Finding proper tire pressure

[DaveT319]

How do you find out what the proper tire pressure is for your bike and tires? The manual for my bike says that the front should be 28 psi and the rear 32 psi, but that is for Metzeler Marathon tires. I recently put Shinko Tourmaster 230 tires on, but I cannot find a recommended pressure on the manufacturer's website. Other people who use these tires on their Vulcan have said that they take the maximum pressure number listed on the sidewall and subtract 10%, but that seems a little high to me considering the Metzelers have a max of 42 and 49, yet are supposed to be 28 and 32 according to the manual.

So how do I know what the right pressure is? And additionally, does the type of riding you are doing effect what kind of pressure you should be running? Like the 28 and 32 in the manual, should it be higher or lower if you are doing long distance slab riding vs. pushing it in the twisties? Or do you just stick with one pressure no matter what kind of riding you're doing?

 

[stangmx13]

IMO... experiment. Id start w/ the pressure the manual recommends then adjust them until you find what you like for those tires. u might be able to feel a difference of 2psi when riding, u might need to try 4psi. when it feels good under all conditions and u dont c any funny tire wear, run that psi.

 

[mototireguy]

How much does your bike weigh? This is the primary factor in choosing tire pressures.

I would suggest using the tire pressures recommended in your owners manual or the little sticker on the bike as a baseline and experiment from there with slightly higher/lower pressures.

The PSI number listed on the tire sidewall specifies the maximum tire pressure, not necessarily the optimal tire pressure. This max psi should only be used with x-heavy motorcycles or max weight loading situations.

 

[ST Guy]

Stick closer to the factory recommendations. Remember, the primary support for your bike is the air in the tires, not the tire itself.

 

[jimboFosho]

Interesting topic. I always just kind of ran what worked for me and based it on bike weight, and how I was gonna be riding. Heavier bike->few more psi. More Spirited riding->drop a few pounds and I have just tweaked it to be something that's worked for me I guess.

 

[Smokey94086]

I may be ignant.. But I could not tell a difference between 30 or 32 psi. Hell I've been on 10 psi before without much notice.

 

[DaveT319]

How much does your bike weigh? This is the primary factor in choosing tire pressures.

I would suggest using the tire pressures recommended in your owners manual or the little sticker on the bike as a baseline and experiment from there with slightly higher/lower pressures.

The PSI number listed on the tire sidewall specifies the maximum tire pressure, not necessarily the optimal tire pressure. This max psi should only be used with x-heavy motorcycles or max weight loading situations.

Specs have it as just about 500 lbs.

Experimentation will take quite some time, won't it? And I'm not sure I'll be able to tell the difference all that well. I'm not a racer, though I like to pretend I'm one in the twisties. :teeth

Yeah, that's why I balked at some people who said they were running either the max pressure or close to it.

Stick closer to the factory recommendations. Remember, the primary support for your bike is the air in the tires, not the tire itself.

So you mean the factory recommendation for the bike? Because I haven't been able to find a recommendation from the tire manufacturer.

I may be ignant.. But I could not tell a difference between 30 or 32 psi. Hell I've been on 10 psi before without much notice.

Me either.

Now, something I thought of: The sidewall says max load X at a particular psi (in this case, 506 front and 992 rear at 42 psi). So do I create a formula for my actual load that will spit out a psi I should be running? The load I'm running is ~700 typically.

Or am I over-thinking things? :nerd

 

[ST Guy]

So you mean the factory recommendation for the bike? Because I haven't been able to find a recommendation from the tire manufacturer.

Now, something I thought of: The sidewall says max load X at a particular psi (in this case, 506 front and 992 rear at 42 psi). So do I create a formula for my actual load that will spit out a psi I should be running? The load I'm running is ~700 typically.

Or am I over-thinking things? :nerd

Yes, the bike manufacturer's recommendations for that model.

And yes, you're overthinking things. The number on the tire is the absolute max you should put in when the tire is cold. And only then when the tire is carrying it's full rated load. You could make a chart that starts at the factory numbers and then goes up to the max pressure/max load on the tires, but really, that's not going to tell you much. Most bikes have a GVWR that's lower than what the tires are rated for.

If you'd like, bump the front and rear a couple lbs from factory recommended (bike manufacturer) and see how you like it.

FYI, I have a relatively heavy bike (725 lbs fully gassed without me or anything else in/on the bike), and I normally run 36 front, 40 rear. (Honda recommends 36/42). And I weigh 275 out of the shower. If I'm carrying a heavier load than normal, like touring with gear or a passenger, the rear goes to the max of 42 and the front to 38. Maybe 39.

 

[Smilygo]

What do you guys use to measure the tire pressure? I have tried several kinds but never had luck. Electric ones stopped working after a while. I have few of those guage sticking out when pressure is applied and each shows slightly different reading. I also tried the analog meter type but it didn't last too long either.

 

[DaveT319]

I had seen where people said the Slime digital gauge is pretty accurate, so I use that. Sure, the battery will run out eventually, and there isn't a compartment to replace the battery, but I'll probably open it up and see if I can replace it without ruining it when the time comes.

As for pressure, I guess I'll go with 28/30. Hopefully that will give me a pretty good combination of grip and tire life, though the most important in my mind is grip. I'd rather get 8k out of a set but be rock solid on the road - especially in the twisty stuff - than get 15-20k but have them feel like rocks and worry about the front end washing out.

 

[xerowun]

I recently had some Pirelli Sport Demons put on my Ninja as replacement for the crap IRC Roadwinners that came with it. When I received the wheels back from the shop I noticed that both tires were inflated to 35psi, where my bike as well says 28/32 is the recommended pressure. I dropped the pressures back to 28/32 only to discover that I was getting a fair amount of headshake if I were to take my hands off the bars above approx 40mph. As an attempt to troubleshoot that I bumped the pressures back up to 35/35 and rode that for a day and noticed the headshake had cleared.

Mind you, I primarily commute with that bike. If I were to go up into the hills with those tires I would consider dropping the pressures back down, but you can notice a difference just a few psi can make.

 

[Smokey94086]

but you can notice a difference just a few psi can make.

I guess on the two-fiddy everything matters... What did you have for lunch? :laughing

 

[LongGoneJohn]

On a heavy street bike (like the VFR and Harley) I always ran that 10% below maximum figure. I wanted minimum tire wear and durability, and on the street I don't "push it" so I didn't need low pressure-levels of grip.

I do the same on the NC700x. The manual says to run like 32psi or something, I run 35psi front and like 33psi rear. Does it have the outright grip that it might at 32/28? Probably not, but I don't need it to either.

 

[stangmx13]

i have never seen any actual evidence that a 3-5psi difference appreciably affects durability of street tires, especially modern street tires. more than likely, people are accepting anecdotes as evidence and/or continuing old wives tales.

 

[Wumpus]

i have never seen any actual evidence that a 3-5psi difference appreciably affects durability of street tires, especially modern street tires. more than likely, people are accepting anecdotes as evidence and/or continuing old wives tales.

It would make sense since with more pressure less of the tire is flexing as it is rolling along the road. It can help mileage too, but probably only noticeably in a car.

 

[Hank Wong]

My BMW is 530lb wet. Owner manual says 32/36 for solo riding. 32/36 works fine for Bridgestone BT021, BT023 and Michelin PR3. With Metzler Z8, I have to go up to 40/44 to get the bike to handle right. On my bike, Michelin PR3, handling with Michelin PR3 would change with just 1 or 2 PSI off. It has been a while since I rode Bridgestone tires and if memory serves, the Bridgestone tires seem to be more tolerant to small PSI change.

 

[CABilly]

I may be ignant.. But I could not tell a difference between 30 or 32 psi. Hell I've been on 10 psi before without much notice.

I was on a bit of a long slab trip last week and I had slacked on checking my tire pressures. On the way there, I noticed the front felt really "loose" and wobbly at speed, like a slight head shake. I was afraid of a tankslapper so I checked and saw that it was in the low 20's :|

I filled 'er back up to 34 (I like to be a few lbs over since I do a lot of freeway riding, and I don't otherwise rip around enough to require the benefit from lower pressures) and the problem went away.