[mattsz]

Anybody come across this?  I've got around 7000 miles on this tire; I've never noticed any uneven wear until the most recent 500 miles or so.  It's hard to photograph, but there's a sort of diagonal wear pattern, with each individual tread block worn less on the "leading" edge which first strikes the pavement - more easily seen in the second photo.

I've always kept the front pressure between 18 and 20 psi, as per owner's manual and suggestion of many riders here.  Handling and fuel economy have always been fine.  Tire is nearing the end of its useful tread depth anyway; is this a normal end-of-useful-life thing?

[bluesdaddy2]

Matt,

Not sure if this helps but in the world of 4 wheels they describe your probable cause a shown in the attachment.

[mattsz]

I have seen this kind of wear on 4-wheeled vehicles with alignment problems.  But with 2 wheels? 

No play in steering head, wheel bearings good, front/rear wheel alignment seems good - I've never changed it...

[Ice]

The pics are not loading.

[Richard230]

This type of wear was discussed in the latest issue of Motorcycle Consumer News. It appears to be something that happens to all tires that have blocks or knobs that stick up above the tread carcass. The larger the knobs, the more this type wear will be evident. So I wouldn't worry about it. If the wear is resulting in poor handling or steering, just replace the tire.  And if you didn't like the way the K70 lasted or performed try something else. I agree, the owner's manual recommendation for tire pressures is too low for the U.S.  It appears to be aimed more at slow speeds and dirt roads, such as you might encounter in India.

[mattsz]

Ice - not sure what's going on with the pics... they're showing up fine on my screen.  Looks like Jerry can see 'em, too.

Jerry - by gum, you're right!  I've taken a closer look, here's a close-up of cracking between the "blocks":




If I understand date codes, this tire was made in early August of 2012:



The tire tread is almost gone anyway, scalloping aside, so I'm not too upset about it.  The only riding I have left is a final pre-storage gas-up anyway.

18 psi is the OEM spec - some guys here use more, but many stick with it on the road with no issues.  I figured RE specifies it for a reason.  Handling and performance has been exemplary at that pressure, and I think 7000 miles on a good sticky front tire is just fine (I get 1/2 that on the rear K70).  I can't feel any steering or handling problems, but taking into account all the above, I consider that tire done.

[Vince]

     Every tire will cup like this under the right conditions. In your case the condition is that the tire is under inflated for the load. The stock PSI specification is for the stock tire. Other tires usually require some adjustment. Under inflation causes the tire to squirm. The tire actually ripples as it rolls, and generates excess heat from the squirming. The rippling causes an uneven contact patch with uneven loading, and the excessive heat causes excessive wear.
     Even touring and cruising motorcycles with heavy duty tires exhibit this. The root cause is a tire that is overloaded. The over load can be from under inflation, or excess weight, frequent hard braking for the front or frequent hard acceleration for the rear, with the attendant weight shift, or some combination of these factors. 

[Craig McClure]

I have always run my FRONT K70's between 25 - 30 lbs, I never had that problem. Tube tires usually bleed down, by going up toward 30lbs I get more time between air ups.
  Been running my REAR K70's between 32-35lbs.  Have done so at least 40 years, with no problem.

[mattsz]

Vince - in all the tire threads I've read here, I cannot recall ever hearing that those pressures apply to the stock tire only, and that other tires should be inflated to higher pressures.  Do you know enough about the K70's to recommend a more appropriate front tire pressure?  What about the rear... is the OEM spec 28-30 psi appropriate?

[The Old Coot]

I've "Cupped" more than one knobby on my KLR due to low air pressure. So I'd go up 5-10 PSI and see if it helps. BUT once a tire starts to cup it's a goner.

[mattsz]

That tire's a goner anyway!  But it's given me upwards of 7000 miles of good use before I noticed the cupping...

[CoffeeAchiever]

I've got just over 8000 miles on my 3.25 inch width K70 front tire and it's still in good shape.  I've run my front tire at 24psi ever since I had it installed.  No cupping to report. 

I replaced my bike's 3.5 inch rear tire last Thursday - it's the third rear tire since I replaced the front K70.  I've been averaging 4000 miles per rear K70 ever since I tossed the stock Avons in 2012.  I run my bike's rear tire at 26psi in normal riding and air it up to 28psi when I load the bike up for weekend trips. 

By the way, the running pressures that I use for my K70s (24psi front / 26psi rear) were not my original idea but the inflation advise posted on this forum by experienced Bullet pilots.