Grouperdawg

I just put 5000s tubeless 28mm on my bike and wondering what others run in the front and back

i weigh 195 lbs and ride on pretty decent roads

spdntrxi

try 80/85 and go down from there..

issues : some big tires fell kinda crappy with low pressure and also I find 80ish psi kinda getting close to the upper limit of sealant working well in tubeless setups.

noodle soup

I can't imagine going any higher than 80/85. I'd try 70/75psi.

FTR, I'm 189#, and use 55/60 on 30mm tires

Grouperdawg

Thx 👍

Grouperdawg

ok thx

sshakari

Im 180lbs and ride 28s with 85 psi.

cxwrench

Excellent advice from the previous posters. Here's my formula. It starts w/ a 23mm tire at what I would consider maximum reasonable pressure: 100psi. If you find yourself needing more pressure for whatever reason, you need bigger tires. A test was done recently that tried to determine what pressure to inflate larger tires to if you wanted the same feel as a smaller tire at whatever pressure you were using. Starting w/ the 100psi/23mm tire it just happened to work out to 10psi per tire size. So 90psi for a 25, 80psi for a 28, 70psi for a 32, etc. They used a device similar to a durometer tester that basically measured the surface tension of each tire. At a 10psi drop per tire size the tension reading was nearly identical for each tire size. But...the all important but...as you go up in size you're obviously gaining air volume. More volume, more rim protection. You can actually go down more on the larger tires and gain ride quality and traction by doing so. Rolling resistance? The (very) most minor part of the equation. Don't even worry about it unless your paycheck comes from beating other guys on bikes from point A to point B. It obviously depends on rider/bike weight as well as rider position on the bike so there is some room for adjustment. A 100lb rider will need much less pressure than a 200lb rider on the same tires. I'm about 165, I ride 28mm tires at 70psi rear/60psi front. If you don't stand much or at all you can drop a little more from the front, if you get all over the front of the bike like a monkey ******* a football you might want to keep them pretty close.
ETA: When I used tubeless on the road I never really changed my tire pressures from clinchers as I didn't overinflate them in the first place. I hate road tubeless as much as I think it's the only way to go for mountain bikes. Not worth the hassle when the inevitable cut tire mess happens.

eduskator

What's your rim's internal width? I'd start around 80 & see if you like it. Then, you can adjust.

There are calculators available on the internet that can suggest you optimal pressure. They will ask for a few specs in order to determine it though, including your internal rim width.

mattcalifornia

I'm 181 at my last weigh-in, also riding 28mm Conti GP 5000TL tires. I've been riding 80 in the back and 70-75 in the front. However, I notice that they lose pressure over time, so if I'm going for an extra long ride, I might add a few extra PSI.

Grouperdawg

Thx for all these great responses, I’m not sure the internal width they are dtswiss dicut 1100s

When I had 25s on them I measured them right around 25 so I’m guessing the 28s will be similar

WhyFi

I'm around 180. With 23mm internal width rims, I'm running my modern 28s a little under 60 up front, a little over 60 in the rear. When I had narrower rims (17mm int), I was running them a little over 70.

Seattle Forrest

This image is going to be with me for a while.

wthensler 

I’m 195 and run 75-80 on my 28mm tubeless Bianchi Infinito. FYI, I just bought a Domane and that has 32mm tubeless which I run about 65. Huge difference!!

guadzilla

I go 80f/85r and am quite happy with it. Am 180lb or so.

Trsnrtr

I'm ~200# and run 80 front and 85 rear . These are 25s and are plenty hard at that pressure.

eduskator

180lbs here and I run 90 rear / 85 front (25mm tubeless tires on a 17mm rim inner width though!). I would most likely run 80 rear & 75-80 front if I had 28mms on that same setup.

New bike has 25mms also, but 19.4 rim inner width so I might have to adjust pressure.

jadocs

Sweet spot on tubeless psi will be dependent on rider weight which is why you are getting a range of answers. That being said, I ride 80 rear and 75 front.

Sy Reene

Only if the sweet spot is at a pressure that there'd be worry about pinch flatting on tubed. Eg my ideal rear tire pressure is 95psi for 25mm tire (26mm inflated). I ride tubes, but if I rode tubeless, it would still be 95psi.

jadocs

95 on 28mm tubeless would be way too much for me and I'm not a lightweight.

Sy Reene

Probably, but I was referring to 25mm tires.
Here's an example of what I referring to with respect to sweetspot/pinch flatting.

A 15% drop calculator (eg. Dorkypantsr) would put a 250lb weight rear tire at about 102psi for a 28mm tire.
A optimized tire pressure calculator (eg. Silca) would put that same weighted rear tire at about 82psi

So while 82psi might be ideal for either tire type, it's really only doable tubeless for a 250lb weight. I wouldn't probably myself ride that pressure riding tubed because of increased likelihood of pinch flatting. I'm not sure there's any formula out there though that can calculate pinch-flat likelihoods by PSI. That'll depend on your own riding style and the road conditions you experience.

noodle soup

Thanks, but this doesn't help the OP.

Here's what the OP asked about

Sy Reene

Well yeah, but the OP's question was already answered about a half dozen times and I wasn't replying to his post.