tire wear
 

whats worse under inflated or over inflated?

i already replace a dunlop k571 after 4000-4200 miles and it was bald.
now my front tire was under inflated by 6-8lbs and is half worn( just pumped it up)

i got rear at 40psi on metzler marathon 880
i got front at 30psi on maxxis touring

If I assume that over and under inflation is with respect to manufactures recommendation, and that you do not go above the maximum marked on the tire sidewall, then under inflation will increase rolling resistance and if you go low enough you will encounter handling/steering problems. If you go above manufacturers recommendations then the rolling resistance will go down and the fuel consumption will go down [more mpg] as well...

As I understand it, low pressures give more resistance and build more heat because the tire will buckle more as it contacts the road.

I'd be careful over-inflating cycle tires though.


Jay

UNder inflation is worse.

I run 46psi (nitrogen) on my tires. I get 35-38000 miles uot of them.
When I first got the car 5 yrs ago I ran 32 like a good boy. I got 40,000.
For the improved mileage I'm more than happy.

(but, yhat on a car)

It's interesting that you titled this thread "Tire Wear", then ask about inflation pressure with out refering to wear in your question.

I think you'll find that there is an optimum value for inflation pressure that maximizes tire wear, but there are other consideratiuons such as ride quality, traction, handling, impact resistance, etc. that will have different values - and that may change what you think might be best.

Well, a rear tire often wears much faster than a front. It's the case with my Heidenau K73 pair, of which I had to replace the rear after 10250km (6370mi) (almost reached the wear mark at the 80k maintenance) while the front looks pretty new, the 2nd rear may wear earlier than this front.

With the Metzeler Z6s it was different, they got worn at the same pace, they were replaced together at 28000km (17400mi).

As a rule of thumb, rear wears faster on a stronger bike, and it also wears faster with more weight on it. My Teresa (650cc 50hp single, used mostly <4000rpm) is not too hungry compared to many other bikes today, yet half of that 10250km was 2-up which may count.

I always inflate the tires more than BMW recommends, sidewall max at most (2.9bars with the Z6s and 2.5/2.7 with these K73s).

I was told I was running to much air. 40psi. When it recommends 35-36 psi (rear) that is y my dunlops wore so fast. I still say it was a soft tire.
About 10% of my riding maybe less is 2 up.

High air pressure will be much less likely to cause rapid wear than pressure set too low... same goes for the grip of the tire, too liitle air compromises traction more than too much.

The same here. With too low pressure Teresa behaves, well, strange when cornering. Too high is strange too (at least with these K73s), but too low is definitely much worse.

First off, comparing front and rear wear on a bike is different because the vast majority run differnet size tires. Secondly, you have different model and brands of tires front and rear. Depends how you dide a lot too. More cornering will wear the front faster, more long straight driving will wear the rear faster. From several years of reading on several bike forums very rarely do front and rear tires wear at the same rate and in the same way. I have my miles divided between too many bikes to have needed tires so I can't say from experience though.

good article on it
Motorcycle Tire Wear

Thanks for the link, it was an interesting read! Especially that I have clear signs of left side wear on my front. I was quite surprised when (after almost 30000km on the present front) I saw how much more the left side is worn than the center, which I was measuring before. So much that I'll ditch the front before it could get really close to the wear marks at its center.

Other than that, I'm quite focused on wearing the rear instead of the front. Trying to avoid braking spares front, riding at lower speed than most other riders spare both - but P&G uses much more acceleration than keeping reasonably constant speed. So I definitely put much more stress on the rear than on the front.

I can't do the math because of many unknown factors, but I probably only convert worn rear rubber to saved gas with P&G, instead of clearly saving anything. But it's more fun this way...

Bikes are fairly critical of the pressure they need in their tires. Too little and they wear and overheat from buckling, too much and the tiny hard non-compliant contact patch will have very little traction. When riding daily on two wheels your life is all about traction. I would not consider exceeding the sidewall max pressure.

15,000 miles on my CBR250R and the rear is almost gone. The front is maybe 1/2 way.

It was the dunlops. Way too soft.

Now have metzlers 880 me got 7k on the rear with not much wear. Notice not much difference in grip. The 40hp cruiser don't need sticky tires.