[hawkinspeter]

wtjs wrote:

it’s worth avoiding fumes from petroleum products and isopropanol alcohol

I am suffering from an infection with staphylococcus pedantreus, so you can’t have ‘isopropanol alcohol’

From https://en.wikipedia.org/wiki/Isopropyl_alcohol

Isopropyl alcohol (IUPAC name propan-2-ol and also called isopropanol or 2-propanol)

[hawkinspeter]

Xenophon2 wrote:

I once used an oven at low temp to dry a chain that was first stripped with naphta, rinsed with isopropanol, then ultrasonically cleaned, then rinsed with water.  It smells a bit  even at low temperature.  Since all smells are particulate, something comes off and I’m not too sure that that something is safe to breathe in.

I doubt that any lingering smell will impact your health, though it’s worth avoiding fumes from petroleum products and isopropanol alcohol.

[hawkinspeter]

I don’t follow how it’s an

I don’t follow how it’s an international concern when they’re complaining about plans for Oxford (which they aren’t correct about anyway). The ony way I can see that it’s international is if it’s an environmental push-back by fossil fuel concerns – probably funded by the likes of Exxon https://thecompost.io/articles/exxonknew

What’s really ironic is that there has been a massive conspiracy by oil companies to gaslight the public about climate change and refute climate science so that they can continue to make money before society collapses, yet we keep getting people that argue on the side of continuuing to design everything around cars and not figure out more sustainable ways that people can get around.

[hawkinspeter]

Pffft!

Pffft!

You can buy a new pick-up truck for $2000: https://supercarblondie.com/car-reviews/cheapest-pickup-truck-china-chang-li-explorer/

[hawkinspeter]

brooksby wrote:

Please put any comments below HP’s forum post instead 

Cheers – I could do with the extra ad revenue.

I suspect road.cc will pick up on this in due course anyhow as they’ve covered Whiteladies Road previously.

[hawkinspeter]

I’m keeping an eye on that as

I’m keeping an eye on that as I’m going to need to replace my original Fly12 model at some point. It’s been dropped multiple times, has a bit of a rattle and I’ve accidentally removed the charge port cover, but it’s still working.

[hawkinspeter]

mattw wrote:

I think that’s probably fair comment from Ashley, even though some here may feel it is making it about smeone else – there’s been at least one account in AN’s comments recently of a driver in an accident later killing themselves.

Important elements of a necessary conversation where all sides need to try to avoid getting too angry.

As a regular reader and commenter both over there and here, I think the headline on this article is unnecessarily confrontational.

Obviously, we don’t want drivers (or anyone) taking their own lives due to just trying to get around the public roads, but I don’t think it’s a useful point to bring up when there’s pedestrians and cyclists being killed regularly by poor driving. Imploring cyclists to follow all the car-based rules on the roads by asking cyclists to think of the poor drivers is unlikely to be a successful gambit when it’s clear to cyclists that they are themselves vulnerable and errors of judgement usually end up wiith a lot of pain.

[hawkinspeter]

marmotte27 wrote:

marmotte27 wrote:

The video only shows that/how the energy is stored. The amount of energy absorbed through a temperature rise by the frame will be so small as to be negligible. With a frame flexing at the rate of 90rpm I’m your pretty sure you’re not getting even a temperature rise of 0.01°C. It has been shown that riders put out more power on flexible frames : https://www.renehersecycles.com/the-biomechanics-of-planing/ (Just in case : please don’t come out with any René Herse bashing now, without providing contradictory sources of at least equal quality.)

That’s much more like it. Finite element analysis and double blind testing, but shame that the issue isn’t online: https://www.renehersecycles.com/shop/print/issues/bq-24/

Now that I can see that there is some science/explanation of the benefits of flexy frames, I’m much less sceptical of flexy frame anecdotes.

[hawkinspeter]

Backladder wrote:

I want to see them do it again with the pedal at the bottom of the stroke, because that is where the frame tension is released in normal riding, that experiment only works because the crank arm is nearly horizontal.

I wonder how much of the flexing is the frame/bottom bracket and how much tension is stored in the chain and brakes. With the crank vertical, there should be no tension in the chain and no need to apply brakes, so I agree and think that experiment wouldn’t work.

[hawkinspeter]

Interesting video – shows

Interesting video – shows nicely the stored energy in the frame. It does show that the same effect happens in stiffer frames too, so it doesn’t work to differentiate the efficiency of stiff vs flexy frames, and I’d argue that the stiff frame test demonstrates more stored/released energy in that particular setup which exaggerates the forces applied whilst riding.

However, it is thermodynamically impossible for a frame to flex and not waste energy/heat up and I’m not convinced by your explanation of energy going into the rider’s body (whether stiff or flexy, the energy is still going to be stored/released in the same manner).

[hawkinspeter]

Thanks for that.

Thanks for that.

Their choice of categories based on frame flex implies to me that it’s just a case of more flex leads to more comfort and less flex leads to a faster ride.

There’s some other considerations about flexy frames. Generally, stiffer frames use more material and are heavier (for the same frame material), so there’s a trade-off there with carbon frames designed to have beefed up areas that you’d want to be as stiff as possible. There’s also a correlation between lateral stiffness and vertical stiffness although there are tricks to getting vertical compliance (good) without horizontal complaince (bad) such as arranging carbon fibres in certain directions.

What I have trouble with is the idea that ‘lively’ frames are faster due to them acting like a spring and returning some energy back to the rider. Springs do absorb energy when flexing (they get warmer), so isn’t it more efficient for there to be minimal flexing?

[hawkinspeter]

I’m sceptical about huge

I’m sceptical about huge differences between frame materials. Ultimately, flexing is going to absorb energy which is good for road bumps, but bad for transmitting forces from the pedals to the back wheel. I can see maybe better comfort for the rider if the frame is more compliant, but unless your tyres are super hard, then they’ll be providing the majority of the shock absorption.

What makes me really sceptical is the lack of numbers. How much frame compliance provides the maximum benefit? If the frame is really flexy, then it becomes unrideable, so somewhere between unrideable and super stiff is the supposed sweet spot of compliance, but I’m not aware of frame builders showing figures except for a vertical compliance.

Also, considering that the power gets transmitted from the foot to the pedal, through the cranks, chainwheel, chain and ultimately back wheel, then which part do you want the compliance and in which direction?

[hawkinspeter]

David9694 wrote:

Triggered. I’m not a pensioner, but I am old enough to remember when cheques were a thing in shops (and when shops were a thing).  I remember debit cards becoming a thing (credit cards already were, but M&S and John Lewis didn’t accept them for a long time.) 

It must be a blast in the quaint shops of Cirencester.  My blood pressure is better these days:

“that’s £74.99” Rummage for cheque book, rummage for pen, items moved to create writing space, “how much again?” “£74.99” “what’s the date today? / Do you have stamp/who’s it to?” “Bloggs ltd”. Rummage for cheque card, assistant hand-writes the number on the back. In Halfords, the till had a slot on it which imprinted more info on the back. “can I change it if it’s not right?” 

I remember the original credit card machines that used carbon paper to imprint the details onto paper that you then had to sign

[hawkinspeter]

hirsute wrote:

[quote=hirsute]Seasonal one. Not a good ad for armoured personnel carriers though ! https://www.bbc.co.uk/news/uk-england-cornwall-64082342%5B/quote%5D

I hope that “wedged in a hedge” takes over from elf on a shelf

[hawkinspeter]

chrisonatrike wrote:

Only King Wenceslas would see someone walking with a Christmas tree and think “peasant”!

Surely the most efficient solution is simply to plant one where you want one at some point?  Although being a techie presumably having it grow from the root down makes this a little more tricky.

That reminds me, I’ve got pizza for dinner tonight. Deep and crisp and even

[Author]

Replies