Clearance and appearance

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Cycling x2 20 x 1.5 Schwalbe Marathons. I would like a Schwalbe Marathon Plus 20x 1.5 on the rear for additional security. Unfortunately Shwalbe dont do 'em. So 20 x 1.35 or 20 x 1.75? I am worried about 1.75 clearance with my mudguards,but wouldnt like to undo the uniformity of the appearance of the tyre(s) on the bike by having the rear tyre looking at odds with the wider tread of the tyre being on the front. Still...

Go less, or more?

Appearance wise,is their much difference between a 1.5 and 1.35. If the 1.35 was at the front I dont feel it would compromise the appearance of the bike. But t'other way round?

1.75 might just catch those guards......maybe...?

Your thoughts?

[JohnR]

I can more easily visualise small numbers in millimetres: 1.5 inches is 38.1mm. 1.35 inches is 34.3mm (- 3.8mm) and 1.75 inches is 44.4mm (+6.3mm). 3.8mm isn't much of a difference and I suspect will be barely noticeable, particularly since half the tyre is covered by the mudguard. Nonetheless, there's logic in having the rear tyre larger since it's carrying more load. Is there any potential for moving the rear mudguard out slightly if necessary? There's also the issue of nominal vs actual tyre sizes with the latter also being affected by the rims (see https://www.bicyclerollingresistance.com/specials/schwalbe-marathon-32-37-40-47 for some examples of actual measurements). You'll only find out how the actual tyre sizes compare by fitting them to your rims. Or would an alternative strategy to improve puncture tolerance be to put some sealant in the inner tubes?

[PH]

Clearance - Suck it and see.  Get some cloth, or paper and some tape of some sort and wrap it around a small section of the current tyre till it measures 1.75.  Spin it and see how it clears the guard.  Ideally you'll have 10mm of clearance on all sides, this seems to be the happy medium between best coverage and not getting clogged up.  If the guards have been neatly fitted around the current tyre size, there may not be any spare in the stays to let them out, but replacement stays are available.
Appearance - I run a wider tyre at the back on several bikes as a preference, 32/28, 40/35, 2"/2.15".  If anyone has noticed, they haven't commented and I frequently ride with the sorts of people who like to comment
I think you'd have to be looking closely to notice the difference between 1.5 and 1.75, IMO you're more likely to notice the extra comfort, though that my be negated by the "Plus"

[lewis noble]

I think a lot also depends on the sort of terrain you ride in.

My Mk 3 Audax was originally specced with 700/32 Supremes - and yes, as the brochure states, they did fit - just - with obviously extremely careful mudguard installation by Thorn.  They gave a lovely ride.

But at the time, a lot of the roads in our city (Sheffield) were being resurfaced / rebuilt . . . . . and gravel on the road surfaces was very common.  Gravel pieces stuck and scraped between the tyre and guard; never actually jammed or even perceptibly slowed me down, but I found it unnerving and not a good thing. 

The same happened on some of the rural roads around here.

So I swapped to 700/28s. Ride not quite as good, but less scraping and chattering.  If I could me more confident about surface quality on a long tour, I would probably revert to 32s.

I'm keen on quite generous clearance.

Lewis

[tyreon]

I would like to thank all those who replied to my query: thanks.

 I will do another sighting review of the clearances I have.

Its an irksome problem

I am not one for close tolerences. And too close can bring chatter or noise...and aint right!

[tyreon]

Update: Ordered 1.35 shwalbe marathon plus. 1.5 started rubbing rear mudguard yesterday after getting bike out from the car. Irksome

[Andre Jute]

0.15in is 3.8mm. Whether it will be enough extra clearance will depend on where you ride, as Lewis says. I've ridden for years with tiny clearances, between one and five millimeters, but I ride almost exclusively on clean blacktop, though the surface is potholed. I've found that the potholes are not a problem for clearance (though twice in a dozen years fishmouth punctures have caused spectacular decompressions in my ultra-low inflation regime, one of which caused a serious accident that could easily have been fatal were it not for the quick reactions of the motorists behind me) but cheap chip and seal roadworks cause nasty chattering and scraping between the tyre and the mudguard. To avoid giving up my beloved Big Apples or even scale them down*, I just don't ride on newly remade roads -- there's always a parallel lane.

*The late Kalle Kalkhoff, who developed the best of the modern Pedersens (now manufactured by Utopia-Velo in Germany, who bought the manufacturing rights), told me that he envied the 60mm Big Apples on my utility bike, but he'd have to sacrifice the mudguards on his bike, so he rode in the winter on 50mm Big Apples. In the summer he threw the mudguards off and felt no envy on 60mm Big Apples. He pointed out that a 50mm balloon already contains 50% more air than a 38mm tyre. Later I worked out why the effort was worth it for him: a 60mm tyre contains 50% more air again than a 50mm tyre. Regardless of your attitude to restrictive clearances, for comfort and roadholding your tyres should be the biggest you can usefully fit on your roads.

[tyreon]

Thanks all for replies. All wisdom.

I bought the schwalbe marathon plus 1.35. Today I went about my area to test the newly bought Brooks Cambian 17(?),cut out version. Oh dear. Has anyone any experience of these marathon tyres? I pumped mine up to maximum pressure and found them slippery on the back. Too high a pressure? I released some air. But they just dont feel...secure/safe. I wondered what was happening to my bike. Something amiss. Checked. All secure. Only thing I can think of was that I had the schwalbe 1.5 on the front and the 1.35 on the rear which could be a mismatch. The rear wheel drive felt very skitty. I'd be pleased to know if any others have had any similar experience.

As it was I was testing the Brooks Cambian cut out 17(?) I was out yesterday, and on the ride home...my ride was uncomfortable. This saddle is just not the leather B17...and I so wanted it to be so.

Have been out in the garage all morn forward shifting,back tilting the saddle alongside gauging the skittering marathons. More tiring and exhausting than doing any hilly fifty miler. Very frustrating

[PH]

It's not always a good idea to judge new tyres in the first few miles, it could just be the residue from the mold, the release agent, it wears off pretty quickly, but you could give them a scrub with an abrasive cleaner to speed it up.  Schwalbe are not usually bad for this, I've had a couple of pairs from Vittoria that were like riding on ice for the first twenty miles.
The size differential isn't going to make any difference. Each tyres grip is going to be independent of the other,  Even if not, the difference in contact patch which is the only bit that matters is going to be miniscule.

[Andre Jute]

I have experience of Schwalbe Marathon Plus and the lookalike, workalike American Bontrager Hard Case Elite. There are quite a few other posters who have mentioned their Marathon Plus over the years.

They're good for two things, and as far as I'm concerned, only those two things. They last a huge distance. They are just about puncture-proof.

On the downside, they are so stiff they're hell to get onto the rims. And, even worse, their ride is extremely harsh. But worst of all, they last a long time, so that eventually I hung up half-worn tyres when the small of my back could no longer take the banging. I went to Schwalbe's Big Apples instead, on the principle that they make good tyres and that the Marathon Plus was not misrepresented: it does what Schwalbe promises, which is to reach an impressive lifespan without undue (or any) punctures.

I was horrified to see you pumped your Marathon Plus up to the max, and not surprised at all by the poor initial impression they made on you. It is not necessary for either roadholding/handling or a long life. Try the minimum instead and you'll be a more comfortable and get better roadholding too.

Good luck with finding an inflation regime to suit you.

[tyreon]

I liked Andre's rebuke  . Thanks. Good wisdom offered. I think I can see reason in the 'over-inflation' as the tyres on feel alone feel like rock. I will be letting out some air. At the same time,I can see thee tyre has some shiny-slippery surface so that when pumped high and hard that could make them more skittery.

I cannot go to the garage today! My back and age preclude me promising 'it will only take 5 minutes' to my wife wherein through a lot of faffing I am out there an hour and cycling up and down my street to test my bikes ride. I'm better assured by the comments above. I'm now only left with the Cambium to sort out. The '5 minute' but-takes-an-hour alter-test-ride-alter-again-tilt-test ride-alter again-now less forward-now forward faffing is taxing. And I believe you can only get the true measure of any saddle setting after riding it for at least 10 miles. Many on here are more experienced than myself! It's why I dont like my garage and hate to say...It'll only take 5 minutes!

[martinf]

I have experience of Schwalbe Marathon Plus.

They're good for two things, and as far as I'm concerned, only those two things. They last a huge distance. They are just about puncture-proof.

But, having fitted recent models of Marathon Plus to visitor bikes to reduce tampering with the rear wheel to a minimum, I reckon the current models are less horrible to ride than the ones from a few years back. 

Having 50 mm section instead of narrower widths probably helps as well - in the narrow 700C x28 Marathon Plus with the space taken up by thick sidewalls and puncture protection layer there isn't much room left for air.

[Andre Jute]

But, having fitted recent models of Marathon Plus to visitor bikes to reduce tampering with the rear wheel to a minimum, I reckon the current models are less horrible to ride than the ones from a few years back.

Thirteen years since I took the vow, Martin: "Never again Marathon Plus!" I'm too soft now to go back to RealCycclistHardTyresAndHarderSaddles. My Brooks B73, though slightly scuffed under the wax, is amazingly still the same shape as it was 15000km ago, though I can't remember when I last took the little spanner to it. Best fifty quid I ever spent on a bike component, at a big sale SJS had in the early years of the century.