Search found 984 matches

by BigG
3 May 2019, 2:39pm
Forum: Does anyone know … ?
Topic: How to calculate metres travelled per crank revolution?
Replies: 22
Views: 2037

Re: How to calculate metres travelled per crank revolution?

A truly accurate measurement is difficult by the system you suggest as your wheel diameter can only be approximated. Its true rolling diameter depends not only on the size of the tyre but also on its pressure, your weight (or the proportion of this that is carried on the back wheel) and the amount t...
by BigG
15 Mar 2019, 5:42pm
Forum: Bikes & Bits – Technical section
Topic: cassette gear increments
Replies: 19
Views: 1370

Re: cassette gear increments

I agree theoretically at least with MickF and try to keep to a constant power input (constant cadence and constant pedal pressure}. However, it feels more natural to me to use a greater pedal pressure when climbing together with, if necessary, a slower cadence. This has the (unintentional) advantage...
by BigG
10 Feb 2019, 5:37pm
Forum: Does anyone know … ?
Topic: Changing from 1st to 12th
Replies: 50
Views: 5655

Re: Changing from 1st to 12th

The gear drop between rings (as a percentage) will be roughly equivalent to a number of rear sprocket shifts. On my bikes it is carefully arranged to be almost exactly equal to 3 rear shifts. The technique in changing down is to first drop down one ring leading to an immediate rise in cadence, and t...
by BigG
7 Jan 2019, 9:31am
Forum: Bikes & Bits – Technical section
Topic: 9 speed cassette: 12-36. Too spaced out for front double?
Replies: 40
Views: 2145

Re: 9 speed cassette: 12-36. Too spaced out for front double?

Like CJ,I am a little sceptical about the need for closely spaced gears for leisure cyclng. I often ride behind riders with closely spaced sprockets and regularly notice that when they change gear it is more often two or three cogs at a time than just one. Of course, the roads in Devon are seldom at...
by BigG
27 Dec 2018, 10:32am
Forum: Bikes & Bits – Technical section
Topic: 9 speed cassette: 12-36. Too spaced out for front double?
Replies: 40
Views: 2145

Re: 9 speed cassette: 12-36. Too spaced out for front double?

I use an even wider 8-speed (11-13-16-19-23-28-34-41) cassette with a RD761SGS rear mech and have no trouble at all in indexed changing despite the mixture of cogs. The 16 to 34 are coherent and came from a 7-speed but now with 9-speed spacers on an 8-speed hub. The top pair are from a 9 speed and t...
by BigG
22 Nov 2018, 10:34pm
Forum: Bikes & Bits – Technical section
Topic: Standard versus compact gears
Replies: 25
Views: 1286

Re: Standard versus compact gears

+1 for your 22/36. I ride a comparable 22/38 on my old Freddie Grubb (a 5 x 3 triple) and use it quite often on the mid-Devon hills. The low gear does nothing to increase my speed which is controlled by my heart and lungs, but it does allow me to remain seated with a cadence of 60 or more (about 3 m...
by BigG
7 Nov 2018, 8:07pm
Forum: Bikes & Bits – Technical section
Topic: Alpine double
Replies: 48
Views: 2234

Re: Alpine double

Apologies to reohn2 - my mistake. However his gear gaps do not really get larger in the lower gears. The 15T/17T gap is identical to the 30T/34T one at the bottom end.
by BigG
6 Nov 2018, 9:56am
Forum: Bikes & Bits – Technical section
Topic: Alpine double
Replies: 48
Views: 2234

Re: Alpine double

Despite reohn2's comments near the top of this thread, his preferred 9-speed cassette actually has its biggest gap at the top end from 11T to 13T, a gap of 18%. The biggest gap at the bottom end is from 26T to 30T, a gap of 16%. Keeping a reasonably constant percentage gap as he does gives the most ...
by BigG
8 Jun 2018, 9:41am
Forum: Does anyone know … ?
Topic: How many shifter types do you have?
Replies: 37
Views: 1589

Re: How many shifter types do you have?

Just one! Once I discovered Suntour Command Shifters about 30 years ago I stopped looking. I have them fitted to all 3 of my bikes controlling a 5-speed Huret Duopar, a 6-speed Shimano XT 761 SGS and an 8-speed (9-speed spacing on a 7-speed hub) XT 761 SGS. The front mechs are all old Suntour revers...
by BigG
28 Mar 2018, 7:59pm
Forum: Bikes & Bits – Technical section
Topic: Cheap as chains? Or too cheap?
Replies: 27
Views: 2262

Re: Cheap as chains? Or too cheap?

I paid about £4.00 each for my TAYA chains including postage (purchased three at one time at £2.95 ea. plus postage). These and their predecessors have always served me well although I prefer (and normally use) the KMC links. Mine are 7/8 speed versions (TA 50 or 51 IIRC). Whether the Wilco ones are...
by BigG
21 Mar 2018, 11:24pm
Forum: Does anyone know … ?
Topic: Misunderstood terminology
Replies: 86
Views: 6362

Re: Misunderstood terminology

Power most certainly does have an element (strictly a dimension) of time despite tatanab's statement. It is work that has no time component. The work done to climb a hill slowly (to allow air resistance to be ignored) is the same whether it takes 1 hour or 10 hours. It is the power that varies being...
by BigG
18 Mar 2018, 11:07pm
Forum: Does anyone know … ?
Topic: Misunderstood terminology
Replies: 86
Views: 6362

Re: Misunderstood terminology

MickF is close, but not quite right. Work is torque (or force) multiplied by distance. Power is work divided by time. These are not definitions, just indications of the calculation process.
by BigG
9 Mar 2018, 7:17pm
Forum: Bikes & Bits – Technical section
Topic: Cheap as chains? Or too cheap?
Replies: 27
Views: 2262

Re: Cheap as chains? Or too cheap?

mjr's comment on the quality of at least some of TAYA chains underlines the reputation that this company has with some cyclists. I have used TAYA chains for many years without any problems. They may not be the most long lasting but they have always given me good value. I have asked before on this fo...
by BigG
15 Feb 2018, 10:44pm
Forum: Bikes & Bits – Technical section
Topic: Front and rear derailleurs for my retirement present (to myself)
Replies: 15
Views: 1283

Re: Front and rear derailleurs for my retirement present (to myself)

You may find the Shimano RD761 SGS better than the 771 as it has the cable adjuster built in. It is usually available on ebay. In all other respects, the two types perform equally well.
by BigG
12 Feb 2018, 8:19pm
Forum: Bikes & Bits – Technical section
Topic: Spoke tension underbraking..
Replies: 14
Views: 618

Re: Spoke tension underbraking..

What I have difficulty with is understanding why there should be any difference between discs and rim brakes. In the fact that rim brakes effectively stop the part in contact with the road, i.e. the tyre, still puts tension on the spokes because the braking force is transmitted through the spokes t...