I know that everyone has their own preference for tire pressure but I'd like to hear them for this specific tire. I've been running 35f 40r and I feel like that's too much. I believe the HD manual says 30f 35r for the Dunlops. Thanks in advance

 

There are so many things that can factor into that- tire casing construction, rubber compound, tire size, the weight of the motorcycle (and everything/everyone on it), ambient temperature, surface temperature, speed, the type of riding you're doing, the degree to which you're doing that particular type of riding, and so on. It's not possible to just cite an arbitrary number that would be suitable for everyone.

One of the best ways to determine your correct tire pressure, is by measuring your tire pressure rise from cold to hot. Some people express this as a percentage of pressure rise (10% for example), some people express it as a certain number of PSI increase, but they're basically talking about the same thing.

The basic idea is that if you're not getting the pressure rise you're looking for, you let out some air, and if you're getting too much of a pressure rise, you add some air. A lot of lay people get that part backwards, so make sure you understand it. Pressure rise comes from heat, heat comes from tire deformation while riding, and tire deformation is controlled by tire pressure.

So if, for example, we were shooting for a 4 PSI pressure rise from cold to hot, and started out at 35F/40R cold in the morning before riding, and immediately after riding it your hot tire pressures were 37 and 41, then you'd want to let out some air. So let's say that the next day, you try it again, starting out at 33F/38R cold, and after riding you get 36F/40R. So you let out some more air. Let's say you try again on the third day, at 31F/36R cold, and you get 35F/40R hot. That's 4 PSI pressure rise from cold to hot, and you'd be good to go.

 

I run Michelin Commander II on my Road Glide on the side of the tire it says Max tire pressure cold mine is 40 rear 41 front cold maximum. I have always ran them at max and like the tight response in the corners. I feel it in the bumps a little harder, but also get maximum gas mileage. When running Dunlops I found that anything below max and they would cup. Third season on Michelins all good about half worn, I average 20,000 km per year.

 

Yep 40f and 40r...b.

 

I'm definitely going to try this! Thank you and everyone else for the help

 

Run 36 F 40 R on Com II's & Pirelli ND's Both with Great Results ..

 

Just arbitrarily running the tires at the maximum pressure listed on the sidewall is a bad idea. It prevents the tire's tread compound from coming up to proper operating temperatures while riding, which limits the tire's tread rubber from gripping the pavement. It also minimizes the size of the tire's footprint on the pavement, which also limits traction. And it also causes the tires to communicate way too much meaningless feedback "white noise", which in turn masks the actual meaningful feedback that the tires should be communicating to the rider.

And all of this is happening on a motorcycle using tires that don't provide a great deal of traction to start with, because they're made out of something like granite, and on a motorcycle that doesn't provide much meaningful feedback to the operator anyway.

 

What kind of crap is that!! Are you the tire expert or just the all around expert? A tire is going to increase in pressure in and around 2 psi, temperature is changing all the time. Never ever heard of optimal temperature. The contact patch on a motorcycle is minimal at any temp or psi because you are using the circumference at any given point. Under inflated tires will cup experience has proven this fact to me, it is personal preference. As far as white noise and communication go, when I am sailing through a sweeper at 85 foot board almost touching the ground and accelerating coming out the other side that is pretty good communication to me.

 

The HD manual says tire pressure on the Dunlops for my bike should be 36f and 40 rear.
however the commander 2 has on the side of it 41f and 42r (max cold) I run mine at 40f and 40 r. I find that my ultra takes corners a lot better at these pressures. But I would guess you can still go with the pressures in the Harley manual an be fine. I just like mine where they are.

 

XRX is right. The maximum pressure on the side of the tire is the correct pressure if you're loading the tire to its maximum weight rating. Anything less and you end up with less than the optimal contact area. For every pound under the max the contact patch gets smaller. With a lightly loaded tire at its maximum pressure it's like riding on a ball bearing instead of a tire.

A very rough way to arrive at a reasonable pressure is to take the weight rating of the tire and divide it by the maximum pressure, then multiply the result by the actual load on the tire.