Recent Posts

11

The Knowledge / Re: Deore XT rear hub ball bearing question

« Last post by Brucey on Yesterday at 11:25:05 pm »

more balls please; 13off  loose balls would be right if the bearings share the same geometry.

FWIW some of these hubs are pretty much doomed to have short bearing life because the cone adjustment system is the most half-assed POS I have ever seen in my entire life.

Remember that the hub sees reduced clearance/increased preload when the skewer is tightened; it is easy to apply an excessive preload to the bearings this way.  The correct adjustment is a little free play that just disappears as the QR is tightened.

cheers

12

Audax / Re: Island randonnées

« Last post by Jaded on Yesterday at 11:22:53 pm »

Have we had the IoW?

Only 100km but possibly AAA?

13

The Knowledge / Re: Engineer tears apart Cervelo quality control esp. BB shell tolerances (video)

« Last post by Brucey on Yesterday at 11:20:11 pm »

I don't think I have thrown anyone's conclusions out of the window but I have pointed out that to draw any conclusions about cartridge bearings requires testing under representative conditions (which includes spoke, QR and service loadings) and/or assumptions about the tolerances of the bearing and its installation.  IME you could test some parts and then get rather different results with others, because the (non adjustable)  tolerances would have to be held within a handful of microns.

I don't think it makes that much difference if you are talking about through axles or not; the flanges still see spoke loads and these will interfere with the fit/preload of the bearing. The skewer will still compress the spacer between the bearings and that will alter the contact angle of the bearing.


Campagnolo have had CULT BB bearings for some time so it isn't a big surprise to see them in hubs too.  The new one is USB (ultra smooth bearing) which is seemingly less smooth than CULT or something.  In USB they mention the bearings have  low friction once and smoothness/low weight  many more times.   Well  cynical little old me says that honey is smooth but not low friction and the bearings can have low friction but when they are installed the friction could increase dramatically.  Low weight is an easy (but almost irrelevant) selling point.

CULT bearings can have low measured friction because they are only lubricated with (thinnish) oil and they have no seals to drag.   Big whup; folk were setting up TT bikes this way decades ago. The main difference is that campag are selling this as being suitable for road use in the longer term but  it isn't.  The bearings have ceramic balls and nitrided stainless steel raceways. Because the bearings are not protected the raceways are soon damaged and the friction in these bearings can increase to more than a standard bearing after a fairly short period of time. The nitrided stainless steel raceways can easily corrode in our delightful climate too. 

The other differences are  that the smaller balls found in such bearings  have inherently higher rolling resistance than bigger balls and there is likely to be appreciable  preload on cartridge bearings.  The net result of all this is that the friction in such bearings might vary from sample to sample once installed and any benefits might be rather temporary, or only apply when the bearing is not loaded.

Cyclists usually get as far as twirling hub spindles between their fingers and spinning wheels; neither of these tests involves the applied service load so don't tell you very much about rolling resistance in service.

If you want low friction in cartridge bearings the best you are likely to manage is to buy bearings with a small internal clearance and then fettle the housings/bearings so that the interference fit doesn't quite remove all the clearance in the bearing. Then remove the inner bearing seals permanently (they serve absolutely no useful purpose), remove the outer seals temporarily (or replace them with shields), use a lubricant that isn't too viscous yet provides low friction/high film strength at the speeds/loads  in question.  The do your race or whatever and afterwards expect to have to replace the seals and lubricant at least, if not the bearings as well if they get contaminated.

You will do better than a CULT bearing with a few miles on it and you never know you might do as well as a high quality cup and cone bearing...

cheers

14

The Knowledge / Re: Deore XT rear hub ball bearing question

« Last post by toontra on Yesterday at 11:18:37 pm »

Thanks.  Would I replace with the same number (11) or fit an extra loose ball - looks like there would be plenty of room?  There are 13 (loose) on the drive side.

15

Audax / Re: Island randonnées

« Last post by FifeingEejit on Yesterday at 11:16:38 pm »

There will soon be a legal definition of Island in Scotland at least for the purposes of the "Islands (Scotland) Act 2018"

Code: [Select]

1Meaning of “island” and of “inhabited island”
(1)In this Act, “island” means a naturally formed area of land which is—
(a)surrounded on all sides by the sea (ignoring artificial structures such as bridges), and
(b)above water at high tide.
(2)In this Act, “inhabited island” means an island permanently inhabited by at least one individual.

So Kintyrites can "shut up" about Magnus' scam that tricked Malcolm into letting him have the island for the Kingdom of the Isles.

16

The Pub / Re: Weird/funny dreams you've had

« Last post by Efrogwr on Yesterday at 11:15:54 pm »

I dreamed that I dreamed that Mrs E and I were staying somewhere we hadn't been before in mid Wales. However, I was convinced that we had been there before, and done all the same things andeaten the same meals. This was puzzling.  Then I realised that I had dreamed our earlier visit and woke feeling relieved to know what had "really" happened.

Then I really woke up...

Nested dreams?

17

OT Gallery / Re: Fungi

« Last post by Pingu on Yesterday at 11:08:04 pm »

It's that time of year again.

I thought exactly that when I looked at the drying green this evening 

Also, you're late this year: https://yacf.co.uk/forum/index.php?topic=52196.msg1920895#msg1920895

 

18

Audax / Re: Island randonnées

« Last post by FifeingEejit on Yesterday at 11:06:51 pm »

The first Arran 200 falls foul of the "riding the same road in the same direction more than once" rule.

Believe it or not, no such rule exists. YACF folk-law.

I think it's an over-interpretation of Regulation 9.8.2 (b).

https://www.audax.uk/media/1806/auk_regulations_050418.pdf

"A route may visit a control more than once, but routes consisting of repeated passes over the
same circuit will not normally be approved."

It's possible the wording of that regulation was different in the past, and the wording may have previously been more along the lines of the accepted lore, but has now been simplified / clarified to make the intention of the regulation more plain.

When I rode the Mull one I had a mini panic about the middle road and went the long way round to avoid double passing. when I mentioned it to the DIY orgaqnizer I got an e-mail back which included "You are allowed to ride the same road twice in the same direction, it’s continuous loops, ie. multiple laps, that’s banned.".

If you setup them up as "proper" perms, remember to create a badge for them as well - the whole world will want to ride then!

As IanDG pointed out when I wondered aloud about the lack of a perm on the Western Isles chain for his end to end, theres no where on Vatersay to control.
Some of these may be possible to define with real controls however in reality unless Perms are changed so that validation by GPS is available without it also having to be validatable by paper proof of passage... basically perms in much of Scotland are fucked,
What's more a significant portion of Teuchterland ATMs don't print the location on receipts either as Notemachine run the machines stationed in Scotmid Co-Ops.

However a badge is not a bad idea and one I've already been ponderiung
Provided I could get some form of computer based proof of what a DIY was and tie it up with the DIY on a riders result list it's doable.

This got me thinking about if this would be possible on a Dutch island.

Texel is the biggest of the Waden Islands, best I can come up with is a 100km:

https://www.strava.com/routes/22238153

I'm wondering if it would be possible to do it as a 200 by basically doing it in one direction, then doing it in the reverse...

J

You may notice on interrogating some of the routes above that I have essentially done a loop in one direction then used a bit more of the road network to reverse it.

19

On The Road / Re: DOTD

« Last post by Kim on Yesterday at 11:01:42 pm »

I was in a genuine bicycle traffic jam on the shared-use bollocks up to Mr Sainsbury's Emporium Of Toothy Comestibles earlier.  The cause of the hold-up was a FOREIGN PSO on a sensible^[1] Ridgeback failing to keep up with her friend on some kind of electric-assist clown bike, particularly on the uphill bit.  I suspect this was because - either through ignorance or mechanical necessity - the gears were in small:small, but the handlebar danglebag certainly wasn't improving matters.

A pedestrian-free gap eventually opened up, and I passed her as she tacked across to the pedestrian side of the path.  This was a tactical error, as she startled and wobbled into me.  Fortunately I was able to avoid actual contact by speeding up^[2] and moving right.  The cyclist behind me had dismounted as soon as the Z-axis came into play, so further conflict was avoided.

All in all, I consider this to be a good sign.  People using bikes!  In Birmingham!


_{[1] Mudguards, rear rack, etc.
[2] I may have reached 10mph.}

20

OT Gallery / Re: Fungi

« Last post by Pingu on Yesterday at 10:59:59 pm »

It's that time of year again.

I thought exactly that when I looked at the drying green this evening