Cycling UK Forum

fastpedaller wrote:

Chris Jeggo wrote:

531colin wrote:Nothing will convince me that half a turn wind-up shortens the effective length of the spoke by the equivalent of one quarter turn of the nipple.

If the nipple does not move, and the spoke head does not move, but the threaded end of the spoke rotates half a turn in the nipple, then the threaded end of the spoke has moved radially by half the pitch of the thread. How important that might be is another matter.

But surely the wheelbuilder has turned the nipple 1/2 turn with the threaded end 'in unison' with the nipple, so the pitch of the thread has no consequence! the spoke has been wound by 180 degrees along it's length (ouch)

What you say is true when the wheelbuilder backs off the twist by turning the nipple. I am talking about when the twist in the spoke releases itself during the stress-relieving process. I am assuming that the spoke moves in the nipple, but that the nipple does not move in the rim because its greater radius means that the friction torque between the nipple and the rim is greater than the friction torque between spoke and nipple, the friction forces being similar because the normal forces (equal to the spoke tension) are the same and the coefficients of friction are similar. If my assumption is wrong, then my conclusion is wrong. However, it seems to me that when you hear pings as you turn a nipple it is the spoke moving in slip-stick-slip-stick fashion that causes the sound, because when you back off the twist by turning the nipple you don't get the sound. To my ears it sounds the same when a newly trued wheel pings when stressed. This is the basis for my assumption, but I have to admit that I haven't observed closely by eye what happens.

531colin wrote:

Chris Jeggo wrote:.............
If the nipple does not move, and the spoke head does not move, but the threaded end of the spoke rotates half a turn in the nipple.......

Why would that happen? When you ping a wheel, the nipple rotates with the spoke.....just like the spoke winds up when you twist the nipple in the first place.

It you're certain of that, Colin, and I defer to your much greater experience, then obviously I have learnt something new today.

531colin wrote:Nothing will convince me that half a turn wind-up shortens the effective length of the spoke by the equivalent of one quarter turn of the nipple.

If the nipple does not move, and the spoke head does not move, but the threaded end of the spoke rotates half a turn in the nipple, then the threaded end of the spoke has moved radially by half the pitch of the thread. How important that might be is another matter.

Residual twist in a spoke matters. There is friction between the spoke and the nipple, the higher the spoke tension the higher the friction, and therefore the higher the torque that can be sustained. Spoke tensions vary as the loaded wheel rolls, so a twisted spoke can untwist a bit when its tension reduces, and you hear a 'ping' as it goes. This alters the effective length of the spoke and the wheel goes a bit out of true. So spoke twist is one of the stresses that needs to be relieved. So (1) experienced wheel builders over-adjust a spoke and then back it off a bit, and (2) lubricating the thread helps, as others have said above.

Piano tuners have a similar problem; strings go out of tune it the tuner hasn't 'set the peg'. There is a short length of wire from the fixed peg to a bridge, then the sounding length to the second bridge, then another short length to the tuning peg. The three tensions in these three lengths of wire are not the same because of friction between the wire and the bridges. If the tension difference across a bridge is large then the string can move because of vibration, moving the instrument, diurnal and seasonal temperature variations, etc, and then the string goes out of tune. A competent tuner produces a piano that is in tune; a good tuner has techniques to minimise tension differences and produces a piano that stays in tune for a much longer time.

Sweep, I've sent you a PM.

Would you like to try this 44t 9-speed Deore ring?

It's done 6000 miles - teeth look a little bit hooked. I live in Woking, not a million miles from London. I could post it.

Psamathe wrote:(e.g. I'd assume CTC will be buying back CTC branded goods and paying for replacement publicity, etc.)

Ian

Like!

mjr wrote:Is the rebranding going to annoy the heck out of local groups like Norfolk CTC who I don't think have long had a new set of jerseys?

West Surrey CTC is going to convert to an affiliated club 'West Surrey Cycling To Cafes'. No it isn't, I just made that up. But, lots of our members have recently spent lots of money buying our latest kit: wind jackets, gilets, softshell winter jackets, bib shorts, full length tights, and/or winter bibtights, all promoting 'West Surrey CTC' in large letters.

West Surrey CTC runs a number of Audax rides. The most popular is the 'Tour of the Hills' based on Shere in Surrey. It's been running since 1982, attracting on average over 100 entries from all age groups (except children) and all types of cyclist, including racing club members and tri-athletes. The entry fee for 2016 is £8, which is a fraction of the entry fee for a sportive. You get a great event (see the write-ups by 'Cycling Weekly' and in 'Arrivée') with good food provided. What you don't get is showers, bike washing or servicing, broom wagon, or electronic timing to the second. You also don't get a waymarked route, but who needs that nowadays - we provide a downloadable route for your GPS. If you want emergency support then the area is a good place for non-cycling friends/relations with a phone and a vehicle to spend the day, with walks, places of interest, cafés, pubs, ducks to feed, etc. The ride's a challenge; for some it is simply climbing all those hills, for others it is getting a fast time, possibly in a private contest against club-mates. Most wear a helmet but you don't have to. It's the sort of event we like to organise, and people like to ride it; many years we hit the limit on the number of entries (the lanes in the Surrey Hills can be busy on Sundays). It's profitable too; it is a great help in keeping our local group afloat. To turn it into a sportive would require more manpower than we can muster, as many of our members want to ride it. We cannot compete with the likes of Wiggle and Evans Cycles. If you want to ride events like theirs you have to pay a lot more.

hujev wrote:After reading this post a couple months ago (and DL'ing the shows in rather mediocre quality offa u-tube) I was reading a CTC 'cycletouring issue from the late 70s or early 80s a while later and came across a short article where Briercliffe was discussing his new Galaxy and how it rode. I remembered this thread and thought 'aha, the conclusive evidence', then forgot - until this thread arose from the dead. If anybody's really curious I could find it and scan and post.

clednova wrote:This one has intrigued me - here's the answer. Clare Balding was riding a Dawes Super Galaxy ... from about 1977 or possibly 1978 ... owned much later in his life.

I happened to have 70's and 80's "Cycletouring"s out of their box at the moment so flicked through a few and found some adverts and reviews and scanned them. They can be viewed at http://www.jeggo.org.uk/dawes_super_galaxy_in_ctc_mag/. Harold Briercliffe was riding a 1979 Super Galaxy.

I find that Gatorskins roll better than Schwalbe Marathon Kevlar, and are pretty robust. My rear tyre that is nearly worn out has some nasty-looking gashes in the tread, but the next, protective mesh layer has done its job and the carcase is undamaged - no bulges.

AM7 wrote:The image I posted before doesn't really do justice the subtly different shapes of some of these bars, eg: .....

Yes, my father's pre-war bike had a Lauterwasser bar just like this. It is closer to a moustache bar in that the ends/grips are parallel, whereas the ends/grips of the North Road bar are splayed. My wife's Falcon (mid-70s) has an all-rounder bar, which was popular from at least the 50s, and which is distinctly different from the North Road bar in that the grips are almost level with the centre. As schoolboys in the 50s and 60s we called an all-rounder bar 'straight' to distinguish it from 'sit-up-and-beg' and 'drops', but it was certainly not straight. The bend gave what I found to be a comfortable wrist angle where the modern straight bar does not, being almost perfectly straight. If I get round to it I'll post photos of the all-rounder. It's a pity it appears not to be on the market any more.

Are you actually starting from Amsterdam, or from the UK and have already worked out how to get to Amsterdam without flying? In any case, take a look at 'The Man in Seat 61' http://www.seat61.com/ - it's a mine of information.

Edit: see also http://www.seat61.com/bike-by-train.htm#.Vpp8OE8zoQo

My previous posts were based on the fact that I had 'done the experiment' and 'knew the answer', but having contributed them, I started thinking a bit more about what others had posted here, and about correspondence on chain rotation in West Surrey CTC's magazine. There was obviously more to it than I had previously thought. Then came Brucey's erudite reply confirming just that. Thanks, Brucey.

I have now found my maintenance notebook that goes back to 1979 and found that I did the experiment twice, during 1980-82. I was running a 5-speed bike with 14-17-20-24-28t sprockets, the 17 giving my 'normal' gear. I made two Suntour 'Perfect 888' screw-on freewheel blocks (freehubs and their cassettes had yet to appear on the market) each last two chains, more or less the way I described previously. Firstly, with block #1, two Renolds chains lasted 2100 and 2200 miles. Secondly, with block #2, two Shimano Uniglide chains lasted 2100 and 3600 miles.

So, looking at Brucey's list of things that make skipping more likely:
"- a full tooth form on the sprockets" - certainly true of those Suntour sprockets;
"- much heavier wear on a few sprockets than others" - certainly true, and
"- use of small sprockets rather than large ones" - also true, the 14 and 17 sprockets giving most skipping, and the 24 and 28 not at all;
"- chain rollers without much slack in them" - quite possibly the case for those bushed chains, quite different from modern bushing-less ones.

My rear mechanism at the time was a Shimano 'Crane', but I have no idea, at this distance in time, whether that produced "short chain wrap" or "low chain tension from the rear mech". Maybe you know, Brucey.

We live and learn. Maybe I will give chain rotation another try using the modern kit.

Mick F wrote:... none of them ever got beyond 1/6th inch over the whole of my 39" steel rule!

That's 0.4%. We are in good agreement.

1/16 of an inch in one foot is one part in 16x12=192, i.e. 0.5%.

My Park Tools chain wear gauge is a two-sided go/no-go gauge, that is, one side tells you whether or not the "wear" exceeds 0.75% and the other side tells you whether or not the "wear" exceeds 1%. What it actually measures is (a) the wear between pins and bushes, plus (b) the slop between rollers and bushes (and there's always some of that). What you actually want to measure is (a), hence a ruler is the thing to use.

The "accepted" wear limit is 0.5% for some people, more for others.

My experience is that replacing a chain when the wear is far less than 0.5% still results in some chain skipping. I thought I would make a freewheel block last two chains (this was before cassettes were invented). After new chain A had run for 500 miles on a new block I removed it for thorough cleaning and re-lubricating and fitted new chain B. Some skipping occurred on the most-used sprockets, but reduced to nothing over the next 100 miles or so. After chain B had run for 500 miles I removed it for a clean & lube and re-fitted chain A. Some skipping occurred ... as before. I kept repeating this process until everything wore out, and the behaviour kept repeating itself likewise. I never repeated this chain rotation because (1) although the skipping was not bad, I did not like it, and (2) I spent hours removing, cleaning and refitting chains. I have no record of, nor memory of, measuring the wear after the first 500 miles, but I estimate that it must have been so small that it would have been extremely difficult to do so using a ruler.

So my experience, and that of some of my friends, is that chain rotation does not work. Some people say that chain rotation does work if wear is less than 0.5% but I find that hard to believe. Other people say merely that chain rotation works without saying how they get it to work. Maybe they spend a lot of time keeping everything spotless, but I prefer to spend most of my time riding my bike rather than cleaning it.