Author Topic: Actual size of 559-50/26" x 2.0" Dureme and Supreme Tyres  (Read 676 times)

kwkirby01

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Actual size of 559-50/26" x 2.0" Dureme and Supreme Tyres
« on: March 26, 2020, 04:40:08 PM »
I'm looking to fit larger tyres to Sherpa to get a little more comfort. The frame will take them and my mudguards (50mm Gilles Berthoud) still have a lot of clearance.
I've measured my existing "40mm" Supremes and discovered they are closer to 34mm...
So, how big are 2.0"/50mm Duremes and Supremes when fitted - does anyone know?
Thanks, Kevin
Kevin K. Glasgow

Danneaux

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Re: Actual size of 559-50/26" x 2.0" Dureme and Supreme Tyres
« Reply #1 on: March 26, 2020, 05:06:13 PM »
Kevin, I had the same question when I got my first pair of Duremes, so I measured them with a caliper.

I found the actual width varied as a result of pressure, age (they stretch ever so slightly with use), and the width of the rim they are mounted on.

I have 6 pairs mounted on 3 bikes. The narrowest combination when new was mounted on a Rigida/Ryde Andra 30 rim and was an actual 47.1mm wide. The widest is a well used Dureme (standard, not tandem edition) on an Andra 40 rim on the rear of my tandem. It measures 49.237mm wide.

Best,

Dan.

kwkirby01

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Re: Actual size of 559-50/26" x 2.0" Dureme and Supreme Tyres
« Reply #2 on: March 26, 2020, 05:24:38 PM »
Thanks for the prompt response Dan. Any idea of the height, which I think might be the limiting factor on my bike.
Kevin K. Glasgow

Danneaux

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Re: Actual size of 559-50/26" x 2.0" Dureme and Supreme Tyres
« Reply #3 on: March 26, 2020, 06:35:32 PM »
I'll check when I get the chance, Kevin. Most bicycle tires (not all, but most...depends on the angle of the bias plies) have a 1:1 ratio where height from the edge of the rim to the outside of the tread is equal (or nearly so) to the inflated width at the widest point.

EDIT: If it helps, Thorn fitted Mk 2 Sherpas with 2.0 Duremes as standard back in 2011 and to the end of the production run. I had no clearance issues running 26 x 2.0 Duremes on my 2011 Sherpa Mk 2 with SKS P55 mudguards. Thorn had fitted nuts as spacers between the 'guards and the brake/chainstay bridges and under the fork crown. There would have been even more clearance with those removed. Photos attached to show how things looked.

All the best,

Dan.
« Last Edit: March 26, 2020, 07:21:53 PM by Danneaux »

Danneaux

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Re: Actual size of 559-50/26" x 2.0" Dureme and Supreme Tyres
« Reply #4 on: March 26, 2020, 07:19:03 PM »
Okay...just checked. To make sure of a maximum measurement, I pumped 50psi into one of my Duremes mounted on an Andra 30. The 1:1 ratio held. On the front of my Nomad Mk2, the tire measured an actual 47mmx47mm (rounding fractional millimeters).

As I mentioned earlier, most but not all bike tires inflate to similar 1:1 profiles (or nearly so). In the early--mid 1980s, Panasonic introduced and marketed a tire for the triathlon market that had the belts biased so the tire constrained laterally and allowed to grow vertically so it was oval when inflated. In those days, even racing bikes still had pretty generous bridge/fork clearances but often had narrow forks. The idea was to add some cushioning and rim protection vertically while keeping the tire as narrow as possible. It sold very poorly and was discontinued shortly thereafter.

A touring bicycle I purchased in 1989 was equipped from the factory with radial tires, a special model supplied to the maker under contract and again from Panasonic. I soon swapped them out for standard bias-ply tires because while they worked well enough, they felt horrible under me. The tread would stay planted while the sidewalls would move sideways over the contact patch, making it feel as if the tire was sliding out form under me, especially when cornering and carrying a touring load. The only "cure" was to run them inflated so they were rock hard, which defeated the purpose. They were soon pulled from the market as well.

'Hope the measurements help you.

Best,

Dan.

mickeg

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Re: Actual size of 559-50/26" x 2.0" Dureme and Supreme Tyres
« Reply #5 on: March 26, 2020, 07:21:33 PM »
I have used 50mm or 2.0 width Dureme on the front of my Sherpa and 2.0 or 50mm width Extremes on the rear.  That was what I used on trips that were mostly gravel.  The attached photo has these 50mm tires.

I have 40mm tires on my Sherpa right now, so can't get you any measurements, I use 40mm Marathons (with greenguard) on trips that are mostly pavement.

I have fenders, I do not recall the model but they were made by Planet Bike and are 60mm wide.  The 50mm tires fit fine inside those fenders as shown in the photo.

Second photo also has the 50mm tires on the Sherpa.  Disregard the blue tape, I wanted to protect teh paint from the receiver hitch rack on a long drive.

There are several different versions of Sherpas, not sure which mine is, I bought the frame used in 2010, so it is at least that old.  I do not know if tire clearance changed over the different versions, my frame size is 610S and it has a pump peg on the rear seatstay.

mickeg

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Re: Actual size of 559-50/26" x 2.0" Dureme and Supreme Tyres
« Reply #6 on: March 26, 2020, 07:25:47 PM »
One more thing, with the 50mm Dureme, I have a tire circumference of 2057mm which is what I use for my bike computer, I am sure that the number has a plus or minus of several mm.  If you need a radius of the wheel, I will let you calculate that.

kwkirby01

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Re: Actual size of 559-50/26" x 2.0" Dureme and Supreme Tyres
« Reply #7 on: March 28, 2020, 05:08:58 PM »
Thanks to both of you for responding. Having looked again at my mudguards in light of "real life" measurements, I suspect I will need bigger mudguards to fit the larger tyres.
Kevin
Kevin K. Glasgow

mickeg

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Re: Actual size of 559-50/26" x 2.0" Dureme and Supreme Tyres
« Reply #8 on: March 28, 2020, 08:14:00 PM »
I usually try to have fenders (mud guards) at least 10mm wider than my tires, but sometimes with fenders that have pretty wide brackets I can get away with 8 mm wider.

djb

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Re: Actual size of 559-50/26" x 2.0" Dureme and Supreme Tyres
« Reply #9 on: June 15, 2020, 12:05:22 PM »
I'm looking to fit larger tyres to Sherpa to get a little more comfort. The frame will take them and my mudguards (50mm Gilles Berthoud) still have a lot of clearance.
I've measured my existing "40mm" Supremes and discovered they are closer to 34mm...
So, how big are 2.0"/50mm Duremes and Supremes when fitted - does anyone know?
Thanks, Kevin

Greetings. Saw this topic and wanted to add my experience with 2inch Supremes. Rim width  plays a part in how a tire width plays out. On my "tough trip" bike, a surly troll, the Supremes which should be 50mm measure out to 45mm on my rims.
I've measured my rims in the past, inner and outer, but don't recall the numbers off hand.
But I'm fairly sure that a wider rim than what I have would result in a slightly wider real life tire measurement.

If interested, get back and I'll measure them.