Cycling UK Forum

Brucey wrote:just to put some numbers to it, if you plus the bike weigh about 100kg and are doing about 30mph down a ~7.5% slope, you have a ~1kW 'gravity engine' pushing you along.

A racing cyclist on the drops typically needs about 500W to do about 30mph on the flat. If when tucked you don't manage 40mph or so down a hill like that, there must be a very strong headwind or your tuck position is not very aerodynamic. Pedalling at those speeds needs a gear of about 130" if your cadence is to be kept sensible and adding 200 or 300W (if you can do that when tucked) won't increase your speed much anyway.

cheers

Aha - some data. It meshes with my experience-based knowledge that tucking in properly when going down a significant hill will gain much speed if the gravity-watts are not wasted by air-tugs at one's person.

So, the other side of the equation here is: how much is gained/lost in the way of gravity-generated watts by the air dragging effects of various positions upon the bike? In particular, what is the difference in these losses of watts to the air between a fine knees & elbows-in crouch and the churning perch of a frantic pedaller on the same hill?

My experience tells me that I can outdistance any such pedaller on a significant downward slope except for those who really are Froomish so can output an enormous number of watts in a very crouched (aero) position. I know few such, bordering on none.

These elusive downhill super-pedallers are, of course, the same fellows who need an 11 sprocket or even a 12. We ordinaries will find a 13 or 14 more than sufficient and also supportive of the close ratio cassette, which adds further efficiency & speed to our cycling, upon the less downhill roads.

Cugel

Mick F wrote:

Samuel D wrote:I can’t count the number of people I drifted away from ...........

Same here, and not just through pedalling.

An example, and there have been plenty.
I was cycling with an End2Ender a few years ago and we turned off the main road onto a minor one. We chatted as we rode along.
I was freewheeling, and he had to keep up by pedalling. I put that down to my having faster tyres and wheels than his as we were similar sizes and weights.

Conversely, I was cycling with another End2Ender heading west on the old A30. He was the first rider that didn't need to pedal to keep up with me. Therefore bikes and efficiency vary.
...........

Indeed - it still surprises me that even the racing lads of the club cannot seem to grasp basic mechanics or physics and so throw away their work on all sorts of rubs, writhes and general wastage of watts. I have this theory that folk who didn't do physics and mechanics at skool are at a great disadvantage when it comes to the 1001 pertinent matters of everyday life (including cycling) where a basic understanding of forces and energy would be advantageous.

On virtually every club run when I find myself on the front and on a downward slope of any significance, I'm freewheeling away from the un-tucked pedallers. They never learn! Same story when we're pushing along a bit and there they are aside me sweating and panting not because I'm fitter but because they throw away 1/Nth of their watts writhing about on the saddle, weaving their line and gripping manfully on the bars for reasons that escape me. Cuh!

ALso there's the tyre thing. They won't accept wider and lower pressures, despite the evidence I provide for them that the fat low pressure things wrapping my rims are going along rather well and not losing traction on them back lanes neither.

Then there's the [that's enough moaning about other cyclists and their inferiorities - the forum decorum monitor].

Yes, they all have 11 sprockets too .... and Garmins .... and power meters .... and various other stuff the function of which seems to be only "empty wallet via fashion show and churn".

Cugel

Brucey wrote:remember also that some folk (mostly not experienced cyclists) tend to pedal at near glacial speeds, and insist on having absurdly high gears fitted, else won't buy a given bike. Many is the time when (on the basis of riding 100 yards down the road in a state of some over-excitement) someone has said "I need bigger gears than this", confidently proclaiming that a 100" gear is 'too easy'. A deal of patient explanation is then required to persuade them that if they were to use that gear properly, they would be averaging about 30mph, not 15mph....

cheers

When I were a lad, 142 years ago, a 4 speed Benelux was enough. In fact there was a 46/49 double chainwheel too, with seat tube changer - but I never used it and wore out the 46 ring whilst the 49 remained pristine.

However, I was then young and ignorant. Over a lifetime of cycling (well, 58 years) I have come to have a "need" for close ratios at the back. I can't abide a 2 tooth jump at the fast end and must even have 18-19-20 in the range! The three rings at the front provide three ranges, for fast, normal and Pennines (or anywhere in Wales).

Happily I raced (when at my fittest) on a highest gear of 52X13. In fact, I employed a schoolboy block of 15-21 for many races as it had 1 tooth jumps all the way through. Always I was in the sprint, although on occasion I couldn't twiddle quite fast enough to see orf that Mathews.

Call me a pea-sensitive Princess but I go best when the gear ratios are close, even now that I'm an old tourist. And all those tiny sprockets are a waste of ratios. Oh yes they are!!

So, although I have the 52/39/30 triple rings, I also have a chopped 11-speed cassette of 14-32. I had to buy two (11-32 & 14-28) to make this, which is annoying. I fail to see the point of adding cogs at the back of the 12 & 11 variety! Who are all these MAIMILs foolishly peddling down 1 in 4s at 40mph when they could be freewheeling at 52mph if they just tucked their knees and elbows in?

Cugel

I recently fitted some Shimano icetech discs in place of some cheap generic steel discs (both 160mm). The Shimano discs brake just as well as the generic steel ones but make a rubbing noise.

No, not the usual rubbing noise of a badly-set brake shoe or bent disc but a temporary racket that only occurs when I've braked a lot going down the very steep & bendies. Nor does the noise occur during braking, only when I let go of the brake lever and the brake shoes retract. For some seconds (maybe 3 - 5 seconds) the front brake in particular makes a rubbing noise but then fades rapidly away to silence.

This doesn't happen with common-or-garden braking for junctions or other less demanding slowings or stoppings - only on the very steep hills where a lot more brake application is needed.

I'm assuming that the rub has something to do with the temporary expansion of the Shimano disc steel & aluminium sandwich, as heavy braking heats it up. Perhaps this is why the front brake seems noisier (and more inclined to make this noise) than the back brake? I tried changing the brake pads (from organic to sintered) but this makes no difference to the temporary noise-effect after heavy braking - although I must say that the brakes do work wonderfully well otherwise.

The discs are perfectly set between the brake shoes - parallel to the shoes and with the same small gap either side of the disc. There's no rub when the brakes are cold and I spin the wheels, which spin for a good while.

Is this noise normal with Shimano icetech discs?

Cugel

The cycling stuff was a week or three ago but this week seems to be ski stuff week. There are fine merino things to be had for not much, all of them suitable for winter cycling too.

Two other items are of note:

A pair of bike lights that look like Lezyne clones - apart fro the price. A mere 14.95 for a pair of Aldi lights, with a 3 year warranty. I can't say what the lumens are or how long they run but they're very bright, with 4 levels of steady and 4 levels of flashing for each. They're also lithium-ion rechargeable via USB. They seem very well made, with metal body and good rubber straps for bars or seatpost.

For those fuelled by coffee, how about a proper espresso machine for £50! Yes, it's red and chrome (there are white & grey versions too) with the standard set of functions (including milk steamer-frother) and a 4 year warranty. Having used the beast for three days I can tell you that it makes very proper espresso (with crema) as well as cappuccinos et al. Having looked at Gaggia machines and felt my wallet wilt, I am very pleased with this item, which pleasure may have been amplified by my coffee jags, true...

foxyrider wrote:Is the OP's friend equally unlucky off the bike? Maybe he's just accident prone in general, some people certainly seem to be. OTOH others seem to get through life without a scratch .....

In 50 years of cycling, many of them within various bunches of others, I've come to the conclusion that some people are accident prone whilst others have a highly-honed sense of safety and caution. There seem to be many factors involved: the incautious are often just unimaginative, habitual in their general behaviour and often inclined to wishful thunks ("I don't want it to happen so it won't" - a mental condition common in well-protected modern societies).

Those who are more cautious can, paradoxically, take more apparent risk, as they have often edged their envelope of cycling skills wider and wider without stretching it so far that it deposits them into an "accident". Because they are more cautious, they become better at judging where the risk boundaries really lie. The incautious are just making wild guesses, generally via those wishful thunks. They oscillate between over-the-top caution and semi-criminal incaution!

Cugel the Cautious (and thus the fastest down hills and 'round bends).

E-bikes, like all technological innovations, will have an associated list of intended benefits, advantages, pleasures and other good effects. As with all other technological innovations, e-bikes will come with a raft of unintended consequences, a number of which will turn out to be detrimental or even the antithesis of an intended good effect.

For example, it's almost certain that novice cyclists able to go at 15.5mph right from the off will get into trouble because they haven't developed, at safer speeds, the necessary skills for riding a bike besides that of pushing vigorously on the pedals for hours. They will hit things or fall off because they're going faster than their various cycling skills can cope with.

If they're lucky, no one will be seriously hurt and they'll get a valuable stimulus to the rate of their cycling skill development. The unlucky will cause themselves and others serious damage. I recall a recent media story of older Dutch born-again cyclists harming themselves and others with their new e-bikes as they hurtle about - although the worst cases had e-bikes not limited to a mere 15.5mph.....

Cugel, planning to get one when my FTP drops below 150 watts, hopefully not for many years yet.

These factors make a significant difference to hill climbing as they absorb more or less energy rather than raising you up the hill:

The absolute weight of the bike; the efficiency of pedal-energy transfer to the rear tyre; the drag of wind & surface on the bike.

Generally (with some exceptions) a road bike loses less energy than an MTB to these factors. However ....

Road bikes are designed for roads (surprise!) whilst MTBs are designed for tracks or raw countryside. The road bike will tend to go up tarmac hills better whilst MTBs definitely go up muddy rocky tracks better. Well, unless you have a cross bike perhaps. Or an MTB with no suspension, slick tyres and a low-set handlebar.

Asking if a road bike or MTB is best for hill climbing is a bit like asking whether a sausage or a beefburger is best to eat. It depends what's in 'em. Either may be highly nutritious or made of nastiness.

Cugel

I just noticed this thread.

I use a triple chainset but also have STI hydraulic brakes. The simple solution is to also install a friction bar-end shifter to change the front derailleur, after disconnecting the LH STI cable and connecting it to the bar-end lever.

Is this a bit of a queer arrangement? Perhaps; but a bar-end shifter for the front mech is used far less than the rear and so reaching very occasionally to tug it is no problem. Moreover, it's a great deal easer to trim the front mech with a bar-end lever than it is with a triple STI. The changes may also be less clangy than they tend to be with the LH STI, as one gets adept at tugging the bar-end just-so.

Gattonero wrote:Having fitted many thousands cassettes let me tell you: it's theory that hardly meets the real world. You can tighten the lockring even to 60Nm if you were able to, still getting the cassette to mark the alluminium freehub bodies. The reason is that they were never meant to be alluminium in the first place (there could be a lot to talk aobut this, just ask yourself why Campagnolo went from shallow splined on the 8sp cassettes on steel freehubs, to deep splines of the 9/10sp cassettes which had alluminium bodies) in fact Shimano has never done a proper HG freehub (except the short-lived "HG10") out of alluminium, always steel or titanium. There ought to be a reason!

By tightening to 40Nm you are only getting close to strip the threads of the alluminium freehub, nothing else.
Btw, the steel insert on the Hunt wheels (TW hubs) IIRC is from an original American Classic idea. It does work a bit, you still get marks on the freehub but they don't go far

I bow to your extensive experience (always a better teacher than mere theory) but I have to say that tightening the lock ring as much as one can seems to stop individual sprockets from biting so hard on alloy freehub bodies. As I mentioned, I have a several in which the alloy freehub is bit but the bites are small and even across all sprockets-splines, including those in any clusters of two or three at the big end.

There are a lot of pics and stories about on the web indicating alloy freehubs with deeper bites, in which the cassette is very hard to get off .... or on again without some filing away of the distorted alloy around the deep bites. I've never had that problem, despite putting some severe stomps through the cassette.

****
The puzzle is: why do Shimano make the lock ring so short? I've now fettled my Hunt lock ring problem by using a Token alloy lock ring, which arrived this morning. It's only 1mm longer than the steel Shimano lock ring and comes nowhere near bottoming inside the freehub before tightening on the smallest sprocket - but the extra 1mm of length means that the threads engage properly, both when starting the insertion/turn and when reaching full tightness. I'm presuming that having enough thread for a proper start also means that the lock ring squishes the cassette sprockets and spacers a bit more thus making even more lock ring-to-freehub thread engage.

***
I recall the early cassette clusters from Shimano (7-speed, in the early 90s) where the cluster was bolted together with three long thin bolts going from the big sprocket through all the others to screw into small threaded holes in the smallest sprocket. Nowadays the less expensive Shimano cassettes have a similar arrangement using riveted pins. Presumably the function of these is to transfer the forces applied from chain to sprocket across the whole cassette and it's splines ..... ?

****
Anyroadup, the Hunt Wheels with their tubeless Schwalbe G 300mm tyres are now fully installed and a joy to ride both up & down the filthy scabby lanes. These are my first tubeless tyres and I'm looking forward to discovering their advantages and the other sort of vantages.

Cugel

Brucey wrote:isn't that enough?

cheers

No.

What if we rejected all other aspects of the physical world because they were less than perfect? One would have to live in space, where even the odd neutrino or gamma ray might prove a nuisance and have to be sent back. I prefer to find a fix to these small problems and so stay fully installed within the admittedly trying world.

Cugel

Gattonero wrote:Sram alluminium lockrings seem to be just so slightly deeper.
Still, I'd check there's no dirt/grime in between the sprockets, often that is enought to not make the sprockets engage well. Also, the "40Nm" for the lockring is a value that's too high, you can do with 25-30Nm

I've checked for grime by polishing every sprocket and spacer. (Well, not quite - but they have been thoroughly cleaned).

The 40Nm is justified, as Brucey mentions, because it squeezes the individual sprockets and spacers together hard enough to avoid one sprocket slipping agin' t'others and thus exerting a concentrated pressure on an alloy freehub to bite into the splines. In truth, even when all the sprockets do act as one, alloy freehub splines do still get bitten - although the bites are less severe as the biting force of one's pedal thrusts are spread out over all 10 or eleven sprockets.

I do have a number of alloy freehubbed wheels, all of which have bite marks but none of which are troublesome enough to stop the cassette from going on and off the freehub. Much more severely bitten freehubs may be viewed on the interwebbing, presumably because the installers failed to apply the full forty Newtons and so each individual cog applied it's own bite.

Personally I would prefer to have at least the freehub splines made of steel; but the more upmarket wheels all seem to have alloy freehub bodies, presumably because of the obsession with even tiny weight differences. The Hunt's have a single steel spline bonded to the otherwise alloy freehub, supposedly to prevent or reduce the bite effect. I'll do a few hundred miles then have a look.

Cugel

Brucey wrote:

Cugel wrote: .... but the wheels are very good....

I would say there is ample evidence that this is not the case....?

cheers

What evidence? Explicit list of meaningful un-goods plis. I'll give you a start:

* The freehub doesn't easily engage my particular Shimano 11-speed Ultegra cassette lock ring on the freehub of my particular set of wheels.

Over to you.

Postboxer wrote:Assuming they're new wheels, you could return them as not fit for purpose. Unless there is a problem with the cassette, have you measured it against another, as you say it only just fits on your other hub?

The cassette in question will go on to other 11-speed hubs I have (body length 36.75mm, as is the Hunt's, all measured by me with me vernier) with the Ultegra lock ring grabbing at least 1.5 turns of thread, which does not come undone and can be done up to the recommended 40 Newtons torque. 1.5 turns of thread doesn't seem enough, though, does it? But of all the Shimano cassettes and freehubs I have, of all "speeds 9-11, not one has a lock ring that grabs more than 2 of the available threads.

Hunt does have a no-questions return policy but the wheels are very good and if I can get a deeper lock ring, so I can feel more confident about the cassette staying put, I'll be happy. I feel that it's a Shimano issue at bottom - lock rings could and should be deeper, to allow them to grab more threads. If one happened to be a bit too deep it could easily be packed with a washer to ensure it was retaining the cassette sprockets properly.

amediasatex wrote:

Today I received a set of Hunt wheels with an 11-speed hub into which I can't get the lock ring of an Ultegra 11-speed cassette to engage at all

IF everything is in spec, then presumably you wont have been the first person to have this issue....have you asked Hunt about it?

I have asked Hunt about it, and they responded within one hour of the email, telling me the problem is not unknown but vanishingly rare (4 or 5 cases in a year). They've sent me, free of charge, a spare freehub to try just in case there is something not quite perfect in the machining of the current hub. Good service, that.

They mention that a Chris King lock ring is significantly longer .... but also about the price of a whole Ultegra cassette.

By the way, the wheels (Hunt 4-seasons) with Schwalbe G 30mm tubeless tyres mounted do roll and stick exceedingly well on the filthy shattered lanes of the cold dark north. (55 miles of it during a convoluted back road ride from Lancaster to Arnside and back, today).