Schwalbe Marathon/Marathon Plus de facto PSI

[Zenroad]

I'm about to shift allgiance (I think) from Continental to Schwalbe, and I'm curious about ACTUAL psi for the Marathon or the Marathon Plus, 26 x 1.75. The rating is 45-70psi. Is anyone running these tires above that?

My old Continental Travel Contacts (26 x 1.75) are rated at max 80psi, but I consistently run them at 90 without a problem.

Is anyone inflating the Marathon (or Plus) to 80 or 85?

 

[Stonepark]

Running marathon plus tours and marathon winters at 90 psi on rear and 45psi on the front, if you are looking for a commuting tyre, use a narrower tyre.

Both about 1.5 inch, tyre safety pressures are usually under twice the maximum the tyre can take, so you should be ok.

 

[Zenroad]

Thanks, Stonepark. Yeah, I know that tire ratings are usually well under the real safety limit.

As for width, 1.75 is as narrow as I want to go. I know that Schwalbes are tough, so I hope that 85psi is not pushing it too close to the limit. These will be for 95% on-road usage.

 

[willem]

Why would you want to inflate a tyre this much? It will negate all advantages of Mr Dunlop's wonderful invention. A much better strategy would be to use a more flexible tyre at lower pressures. That way you are far more comfortable, and significantly faster on any road surface other than a poole table. A 50 mm Schwalbe Big Apple at reduced pressure would be a much better choice, and more than sturdy enough. In winter, use the Conti Topcontact Winter II.
Willem

 

[hoopdriver]

Yes, there is no point in running them that high. It's silly. I run mine at about sixty five psi on my winter bike, which gives a nice blend of rolling and comfort.

 

[BigonaBianchi]

I just rode schwalbe marathon plus 28's across america at 100psi ..no flats at all and roll beautifully.

 

[SpokeyDokey]

32mm Marathon Supremes 90psi front and rear.

 

[hoopdriver]

Those aren't 26" tyres. I thought the OP was referring to 26" tyres. If they are 700c I too would run higher pressures, but for the 26" M+ on my winter bike I definitely keep to 65-70psi.

 

[ankaradan]

I'm about to shift allgiance (I think) from Continental to Schwalbe, and I'm curious about ACTUAL psi for the Marathon or the Marathon Plus, 26 x 1.75. The rating is 45-70psi. Is anyone running these tires above that?

My old Continental Travel Contacts (26 x 1.75) are rated at max 80psi, but I consistently run them at 90 without a problem.

Is anyone inflating the Marathon (or Plus) to 80 or 85?

Can I ask why?

I'm in the process of stripping large knobbly tyres of an old MTB, to use it on road/tracks. I'm looking at various Schwalbe and Continental tyres, and unsure what to go for

 

[Jimmy Doug]

I run mine at about 6 bar (85 psi). Never had a puncture in 6000 kms. I wouldn't go above this, however.

 

[Bodhbh]

Is there an issue with blowing rims when running large volume tyres at such high pressures? Not a rhetorical question, just wondered.

 

[robgul]

Is there an issue with blowing rims when running large volume tyres at such high pressures? Not a rhetorical question, just wondered.

... unless rims are knackered I would suggest it's highly unlikely

My 2p on pressures - I run every bike I have at 10 or 12% above the max it says on the tyre-wall ... better rolling, fewer flats .. and the ride isn't really affected in terms of comfort. (That's from 23mm on my fixed to 32mm on the tourer)

Rob

 

[Crankarm]

There might be a wide margin above which you can inflate the tyre but as Bod suggests think of the rim as well. A new rim might not be so much of a problem but a not so new one might fail even quicker than it might have. Might only apply to rim braked rims although disc rims can fail as well, although unlikely.

I inflate my Marathons and Specialised Nimbus' to max rating on side of tyre.

 

[willem]

Running wide tyres at high pressures can easily blow up your rims, and you could get badly hurt. I cannot now retrieve the sums I once saw, but blowing up a rim is easier than you may think. As for the benefits of high pressures, there are very few. High pressures increases (yes) the risk of punctures because the tyre is pressed onto the debris rather than gently fold over it. For the same reason, because wide tyres can be run at lower pressures, you will have fewer punctures from road debris the wider the tyre (and as long as you avoid snake bites). Finally, on real roads rolling resistance does not decrease with higher pressures. On the contrary, because a wheel with wide tyres and low pressures rolls more smoothly over an uneven surface. Ultra stiff tyres like Marathon Plusses are a partial exception to this, because they will not flex much even with lower pressures. They are always slow (and uncomfortable).
Willem

 

[snailracer]

...on real roads rolling resistance does not decrease with higher pressures. On the contrary, because a wheel with wide tyres and low pressures rolls more smoothly over an uneven surface...

+1

Inflating tyres harder will transmit more vibration to the rider's body/luggage, which jiggle more (so-called "suspension losses") and dissipate more power i.e. slower.

Running tyres that are too soft increases friction/deformation losses within the tyre, which also wastes power and is well-known as classic "rolling resistance".

It turns out (or, rather, tyres are designed that way) that power losses from both these effects are of similar magnitude for real-life roads and practical tyre pressures, and so there is a pressure sweet spot where the combined power losses from both phenomena are minimised. Empirical testing by some sources suggest that the sweet spot pressure is where the tyre drop of the loaded wheel is 15%:

http://www.dorkypantsr.us/bike-tire-pressure-calculator.html

http://www.bikequarterly.com/images/TireDrop.pdf

Note that the optimal pressure varies a lot with wheel load, which may be very different between different riders and front/rear, so one would have to find out the weight on each wheel using scales while sitting on the bike.

For smoother roads, a higher pressure will be faster, and vice-versa for rougher roads. However, as road roughness is hard to quantify, it is better (from a speed point of view) to err too low than too high, because suspension losses increase much more sharply (per PSI of over-inflation) than rolling resistance losses do (per PSI of under-inflation).

...Ultra stiff tyres like Marathon Plusses are a partial exception to this, because they will not flex much even with lower pressures. They are always slow (and uncomfortable).
Willem

While I do not discount your theory about stiff tyres being less comfortable, I am not convinced that even a super-stiff tyre is stiff enough to transmit much more vibration than a more flexible tyre. One possible confounding factor is that MP's and similar utility tyres tend only to be available in the larger sizes - it is often not possible to inflate them to low-enough pressure to give a 15% tyre drop, so they tend to be over-inflated and therefore uncomfortable.

For example, I would have to inflate my front 1.75" MP tyre to only 30 psi to carry the 30kg load on my front wheel - this would conflict with Schwalbe's instructions, which mandate they be pumped to at least 45psi to keep them secure on the rim. The result is, I pump them to 45psi and accept the extra discomfort.