Take a look at the OEM Dunlop 402F's that came on pre-09 touring bikes. That tread pattern is similar to what some are now calling "backwards" on the new replacement 408's. I don't think that the 402F's are dangerous because of a "backwards" tread design.

I trust Dunlop to engineer and design a safe tread pattern over "Joe Public" deciding it's unsafe just by looking at it.

 

I don't think most folks are assuming they know more than engineers at Dunlop and can judge a tire performance by just looking at it. The odd thing is that the tires shipped one way originally, and now Dunlop suddenly issues a brand new part number and simply reverses the rotational direction.

If the tread design is not dependent on direction, why bother specifying a rotational direction? If the engineers got it right the first time, why reverse it when going from the 407F to 408F?

FWIW, I have ridden my 408F in rain, dry pavement, hard packed dirt, and dirt/sand/gravel - and haven't noticed any problems so far.

 

I agree with what you said, and FWIW I have not had problems with mine either. I'm not trying to say I know anything about it. Just doesnt seem right to me is all.

 

Wonder if they really changed the tread direction or just reversed the arrow . I have a new unmounted 407f, could it be mounted backward ?

 

My 402's are doing good as can be expected. 7K and the rear is coming close to replacement time. The front looks good for another season.

 

I think it has to do w/ the way the belts are butted and wrapped together on the circumference as to the direction of the arrows. This joint is more like a long bevel joint, and it's stronger in one loaded rotational direction (torque) than the other. The front tire takes a "reverse torque" when braking, and the rear gets a "forward torque when accelerating (it also has a reverse torque when braking, but the accel torque is much greater). Years ago we'de run rear tires on the front, but reverse the arrow direction. There was never a "hydroplaning" problem. I'm guessing that the arrow points w/ the correct belt joint/wrap, and that is why Dunlop doesn't want you to run a D407F opposite the arrow. I assume all they did for the 408 was change the tread or grooves around, and kept the arrow and belt wrapping the same (also gave the tire a new model no. to signify this change). As witnessed on other tires (D402F's etc), the tread grooves go opposite of the D407F's and "hydroplaning" isn't a problem on either. But there are problems of early cupping on D407F's, so I guess they just reversed the groove pattern so the tread blocks don't "feather out" as quickly. It'll be interesting to see what mileage a D408F gets.

 

There is a guy on here that works at Dunlop , said they couldn't keep up with demand. Maybe he can shed some light as to what they actually did.

 

The D408F is still going strong!
9780 miles in 23 days. Left Dallas area on June 10 with lots of rain all the way to Fairbanks then hot roads all the way back to DFW. (we hit the Alaska HOG rally on the 18th). Bike worked great and tires (both F and R) are in good shape. The D408F has worked to fix the cupping problem i had at 7000 miles.
Great trip on a great bike.

 

Damn if it ain't so! Never noticed it before, but the rears are the opposite. The tread grooves in the front extend into the center unlike the rear, however.

 

My dealer is calling HD on Monday to see if they will cover switching the 407 on my SG front to the 408...We shall see but I'm not holding my breath.....Oh, nothings wrong with my 407 as of now with 2400 miles but who knows what the future will bring....