Search found 184 matches

by Chris Jeggo
24 Apr 2020, 12:49am
Forum: Bikes & Bits – Technical section
Topic: transmission noise
Replies: 9
Views: 358

Re: transmission noise

Does it only happen in top gear? I had that happen once, a click once per crank revolution. I was using track cranks (with a single chainring) with gears, and when everything flexed a bit under pressure, the clearance between chain and crank became negative. It took me a while to find. The little ma...
by Chris Jeggo
22 Apr 2020, 12:38pm
Forum: Bikes & Bits – Technical section
Topic: New front mech needed
Replies: 7
Views: 335

Re: New front mech needed

Have you tried PlusGas penetrating oil on the seized screws?
by Chris Jeggo
18 Apr 2020, 2:17pm
Forum: Bikes & Bits – Technical section
Topic: Erroneous Dings
Replies: 46
Views: 1470

Re: Erroneous Dings

In tradional Meccano there is a part called a cord anchoring spring which can be pulled off or pushed on to a rod (e.g. an axle) if it is simultaneously twisted in such a direction as would expand the coils. If you twist it in the opposite direction you can't move it at all. Meccano_cord_anchoring_s...
by Chris Jeggo
13 Apr 2020, 12:09pm
Forum: Bikes & Bits – Technical section
Topic: Campag experts - parts identification please
Replies: 18
Views: 673

Re: Campag experts - parts identification please

Gentlemen, many thanks for your helpful replies. Brucey, particular thanks for directing me to velobase - I have spent some time exploring it. These components were on a 'King of Mercia' I bought off the Veteran-Cycle Club about three years ago. It was described as 'unridden' but had in fact done a ...
by Chris Jeggo
10 Apr 2020, 12:47pm
Forum: Bikes & Bits – Technical section
Topic: Campag experts - parts identification please
Replies: 18
Views: 673

Campag experts - hub identification please

I would be grateful if you could name the model of this pair of hubs - believed to be ca 1991.
DSC08950_front_hub.JPG
DSC08952_rear_hub.JPG
DSC08951_front_hub.JPG
DSC08953_rear_hub.JPG
by Chris Jeggo
10 Apr 2020, 12:44pm
Forum: Bikes & Bits – Technical section
Topic: Campag experts - parts identification please
Replies: 18
Views: 673

Campag experts - parts identification please

I would be grateful if you could name the models of the following gear mechs and levers - all believed to be ca 1991. Also, some of you probably trade on eBay, or at jumbles, much more than I do. If you would care to suggest how much I might sell them for I would be grateful. I think they have had o...
by Chris Jeggo
3 Apr 2020, 1:37am
Forum: Bikes & Bits – Technical section
Topic: Both brakes off one lever
Replies: 27
Views: 1079

Re: Both brakes off one lever

My introduction to tandeming (in 1977 IIRC) was a Gitane, which had a rim brake on each wheel operated from a single lever with two cables coming from it, and a rear hub brake operated by the other lever, so it should be possible for you to find a 2-cable lever. How you adjust the two cables to get ...
by Chris Jeggo
18 Mar 2020, 12:32pm
Forum: Bikes & Bits – Technical section
Topic: seatpost sizes
Replies: 11
Views: 571

Re: seatpost sizes

tatanab wrote:That sticker is plain gauge 3 main tubes only. ...

Agreed.
1-1/8" is a gnat's wotsit under 28.6mm and PG tubing is 1mm thick so I agree with
Brucey wrote:If the tube walls are sized for touring purposes then the seat pin often ends up being 26.4mm (reamed) or 26.2mm (unreamed). ...
by Chris Jeggo
12 Nov 2019, 8:38pm
Forum: Bikes & Bits – Technical section
Topic: Is this (disc brake adapter) going to be OK like this?
Replies: 13
Views: 674

Re: Is this (disc brake adapter) going to be OK like this?

If so, skidding a high-grip tyre on a high-grip surface is the worst case for the fork to withstand. Can't do it, not on a solo anyway. You'll go over the bars first. You can do it, but only for a split second before you go over the bars. You'd let go of the lever PDQ! [solos only] In general, &quo...
by Chris Jeggo
12 Nov 2019, 6:01pm
Forum: Bikes & Bits – Technical section
Topic: Is this (disc brake adapter) going to be OK like this?
Replies: 13
Views: 674

Re: Is this (disc brake adapter) going to be OK like this?

Am I right in thinking the torque on the fork is limited to the maximum torque the road exerts on the wheel? If so, skidding a high-grip tyre on a high-grip surface is the worst case for the fork to withstand. Edit: I've just realised that it's not quite as simple as that. Caliper brakes exert a tor...
by Chris Jeggo
9 Nov 2019, 4:46pm
Forum: Bikes & Bits – Technical section
Topic: Tyre wear - mileages
Replies: 30
Views: 853

Re: Tyre wear - mileages

One cause of tyre wear is rubbing contact between tyre and road, because arc length and chord length between two points on the circumference are not the same. Can you expand on this a bit? How do you define rubbing contact? How does the difference in arc to chord length affect the rubbing contact? ...
by Chris Jeggo
9 Nov 2019, 2:22pm
Forum: Bikes & Bits – Technical section
Topic: Tyre wear - mileages
Replies: 30
Views: 853

Re: Tyre wear - mileages

One cause of tyre wear is rubbing contact between tyre and road, because arc length and chord length between two points on the circumference are not the same. If the two tyres (Moulton and Mercian) are the same width and running at the same pressure then the lengths of the footprints will be roughly...
by Chris Jeggo
8 Nov 2019, 11:24am
Forum: Bikes & Bits – Technical section
Topic: Python Paragon gear change problems
Replies: 16
Views: 482

Re: Python Paragon gear change problems

As both Brucey and reohn2 have said, the cable should be slack when low gear is selected, and it clearly isn't. Try winding the L screw back in a couple of turns, and then getting the cable slack but without a lot of slop. Then get the L-screw right, if possible, followed by final adjustment of the ...
by Chris Jeggo
5 Nov 2019, 11:47am
Forum: Bikes & Bits – Technical section
Topic: Tyre/wheel sizes
Replies: 21
Views: 782

Re: Tyre/wheel sizes

Brucey has mentioned ISO bead seat diameters of 584 and 590 above. These sizes were common in the UK for many years, but under another name. 26" wheels were in the majority, and their overall diameter, including the tyre, was pretty close to that nominal 26". The two common sizes were 26 ...
by Chris Jeggo
4 Nov 2019, 9:54pm
Forum: Bikes & Bits – Technical section
Topic: Tyre/wheel sizes
Replies: 21
Views: 782

Re: Tyre/wheel sizes

Brucey has mentioned ISO bead seat diameters of 584 and 590 above. These sizes were common in the UK for many years, but under another name. 26" wheels were in the majority, and their overall diameter, including the tyre, was pretty close to that nominal 26". The two common sizes were 26 x...