Search found 3027 matches

by CJ
18 Jun 2020, 9:32pm
Forum: On the road
Topic: Kilometres or miles
Replies: 106
Views: 2069

Re: Kilometres or miles

Our reaction times are the same in all cases, we "adapt" by making sure we are further apart thus a combination of reaction time and distance balance up to make sure all is well. Unfortunately some people's vision is not good enough to realise, when still at a greater distance from the ve...
by CJ
18 Jun 2020, 9:07pm
Forum: Bikes & Bits – Technical section
Topic: Shimergo - latest news
Replies: 39
Views: 1563

Re: Shimergo - latest news

You just don't have to mind that the chain dangles loosely in the little ring and the two or three smallest sprocket combinations you never need anyway. That dangling never, ever does any harm in my very long experience (there was even a bunch of 1930s Frenchies used to ride like that all the time,...
by CJ
18 Jun 2020, 9:03pm
Forum: Bikes & Bits – Technical section
Topic: Shimergo - latest news
Replies: 39
Views: 1563

Re: Shimergo - latest news

P.S. Recently went for a ride, only 20 miles but 700m of climbing, so lots of shifting. Still works a treat. And note: this is a chain and cassette that are half worn out already, so I think I know that this isn't an 'only works when new' phenomenon.
by CJ
18 Jun 2020, 9:01pm
Forum: Bikes & Bits – Technical section
Topic: Shimergo - latest news
Replies: 39
Views: 1563

Re: Shimergo - latest news

the front difference plus the rear difference is the 'total capacity'. GRX mechs have a large total capacity and normally use most of it in the cassette. If you are not using the full capacity at the rear, you can have a bigger front difference. You can ALWAYS have a bigger front difference. You ju...
by CJ
14 Jun 2020, 10:54pm
Forum: On the road
Topic: Kilometres or miles
Replies: 106
Views: 2069

Re: Kilometres or miles

Most human beings can just about cope with differences of speed of up to 20mph. Closing speeds much higher than that do not allow enough reaction time for the average not-so-very-attentive driver to slow sufficiently, or take avoiding action. Where does this come from? The number of times I've been...
by CJ
14 Jun 2020, 10:43pm
Forum: Bikes & Bits – Technical section
Topic: Any way to assess toe(clip) overlap on x frame?
Replies: 10
Views: 501

Re: Any way to assess toe(clip) overlap on x frame?

I have always found "wheelbase minus chainstay" to be near enough for practical purposes. Gives a result about 1cm less than the actual dimension. As a lot of bikes (Spa tourers included) give me less than 5mm, that's not near enough to be useful. Unless, of course, you're comparing two b...
by CJ
11 Jun 2020, 12:59pm
Forum: On the road
Topic: Kilometres or miles
Replies: 106
Views: 2069

Re: Kilometres or miles

As a cyclist and a driver...no. 60kph is ludicrously slow. They've just lowered a NSL road near to where I live to 40mph and it is just a bit silly really. You are the silly one. Most human beings can just about cope with differences of speed of up to 20mph. Closing speeds much higher than that do ...
by CJ
11 Jun 2020, 11:53am
Forum: Bikes & Bits – Technical section
Topic: Any way to assess toe(clip) overlap on x frame?
Replies: 10
Views: 501

Re: Any way to assess toe(clip) overlap on x frame?

I've put those formulae (plus another that uses Reach, Stack, Head angle and Fork offset) into an Excel spreadsheet you can download from here.
by CJ
11 Jun 2020, 10:46am
Forum: Bikes & Bits – Technical section
Topic: Shimergo - latest news
Replies: 39
Views: 1563

Re: Shimergo - latest news

If I read Chris's measurements correctly they are pretty close to the ones I made. If CJ says it shifts OK in his setup it must do but I have to say I am surprised; IME ~0.3 to 0.5mm errors in RD position noticeably affect shifting performance in most systems and ~1mm errors are usually not at all ...
by CJ
11 Jun 2020, 12:12am
Forum: Bikes & Bits – Technical section
Topic: Shimergo - latest news
Replies: 39
Views: 1563

Re: Shimergo - latest news

I've spent the afternoon measuring, put the numbers in my old Indexing spreadsheet and produced this (9th is the zero point): ShimergoGRX400.gif Tweaking the zero position to minimise shifting errors results in a maximum alignment error on any sprocket of 1mm, which does not seem to be any problem. ...
by CJ
10 Jun 2020, 11:23pm
Forum: Bikes & Bits – Technical section
Topic: Wheel building machines
Replies: 69
Views: 1972

Re: Wheel building machines

Inflating a tyre on a rim causes spoke tensions to drop; because of the differential tensions on the DS and NDS the rim will tend to pull over to the DS. Another advantage of differential spoking to balance the dish (thicker on the right, thinner on the left, so that stresses and elongations are eq...
by CJ
10 Jun 2020, 3:32pm
Forum: Bikes & Bits – Technical section
Topic: Any way to assess toe(clip) overlap on x frame?
Replies: 10
Views: 501

Re: Any way to assess toe(clip) overlap on x frame?

It's not easy but there are ways. The key frame geometry dimension is Front centres Fc , distance between bottom bracket and fork end. But as you've no doubt observed, a lot of brands omit that dimension from their geometry tables. Usually they'll give the Wheelbase Wb and Chainstays, what I call Re...
by CJ
10 Jun 2020, 12:38pm
Forum: Bikes & Bits – Technical section
Topic: Wheel building machines
Replies: 69
Views: 1972

Re: Wheel building machines

If components were more readily available for building better wheels (eg implementing 2:1 spoking in a 36h wheel) then I'd do that like a shot. As it is one can only dream of such things and in the meantime be content with building wheels (using conventional parts) as well as is possible. In that c...
by CJ
10 Jun 2020, 12:21pm
Forum: Bikes & Bits – Technical section
Topic: Wheel building machines
Replies: 69
Views: 1972

Re: Wheel building machines

I think we are going to have to agree to disagree to some extent here, in that badly built front wheels break spokes too, just not as quickly as badly built rear wheels. Okay, it is possible. I even had a spoke break once in my front wheel. It was an early stainless-steel spoke, Saba brand. They we...