Search found 2960 matches

by CJ
26 May 2019, 3:56pm
Forum: Bikes & Bits – Technical section
Topic: Rusty bolts and aluminium fittings...
Replies: 16
Views: 765

Re: Rusty bolts and aluminium fittings...

Hi If the bolt is stainless steel that is, by the way, very bad for corrosion of the alloy, because chrome and aluminium are a long way apart in the electrochemical series The electrochemical series is an indicator of risk and needs to be looked at in specific situations, which interests me on a pr...
by CJ
26 May 2019, 1:24pm
Forum: Bikes & Bits – Technical section
Topic: Simple guide to worn rear cassette
Replies: 15
Views: 743

Re: Simple guide to worn rear cassette

If you get 3 chains @ 0.5% to 1 cassette, rather than 1 chain @ 1% to 1 cassette, then for the same (3%) cumulative chain wear the equation is 2 (3 Cn + S ) < 3 ( Cn + Cs ) i.e. Cs > 3 Cn So in that case the cassette needs to cost more than 3 times as much as the chain to justify changing the chain...
by CJ
25 May 2019, 5:03pm
Forum: Touring & Expedition
Topic: easyjet NOT accepting poly bags May 2019 (Maybe?)
Replies: 12
Views: 725

Re: easyjet NOT accepting poly bags May 2019 (Maybe?)

Last year on our return from Kalamata by EasyJet on a group booking for 17, all with bikes, the staff were most delighted to receive bikes packaged in clear polythene. This was on account of Kalamata's small airport's X-ray scanner being too small to swallow anything bigger than a regular suitcase. ...
by CJ
18 Apr 2019, 8:43pm
Forum: Bikes & Bits – Technical section
Topic: Simple guide to worn rear cassette
Replies: 15
Views: 743

Re: Simple guide to worn rear cassette

FWIW there is a tool which is sold for this purpose; the Rohloff HG/IG checker https://cdn.hibike.com/image/product/WRZ/WRZ_RoCEK-il.png the idea is if you lean on the handle, and see if the last link engages easily with any given sprocket or not, you can assess if the sprocket is so badly worn tha...
by CJ
18 Apr 2019, 8:35pm
Forum: Bikes & Bits – Technical section
Topic: Rusty bolts and aluminium fittings...
Replies: 16
Views: 765

Re: Rusty bolts and aluminium fittings...

Grease is a mixture of oil and soap. When mixed, the soap forms a stringy sponge that contains the oil and when squeezed, lets a bit out to do its lubricating job. When all the oil is squeezed and/or evaporates out of grease, the now dry soap is free to absorb water and react with the metals it's in...
by CJ
18 Apr 2019, 8:05pm
Forum: Bikes & Bits – Technical section
Topic: Derailleur Hanger alignment tool ?
Replies: 49
Views: 1435

Re: Derailleur Hanger alignment tool ?

I'm just back from leading a tour where on three other people's bikes (one because it was bent already, two after crashes!) I straightened gear hangers by the simple expedient of poking an allen key into the derailleur's attachment screw socket and pulling. Most bikes with aluminum hangers can be d...
by CJ
18 Apr 2019, 7:50pm
Forum: Bikes & Bits – Technical section
Topic: Derailleur Hanger alignment tool ?
Replies: 49
Views: 1435

Re: Derailleur Hanger alignment tool ?

Sorry to be a hallion but ... i used a pair of molegrips and my eye on the 1 occasion i've had to bend a gear hanger straight ... worked fine .... :) :) Allen key in the mech bolt is much quicker - a ten second job - and easier with the mech in place to see when it's near enough straight. I've done...
by CJ
18 Apr 2019, 7:38pm
Forum: Bikes & Bits – Technical section
Topic: Derailleur hanger, B-screw, chain tension...?
Replies: 7
Views: 523

Re: Derailleur hanger, B-screw, chain tension...?

The B-screw is not for tensioning the chain, it is for adjusting the clearance between the mech's guide (top) pulley and the biggest sprocket. Too close (ie fewer than four free links of chain between pulley and sprocket) and the chain might not be able to escape the clutches of the big sprocket's t...
by CJ
18 Apr 2019, 7:18pm
Forum: Bikes & Bits – Technical section
Topic: Derailleur Hanger alignment tool ?
Replies: 49
Views: 1435

Re: Derailleur Hanger alignment tool ?

I'm just back from leading a tour where on three other people's bikes (one because it was bent already, two after crashes!) I straightened gear hangers by the simple expedient of poking an allen key into the derailleur's attachment screw socket and pulling on it until everything looked alright. In e...
by CJ
6 Mar 2019, 5:23pm
Forum: Bikes & Bits – Technical section
Topic: Unscrewing presta valve after pumping
Replies: 52
Views: 5248

Re: Unscrewing presta valve after pumping

I concur. Twinheads are better than one - however 'Smart' it claims to be! :wink:
by CJ
26 Jan 2019, 11:07pm
Forum: Bikes & Bits – Technical section
Topic: Unscrewing presta valve after pumping
Replies: 52
Views: 5248

Re: Unscrewing presta valve after pumping

I'm not aware of the thumb lock on any of my pumps depressing the valve piston on any type I've got (Presta, Schrader or Woods - which has no piston). Surely only air pressure should open the valve? Watch this video from Topeak , how to convert a pump from schraeder to presta. When it gets to the p...
by CJ
26 Jan 2019, 10:24pm
Forum: Does anyone know … ?
Topic: 20-25 tubes in 28mm tires??
Replies: 33
Views: 3597

Re: 20-25 tubes in 28mm tires??

If using large or even oversized tubes on wider tyres at lower pressures - are you more liable to get pinch flats? My (probably wrong) logic has it that a smaller tube would be less liable. Whether the tyre gets pinched at all in the first place, is purely a matter of tyre size and pressure versus ...
by CJ
26 Jan 2019, 1:22pm
Forum: Does anyone know … ?
Topic: 20-25 tubes in 28mm tires??
Replies: 33
Views: 3597

Re: 20-25 tubes in 28mm tires??

I'm not sure puncture resistance is affected by the inner tube thickness, but editing this I see Brucey thinks it does. Me too, and neither of us (I think) are so concerned about thickness per se, as what you might call 'stretched-ness'. I don't even like to use a tube at the upper limit of its rec...
by CJ
26 Jan 2019, 1:13pm
Forum: Campaigning & Public Policy
Topic: Should cyclists be allowed to use (some) M-way hard shoulders?
Replies: 44
Views: 9712

Re: Should cyclists be allowed to use (some) M-way hard shoulders?

Of course no sensible cyclist really wants to ride on a motorway hard shoulder, but that the suggestion can even be made should focus our moral outrage upon all those general purpose roads that have gradually been 'improved' into VIRTUAL motorways - without providing anywhere else for slow traffic, ...
by CJ
25 Jan 2019, 10:52pm
Forum: Bikes & Bits – Technical section
Topic: Unscrewing presta valve after pumping
Replies: 52
Views: 5248

Re: Unscrewing presta valve after pumping

If you were to search though my posts on this subject, you will find a little nugget of mine. If you connected a Topeak Twinhead like wot I had, you'll find that each time you connect to a Presta, you lose a little bit of pressure from the tyre. Also, each time you disconnect, you lose a little pre...