So i've been a 120psi front and rear because it's easy kind of guy since I bought my first bike in June. Ive just recently heard mention of a few people saying that depending on your weight, you should ride at XX psi instead of 120psi. Can anybody explain this to me? I'm right at 5'9 and 160 lbs. so I have no idea if its better or worse to ride at 120psi f/r.

Thanks in advance for dumbing it down.

Being the weight you are you can run your tires at a lower PSI and for sure you can run the front lower than the rear. This will get you a bit of comfort. I, being a fat butt, run my tires nice and high so I don't get flats.

is that the only advantage to varied pressures? because im not uncomfortable riding my bike as it is

If you are happy then ride it that way...one thing you may want to do is run a lower pressure if you ride in the rain...it supposedly gives a bit more contact patch and better traction.

I'm the same weight as you, and run 105 psi in the front and 110 psi in the rear. I used to do 120 in both before, and "thought" that was fine. Then I experimented a bit, and found my setup to be optimal for me. No loss of speed, and noticably more comfortable.

I am 6', 200 lbs and I am running 105 psi front and rear. is that good or bad?

If I was 200 I'd probably do at least 115 at the minimum...give it a whirl and see how it goes. Doesn't hurt to experiment.

700x23, right?

yea 700x23, but on my michellen tire, it says maximum 116 psi.

Somewhere floating around here is a chart that purports to give the psi to obtain the optimal amount of tire deflection based upon tire size and rider weight.

There has been a good bit of "expert" advice leaning toward heavy'er riders lowering the PSI a bit. I'm 210 at 6'1'' and a couple of years ago quit using 120 PSI in 23's lowering it to 100, seems to give a more comfortable less compliant ride, hell I'm not racing so it works for me. If you want to know more of what the so called experts at roadbikerider.com say about the subject you got to give them money for a subscription to their site, no thanks the guy at my LBS knows just a much as "uncle al" at RBR and he will share it for free. However if I wanted advice on doing a 200K brevet I may want to pay for it from Ed Pavelka who is a legend at those types of events..........................

Here an excerpt from their free news letter

Thirty-six hours later, Ed was riding a 200-km brevet around Massanutten Mountain in northwest Virginia, and things were not going well. The climbs were relentless. A headwind was gusting to 20 mph. His pace felt rhythmless. He was overdressed and getting damp as daybreak's 28F degrees rose toward 68. He was low on fluids and beginning to ration his remaining sips. Twice, half-eaten energy bars fell from his jacket pocket and disappeared into the roadside vegetation. That made him worry about having enough food as well as enough to drink. In short, the ride was falling apart. And there were still 75 miles to go.

Exciting aint it...............


https://roadbikerider.com/

195 lbs and run 120 in the back. Any less than that and I am risking a pinch flat and a noticable decrease in speed. 100-110 in the front is just fine.

That's fine and good, but you run a much higher risk of pinch flats if you go too low for your weight.

Then again, my OCLV Trek combined with 105 in the front tire and 110 in the rear tire rides great. I've run my front tire at 80-85 psi before (got a flat on the road and used a hand pump - checked the psi when I got home after doing intervals), and while I was still able to ride the same speeds for the most part, it was too soft. And I weigh 50 pounds less than you.

I shoot for 110-115 front and 115-120 rear but I'm 240.

I've never seen a single manufacturer ever recommend different PSI for weight, they all say run at recommended, usually 120psi for clinchers.
lower pressure may be more comfortable, but prepare for more cuts and flats, and greater rolling resistence.

https://sheldonbrown.com/tires.html#pressure

/thread

I'm also 240 lbs and I run 100 front and rear (700x23). Lots of cracks in the roads here, more pressure than that and the ride can be pretty ruff. For gravel bike paths (rail to trail kind of thing and 700x25) I run 95 front and rear.

Long ago, I recall a team mate chick asking why her bike was so skittish around corners at speed even though she was riding sewup tires. We asked here how much pressure she ran ... "Oh, usually around 170 lbs". Ohhhhhhhh ......

jw

Something like 60% of the weight is on the rear tire so it makes sense. Sheldon Brown says:

I created this one based on Sheldon's data points. It allows you to extrapolate using the curves to find the recomendation based on your weight. I should just post the formulas one day....

https://www.bikeforums.net/attachment...1&d=1154461177

Can you post the formula? I'm 145-150 lbs, running 28s.

Dan

Formulas:

Only the intercepts change for tires between 20-28 widths. Larger widths and the slopes change. Obviously these are generalized and assumed to be linear. While not 100% correct they will give you a great place to start.

Tire Width=20: Pressure(psi) = 0.33 * Rider Weight in lbs + 63.33
Tire Width=23: Pressure(psi) = 0.33 * Rider Weight in lbs + 53.33
Tire Width=25: Pressure(psi) = 0.33 * Rider Weight in lbs + 43.33
Tire Width=28: Pressure(psi) = 0.33 * Rider Weight in lbs + 33.33

Tire Width=32: Pressure(psi) = 0.17 * Rider Weight in lbs + 41.67
Tire Width=37: Pressure(psi) = 0.17 * Rider Weight in lbs + 26.67


Example: You are 150lbs running 28's

Pressure (psi) = (0.33*150) +33.33 = 82.83psi (rear)
Front Pressure = .9*Front Pressure = .9*82.83psi = 74.55psi front

You could start by running 85 rear 75 front and adjust from there. For your weight I would step down to 23's which you could run at 92F - 102R. That would be nice and comfortable and have less rolling resistance than the 28's.

Wow, that seems low. The tires say 120 max.

I'm running 28's cause they came with my bike (Trek Pilot 1.2). I have considered going down to 25s. Not sure if 23s will fit on my rims.

I assume that the upshot of all this is that the lower PSIs (as adjusted for weight) give more comfort without sacrificing performance or durability. Do I have this right? I'm a little confused about the comments that lower PSI helps protect against flats (crossing fingers: I've never had one going back to 74 when I got my Stella 10 speed; which is still a pretty functional bike, by the way). At least on car tires, they say higher PSI gives better durability. Is this apples & oranges? Thanks for the info.

Dan

I rememebr this post from the RoadBiker newsletter. Interesting take on lowering pressure a bit:

https://www.roadbikerider.com/UArant....ire%20Pressure

Sorry...let me step back from my recomendation. The pressure seemed low in my eyes as well, but for your light weight on such a large tire they don't seem totally out of line. I believe your rim on that pilot would handle a 23, but 25's would probably be a better recomendation(83F-92R).

The "correct" pressure in your tire is what will allow it to perform the best for both comfort and durability.

BTW the "Max" pressure listed on the sidewalls has more to do with legalities than with performance.

Here is another chart.
https://www.precisiontandems.com/phot.../tirechart.jpg
Keep in mind for weight use the total load - the bike weight, plus rider, plus clothes (shoes, helmet), all accessories, etc.
Al

The important thing to note is 120 max. Many manufacturers also talk about min pressure.
I had trouble getting my melon around that. This is how I think about it: there are pinch flats and there are puncture flats. Pinch flats are from too low a pressure and those we can all understand (tube gets pinched between rim and pothole.)

Puncture flats are harder. Think of the "bits of glass" as a high school ring on the fist of some guy in a bar fight. The tight skin in your forehead is the high pressure tire and your cheek -- the lower pressure tire. If he hits you in the forehead, you are going to bleed. Blood here = air in your tire. He hits your cheek, your blood stays yours.

As always... the best thing you can do is avoid the "bits of glass."