Typical Air Pressures for Tires??

[Guest]

I'll have to go look again to tell you exactly which tires I have on my bike, though I know they are Metzers. Just not sure of the model number. I'll get back to you on that.

In the meantime, they have maximum air-pressure ratings of 45 F, 42 R.

What are the typical air-pressures that people run on their GS850s??

Thanks,

[Steve]

The owner's manual will have suggested pressures, but they were based on the tires that were available "in the day".

Typically, today's tires are rated to carry their loads at higher pressures, so your pressures will be higher than what the book says.

As a suggestion, start with 30 in the front and 35 in the rear. Go for a ride to get them warmed up properly. Check the pressure when the tires are warm. You are looking for a 10% increase in pressure. If the increase is less than 10%, the initial pressure was too high (the tires did not flex enough to create the heat that raises the pressure), so wait until the tires are cool, drop the pressure about 2 psi and try again. It follows, then, if your warm pressure was more than 10%, the tire flexed too much, so raise the pressure about 2 psi and try again.

Note that pressure on the rear tire needs to be increased for the additional load of a passenger, so you will have to do some more riding to verify proper pressures for the rear.

By the way, you don't have "Metzers", you have METZELERs.
(Good tires, as long as you didn't get one from the batch that spit chunks of tread. )

Oh, my THREE 850s have different brands of tires, so they have different pressures.

.

[jbs80106]

um, i run what the manual says for the bike given temps and load I'm carrying on the bike. I do the same with my cars. Tires on my 650 are 25/28 psi. Tires on my k75 are 38/42.

Be interesting to see how tire variation might come to play.

[sharpy]

um, i run what the manual says for the bike given temps and load I'm carrying on the bike. I do the same with my cars. Tires on my 650 are 25/28 psi. Tires on my k75 are 38/42.

Be interesting to see how tire variation might come to play.

Your BMW would be running radials. Most big GS's should be about 32f/36r for a good start. Bump them up a couple of psi for highway use. Even the 450/250's should be around 30f/34r.Those 42/45 readings are max load pressures moulded on the sidewalls. DONT use those settings.

[BassCliff]

Hi,

I use the "10% method" as described my Mr. Steve. Most of the time that works out to about 32f/36r for me and my bike/tires. It can vary a little between winter and summer.


Thank you for your indulgence,

BassCliff

[cowboyup3371]

Steve and Cliff,
How close to the 10-percent rule should a person follow? If my front raised by 2 psi from 36 to 38 and the rear raised from 38 to 42, is that close enough to be okay or do I need to tinker with it?

[Billy Ricks]

Steve and Cliff,
How close to the 10-percent rule should a person follow? If my front raised by 2 psi from 36 to 38 and the rear raised from 38 to 42, is that close enough to be okay or do I need to tinker with it?

The only way to know is checking cold vs hot pressures. Nobody can tell you what you should be running, at least you shouldn't be listening. Road temps and surface, tire compound, the amount of weight the tires have to handle, how hard you're riding, and other variables determine how hot a tire gets. As Ed says, "To measure is to know." You want to see a 10% increase in pressure once a tire gets hot.

[BassCliff]

Steve and Cliff,
How close to the 10-percent rule should a person follow? If my front raised by 2 psi from 36 to 38 and the rear raised from 38 to 42, is that close enough to be okay or do I need to tinker with it?

Hi,

This sounds like your front tire pressure is too high when cold. From 36psi the 10% higher "warm" pressure would be between 39 and 40 psi, which is probably too high for a font tire. Start with less pressure, maybe 32 or 33 psi when cold and re-measure when warm (about 50 miles of continuous riding).

The rear went up a little more than 10% but it's very close. You might want to start cold with 36 or 37 psi in the rear and measure again.

It takes a little trial and error. But you'll figure it out.


Thank you for your indulgence,

BassCliff

[cowboyup3371]

That's what I thought but wasn't sure. Unfortunately, I can only get in 25 miles which is my way into and home from work and those are highway miles (70 - 75mph); unless I want to make one heck of a good trip into town going the wrong way and then back out to my place.

But I'll see what I can do then. Thank you

[Steve]

The miles you are putting on to warm the tires are certainly adequate.

I agree with Cliff. The rear looks fine, but the front is a bit high. You might try 32 psi cold.

.

[BassCliff]

Hi,

Yeah, OK. Perhaps 50 miles is overkill. Set them cold before you leave for work and then check them again as soon as you get there. A jaunt on the freeway at 75mph for 15 or 20 minutes should get them up to temp.


Thank you for your indulgence,

BassCliff

[GS750]

Hi,

This sounds like your front tire pressure is too high when cold. From 36psi the 10% higher "warm" pressure would be between 39 and 40 psi, which is probably too high for a font tire. Start with less pressure, maybe 32 or 33 psi when cold and re-measure when warm (about 50 miles of continuous riding).

The rear went up a little more than 10% but it's very close. You might want to start cold with 36 or 37 psi in the rear and measure again.

It takes a little trial and error. But you'll figure it out.


Thank you for your indulgence,

BassCliff

I can also add that it is very important that you use the same tyre pressure gauge to take each reading. It is well worth it to buy a GOOD QUALITY one, and you can get ones that read half PSI increments (look at quality automotive and racing stores)

Also, every time you take the pressures you will loose .5 - 2psi

[simon kuether]

I run 34 front , 38 back as a rule .
I check them on the run by riding along , and crossing any defects in the road surface . The bike should track straight across them with no wobble .
Check your tyre pressures OFTEN . I do mine at least every second ride , or if I'm not riding often , EVERYTIME .
A drop of a couple of psi can affect the handling greatly . Dangerously .

Cheers , Simon .

[bccap]

Just found this thread after checking my tire pressure on my gs750e. I just had them changed from my 28 year old rubber to kendas. Now I am really confused. The mechanic put in 45 front 45 rear. I am a heavy guy. What's up?

[sedelen]

Wow! You guy really run some high pressures. I run them at what the sticker says to, for my GS1000E and GS1100E, that's about 26 psi front and 32 psi rear. Running them too high makes them too slick for me, too likely to skid and too hard (feel every little pebble) plus tends to oversteer. Now you got me thinking I'm running too low a pressure, but I believe high speed dual riding for the front is around 30 and 35 or so for the back, I'll have to check on that, but I do check pressure often, and I go with recommended pressures for my riding.