Tire Wear in Heat vs. Cold

[Bobby G]

I changed out my rear tire this week after 11,200 miles, and it was the poorest performance on a rear tire I've had in 4 years. I'm a big fan of the ME880, and I've always gotten 15K+ miles from them, and significantly more on the front tire (my current front tire has 22K on it, and still has very good tread).

 

I'm wondering if the combination of more long distance trips over the last 9 months, greater weight on the back (between riding two up and/or carrying heavier luggage for longer distances), and especially the more excessive heat conditions we've had this year on our trips are all playing into this poorer-than-average mileage I got this time around on the rear tire. Or maybe I just got a sub-standard tire back there to start with last time around. The date stamp on it was 5110, so it wasn't a very old tire when installed in September of 2011.

 

I always keep 40 - 42 psi in the rear, along with 25 to 30 psi in the shock, so those variables are pretty consistent.

 

Is there any intel on overall motorcycle tire performance with heat as a variable? I've Googled the subject, and there's not much out there.

[V7Goose]

Heat makes rubber softer; therefore, it will wear faster. I have no information on how much faster, or if the difference is even significant.

 

Weight, on the other hand, generally makes tires last LONGER. By increasing the tire contact with the ground and resisting even minor slippage, there is less friction to scrape off the rubber. I first saw this information from one of the motorcycle tire manufacturers (Continental), and since it both came from a good source and makes logical sense to me, I believe it.

 

The biggest variable beyond personal riding style (throttle, clutch, shifting, brakes) is road condition, including surface type and how curvy. Some surfaces that have a rough texture will chew at the rubber as it flexes over the sharp edges.

 

Long distance riding often equates to faster tire wear simply because it often results in many more miles in a straight line - thus wearing out the center of a motorcycle tire more with every mile. Think of it this way - if you get 10,000 miles from a specific tire riding only straight, you could theoretically get 30,000 miles out of the same tire if you rode 10,000 miles one direction on a race track oval, then reversed directions and did another 10,000 miles on the same oval before riding your last 10,000 miles in a straight line.

Goose

[dacheedah]

I can tell you on our hot days, with the same temperature out, on newly overlaid roads the temp jumps up noticably, like 20 degrees. Ask an over the road driver if they see more tire pieces on the roadway when it's very warm out or cold. I would think that heat and friction all have to do with tire wear in addition to the roadway surface type. When determining the minimum speed a vehicle was traveling prior to a crash, you determine the coefficient of friction of the roadway surface, or surfaces. More friction and your stopping distance will be shorter and the more efficient your tires will be gripping the surface ( go and wowe) .

[Bobby G]

Heat makes rubber softer; therefore, it will wear faster. I have no information on how much faster, or if the difference is even significant.

 

Weight, on the other hand, generally makes tires last LONGER. By increasing the tire contact with the ground and resisting even minor slippage, there is less friction to scrape off the rubber. I first saw this information from one of the motorcycle tire manufacturers (Continental), and since it both came from a good source and makes logical sense to me, I believe it.

 

The biggest variable beyond personal riding style (throttle, clutch, shifting, brakes) is road condition, including surface type and how curvy. Some surfaces that have a rough texture will chew at the rubber as it flexes over the sharp edges.

 

Long distance riding often equates to faster tire wear simply because it often results in many more miles in a straight line - thus wearing out the center of a motorcycle tire more with every mile. Think of it this way - if you get 10,000 miles from a specific tire riding only straight, you could theoretically get 30,000 miles out of the same tire if you rode 10,000 miles one direction on a race track oval, then reversed directions and did another 10,000 miles on the same oval before riding your last 10,000 miles in a straight line.

Goose

 

Good points Goose. But if excessive weight makes more of the tire surface make contact with the road, there is MORE friction, not less, the same as if the tire is under-inflated. Logic (not science) tells me that under-inflated tires wear faster. And like added weight, if tire pressure is too low, then too much of the tire's surface area touches the ground, which increases friction between the road and the tire. Thus, tires wear out earlier, and they could also overheat (more friction). Again, not exactly a scientifically based argument, but one to consider.

 

Having said that, and also considering your point on weight, distance and speed, I'm guessing that even if I had proper tire inflation, which I'm pretty sure I did, these conditions could still have significantly contributed to this more rapid tire wear. I'm also guessing that temperature played a part as well.

 

Thanks.

[V7Goose]

Good points Goose. But if excessive weight makes more of the tire surface make contact with the road, there is MORE friction, not less, the same as if the tire is under-inflated. Logic (not science) tells me that under-inflated tires wear faster. And like added weight, if tire pressure is too low, then too much of the tire's surface area touches the ground, which increases friction between the road and the tire. Thus, tires wear out earlier, and they could also overheat (more friction). Again, not exactly a scientifically based argument, but one to consider.

I have to quibble on a couple of points. Most importantly, "contact" does not equate to "friction", nor does it cause friction. If you set a brick on your desk, there is no friction, nor any wear to either the brick or the desktop. If you SLIDE the brick on the desk, you get both friction and wear.

 

Now a rolling tire is not like a flat brick - we all know that, but the principle is similar - the more perfectly a tire or wheel rolls, the less friction. That is why higher air pressure (aka harder tires) increases fuel mileage. It is the slipping caused by both acceleration and deceleration that causes most tire wear. More weight on the tire reduces the slipping. Note that the "slipping" to which I refer is rarely obvious as spinning tires or locked brakes - all changes in speed between a road surface and the tire surface will try to generate some slip. Even if the weight is enough to almost totally prevent surface slip, the flexible rubber will deform against the road surface while the tire tries to change the speed, and then as it reaches the edge of the contact patch the rubber will loose grip and be scraped briefly as it snaps back into its normal position.

 

Under-inflated tires wear faster primarily because they flex a lot when they are in contact with the road surface - the flexing causes the rubber to slide and scrape.

 

Heat in tires is mostly caused by two things - the flexing of the carcass (exacerbated by under inflation) and the movement of the air molecules against the inside of the tire as it rotates - since that air is trapped, the heat cannot be blown away.

 

Finally, if the load is within the rating of the tire, and the tire is properly inflated for each load (light load or heavy), then the contact patch is not significantly different, nor is the flexing much different.

 

As a side note, the suspension of a vehicle can have a HUGE impact on tire wear, and wear cased by poor suspension design can be massively exacerbated by additional weight. On a motorcycle, the tires always move in a straight line with the axis of the bike, so the biggest impact the suspension can have is if it is not properly tuned for the weight of the vehicle. The compliance of the tire with the road surface over bumps will change the perceived weight between the tire and the road; then contributing to more slip.

 

A three or four wheeled vehicle has many more suspension issues to deal with. Poor suspension geometry will destroy anything. Cheap independent suspension designs often have the axle attached in a fixed position to the control arm, allowing the tire to move in an arc around the control arm attachment point. This could be easily seen on old Volkswagens and Ford Escorts, where a loaded vehicle would look like the tires were splayed out on the bottom and leaning in at the top. This type of suspension causes the part of the tire in contact with the road to constantly scrub back and forth (sideways) with every bump, scraping off rubber at an amazing rate. In contrast, better suspension designs keep the tire vertical with the ground as it moves up and down, reducing this type of wear.

 

Goose

[hi 05 silver]

I changed out my rear tire this week after 11,200 miles, and it was the poorest performance on a rear tire I've had in 4 years. I'm a big fan of the ME880, and I've always gotten 15K+ miles from them, and significantly more on the front tire (my current front tire has 22K on it, and still has very good tread).

 

I'm wondering if the combination of more long distance trips over the last 9 months, greater weight on the back (between riding two up and/or carrying heavier luggage for longer distances), and especially the more excessive heat conditions we've had this year on our trips are all playing into this poorer-than-average mileage I got this time around on the rear tire. Or maybe I just got a sub-standard tire back there to start with last time around. The date stamp on it was 5110, so it wasn't a very old tire when installed in September of 2011.

 

I always keep 40 - 42 psi in the rear, along with 25 to 30 psi in the shock, so those variables are pretty consistent.

 

Is there any intel on overall motorcycle tire performance with heat as a variable? I've Googled the subject, and there's not much out there.

We are a Metzeler dealer and at our shop we too are fans, and most of our customers, of the me880 on rsv, rstd, and many other bikes. Heat does effect tire wear but not as much as improper inflation pressure. Metzeler tires are high perfomance tires and run higher inflation pressures. The Metzeler factory fitment guide says for rsv,and rstd 36/42 for front, 44/49 for rear. The lower pressures are for solo only,the higher for two up. If these tires ,or any tire for that matter, are run low they will run hotter than they should and wear. Metzelers run higher inflation pressures than other brands.

[Miles]

Ya know...I tried to stay out of this one, because I saw it going downhill fast. However, when advise that is given is absolutely wrong, someone needs to step in and say...whoa !

 

V7Goose, it is a fact that more weight equates to more wear on a motorcycle tire. Yes, there are other factors involved, and the two of you have covered most of them. I do not want to rehash what has already been covered. But when you tell BobbyG that extra weight on a motorcycle does NOT contribute to wearing out a motorcycle tire faster than an unloaded motorcycle, then I have to say...BS. When you say, "Weight, on the other hand, generally makes tires last LONGER ", something is wrong with your thinking, or experience.

 

First, BobbyG, your Metzler ME880 tire is underinflated. You should be running 44 - 49 psi in that rear tire, on that bike. No if, ands, or butts about it.

 

Secondly, given all the parameters that you, BobbyG, initially stated in your original post, yes...you will wear a rear tire faster than in previous years. Accept it, live with it, and decide if you want to carry all that extra weight, or what.

 

Extra weight is not the only contributing factor, but it is a big factor in tire wear. For anyone to think that extra weight on a motorcycle does not contribute to extra tire wear...quite frankly...they must be drunk, or not at all experienced in science theory.

 

As I said, there are many other contributing factors, that you two have already covered, but...do not think for one second that added weight on a motorcycle does nothing to the wear of a tire.

Edited July 20, 2012 by Miles

[V7Goose]

V7Goose, it is a fact that more weight equates to more wear on a motorcycle tire.

You think I am wrong, and I am positive you are wrong - I guess we'll have to just agree to disagree on this and let the readers decide for themselves based on information provided and their own research.

Goose

[Miles]

V7Goose, I did not state that I "think" you are wrong. I too can make the statement that I am "positive you are wrong".

 

I could very easily challenge you to a riding contest, using exact same bikes, same years, same models, and we ride side by side for the next 15,000 miles. The only difference would be that my bike would only be carrying me...and your bike would be carrying you, plus 300 additional pounds of weight on the back seat. Gee...all you other readers...which one do you think would wear out their rear tire faster ?

 

Given that I have used up 200 sets of tires over the past 42 years of riding, and that Dunlop used me as a test riders for 3 years, shipping new product tires directly to my home, from England, and asking me to put 10,000 miles on a new tire in one week, in such 'n such corner of the USA, then ship the tire carcass back to them, I would state, unequivicably, that I have more miles and years of tire riding experience than you.

 

Once again, my only point of contention here, is that added weight on a motorcycle DOES increase the wear factor on a motorcycle, and you say...weight does NOT add to the wear factor.

 

WOW !

Edited July 20, 2012 by Miles

[V7Goose]

Personal attacks do not in any way increase your credibility. Please stop such unacceptable behavior on this site.

Goose

[Freebird]

I can easily resolve this issue...a Texas rider that riders Italian bikes...hmmm...a recipe for disaster.

 

 

I agree that the above statement was uncalled for. It's ok to have differing opinions but this type of comment does nothing to resolve any differences.

[bryan52577]

I know this is about bicycle tires but very interesting read anyway. And kind of goes right along with what V7Goose was saying. I'm sure you can see the similarities between bicycle and motorcycle.

Our company changed out all our tractors and trailers for the "wider" tires as they got nearly 20% MORE life as the "narrower" duals. (IE wider = more contact patch).

WEAR TEST DATA for SELECTED BICYCLE ROAD TIRES

 

Compiled by Kerry Irons

New tire data (23mm unless noted). Thickness in 0.001 inches.

 

http://biketechreview.com/tires_old/images/img2B4.gif

TIRE USAGE/WEAR DATA (all tires 23mm unless noted). Thickness in 0.001 inches.

http://biketechreview.com/cache/multithumb_thumbs/b.600.600.16777215.0...tires_old.images.img2B6.gif

TUBULAR TIRES

http://biketechreview.com/tires_old/images/img2BA.gif

http://biketechreview.com/tires_old/images/img2BC.gif

 

 

 

TESTING NOTES:

(a) Tire not worn out but significant tread wear.

 

(b) Tire not worn out but significant aging (crazing, cuts)

 

© Tire worn so that casing just showing

 

(d) Tire worn so that casing showing extensively

 

(e)Tread separating from casing

 

(f) Ridden by one rider who felt it was worn out at 1500 miles, then ridden 1100 more miles before the casing started showing through tread.

 

All tires 23 mm marked size unless noted. F/R refers to whether and how much the tire was used on the front or rear wheel. Tires were weighed on a Mettler balance accurate to 1 gm. Thicknesses (tread and sidewall) are in thousandths of an inch, as measured with a micrometer accurate to 0.001". Tread thickness was measured in the center of the tread in at least 5 locations around the tire. Sidewall thickness was measured in at least two locations away from any lettering or labels. Since rubber can be compressed, an attempt was made to apply equal pressure (by feel) on each measurement. Variations in pressure could have caused thickness measurements to vary by 0.003 - 0.004". Vredesteins have softer tread than the Michelins or Contis, making it harder to get consistent readings.

 

If people are willing to send me their worn out tires along with some key data like rider weight, mileage, use on the front or rear, and riding style, this data base can be updated with results from the newest tires. If you're interested in contributing, e-mail me for details: irons54vortex at sbcglobal dot net.

 

OBSERVATIONS

 

Tire wear is proportional to rider power output, which is typically proportional to rider weight. The mechanism of tire wear (weight loss) is that small particles of rubber are abraded from the surface of the tire. Force per unit area grinds off the rubber, so higher rider power and lower contact area increase the rate of wear. For a given amount of power dissipation, lower speed (e.g. when climbing hills) means that the tire will wear faster because that amount of power is not spread over as large a total tire area in a given period of time. Higher tire pressure results in a smaller contact patch and faster wear.

Because power dissipation is mostly through the rear tire, most wear occurs on the rear tire, far more than can be explained by F/R weight distribution. Unless there is a LOT of heavy front wheel braking, a front tire can lose minimal weight due to wear, even after thousands of miles. Front tires may thin a little due to "cold flow" of the rubber on the casing. Front tires "age" due to environmental exposure, and so wear much faster if they are subsequently mounted on the rear. If a front tire accumulates significant mileage and is then moved to the rear, it will show about 1/3 faster wear than a new tire mounted on the rear.

If there is significant hard braking (e.g. lots of steep down hills) then front tires can wear due to power dissipation. Riders who do lots of intervals, "stomp" rather than "spin," corner hard, etc. will accelerate tire wear.

 

Road bicycle tires are worn out (casing threads beginning to show through the tread) when they have lost roughly 10% of their weight. Obviously, there are wide variations in tire construction which can shift rubber (and weight) to the tread or away from it, but for the lightweight road tire this general rule applies.

 

There is a significant difference in construction philosophy for different tire brands and models. For example, with nominally similar high performance tires, side wall thickness has been measured between 0.020 to 0.040 inches. For tires at similar weights, this can mean tread thickness (including casing) ranging from 0.030 to 0.050 inches for tires targeted at the same performance rider. The extra tread thickness, along with rubber compound differences, explains the significant mileage differences seen between brands and models of tire.

About the author:

Kerry Irons is a recently retired chemical engineer who has been an active cyclist since the mid-1960s. Irons began self-supported touring with high school friends in 1965, which led to a Michigan- Seattle-San Francisco solo ride in 1970, and a ride around Lake Huron in 1971. Since that time, Irons’ annual riding has averaged 7,000-12,000 miles, including commuting to work year-round and many roller miles in the darkness of Michigan winters. From 1980 to 1985, Irons operated Cyclo-Pedia, a mail order bicycle parts business. Irons rode tubular tires for nearly 30 years, but converted (along with his wife) to clinchers in 1998. This stimulated him to record tire wear data as a way to find better tires and to understand the issues of tire wear. Discussions with members of CyclingForum.com resulted in several riders sending worn out (and not so worn out) tires to Irons for measurement, the result of which is the information presented here

[Kirby]

Fellas, let's just chill a little. I think there has been a little misinterpretation here. Goose said,"Weight, on the other hand, generally makes tires last LONGER." I don't think Goose or anyone else believes that I should go out and overload my bike so that the tires will last longer. He was just explaining that reduced friction, by increasing weight on the tire, will stop or reduce the slipping which causes wear. If a tire is forced to turn under power, that power will try to break the tire loose and cause it to spin. Case in point, a burnout. If the weight on the motorcycle was so much that the power could not turn the tire then it would be impossible to do a burnout. How long would the tire last? Unknown. Same principle, different case, during stopping. How many have slid the back tire and got a flat spot on the tire? If the load were such that the tire couldn't slip, there wouldn't be a flat spot created on the tire. You'd have some really great traction and it would be like running into a brick wall, because the stopping power would probably throw you from the bike.

Now getting back to the issue. If a tire and bike is loaded within the manufacturers' specifications then the tire wear is mostly left up to road conditions and the rider's driving habits. As with anything that has a tolerance, once you leave the optimum specs and go toward out of tolerance, more wear will naturally occur. Goose and Miles are both right, but this being a forum with where vocal tones and expression are left to words that are typed out, it's so easy to be misunderstood.

[V7Goose]

Well stated, Kirby. It is important to realize that we are talking about motorcycle tires here, where the power to weight ratio is very different than most other vehicles. That is why bike tire wear is so significantly affected by riding style. ANYTHING that reduces the amount of slippage between the tire and the road will have a huge positive impact on tire wear. This means that added weight WITHIN THE LOAD RANGE OF THE TIRE has fairly insignificant negative impact on wear from the load (compared to other causes of bike tire wear), and a huge positive impact by reducing the slip.

 

If we were talking about trailer tires, the whole discussion would be totally different. Trailers do not exert acceleration or deceleration forces on the tires (ignoring trailer brakes), thus the only real factors that affect wear are alignment, inflation and weight. In that application, if we assume alignment and inflation are correct, that leaves only the load as a significant factor over similar road surfaces.

 

But to restate the obvious - we are talking about bike tire wear, not trailer tires. I only brought trailer tires into the discussion to help illustrate how important it is to focus on the application instead of a generic imagination about tires.

Goose

[pmelah]

ok im no expert on tires but i do have personal experiances with them same type of therory (IKMS) tires on my truck only weight i needed (tools and parts) compressed air to 35psi 40,000 mi rating wore out in 35,000 mi. same load senarieo same brand of tires 50psi wore out in 48,000 mi 3rd set same 50psi with nitrogen wore out 52,000 mi next set all tools and part + extra parts 40 psi nitrogen wore out 35,400 mi. 2nd set 40 psi compressed air 32,000 mi. for a total of 202,400 mi. on my truck 3rd set 50 psi nitrogen i i now have 53,266 mi on the tires and have about 47% tread left on the tires i will post pics of milage and tire penny trick for this set of tires and will try to dig up my old tire reciepts that show mi. tires were changed out @ so weight does seem to help in my case suckson fuel milage im only getting 18 in the city 22 hwy in my 99 suburban on bfgoodrich longtrail t/a tires

 

also wife has 2011 ford fusion with 93,000 on oem tires 38psi nitrogen and i am about to change here tires out soon she carries no weight in the car exept for collage school books computer work stuff half the store and i think she has the kitchen sink in there some where i haven seen it for a while now

[MikeWa]

I agree with all of you guys.

Mike

[Bobby G]

Been gone for several days and just now catching up with all of this.

 

Thanks for all of the feedback, suggestions, rationale, argument, perspective and point of view. If we can all sift through the chest pounding and "right vs. wrong" pontification, I think we can all learn a few things that just might be important to us in one way or another.

 

I will look further into the rear tire inflation issue for the ME880 and make the appropriate adjustment. I also see the value in making sure my suspension is working properly, as the bike is 13 years old and is pushing 100,000 miles on the original shock. Hard to believe, but true, but it seems to be fine. But I'll check it.

 

Other than that, some of this made for great reading and research, and I appreciate everyone weighing in.

 

Thanks!

[Bobby G]

Just to validate what was suggested as the correct tire pressure for the Metzler ME880, I pulled this directly off the Metzler web site:

 

ME880

 

Solo: Front 38 - 40 Rear 44 - 46

2 Up Light: Front 40 - 42 Rear 46 - 48

2 Up Heavy: Front 40 - 42 Rear 48 - 50

 

I will be making the appropriate inflation adjustments accordingly.

 

Thanks again for the suggestion.