the linked sites and can't find the answer.

I'm 5' 10" and 200# and ride Conti gatorskins 700X25. What would my best PSI be? I often ride on sketchy roads and I'm an older rider, so control and harshness are two concepts important to me.

Okay, y'all have convinced me to try it. I'm 160# with 18# bike. Next time I ride I'll lower the pressure from 130 down to about 105 and give it a try.

I'd start out with 100 psi front and rear. Then back-to-back, try 90. If 90 is more comfortable and you aren't squishing the tire, try 85. you'll get to the best mix of pressure, rolling resistance and flat-resistance.

A caveat, though. If you are racing almost all of your time will be lost on the hills. Lighter is better when you are climbing, so those comfy 28s start to look a little worse. So...you still have to consider weight trade-offs along with tire pressure/rolling resistance.

Otherwise, I'd be running 1200 gram Rubber Queens, for sure!

Go further. 90 F / 100 R. You'll like it.

There are various recommended presure charts -- like this one from Michelin -- based on weight combo. But you also need to take into consideration road surface.

Generally, you'll go faster on surfaces like chipseal with lower pressure. Even major manufacurers have recently concurred that "Wider tires roll easier, yield higher mileage and offer more comfort and grip" ~Continental, and are offering more choice in performance tires.

And this is true. Tire construction is the greatest arbiter of comfort and speed, not pressure, though any overinflated tire exerts a negative effect on both.

My tires started flatting like crazy at 120. I put another tire on and the sidewall burst at 120 before I even rode the thing. I now put about 105 in the tires and don't even notice a different. And I am not flatting like before. Gotta find your own balance of reliability-to-comfort-to-whatever-to-other things. =)

I've experienced the same..... since I stopped running max pressure I've stopped flatting as frequently as I once did.

Use the attached table to find the Optimum Tire Pressure for Your Weight

Example: Rider and bike weight: 100 kg. Weight distribution: 45%/55%. Wheel loads: 45 kg/55 kg.

It's looking like as close to max 120 psi rear as possible and around 105-110 psi for the front as a starting point for me. Thanks for the resources!

No problem ... enjoy the ride ...