Richie92

Hello, I just created this account to find out what PSI should the tires be pumped. I had the bike looked over the my LBS and the tires were pumped up max. I only rode it once. After 3 months, the tires are a bit soft.

I tried to find the PSI on the tires. I am confused about what it says. "Max Load 80KG at Rec. Pressure 350kPa"

It is a 700x38c tire.

katsup

50 PSI
https://www.convertunits.com/from/kPa/to/PSI

dabac

Bike tires aren’t like car tires, they lose pressure a lot faster.
It’s quite common for regular riders using narrow tires to top up weekly, or even more often.
I’m slightly surprised the bike wasn’t standing on the rims after 3 months.
"Max Load 80KG at Rec. Pressure 350kPa" means they think the tire should be inflated to 350 kPa = 3.5 Bar = 51 PSI IF the rider weighs 80 kg(176 lbs) or less.
There should be a max pressure rating somewhere on the tire, which probably is higher than 350 kPa. If you’re heavier than 80 kg, they think you should inflate to more than 350 kPa.
It shouldn’t harm anything but ride comfort to use max allowed tire pressure.
Tires will generally tolerate quite a bit of overpressure, but it’s usually not much point in using deliberate overinflation. The ride gets very harsh and it doesn’t bring you anything good.

Richie92

I looked everywhere on the tire, I don't think it is written.

I thought that 51 PSI was the max. I weigh 97 kg so that is 17 more, I guess I will pump it up to like 65 PSI and see what happens.

pjthomas

64 PSI seems a little high for a hybrid. You might pop a tube. Note that the 80 kg listed on the tire is not your full weight since your weight is distributed across both tires. More likely only 60 kg of your weight is on the rear tires. I'd go with 55 psi and ride it. Let a little air out until the you can still feel the road but it doesn't feel harsh. The measure the tire pressure for future reference.

Club1820

I’m also looking for help with ideal tire pressure for Schwann trailway 28” tire. It also says

Max load 80 kg at Rec Pressure 350 kPa
:
Min Pressure 40 PSI
Max Pressure 73 PSI

I weigh 190 lbs

i tried to determine optimal PSI with the info provide by Dabac but not sure I come to right number. I currently have PSI at 60 PSI. It seems fine but not entirely sure if this is the correct recommended PSI

Thanks in advance

hokiefyd 

How wide are your Schwinn Trailway's tires, in milimeters? It should say somewhere on the sidewall, and it'll probably be in the range of 32-38mm or thereabouts. At 190 pounds, I'd probably run tire pressures in the 40-60psi range depending on where and how you ride. If typical suburban path or light gravel riding, those pressures should be fine. The 60psi you have in there now will work, but you could probably try going lower as well. I probably wouldn't go much higher, only because comfort will quickly deteriorate and for not a lot of gain.

Mojo31

The type of bike is not the determining factor. It will depend on the size and construction of the tire.

My hybrid came with 700X32 tires with a recommended pressure of 85-95 psi. I just changed to 700X28 tires with a recommended pressure of 90-115.

For the OP, the recommended pressure range should be on the sidewalls of the tires he has. I've never seen a clincher type tire without it molded into the sidewall.

Club1820

Thanks for the quick reply.

So my tire has 700 x 38C on it, in addition to 28 x 1 5/8 x 1 1/2. I’m assuming then the width is 38mm as you suggested.
I’ll be riding it strictly on city/suburban paved streets. When initially inflated it was at 40 PSI but I could tell immediately that was too low as there was way too much give in the tires. So I raised it to 60 PSI. It seems ok now just not entirely sure of how it’s
“supposed” to feel. It’s been a long time since I’ve ridden a bike (15 yrs?).

thanks

hokiefyd 

A lot of it is personal preference. I weigh 240 pounds and I run 38mm tires at about 40-50 psi. At 50 fewer pounds, that inflation pressure felt too low to you, which is fine. We all have different preferences on that. The good news is there really isn't a "wrong" pressure to use, other than so low that the tire will roll off the rim (probably in the 10 psi range) and other than so high that you risk blowing the tire off the rim (probably north of 150 psi). Anywhere in the middle (within reason), as long as you're happy with it, will be okay.