How did we delude ourselves about 23mm?

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busb
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Re: How did we delude ourselves about 23mm?

Postby busb » 18 May 2018, 7:31pm

Brucey wrote:re ride quality, this varies hugely with forks stiffness and this varies with build quality, fork material and brake type. Discs + fairly expensive carbon can be tolerable but a similarly engineered bike with rim brakes might well be comfier. Disc brakes and aluminium is liable to be pretty nasty, so fatter tyres are a good option.

Re remote MC on giants. AFAICT Shimano ship their hydro STIs without the hydraulics connected, and they cost a fortune too. Fitting and bleeding them on a production line is potentially very time consuming and any leaks at the MC end easily result in ruined bar tape etc. The remote MCs can be supplied pre-plumbed and pre-bled (which is probably easier anyway than with STIs) in two or three different lengths to fit the different size bikes and just whacked onto the bikes. As a solution it may be cheaper for Giant to buy, too.

For the customer it means that the brakes can be traded for mechanical discs if they can't maintain the hydraulic ones, and they can have a combination of shifter and hydraulic brakes that shimano doesn't offer. All kinds of daft knocks are unlikely to cause problems for the hydraulic system. So overall it isn't such a daft idea; looking at them, it appeared that they would be a piece of cake to work on, both mechanically and hydraulically. You can't say that about shimano STIs.... :wink:

cheers

That I can believe. The Flight is almost 5yrs old, still not been bled - I fitted new Shimano resin pads to the rear this morning - took 10mins.Their IceTech rotors are rather fussy about pads, the old non-Shimano ones weren't badly worn but badly glazed.

amediasatex
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Re: How did we delude ourselves about 23mm?

Postby amediasatex » 18 May 2018, 8:13pm

Mick F wrote:Just done 54miles with 23mm tyres on Mercian today on some very minor roads and also the Old A30. Quite rough tarmac in many many places too.

No issue at all. None in the slightest.


To be honest I don’t have many issues on short or medium length rides either on skinny tyres as long as the rest of the frame is doing the job and it fits well.

I do have one bike that is a bit unpleasant after about 3 hours but I can’t fit bigger tyres in it to compare and I have a feeling it would be like that anyway as it’s a very stiff racy frame.

My Audax bike of choice rolls on supple 25/28s (depends which wheels are fitted) and no issues for a few hundred km/12hr+ rides but it’s a very comfy flexy frame anyway, with a big fork offset so the whole flipping thing is an armchair ride and I’ve no doubt it would be tolerable I’m skinnier rubber.

Having said all that I do like the comfort of decent big 35/38s on my tourer and alternative audaxer and they’re nippy enough too.

Horses for courses and all that...

Peter W
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Re: How did we delude ourselves about 23mm?

Postby Peter W » 19 May 2018, 9:50am

Has anybody accurately tested bicycle tyre noise generation of different widths and pressures, over different road surfaces, and at a full range of speeds? (Rather complicated to test, me thinks.)

Noise has to be generated, and that generation must take energy. Those generating forces may be small, but then so is the claimed rolling superiority of 28 over 23 and that usually given at EQUAL tyre pressures (say 100 for each) which those using the wider tyres wouldn't be inflating them to. The softer pressures they use can give greater comfort, and such would be justification enough, but will they still be giving superior rolling resistance when you factor in that small but extra force needed to generate louder noise from their greater width. (Or are they not louder? Has it been tested?)

As somebody has already stated, people can be keen to believe what they want to believe, and the bicycle makers are not above playing on that!

robc02
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Re: How did we delude ourselves about 23mm?

Postby robc02 » 19 May 2018, 10:21am

.............. but then so is the claimed rolling superiority of 28 over 23 and that usually given at EQUAL tyre pressures (say 100 for each) which those using the wider tyres wouldn't be inflating them to.


Bicyclerollingresistance.com does test tyres at a range of pressures so it is possible to make comparisons that take into account the lower pressures usually preferred for wider tyres. For instance this comparison of a Continental tyre in three widths shows that the 28mm has the same rolling resistance at 60 psi as the 23mm at 80 psi. Similarly the 28mm at 80psi has very nearly the same rolling resistance as the 23mm at 120psi.

In terms of rolling resistance as measured by this test and for this model of tyre, it seems you can have your cake and eat it - the bigger tyre offering lower rolling resistance at the same pressure or the same rolling resistance at significantly lower pressure. As mentioned by earlier posters, there are other considerations to take into account as well, of course.

reohn2
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Re: How did we delude ourselves about 23mm?

Postby reohn2 » 19 May 2018, 10:33am

Comfort shouldnt be discounted either,especially over longer distances where the more comfortable rider will be ĺess fatigued which in turn will be trasferred to forward motion rather than wasted in in heat and tension in other parts of the body.

Consideration should be given to rider weight where tyre size is concerned,bigger rider equals a need for more air in a tyre of any given width.
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amediasatex
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Re: How did we delude ourselves about 23mm?

Postby amediasatex » 19 May 2018, 11:21am

reohn2 wrote:Comfort shouldnt be discounted either,especially over longer distances where the more comfortable rider will be ĺess fatigued which in turn will be trasferred to forward motion rather than wasted in in heat and tension in other parts of the body


Absolutely agree, what is good for an hour or two can be very unpleasant after 6hours, and can make the difference between completing a ride and bailing beyond that. ‘Fast’ isn’t just a matter of instaneous speed, average and ability to maintain that average over time is often as, if not more, important.

reohn2
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Re: How did we delude ourselves about 23mm?

Postby reohn2 » 19 May 2018, 4:39pm

amediasatex wrote:
reohn2 wrote:Comfort shouldnt be discounted either,especially over longer distances where the more comfortable rider will be ĺess fatigued which in turn will be trasferred to forward motion rather than wasted in in heat and tension in other parts of the body


Absolutely agree, what is good for an hour or two can be very unpleasant after 6hours, and can make the difference between completing a ride and bailing beyond that. ‘Fast’ isn’t just a matter of instaneous speed, average and ability to maintain that average over time is often as, if not more, important.

Which is what my worn body found when I began riding 35 and 38mm Hypers,I wouldn't go back to anything smaller :D
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Mick F
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Re: How did we delude ourselves about 23mm?

Postby Mick F » 19 May 2018, 4:50pm

I can six, seven, eight, or nine hours in the saddle on Mercian.
This week - Tuesday - I'm cycling to Exeter 65miles and on Thursday(?) I'll be doing a nice 87mile circuit.

Hilly round these parts. :wink:
Mick F. Cornwall

reohn2
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Re: How did we delude ourselves about 23mm?

Postby reohn2 » 19 May 2018, 5:03pm

Mick F wrote:I can six, seven, eight, or nine hours in the saddle on Mercian.
This week - Tuesday - I'm cycling to Exeter 65miles and on Thursday(?) I'll be doing a nice 87mile circuit.

Hilly round these parts. :wink:

I'll have to keep repeating this Mick,you could,repeat cold,be more comfortable on your Mercian with bigger tyres fitted(I know you don't have the clearances).That's what some people have found and as a result go faster because there's less wasted energy.Of course YVMV but unless you've ridden bigger tyres you won't know.
You're not allowed to say the Mercian is comfortable enough as you simply don't know until you've tried something else,The Moulton doesn't count either :wink:
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amediasatex
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Re: How did we delude ourselves about 23mm?

Postby amediasatex » 19 May 2018, 5:50pm

Mick F wrote:Hilly round these parts. :wink:


I know, I live on the other side of the Moor to you ;-)

Like you I can ride a full day or more on skinnies just fine, but I go as fast, but for longer and in more comfort on slightly fatter rubber.

The key bit for me is *no slower*, there is literally no downside for me, and in some cases I’ve ended up going faster overall due to being less fatigued. The 28mm shod bike is perfectly happy on rides that average over 20mph and no harder work. On longer rides at lower averages is definitely not slowing me down but definitely is more comfy and keeps fatigue at bay for longer. The skinnier tyres are the same speed*
but less comfortable, not UNcomfortable, just less so if it’s not slower why not be less fatigued?

* although as I’ve said in some cases when it’s particularly rough I have found for me they are actually either marginally slower or require more power for same speed, but that is only when it’s very rough.

Thing is you may, and apparently do, find different. But I’m comparing different tyres on the same bikes, often what a lot of people do is conflate tyre performance/differences with the bikes they’re attached to rather than varying in Isolation. Your bike works perfectly well for you in it’s current setup, but as Reohn2 says you simply cannot know if it would be better or worse with other size tyres if you haven’t or can’t try them in that bike. That’s not anyone disagreeing or dismissing your POV, it’s an absolute fact that if you can’t fit say 32mm tyres, then you cannot know how it would perform with them.

My gut feel is that it would be a little better descending due to increased grip, a little worse ascending due to a marginal weight increase but more to do with carcass deformation and high rhythmic input loads and associated losses. Probably virtuallly no difference in speed on the flat at constant 15-20mph on smooth roads, maybe a bit less work on bumpy ones, and a bit harder work on the flat at constant speeds between 25-30mph due to aero losses, but that might tip the other way on rough roads. And probably a bit poorer under hard accelerations again due to carcass squish. It would however likely be more comfy in all those situations. That might be of no value to you, to others it could be the difference between riding and not riding though.

Either way we can’t know for sure if they won’t fit ;-)

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Mick F
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Re: How did we delude ourselves about 23mm?

Postby Mick F » 20 May 2018, 6:15am

I think I could fit 28mm in my frame, but I wouldn't be able to fit brakes. :lol:
I came down Gunnislake Hill on Friday at 47mph, I had to hang on the brakes to get round the bends, so I do need them. :wink:

On Monday, I plan on cycling to Princetown via Yelverton and Peek Hill, then coming back down off the moor by Pork Hill.
I've done 52mph down there in the past. Great hill (both up and down) and it's one heck of a tough climb up.
Mick F. Cornwall

belgiangoth
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Re: How did we delude ourselves about 23mm?

Postby belgiangoth » 23 May 2018, 9:36pm

RickH wrote:I know some folk like to dismiss Jan Heine but his tests are explained and it would be easy to repeat them & show the errors in them or disprove them. So far I've not found anyone who has!

I'll take some issue with that. I have a lot of time for Jan, he's an nice guy and is trying to do something laudable. Unfortunately his work is pseudo-science at best and there are serious concerns about his methodology, statistical manipulation and lack of peer review.
1 - Jan's work has all the trappings of scientific articles, references and all that, but when you check almost all references are to previous articles that he published.
2 - He self publishes his own studies; this does not make them wrong de rigeur, but it is textbook signs of bad science. No one has checked his results before he publishes.
3 - If his results were good enough to publish, why has he not submitted them to an actual academic journal (e.g. the ihpva)
4 - He does not publish his raw data and it is not made available as his work is not peer reviewed. While I understand that many readers will just want the headline this is an issue if you want to be certain of his findings. For example his rolldown tests showing that wider tyres are faster - he does not try to state the errors on his measurements, but then claims that the differences are statistically significant. Unfortunately with reaction times of (typically) 0.2 seconds and making basic assumptions that the rolldown will not match exactly the same path each time (especially on the rough terrain he is aiming to test) his results cannot show the significance he claims.

I don't need to test to show divergent results from Heine, that's not how science works. The way science works is that you gather data and suggest a theory, if someone points out that your theory is not supported by your data you then need to collect more data to show that it is.

Fundamentally the reason why this is still a debate is that there are so many other factors that come into it that you would need an extraordinary amount of data over an extended period of time with a large number of riders. Maybe when we are all on strava with powermeters we could do some sort of world-wide data pool...
If I had a baby elephant I would let it sleep in the garage in place of the car. If I had either a garage or a car. (I miss sigs about baby elephants)

landsurfer
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Re: How did we delude ourselves about 23mm?

Postby landsurfer » 23 May 2018, 10:15pm

I've done another 30 miles today on my steel framed bike with 32 Marathons. These replaced the 28 Marathons.
To be honest the 25 Vittoria slicks from Decathlon are the most comfortable on the rutted roads of S York's ..
The best wave of my life is still out there.

Cugel
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Re: How did we delude ourselves about 23mm?

Postby Cugel » 23 May 2018, 10:18pm

belgiangoth wrote:
RickH wrote:I know some folk like to dismiss Jan Heine but his tests are explained and it would be easy to repeat them & show the errors in them or disprove them. So far I've not found anyone who has!

I'll take some issue with that. I have a lot of time for Jan, he's an nice guy and is trying to do something laudable. Unfortunately his work is pseudo-science at best and there are serious concerns about his methodology, statistical manipulation and lack of peer review.
1 - Jan's work has all the trappings of scientific articles, references and all that, but when you check almost all references are to previous articles that he published.
2 - He self publishes his own studies; this does not make them wrong de rigeur, but it is textbook signs of bad science. No one has checked his results before he publishes.
3 - If his results were good enough to publish, why has he not submitted them to an actual academic journal (e.g. the ihpva)
4 - He does not publish his raw data and it is not made available as his work is not peer reviewed. While I understand that many readers will just want the headline this is an issue if you want to be certain of his findings. For example his rolldown tests showing that wider tyres are faster - he does not try to state the errors on his measurements, but then claims that the differences are statistically significant. Unfortunately with reaction times of (typically) 0.2 seconds and making basic assumptions that the rolldown will not match exactly the same path each time (especially on the rough terrain he is aiming to test) his results cannot show the significance he claims.

I don't need to test to show divergent results from Heine, that's not how science works. The way science works is that you gather data and suggest a theory, if someone points out that your theory is not supported by your data you then need to collect more data to show that it is.

Fundamentally the reason why this is still a debate is that there are so many other factors that come into it that you would need an extraordinary amount of data over an extended period of time with a large number of riders. Maybe when we are all on strava with powermeters we could do some sort of world-wide data pool...


Whilst not disagreeing with most of your observations about the Heine "methodology" I must mention that you have the science = theory from facts thing back to front. In practice, scientists have theories (which are called, when the rest of us have them, "an attractive idea") followed by an exercise that attempts to find facts that prove the theory. The theories are often generated from the cultural matrix of the scientists, who will seek to confirm some related theories they like and/or disprove some related theories they don't like. Ditto "the facts".

Of course, it doesn't stop there (at least with proper scientists) as they also seek facts that disprove the theory. Just one of the latter is enough to do so. Mind, they still don't give up but instead amend the theory to accommodate the recalcitrant fact. Some of the more rascally ones redefine the facts so they fit. Yes, they do.

"Hoi, hoi", you may declaim. "Facts we come across suggest the theories"! Alas, the facts are in essence human perceptions of whatever reality is (already a limited and skewed set, then)... but only a little bit, as most of their definition is culturally generated by the various conceptions, categories, taxonomies and other schemas of things already extant in the language (including the mathematical language); not to mention the influence of already extant theories.....

Still, there is a scientific method and, when rigorously applied, it can result in a proven theory that is able to make predictions about what will occur when various pertinent facts coalesce. Of course, the predictions are often just approximate. Even Newton had to allow those Einsteinien divergences from his clockwork universe.

Anyroadup, scientific theories, like other cultural artefacts, can and do change over history. Even the methodologies change, although many scientists don't like that notion at all! No, they don't - a catechism or even a dogma is loved by all fellows enmeshed in cultural institutions and organisations.

****

As to Mr Heine - at the very least his suggestions are interesting and sometimes do seem to accord with personal experience. Just today I noticed that my 75psi 28mm shod wheels carried me downhill on the rough back roads somewhat faster than those lads on 105psi 23mms. But maybe it's just my fine aerodynamic crouch. Or my disinclination to wear the brake blocks & rims when a bit of extra lean (on more grippy 28mms) will suffice. :-)

Cugel

belgiangoth
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Re: How did we delude ourselves about 23mm?

Postby belgiangoth » 23 May 2018, 10:56pm

Yes, scientifically methodology is more complicated. It remains that not publishing all your results, lack of peer review and self-publishing are all warning signs of bad science.
If I had a baby elephant I would let it sleep in the garage in place of the car. If I had either a garage or a car. (I miss sigs about baby elephants)