Topic: weird wear pattern

[mazingerzeca]

Hello all.
This is the front tyre of my CB750 K8. As you can see, the right side is much more worn than the left side. What can cause this?

[flybox1]

front forks uneven, twisted.
rim out of true.

[bryanj]

Bent frame, wheels out of line, harsh braking

[Elan]

you only turn right, like fedex

[BobbyR]

I was told by a tire shop it is common for the right to have more wear. People tend to turn harder right than left since they perceive it to be easier. Or you have a mechanical defect, or both are correct. 

[lone*X]

I have always been under the impression and seen in print many times that the left side (as seen sitting on the bike) commonly wears more since left hand turns cover longer distances than right hand turns (assuming you are in a country that rides on the right side of the road) and are generally done so at a higher speed and more lean than the short right turns.  Also commonly quoted is the crown on many roadways which cause you to be riding length wise to a slight left side uphill grade.  I doubt road crown has much affect though.

This though looks like an alignment problem of some sort which need to be investigated before a new tire goes on.

[dave500]

its normal,the road camber causes it,my bt45s always wore with that feathered edge aswell,so did my neighbours on a mid 90s gsx,ive been through three front bridgstones,im using sport demons now and its not feathering like that,if something was wrong with the frame or forks etc to cause heavy one sided wear like that you wouldnt be able to take both hands off the bars i wouldnt think.

[DJ_AX]

Have you checked your alignment?

or is it possible that it's actually worn evenly and the groove depth was off to begin with?
I wonder if you can see if the profile  is uneven?

[steven400/4]

as a tyre inspector for pirelli it has nothin todo with the road or tunning unless you spend the hole day going round a round about lol it will be an alignment problem  un less the strip of rubber ran out why the tyre was being made and it was finnished with a diffent batch of rubber witch has happen,d before with car tyres

[millerza]

Just a question, but would alignment not be noticable when driving? Like giving the bars a slight turn to go straight?

[mazingerzeca]

Yes, if you take off both hands from the handlebar, it stirs to left. When you talk about misalignment, you mean that the rear tyre and the front tyre are not in the same line? I have noticed that the rear tyre is almost touching the swingarm, but in another CB750 (K7) that I have the rear tyre is almost touching the swingarm too.
Thank you all for the replies.

[JaysinSpaceman]

I worked as a H-D mechanic for 10 years for a little custom shop and I saw tires like that regularly.  Many H-D riders tend to ride the freeways and straight roads (harleys aren't known for their cornering prowess) a lot and the road camber contributes to uneven tire wear.  If your wheels were out of alignment bad enough to cause that kind of wear you would really notice that it was much easier to turn one way then the other and you would not be able to let go of the handle bars at all without abruptly turning into on coming traffic.  There's my $.02

Jaysin   

[petercb750]

OK, all you tyre experts - my front Dunlop K81 on the 750 shows this sort of wear on BOTH sides of the centre section - the centre part of the tread looks barely worn, but the sides, up to about 1/2 way around show a lot of wear, getting less wear closer to the outer edges. There is a distinct ridge on each side from the centre section to the side sections. If it had been on one side (eg right) I would have suspected road camber or alignment, BUT....both sides?? I keep a close eye on tyre pressures too.

[millerza]

ok so wear pattern on both sides-----you pass people alot lol

[JaysinSpaceman]

OK, all you tyre experts - my front Dunlop K81 on the 750 shows this sort of wear on BOTH sides of the centre section - the centre part of the tread looks barely worn, but the sides, up to about 1/2 way around show a lot of wear, getting less wear closer to the outer edges. There is a distinct ridge on each side from the centre section to the side sections. If it had been on one side (eg right) I would have suspected road camber or alignment, BUT....both sides?? I keep a close eye on tyre pressures too.

I am not doubting that you keep a close eye on tire pressures but that is exactly what it sounds like to me.  One thing that I saw occasionally with wear like this is that while tire pressure was regularly checked it wasn't kept at a high enough pressure for the weight of the bike.  I had a conversation with the tire supplier once and he said that from cold to hot the pressure shouldn't change more then 10% maximum.  If it changes more then that it is under inflated to begin with.  So, if you are running 35 psi cold and the pressure goes up more then 3.5 psi once up to temp it is too soft, if it goes up less then that it should be good.  The caveat to this rule that I found is that you should really start low and increase the pressure until you are at a 7-10% increase cold to hot, because you can always over inflate from the get go.   

Another $.02 (and that may likely be all that it is worth).

Jaysin

[petercb750]

OK, all you tyre experts - my front Dunlop K81 on the 750 shows this sort of wear on BOTH sides of the centre section - the centre part of the tread looks barely worn, but the sides, up to about 1/2 way around show a lot of wear, getting less wear closer to the outer edges. There is a distinct ridge on each side from the centre section to the side sections. If it had been on one side (eg right) I would have suspected road camber or alignment, BUT....both sides?? I keep a close eye on tyre pressures too.

I am not doubting that you keep a close eye on tire pressures but that is exactly what it sounds like to me.  One thing that I saw occasionally with wear like this is that while tire pressure was regularly checked it wasn't kept at a high enough pressure for the weight of the bike.  I had a conversation with the tire supplier once and he said that from cold to hot the pressure shouldn't change more then 10% maximum.  If it changes more then that it is under inflated to begin with.  So, if you are running 35 psi cold and the pressure goes up more then 3.5 psi once up to temp it is too soft, if it goes up less then that it should be good.  The caveat to this rule that I found is that you should really start low and increase the pressure until you are at a 7-10% increase cold to hot, because you can always over inflate from the get go.   

Another $.02 (and that may likely be all that it is worth).

Jaysin

Nothing wrong with that $.02 worth, maybe even $.05...
I too suspected under inflation, but because I am fairly particular, kept saying "nah, couldn't be".
Once the new tyre goes on I will pack the pressure gauge and go for a ride - I usually run 32 in the front when cold, and never check them when hot, so will see what happens.
Thanks for the input.

[BobbyR]

I use BT-45s also and they do wear a bit funny in the front. Yiou mentione 32 lbs presure. I found at least on my bike they need higher pressures or they get squirmy. The newer tires have different sidewalls than the 1970's tires. I run no less that 34-35 in the front.

[mazingerzeca]

Mine are Battlax BT-45 too.