Tread carefully

[Matt2matt2002]

I have been running a pair of Schwalbe Marathon Plus babies on my Dawes Sardar tourer.
One puncture in the last 1,500 miles.

Tred depth is the question.
Should I measure it and if so what depth is safe?

They look like they could easily go another 500+ miles

My riding is 95% of the time unloaded on tarmac roads

Thanks folks

Matt

[Danneaux]

Hi Matt!

On their website, Schwalbe say their tires can be run till the blue under-belting shows through the tread...

In bicycle tires the tread is far less important than for instance in car tires. So using a tire with a worn out tread is less of a problem, that is of course with the exception of MTB tires.

When the puncture protection belt or the carcass threads can be seen through the tread the tire has reached its wear limit and must be replaced. As the puncture resistance also depends on the thickness of the tread layer it may be useful to replace the tire earlier.

The sidewalls of tires often fail before the tread is worn out. In most cases, this premature failure is due to prolonged use of the tire with insufficient inflation pressure. Checking and adjusting the inflation pressure at least once a month with a pressure gauge is most important.

From: http://www.schwalbetires.com/tech_info/tire_wear

Best,

Dan.

[Matt2matt2002]

Jeezo!
And I had looked at the Schwalbe site myself 10 mins ago.
 
Ok - lets broaden this sucker out.

Whats an expected mileage I can expect?
Given average pressure, tarmac and unloaded riding.

Please don't tell me that's on their web page?
 
Matt - who is obviously not tired of this question

[Danneaux]

Whats an expected mileage I can expect?

Hi Matt!

I'm not sure this is answerable in quantifiable terms. As the tire wears, the contact surface area broadens (less tread = more slick) which should actually reduce the rate of wear. However, carbon black is highly wear-resistant, and once you wear through that into the "blue" underlayer (which is more pliable but less wear-resistant), the rate of wear should increase.

Jobst Brandt proved long ago (with Avocet tires) that tread does *not* help wet-road traction (in other words, a bicycle is not subject to hydroplaning in the same way as a car), so if your use is on pavement, and unloaded, you should be able to safely use the tires as Schwalbe recommend. I'm guessing, however, that you'll be come subject to more flats as the tread thins and becomes less subject to penetration by sharp objects.

I'd run 'em till I started getting more frequent flats, then retire 'em and get new. If I were going on-tour, I'd buy and mount new ones before departure.

My two cents, adjusted for inflation.

Dan. (...who, likewise, never um, "tires" of this topic   )

[Andre Jute]

The reason Schwalbe says until blue starts showing through is probably because they don't want you to run the tyre until it is all blue on the tread surface. The grey bits of the tyre have a different constitution to the blue bits of the protection rubber, and the handling characteristics may change. It may even be dangerous to ride on the blue. What is certain is that the blue rubber will wear very fast, because it lacks the carbon in the grey outer.

I run Schwalbe Big Apple Liteskins, and I have one getting thin, so I'll run it till the top surface wears through to see what happens. Don't forget to report here if you discover before I do.

Andre Jute

[jags]

don't think i would fancy riding a well worn tire on wet roads

[Matt2matt2002]

Thanks folks.
That point about tread and hyrdoplaning rang a bell with me.
I was amazed to see some of the motorcycle tyres in my area with little or no tread.

Could you give me a link for the info?

Matt

[Danneaux]

Here ya go, Matt; this one falls readily to my typing fingers, so gets forwarded first:
http://sheldonbrown.com/brandt/slicks.html

Best,

Dan.

[Danneaux]

...and a whole, entire related thread from the Good/bad ol' days of USENET, here:
http://yarchive.net/bike/slicks.html

Best,

Dan.

[Andre Jute]

By golly, I miss Jobst Brandt, probably the finest (and among the handful of most distinguished -- Formula 1 cars still stop on brakes he designed for Porsche more than half a century ago) engineering mind to be turned to cycling in our time. And Ken Kifer, who makes a cameo appearance, who influenced me enormously in my statistical approach to bicycle safety, component choice, etc; I chose Andy Blance after Ken was killed by a drunk driver, because he had the same pragmatic approach.

Andre Jute

[rualexander]

From the Schwalbe North America website : http://www.schwalbetires.com/tech_info/tire_wear
Marathon Plus quoted expected mileage of between 8000km and 15000km.

[Danneaux]

By golly, I miss Jobst Brandt...

Me, too. Andre...have you any word about how Jobst is doing -- long-term -- after his accident: http://search.bikelist.org/beta/TreeView.aspx?id=443462 That's nearly two years old. This update posted October 2011 sounded encouraging: https://groups.google.com/forum/?fromgroups=#!topic/rec.bicycles.tech/hnhG5WjRKSY (with your 2 cents' worth added).

By any chance, do you know if he was able to get back on a bike?

All the best,

Dan.

[Andre Jute]

No, he's not riding. I'm not aware of any more reliable news than that he's out of hospital, at home, lucid and receiving visitors. -- AJ

[il padrone]

Marathon Plus quoted expected mileage of between 8000km and 15000km.

This would be pretty correct. I've been getting 12000 - 15000kms from my Vittoria Randonneur Cross tyres, a similar highly durable touring tyre with high-level puncture protection.

[revelo]

See Jeff Kruys's Schwalbe experiences, in the "Fun, Facts and Figures" sections of his trip journal:

http://www.crazyguyonabike.com/doc/page/?o=1r4vFZo&page_id=81957&v=2Ok