Hi, (Wide Glide with stock Dunlop tires)

I have almost always checked the tire pressure at the gas- or service station. This means the tires are warm while doing it. Just now I stumbled upon that chapter in the service manual and it says to always check pressure while the tires are cold.

For you with more experience than me: Is it going to be any different values with cold or warm tires? Is it just a "safety" that they say to check while cold or does it really matter and can make a difference?

Why I got curious is because first time checking after running in the machine I had way too little pressure in the tires and this was just after it had been on service at the dealer, they "should" check. I filled it up and since then it has been solid numbers.

BUT now putting away the bike for winter storage I definetely see that the rear tire is rather worn. More so than I would like it to be at just shy of 5000 miles. BUT it is also a dreaded Dunlop that people seem to say is worn out fast.

So what do you say? Just the Dunlops being worn out fast or me actually having too much pressure in the tires due to filling them warn instead of cold? I can't check this now since the bike is in storage but this question makes me crazy.

 

I just check mine before a ride. Checking yours hot or cold at a service station has little value if you're depending on their gauges to be accurate.

I have about a dozen tire pressure gauges and no two seem to read the same, so don't trust any until you've cross checked them with known accurate gauges. If you do fill the tires up when hot, just check them later when cool and let air out if needed. A pound or two high won't make that big of a difference anyway on tire wear, especially given the inaccuracies of most pressure gauges.

With 5,000 miles on the tires, that might be their normal life for your riding/road conditions. If your only fault is filling them up when hot, it's no big thing. The tire is going to wear in the middle if all of your riding is in straight lines anyway.

Just get an accurate gauge to carry with you and check them when cold then check them later when hot to see how much pressure is gained to satisfy your concerns.

 

I check mine cold, air pressure definitively increases as you ride--probably due to friction / heat. my car that shows psi on the dash, air pressure can increases as much as 5 psi from take off to destination

 

Experience has taught me to check pressure only when cold. Heat naturally builds up pressure and can varie somewhat depending on what type of riding your doing. I personally think the specs in the manual are pretty right on. I actually run 30psi in the front not allowing it to go below 28psi as it may cause cupping. The rear I stay between 36 to 38psi unless I'm packing then I'll go up to 40psi. I know the tire sellers say you should run at least 40psi in the rear but I dont agree. I just replaced my rear Michellen Scorcher 31 with 14K miles. I'm pretty happy with that. Hemi is right about the gauges too. Spend a little extra on a quality gauge and you'll be fine. The gauges at the gas station take to much of a beating to be accurate.

 

There are a lot of factors involved which can have an effect on determining the proper psi to run... heat, temp, weight, etc....

Here's a method I have always used to determine what psi to run.

As a rule of thumb when your tires are cold the psi shouldn't increase more than 10% after they are warm.

ie: If your tire was 40psi cold it shouldn't increase more than 4 psi after its warmed up.

If it increased to more than 44 psi it was to low, you need to ad some air (a squatting tire will generate more heat).

If it was less than 44 the psi was to high.

I have always had good tire wear using this method

 

I have always check mine cold, before a ride, i leave them at 32psi, have 10k on the rear GT502, needless to say i need a new rear tire.

 

32-35 in mine....Dunlops seem to wear a little quicker than some other brands, softer compound, but not as soft as some. Depends on riding as well...hard acceleration, straight line riding, center wear...most tires get replaced with a lot of side tread left...