How did we delude ourselves about 23mm?

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

Postby reohn2 » 16 May 2018, 4:21pm

pwa wrote:
reohn2 wrote:
pwa wrote:If my ride to work was over cobbles I would be on MTB wheels. The pro riders are actually making do with tyres as narrow as 30mm. But for country lanes I find 25mm fine, faster than 32mm, and I don't remember having too much trouble with 23mm. And when you get down to it, the difference between 23mm and 28mm is only 5mm, which most people would regard as no big deal.

Do the maths on air chamber volume


But does it make that much difference? I don't think it does. 28mm tyres feel only slightly different to 25mm. It's Princess and the Pea stuff. I don't feel all that much more comfy on 35mm Hypers compared to 25mm GP 4 seasons, both being good at taking the sting out of the road. For me the big benefit of the larger tyre is that it removes most of the risk of wrecking a rim on a pothole.

We'll have to agree to differ,though I haven't ridden 25mm GP 4 seasons,I've ridden other 25mm tyres and the difference between them and 35mm is huge for comfort,especially on rougher tarmac the UK is renowned for,though the bigger tyre is slower IME it ain't enough for me to worry about,but one area I really appreciate is descending,where 35mm Hypers are far,far faster and more secure especially on rough/bad tarmac.
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Jezrant
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Re: How did we delude ourselves about 23mm?

Postby Jezrant » 16 May 2018, 5:48pm

mig wrote:
Brucey wrote:if you want to feel the negative effects of the road surface on speed, just find a rough surface on a gentle downslope, and ride down it (eg coasting) a few times using narrow tyres, pumped up hard, but just sitting on the bike differently. You will find that if you

a) ride sat in the saddle (like a sack of potatoes) with your arms locked rigid and then change to

b) raising one's backside out of the saddle so that the majority of one's weight is supported on the pedals, with a light grip on the handlebars only,

you will go appreciably faster in the latter case. The difference is in the so 'called suspension losses'. There are many shades of grey inbetween, involving fatter tyres, and/or lower tyre pressures, or different ways of sitting on the bike that influence whether the bike works as part of the sprung or unsprung weight. Note that quite small differences in speed may represent quite large changes in the losses, depending on how much aero drag there is.

Not that I think it is remotely representative of any kind of normal riding, but Jan Heine has ridden down rumble strips at speed and reckoned that with skinny tyres it might cost you 300W or so, but nothing like so much with fat tyres. On a local TT course I used to ride regularly, there were concrete edging stones by the side of the road. In parts this left a very smooth surface about 7" wide that you could ride on, if you concentrated hard. I reckoned it was worth about 0.5mph over the less smooth parts of the main carriageway, in other places where the road surface was a bit smoother anyway, a fair bit less.

BTW an obvious practical point is that if you ride on (normal) bumpy roads, have mudguards on your bike, and you like them, you may as well choose your next set of tyres to be as wide as the mudguards are, more or less; you may get an aero benefit (over skinnier tyres under mudguards of the same width) as well as an effective Crr reduction.

On a bike without mudguards fitted it is less clear what is the best thing to do; much fatter tyres may roll easy at low speeds on bad surfaces but may result in a net loss of speed due to the poorer aerodynamics when you are riding on average surfaces.

cheers


the origins of marginal gains! :wink:


Pro riders do something similar on the cobble sections in the Paris-Roubaix. They've also been using wider tyres recently, as wide as 30mm, with different frames that have more clearances and longer brake calipers to fit the wider tyres.

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The utility cyclist
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Re: How did we delude ourselves about 23mm?

Postby The utility cyclist » 16 May 2018, 7:33pm

Samuel D wrote:
The utility cyclist wrote:Liam Tanfield rode tubeless at Tour of Yorkshire, whilst GC leader his tyre burst off the rim, destroyed his carbon wheel and nearly put him out the race and lucky not be seriously injured.

Do you mean Harry? I hadn’t heard about this tubeless experiment. Any more details?

Yeah, I had Liam imprinted in my mind for some reason even though I watched him in the commonwealth's and the ToY.
The only reason I knew he was tubeless was when he mentioned the tyre blowing off and causing him to crash.

The article linked didn't mention what width he was using but I notice the 28mm tubeless Maxxis Padrone is the same weight as my 27mm Veloflex tubular, once you add in the extra weight of the wheels (300g more than my Campagnolo Bora's), the risk of a blow off on a tubeless and I'm only seeing sponsorship as the reason to use them, it can't be for outright performance.
people keep mentioning pinch flats but I've never had one, I'm sure some punctures are slowed/avoided but when you puncture very, very infrequently anyway I don't see the point, not for all the hassle/cost.

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

Postby Peter W » 17 May 2018, 8:03am

Yes! Clicks, creaks, coughs (all me not bike), rattles and whistles (all bike not me) certainly affect my progress more than tyre width, as indeed does whatever piece of music (most annoyingly Wagner) is incessantly churning through my mind at the time. But as for climbing steep hills at plodding speed (think Park Rash etc) I can't think that anything but power to weight ratio plus, in my case, gear ratio really matters.

The new (year old) Spesh Roubaix came with 11 speed cassette with 32 big cog, and standard 50/34 compact front. It wasn't what I needed so had sub-compact 48/32 front rings fitted to give my needed 1 to1 bottom gear ratio. (All my riding is Moors and Dales with steep hills galore.)

But age advances year on year, and last week, I found that the second ramped up corner of Park Rash defeated my efforts. (Had to push about 30 yards past it before riding all the rest.) Fortunately, I have an older Roubaix which has only 9 speed gearing. The beauty of 9 speed is that road shifters are compatible with MTB cassettes and rear mechs. I already had Deore mech and 11/34 cassette on it with standard compact front (1 to 1 bottom) so I've just fitted another MTB cassette 12/36 to give a lower bail out bottom gear. (Park Rash on it today.)The tyres - ordinary G.P. 4000 's 25mm at 95 pressure.

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

Postby Peter W » 17 May 2018, 5:28pm

Success! It's really made my day.

What a difference that cassette has made to being able to hold some semblance of regular cadence, on very steep climbs. Kettlewell to Leyburn in one, non stop. Nothing to 25 year old perhaps, but meant the world to me.

The hardest part I found was the initial straight climb which steadily ramps up approaching that first left hand hairpin, of which the inside part is even steeper than a steep thing. (Front wheel reaching for the sky, or trying to!) But not having rushed that section there was enough in reserve for the second ramped hairpin, and to be able to keep going till reaching the slightly eased rest of the full climb.

What I find now, is with a maximum heart rate of only around 164 (80 years old) the lower gearing is necessary for continuous steep climbing to prevent getting way out of breath. (Gasping to try and fill lungs - not wise anymore.) At just less than maximum effort, with normal deep hard breathing, and average heart rate around mid 140's, the effort can be held for as long as the climb takes, with no sign of distress. This seems to make nonsense of the oft repeated mantra that max heart rate should equal 220 minus age!! (220 minus 80 equals 140, which doesn't match reality.)

There must be many other elderly cyclists here. What do they find?

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

Postby StephenW » 17 May 2018, 10:52pm

MickF, I do I recall you saying somewhere else that you prefer quite a slow cadence? Perhaps this is why you have no problem with narrow tyres. Slow cadence = more force on pedals = less weight on saddle and hands perhaps? I guess the legs are quite good at responding efficiently to vibration, rather than shaking the whole body through the saddle.

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

Postby Mick F » 18 May 2018, 6:26am

StephenW wrote:MickF, I do I recall you saying somewhere else that you prefer quite a slow cadence? Perhaps this is why you have no problem with narrow tyres. Slow cadence = more force on pedals = less weight on saddle and hands perhaps? I guess the legs are quite good at responding efficiently to vibration, rather than shaking the whole body through the saddle.
I reckon you are right.

Yes, I like higher gears and when I had a cadence sensor, my long term average cadence over years and years was 67rpm.

Maybe there's an advantage to cycling like me?
Mick F. Cornwall

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

Postby mig » 18 May 2018, 9:15am

Peter W wrote:Success! It's really made my day.

What a difference that cassette has made to being able to hold some semblance of regular cadence, on very steep climbs. Kettlewell to Leyburn in one, non stop. Nothing to 25 year old perhaps, but meant the world to me.

The hardest part I found was the initial straight climb which steadily ramps up approaching that first left hand hairpin, of which the inside part is even steeper than a steep thing. (Front wheel reaching for the sky, or trying to!) But not having rushed that section there was enough in reserve for the second ramped hairpin, and to be able to keep going till reaching the slightly eased rest of the full climb.

What I find now, is with a maximum heart rate of only around 164 (80 years old) the lower gearing is necessary for continuous steep climbing to prevent getting way out of breath. (Gasping to try and fill lungs - not wise anymore.) At just less than maximum effort, with normal deep hard breathing, and average heart rate around mid 140's, the effort can be held for as long as the climb takes, with no sign of distress. This seems to make nonsense of the oft repeated mantra that max heart rate should equal 220 minus age!! (220 minus 80 equals 140, which doesn't match reality.)

There must be many other elderly cyclists here. What do they find?


thumbs up & applause :)

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

Postby pwa » 18 May 2018, 9:22am

mig wrote:
Peter W wrote:Success! It's really made my day.

What a difference that cassette has made to being able to hold some semblance of regular cadence, on very steep climbs. Kettlewell to Leyburn in one, non stop. Nothing to 25 year old perhaps, but meant the world to me.

The hardest part I found was the initial straight climb which steadily ramps up approaching that first left hand hairpin, of which the inside part is even steeper than a steep thing. (Front wheel reaching for the sky, or trying to!) But not having rushed that section there was enough in reserve for the second ramped hairpin, and to be able to keep going till reaching the slightly eased rest of the full climb.

What I find now, is with a maximum heart rate of only around 164 (80 years old) the lower gearing is necessary for continuous steep climbing to prevent getting way out of breath. (Gasping to try and fill lungs - not wise anymore.) At just less than maximum effort, with normal deep hard breathing, and average heart rate around mid 140's, the effort can be held for as long as the climb takes, with no sign of distress. This seems to make nonsense of the oft repeated mantra that max heart rate should equal 220 minus age!! (220 minus 80 equals 140, which doesn't match reality.)

There must be many other elderly cyclists here. What do they find?


thumbs up & applause :)

+1 Consider my hat well and truly taken off.

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

Postby mig » 18 May 2018, 9:29am

Mick F wrote:
StephenW wrote:MickF, I do I recall you saying somewhere else that you prefer quite a slow cadence? Perhaps this is why you have no problem with narrow tyres. Slow cadence = more force on pedals = less weight on saddle and hands perhaps? I guess the legs are quite good at responding efficiently to vibration, rather than shaking the whole body through the saddle.
I reckon you are right.

Yes, I like higher gears and when I had a cadence sensor, my long term average cadence over years and years was 67rpm.

Maybe there's an advantage to cycling like me?


maybe that tyres with smaller air pockets suit bikes that fit the rider well? or bikes that the rider is well adapted to.

yesterday evening i went for a quick trundle on 23c ultremos but using a new pair of shoes. i quickly found out that they have a lower stack height by maybe 3mm or so and hence the cushioning from the tyres/frame wasn't its usual peachy self as i was 'plonked' that bit more heavily on the saddle. i did most of the distance in 53 x 13 to try to lift myself off the seat that tad and, as you say, absorb any hits through my legs.

i rode the bike again this morning in my normal shoes and back to feeling 100% okay on them (slightly chafed harriss notwithstanding.)

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

Postby Mick F » 18 May 2018, 3:40pm

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.
Mick F. Cornwall

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

Postby busb » 18 May 2018, 5:02pm

My Defy has 25c tubeless & my Flight 3 has 30c tubeless. The Defy is noticeably more comfortable than the Ali-framed Flight. The Defy's pressures are higher. I suspect the difference is down to frame design - my Defy is the most comfortable bike I've owned. I personally wouldn't run 23c tyres again around mid-Berks! As for punctures on either: still none.
As for rolling resistance being better with bigger tyres on correctly sized rims, I don't have the means to refute or confirm this so can only add that folk tend to believe what they want to rather than necessarily what's so.

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

Postby Brucey » 18 May 2018, 5:12pm

which model defy do you have?

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

Postby busb » 18 May 2018, 5:30pm

Brucey wrote:which model defy do you have?

cheers

2017 Defy Pro 1 with original tyres. Stock apart from Giant's CF bars, some Ti bolts & 28-11 cassette. The bars do take out some of the road buzz.
I was on holiday in Frome for a long weekend 2 weeks ago where I visited a LBS that sold Giants. The Defy they had had their cable to hydraulic converter bolted on - seems to be a shortage of hydraulic levers! Some here have posted about rear hub failures - mine's OK but haven't done that many miles so far. Did ask them about this but was told they had not experienced such failures.
Added:
Also ditched the stock saddle for a SI SLR Flow 2017.

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

Postby Brucey » 18 May 2018, 6:13pm

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
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