Front tire wore out very prematurely. What's the cause??

[Bill Hilly]

My KPX has 2,500 miles now, and my front tire has about had it, but my back is still very good. I don't usually gauge my tires before a ride, but I always check them and make sure they seem hard. My tires never leaked on the KPX, and every time I did gauge them the had about 32. A little while back, I purposely aired them down to 27, because I wanted to improve the ride on gravel, but one day, I went to my cousin's in South Parkersburg, about 40 miles away, and went RT 21 most of the way. The bike did find, but when I got there a guy was on the sidewalk, and I could tell he wasn't quite right, but I didn't think too much about it. After a couple hours I left, and the same guy was just sitting on a lawn mower that wasn't even running. I still didn't think anything about it, well I got probably about 8 miles from Ripley, and went through a really sharp low speed turn, and it felt really weird, but just in that curve. I stopped for gas in Ripley, and I noticed my front tire was almost flat looking. I pumped it up, and sped home expecting it to go flat quickly, well it's not gotten low since that, and that's been weeks ago. It was low when I got the bike, but never leaked down after. I have came to the conclusion that either the strange guy, let my air out, or maybe the valve core didn't seat properly, when I aired the tires down a little, but is seated now. The pattern of wear on the front is a lot like the rear knobby from the Hawk, each clear is shaped like a ramp, or a wedge. I adjusted my preload in the rear, but never did anything about front preload, and I wonder if that may be the cause. Any opinions?

[JerryHawk250]

That's about the average miles i would get out the front tires on my Hawk. I haven't put a whole lot of miles on my KPX yet. Something about having too many bikes and not enough time to ride them all. lol

[Dusman]

That “wedging” type of wear on the front tires on a motorcycle is a completely normal form of wear.

[Bill Hilly]

Originally Posted by JerryHawk250

That's about the average miles i would get out the front tires on my Hawk. I haven't put a whole lot of miles on my KPX yet. Something about having too many bikes and not enough time to ride them all. lol

On my TBR7, and my Hawk, the rear tire was the first to wear out, while the front was still pretty good. I see that you sold your old Hawk. I hope whoever bought it enjoys it.

[Megadan]

I wouldn't put it past people to mess with bikes. For some reason there are a-holes out there who think it's funny to do stuff like that, just like there are people out there who just think it's ok to sit on a strangers bike, and mess with the controls. I caught a guy at my last employer who did that with my bike without asking. I asked him for his car keys so I could go sit in his car, fart in the seat, and mess with all of the adjustments. He got the point.

As far as the front wear. It's a bit unusual for the fronts to wear that much more quickly than the rear. It is very possible the added rear preload with no change to the front exacerbated the issue but putting more weight on the front wheel. Your riding position in the seat may also be adding to that. It will also affect the front geometry enough that it could increase wear.

[Bill Hilly]

Originally Posted by Megadan

I wouldn't put it past people to mess with bikes. For some reason there are a-holes out there who think it's funny to do stuff like that, just like there are people out there who just think it's ok to sit on a strangers bike, and mess with the controls. I caught a guy at my last employer who did that with my bike without asking. I asked him for his car keys so I could go sit in his car, fart in the seat, and mess with all of the adjustments. He got the point.

As far as the front wear. It's a bit unusual for the fronts to wear that much more quickly than the rear. It is very possible the added rear preload with no change to the front exacerbated the issue but putting more weight on the front wheel. Your riding position in the seat may also be adding to that. It will also affect the front geometry enough that it could increase wear.

I thought the preload may have something to do with the front wearing out before the rear. The front forks have been soft on the bike from day one. Just standing the bike up causes a lot of sag. I really don't know if the guy let my air out, or not, and have even thought that he probably wouldn't have put the valve cal back on, but I don't know what else could have happened. I hate to jump to conclusions, and I realize the guy was probably very low IQ, to the point of being disabled. He was real small, and skinny, but clean. I remember he was wearing a white shirt, and he had kinda long stringy hair, but his head was odd shaped like really short from the top of his head to his chin. He was looking at me when I got there, and I knew he was probably mentally disabled immediately, but when I left , it seems more like he was giving me a look like someone would give you, if they wanted you to try some strange, or really spicy food. If he did do it, maybe he was hoping I would notice, and may have wanted to let me use a pump, or something. I think if he did it out if anger, or vandalism, he would have cut my tire. He very possibly didn't have anything to do with it, but all I know is that it's been rode several hundred miles afterwards, and not gotten low. I probably won't ever know for sure.

[Megadan]

If you know what the total travel of the suspension is you can check your rider sag. For most road bikes the standard sag ratio is 1 in 3, or 1 inch of sag for every 3 inches of travel. For off road bikes this is often a bit higher, IE 1.25 to 1.5 in 3. So if your suspension has 9 inches of travel it would be at least 3 inches of sag, up to 4.5 (I would aim for 3.5 to 4 max personally). The trick is figuring out what your suspension travel is.

You can use a zip tie to measure the sag. Just tighten one around the fork below the seal on the lower fork tube and put your weight on the bike, then take all of the load off of the suspension and measure the distance from the seal to the zip tie.

[DasEnduro]

Just a random thought, is the tires rotational arrow in the correct direction because if it’s not then the uneven wear could be that.

[Bill Hilly]

Originally Posted by DasEnduro

Just a random thought, is the tires rotational arrow in the correct direction because if it’s not then the uneven wear could be that.

I don't know about an arrow on them, but they are directional. Each row of tread is a V shape. They are in the right direction though.

[IdahoRider]

My front tire was still good through 5700 miles then when I went on my 1900 mile trip to Canada last year, I didn't check my tire pressures the first three days and the front tire had gone down to the low/mid 20's. Then I noticed the significant wear in that 700 miles of riding with the lower pressure. I have been diligent about checking the pressure every day since then but still used the tire to 7800 mile when I replaced it with a Shinko 705. I definitely think running the lower pressure on predominately paved roads is what wore it out prematurely. I'm still running the original rear tire and think it should get to 13,000 to 15,000 miles.

[DasEnduro]

Originally Posted by Bill Hilly

I don't know about an arrow on them, but they are directional. Each row of tread is a V shape. They are in the right direction though.

Mine has arrows but they’re extremely hard to find in my opinion. The arrow is curve and has another symbol with it and is only on one side. It took me a while to find them after reading into swapping tubes and such.

[Thumper]

Knobbies don't have a path for water to escape and prevent hydroplaning, but the lugs have big gaps between them. Many road tires do have channels for water to follow, and some adventure tour tires do to.

As the tire is rolling, there are channels aiming towards the side that allow trapped water to get out from under the tire. If these channels aim inwards as the tire rolls, it can make hydroplaning worse. I've seen tire mounted backwards like this, sometimes even with the "direction of rotation" arrow pointing backwards. It is lots of work mounting a tire. It's like forgetting to put the dust/mud boot on a strut or shock before you mount it... DOOH!

This tire is mounted right. You can see the channels aim out as the tire rolls forward.



This is an adventure tour tire. The rear tire on the right should roll towards the camera, and the front tire should roll away from the camera, when mounted.



I've never seen direction of rotation arrows violate this fundamental rule. Some tire don't have arrows, so they rely on the mechanic to know

I heard that the belt s can be layered inside the tire with an overlap and that this is the main reason why tires have a direction of rotation. I don't know this is true, but the rain grooves should match this.

[Zapkin]

do you rely mostly on your front brake?

[Bill Hilly]

P

Originally Posted by Zapkin

do you rely mostly on your front brake?

No I never use it independently, but I do sometimes use the rear independently. They say the front brake provides thee quarters the stopping power, on a motorcycle. The fact that the front is far skinner than the rear , and the fact that a front brake actually provides more stopping power, possibly does explain some of it.

[ProDigit]

Not sure what bike you got, but a lot of bikes nowadays come with harder, more durable rubber in the center, and softer rubber on the edges.
This for greater cornering grip, while also offering greater longevity of the tire, for straight like riding or cruising.

If you run a flat tire, chances are you are running on the softer rubber, between the center and the sidewalls, which would wear them out.
Not to mention, overinflated or under inflated tires, will always wear faster, as the rubber has to bend more, or the rubber has to stretch more.
Also gravel or dirt roads affect tire longevity a lot more than smooth pavements.

Overinflated tires do especially bad on gravel or sharp rocks.
Under inflated tires do bad on regular tarmac or asphalt.