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Message started by IslandRoad on 01/18/20 at 23:26:32

Title: Weird tire wear?
Post by IslandRoad on 01/18/20 at 23:26:32

Hey guys, so I was checking over the bike today and noticed something weird about my rear tire. I was wondering if anyone has any experience/ideas/comments.

The photo shows strange wear/stress on the outer side of the tread on both sides. The solid part of the tire up the middle is unaffected. The wear is consistent on both sides and all the way around.

Specs: Metzeler Marathon ME880 140/90 B 15 (3513)

Notes: I didn't know about date stamps until a friend pointed it out after I bought the tires in 2018. The stamp shows 2013 ... not happy about that but it is what it is ... after spending near $400 on a pair of new tires! I did some research and apparently some people freak out about tire age while others will accept up to about ten years.

The bike was in storage for about a year. I got it back recently while living on a property with a long 'driveway' which was very rough gravel/stones . When I first got the bike back I didn't check tire pressure and took about a 500 m ride on tires that may have had 10psi in them - just an honest mistake.

The recommended max PSI is 42. I run them at 22psi as it gives the best feel/traction etc.

I do like to run the Twisties pretty hard but not over the top.

Any thoughts on this weird looking wear?

Title: Re: Weird tire wear?
Post by verslagen1 on 01/19/20 at 09:10:37

I would have to say it's 22psi

Title: Re: Weird tire wear?
Post by Dave on 01/19/20 at 09:20:19

Riding on an underinflated tire may well have caused that wear pattern to occur - underinflated tires flex and build up a lot of heat. Suzuki recommends 33 in the rear for solo riding and 36 for double.......not 22 - dropping 11 psi is too much.

And.......your tire appears to be suffering from age deterioration - and the rubber may be getting stiff and brittle. If you look at the angle where the tread block meets the tire carcass, you can see the the cracks that are beginning to form at the base of the tread block.

Title: Re: Weird tire wear?
Post by Gary_in_NJ on 01/19/20 at 09:36:44

I’m gonna have to agree, that wear shows signs of heat damage and slippage. If you are looking for improved ride quality, get rid of the bargain shocks that Suzuki put on the back of the bike.

Title: Re: Weird tire wear?
Post by ohiomoto on 01/19/20 at 11:17:12

Looks like you ride on gravel.

Title: Re: Weird tire wear?
Post by batman on 01/19/20 at 19:43:58

Rather than running the tires under pressurized on dirt/gravel/fire roads , I find the bike handles well simply by running it in the next higher gear than actually needed, and rock ,dips ,puddles encountered can demand your full attention (steering) as any sudden movement of the throttle will have small effect on speed (will not cause the rear tire to brake loose) . There is little need to ride it like a dirt bike (lower the pressure for off road use) ,you're not going to be jumping a Savage over downed trees etc. at least you shouldn't be trying , it's not a dirt bike , it doesn't begin to have the ground clearance or suspension .

Title: Re: Weird tire wear?
Post by Dave on 01/20/20 at 03:38:53

Here is a good article on tire wear. The gaps in the rubber tread of your tire are relatively shallow and located on the side of the tires, and are described as follows:

What are cold tears and hot tears?

Cold and hot tears are types of damage that tires can get if they are either too cold or too hot. While some causes for these can include bike setup and driving style, improper inflation levels can also come into play.

When a tire is overinflated, its contact patch is significantly reduced. It heats up just fine, but it is small enough that it can’t create enough heat for the rest of the tire quickly enough. As a result, when you lean the bike in a turn, it causes a cold tear, which can be very deep damage.

Similarly, when a tire is underinflated, the contact patch is too large, so the tire actually overheats and creates a melting environment. The result is a hot tear on the side of your tire. This isn’t as deep as a cold tear, but it is a tear nonetheless.

https://www.rockymountainatvmc.com/rm-rider-exchange/just-faqs-understanding-motorcycle-tire-wear/

Title: Re: Weird tire wear?
Post by IslandRoad on 01/20/20 at 13:23:49

Hey thanks for all the great feedback and tips guys!

It seems I have a full set of contributing factors to that kind of wear:

1. Tire age
2. Under-inflation
3. Some necessary riding on gravel (taking it easy though)
4. Heat - We've had a heat wave here with temperatures in the high 30s to low 40s Celsius
5. Heat again - I've been riding country highways this last couple of weeks (good quality surface) but the sweeping curves allow for a pretty sweet lean at 80-100 kms per hour

@Gary_in_NJ, Thanks for the advice on the suspension. I read your excellent tutorial on upgrading the suspension some time ago. It's on my list of mods for the future. I did a bit of reading on shocks last night too and will definitely prioritize replacing the shocks.

@batman, that's good advice about the higher gear on gravel. I avoid grave where possible, but sometimes it's unavoidable. I had noticed just how easily the bike can lose traction even at low speeds (that's due to the low end torque, I assume). And boy does the bike get heavy quickly when it gets across the centre of gravity.

@Dave, thanks for the link to the article. It was very informative. Yep, I'd say the tires have 'heat tears'. I had a good look at the tread this morning. I noticed that the tread design has varied depth at different points in the tread. The depth varies along the length of each groove, and the walls of the grooves are different heights on each side of the groove, to the point that one side of the groove can be 6mm deep and the other side is 11mm deep. It looks completely like a manufacturing design and not some strange wear. This is especially along the contact band where the radius moves across to the 'lean zone' of the contact patch. I'd guess that recommended inflation is probably an important factor in maximising the design.

It's been really informative.

I'm off now to pump up my tires and read more about springy things!

Title: Re: Weird tire wear?
Post by batman on 01/23/20 at 05:29:49

IslandRoad, You can buy a set of Shinko tires for around $100,Isn't your life worth that much? Tire or brake failure can cause serious injury, your suspension mods can wait, If the bike doesn't handle perfectly or it doesn't start it probably won't kill you .

Title: Re: Weird tire wear?
Post by IslandRoad on 01/24/20 at 17:17:57

@Batman, thanks for your concern. I really appreciate the advice. Your last comment prompted me to take the bike to a bike shop this morning to get the rear tire assessed. Yep, wear due to underinflation was the diagnosis. Tire age was also an issue but not to the same degree.

As for my previous post about the tread being different heights on either side of the grooves (I assumed it was manufactured that way because it was even) ... well no ... I've managed to halve the tread depth one side of the grooves due to heat and wear.

He told me it's not an emergency and it's fine for riding around town for the moment, but change the tire soon.

So, a new tire has been bumped up to number one on my list.

At the end of the day, being a newbie, I never took the factor of tire pressure all that seriously.

It's been an education.