In praise of riding low pressure tyres fast

[Andre Jute]

Hello, Frank, I'm the OP. I wouldn't worry too much about hijacking the thread; I'm anyway constitutionally averse to staying on some narrow subject because you always miss out on what the other fellow knows but is reluctant to say for fear that he'll be accused of being OT.

The thread is about everything, positive and negative, to do with wide tyres and low inflation. It's just fortuitous that I have some fast downhills on rough roads and have found the Big Apples to be faster over them than one would expect from the common leaning of roadies towards narrow high-pressure tyres.

A prosperous new year to all, and may you cycle safely.

Andre Jute

[E-wan]

if you're worried about the weight, you should spend
the few bucks more and get the Big Apple Liteskins which are pounds
lighter per pair, and the superlight racing tube as well for another
substantial weight saving.

Thinking of getting a pair of 26” x2.15 Big Apple Liteskins for my nomad for the summer (assuming the snow eventually goes)

Are there lighter presta tubes that you can use with them that will still retain their pressure as well as normal 54-559 Schwalbe tubes?

When I have tried light weight tubes in the past I have given up as they have needed toped up with air every few days.

Thanks

Ewan

[julk]

Ewan,
I use some of these
http://www.sjscycles.co.uk/schwalbe-sv14a-xxlight-presta-tube-26-tyres-40-559-to-54-559-prod14897/
and they are half the weight of a 'standard' tube.
They keep the air in for ages.
Julian

[Andre Jute]

Thinking of getting a pair of 26” x2.15 Big Apple Liteskins for my nomad for the summer (assuming the snow eventually goes)

Are there lighter presta tubes that you can use with them that will still retain their pressure as well as normal 54-559 Schwalbe tubes?

When I have tried light weight tubes in the past I have given up as they have needed toped up with air every few days.

You're thinking of "racing" tyres.

These Schwalbe "ultraleich" that I recommend lose air very slowly. I have a proper SKS Rennkompressor (and a nice digital gauge as well) but I use it about every month or two months and I've never applied the minipump carried on the bike to these tubes except when I tried it to see if it actually works. They're now 3 years old and have done 6300km, and they hold air as well as when new. In any event, these fat tyres are very forgiving, and the Schwalbe minimum recommendations are just that, recommendations; you can ignore them with impunity. I weigh 14 stone and have ridden my 60mm Liteskins down to 1.5bar on occasion, and for months on end at 1.6bar, and the fellow who put me onto the Big Apples weighs 350 pounds and rides his at 2bar; more normally I start mine at 2.03bar, which is where I find I have the best compromise between comfort and secure handling on potholed but fast downhill lanes, and a month or two later find they still have 1.8bar in them. Tyres that fat just shrug off rough roads and abuse. It may well be that even lighter tubes, if properly made, would also be satisfactory; I don't know because I tend to stick with Schwalbe and they don't make anything lighter than ultraleich in my size, though they do in yours (see the XX Type 14A).

The ones I use are Schwalbe 62-622 Type SV19A i.e. Presta, 140g each v 220g for the standard T19 tube. They make a definite difference.

American Schwalbe site http://www.schwalbetires.com/bike_tires/tubes

German Schwalbe site http://www.schwalbe.com/gbl/en/produkte/schlaeuche/index.php5?flash=1&ID_Land=38&ID_Sprache=2&ID_Seite=148&tn_mainPoint=Produkte&tn_subPoint=Schlaeuche

It looks like the standard Presta balloon tube for 559mm rims is Type SV13 at 190g, with Type SV14 as the Extralight (bad translation for "ultraleich") tube for 559mm rims, at 130g each. Type 14A appears to be the XX "racing" tube, 95gr. So the tube you want (if the idea is to use the ones I have good experience with) is Schwalbe Type SV14 54-559. It comes wit 40mm or 60mm Presta valves; that's what the SV in the codes stand for, Schlaverand, or French, or Presta valves, which are all the same thing.

If you decide to try the 95gr tubes, don't forget to report here on your experience.

Andre Jute

PS Have you checked the clearances for 2.15 tires?

[E-wan]

If you decide to try the 95gr tubes, don't forget to report here on your experience.

Andre Jute

PS Have you checked the clearances for 2.15 tires?

Thanks for the advice both of you

Decided to give the Schwalbe SV14A XXLight Presta Tubes a shot, as you say Schwalbe tend to make them fairly well and I've never had trouble with their other tubes loosing pressure


I hope 2.15 bigg apples will fit,  currently running 2.1 ice spikers and they fit ok and only clog the mudgards in soggy snow or lots of mud.

Ewan

[E-wan]

Thought I had it sorted but it looks like they don't make folding big apple tyres any more!

I can find the light skin folding version of them still available in 2.0 that's a little narrower than I was hoping for.

Anyone seen any of these still available in 26×2.15 folding?

[Andre Jute]

Thought I had it sorted but it looks like they don't make folding big apple tyres any more!

I can find the light skin folding version of them still available in 2.0 that's a little narrower than I was hoping for.

Anyone seen any of these still available in 26×2.15 folding?

I don't think you'll notice the difference unless you previously had the 60mm Big Apples fitted. I don't have direct experience but it seems logical. It is commonly said by experienced cyclists who have tried both that in normal use the 50mm Big Apple offers 95% of the value of the 60mm. You have to be really heavily loaded (and one of the guys saying it has weighed twice as much as I do, and I'm no featherweight) or ride through obstacles like a maniac, really to get the value out of the 60mm width (and all the associated costs of building a wider bike), or so they say. In any event, though I reckon you should design for the 60mm if you buy a custom bike, on the general principle that the best will soon prove to be barely good enough, there's no disguising the fact that most people consider the 50mm plenty good enough.

Andre Jute

[Danneaux]

Hi Ewan!

To echo Andre's comments (and he has the most experience of any of us wrt balloonbike tires), Schwalbe say the following...

What is the difference between Balloonbikes with 50 and 60 mm wide tires?
60 mm wide tires provide maximum Balloonbike comfort. But also the lighter weight 50 mm wide tires had double the air volume of a standard 37 mm tire. The 50 mm wide tyre is a good choice for anyone who wants a sporty yet comfortable ride. Between these two sizes there is also a popular 55 mm width.

This comes from Schwalbe's Balloonbikes™ FAQ: http://www.balloonbikes.com/en/faqen.html

They have an entire (and newly updated) site on the topic here: http://www.balloonbikes.com/en/

It is a bit hard to dig out, but they consider their 50mm/2.0 Dureme to also be a balloonbike tire, albeit on the "sporty" side. I'm having success running mine between 2.0 and 2.5 bar (~29-36psi) and seem to have settled on F/R pressures of 29/32psi recently when riding my Nomad with a lightish day load. For reference, I weigh 172lb/78kg. The unladen bike weighs 45lb/20kg. With water, a HB bag, and the usual amount of "stuff" along -- and water -- the bike weighs about 65lb/29kg. Add these figures together to get the total bike weight, then halve it for average static load per tire (weight distribution aside). Of course, with a heavier touring load, I'd run the tires at higher pressure.

Running the tires -- particularly the front one -- at these pressures has the effect of a rising-rate spring under compression. In other words, the tires absorb niggling, low-amplitude/high-frequency vibrations wonderfully. I don't even feel expansion joints between concrete slabs, and chip-seal (the bane of American cyclists) feels as smooth as the best-finished asphalt. However, over large bumps, the tires compress initially, then very rapidly firm-up while still protecting the rim adequately. You do still feel the bigger bumps, but the effect is blunted, for lack of a better term. I'm learning all sorts of things from my experiments. For example, on rough logging roads, I sometimes feel the effects in my neck. I had supposed a front pressure adjustment would best address this, but in fact, a (relative) reduction in rear tire pressure made the biggest difference in correcting what amounted to a pitch-moment.

Amazingly, the bike rolls well with the 2.0 Duremes tires at 2.0-2.5bar. Drop below 2.0, however, and it feels like I'm pushing ("wheelbarrow effect") even though sidewall distortion isn't noticeably increased or even visible.

I'm going to buy a pair of mechanical/analog bathroom scales today so I can see what my actual front/rear weight distribution is at various loads. Digital strain-gauge scales don't work well for this, as they "hunt" for awhile before settling down, and if the weight shifts during the calibration process, the result can be wildly "off". I need something a bit more dynamic so I can see what's happening with weight shifts and load distribution.

I still largely go by Frank Berto's 15% drop method as a guide in determining maximum tire pressures; I use his figures as a starting point. Frank updated his tire pressure article from the original that appeared in American publication Bicycling magazine many years ago. It is a bit dated (2006) by current standards, but now includes minimum pressures for 26in/MTB tires in addition to optimum pressures for narrower tires. see: http://www.bccclub.org/documents/Tireinflation.pdf The graphed output is linear, so the trendlines can be exended for higher loads.

A bit more about Frank Berto here: http://www.thedancingchain.com/About%20Me.htm

Best,

Dan.

[Andre Jute]

In other words, the tires absorb niggling, low-amplitude/high-frequency vibrations wonderfully.

This modest-sounding advantage of balloons has far-reaching effects. I'm a writer. A writer is in fact a sort of manual laborer. He operates a keyboard while looking at a blank wall or out of the window. My hands are extremely sensitive to tiny vibrations. Until I went over to balloon tyres, bicycling used to wreck my hands and wrists. Schwalbe's Marathon Plus, which have their advantages too, are especially bad in this regard. An hour on the bike with Marathon Plus fitted was about as much as I could take before the tingling in my wrists became unbearable. We too have the cheap chip seal road surfaces...

But it isn't just me and my professional sensitivity in my hands and wrists. If you're not irritated by these micro vibrations, your whole ride becomes more agreeable, you ride better and further, and you ride safer too because you're not irritable and doing stupid things like cutting off large SUVs. I was saying to my wife yesterday that I haven't given the physio, who once ruled my life, a thought since I bought a Herman Miller Mirra chair and went over to a bike without suspension struts but with balloon tyres.

There are many other benefits to balloon tyres, most of them well canvassed in this thread, but the microvibration damping is so important, it bears stressing -- because it's absence doesn't stress the cyclist!

Andre Jute

[E-wan]

Thanks for the replies and your thoughts and observations.

I had initially been thinking of 2.0 Duremes but thought of opting for Big Apples instead when I noticed they were available in 2.15. My rational at the time was that over the winter I have been running 2.1 ice spikers and have on a few occasions when going over a kerb or root etc felt the rear tyre make contact with the rim. This was with a modest lode in 2 small rear panniers. Admittedly I have been riding the ice spikers at around 2 bar (30 psi) which Is lower than I would intend to run Summer tyres at.

However I just went and measured the ice spikers and found that they are 46mm in diamater across the carcass on my regida andra rims (measures with a pair of callipers pinching the sidewalls). If I measure the distance across the nobbley spiky bits on the edge of the tread this is 54mm. This might suggest that a 2.0 dureme or big apple might actually have more air in it than a 2.1 ice spiker. Therefore seems to make sense to try a 2.0 tyre rather than hint around for one in 2.15 which would be heavier anyway.

Any idea what the difference is between 26x2.0 Duremes folding and 26x 2.0 big apple liteskins? It looks like the duremes are lighter at 630G where the big apples are 675g at 2.0. Also the tread on the duremes looks better suited to a little off road work than the big apples but it’s hard to tell without experience.

Thanks

Ewan

[Danneaux]

Ewan,

I just calipered my 26x2.0 Duremes mounted on Rigida Andra rims measure 47.73mm at 32.1psi/2.21bar. At their full 70psi/5.0bar rating, they measure 49.97mm, so that's when they are 50mm/2.0 inches on Andras.

Mounted and inflated tires often vary from their stated widths, usually in the narrower direction if less than full rated pressure. From the sound of things, your 2.1in Ice Spiker with similar pressure has nearly identical air volume to my 2.0 Duremes.

I've found the tread on the Duremes provides a better mechanical lock with dirt than a road slick or nearly slick tire like the Supreme, yet has tread blocks arranged to create a center ridge while riding. A photo of mine spinning is here: http://www.thorncycles.co.uk/forums/index.php?topic=3896.msg18965#msg18965
...photo linked directly here: http://www.thorncycles.co.uk/forums/index.php?action=dlattach;topic=3896.0;attach=1318 Not much tread contacts the ground in road use. On soft soil, the entire tread width comes into play, providing more traction.

It is not a tire or tread specifically aimed at off-road or on-road use, but a nice compromise between the two, making a good all-'rounder that rolls silently without any buzzing noise or feel. My guess as to the weight difference between the two? Given equal bead materials, I think the more open tread of the Dureme may contain less rubber overall than the Big Apple's larger, incised tread blocks.

Have you looked at the Big Ben? Similar to the Big Apple, but with a different, taller tread design for increased traction. Unfortunately, it seems to be available only in a wire bead listed at a more portly 720g. Schwalbe's North American site lists the 26x2.0 Dureme folding at 590g: http://www.schwalbetires.com/bike_tires/road_tires/marathon_dureme If only all 6 of mine (4 wire, 2 folding) did not wobble...visually distracting but doesn't seem to matter in use.

Best,

Dan.

[julk]

Ewan,
I have recently moved to 26x2 folding Duremes and have been very impressed with them.

I was riding 26x2 folding Hurricanes before - the Duremes feel faster, more supple, easier to steer and just as comfy at the low pressures talked about in this thread. I guess tyre technology has moved on again.
Julian.

[E-wan]

Think I will Go with the 26x2.0 Duremes then & try these with extralight tubes.

Dan is that an clinometer on your bars? where did you get it from And how do you keep it level & Stop it from twisting through road vibrations.

I did consider the Big Ben but it seems to only be available in wire rather than folding at the moment.

Thanks

Ewan

[Danneaux]

Dan is that an clinometer on your bars? where did you get it from And how do you keep it level & Stop it from twisting through road vibrations.

It is! A SkyMounti from Austria. See: http://www.thorncycles.co.uk/forums/index.php?topic=3896.msg20102#msg20102 All info at the link above. They are available in two handlebar diameters and black or red cases. All the viewing windows are clear atop neon yellow-green for high contrast with the black printed numbers and indicators.

It reads directly in slope percentage from the forward and rearward edge of the bubble, which floats in a thick mineral oil and is very stable. The unit itself mounts on a rubber strip and is secured -- securely! -- with two screws that need only slight tightening (overtightening will crack the mount).

I love my SkyMounti inclinometer and have one on each of my bikes. I has added greatly to my cycling enjoyment, and weighs very little.

All the best,

Dan.

[Danneaux]

Hi All!

I now have a pair of identically-reading analog scales and am having fun looking at my weight distribution on the Nomad. What I wanted to look at was the static dry weight of the bike alone and how it was proportioned Front/Rear and the same with me aboard. The point of the exercise was to see the proportion of weight carried by the respective tires so I can adjust tire pressure accordingly to minimize rolling resistance while maximizing comfort. For fun, I did the same measurements with my favorite derailleur rando bike for comparison.

It is early days (I just got the scales), but here's what I found this afternoon...

With only myself (heavier in street clothes and with stuff in my pockets and on my belt) and a dry day-ride load aboard (underseat tool bag, but no other bags and with empty bottles; those are dynamic loads and I wanted to establish a static baseline), F/R weight distribution when riding on the Nomad's brake hoods is 39%/61%.

The front tire carries a lighter load and so can do with less pressure to aid comfort, while the more heavily-laden rear requires more. Further, the proportion is roughly 40/60 -- just as conventional wisdom has long held.

Out of curiosity, I measured the F/R weight bias of the Nomad alone. As above with a dry weight and no bags, the Nomad weighs in at 46lbs total, proportioned at F20lbs/R26lbs, or 43%/57%.

In contrast, the favorite of my 700x32C derailleur rando bikes measured similarly weighs 31lb total, proportioned 14lb/17lb, or 45%/55% alone. The bikes are not comparable in any way, so I can't really say how much the heavier Rohloff rear hub contributes to the 2% greater rearward weight bias (the Nomad has a steel vs. alu rear rack and longer rear stays as well as a ring-lock aft of the bottom bracket)

With me on it, the weight distribution on the rando bike is F81lb/R124lb, or 40%/60% (39.5%/60.4%).

Though we're comparing apples to oranges here and aren't holding constant for anything -- frame size, wheelbase, chainstay length or frame materials --the Nomad with me on it carries only 1% more of its weight on the rear wheel, despite all the weight in the Rohloff hub. In other words, the Rohloff hub along with everything else that makes the Nomad a Nomad, only results in a 1% difference in F/R weight bias when I'm on the bike.

Now, you'd think a 39%/61% weight bias would mean the same for tire pressures, but it doesn't work that way. Running the 26x2.0 front tire at, say, 2.0 bar/29psi would require the rear tire have ~73psi/5bar. This would be unnecessarily harsh and non-compliant at the rear. The front tire carries only 83lbs and the rear only 131lbs -- neither carries the entire load of 214lbs. Instead, if one wishes to adjust tire pressures proportionately, you take the difference between the front and rear: 61%-39%=22% so you take 22% from the front and add to the rear. Going with Schwalbe's 29/36psi/2.0/2.5bar is pretty close for F/R distribution.

Fun stuff!

Best,

Dan. (...who never tires of tire-talk)