Page 3 of 8 FirstFirst 12345 ... LastLast
Results 21 to 30 of 80

Thread: Nobby newby biking questions

  1. #21
    Quote Originally Posted by anthonykay View Post
    Presumably when you've pedalled all the way down from Greenhow to Dibble's Bridge in your 56/10 gear, you can be sure that when you hit the bridge parapet you will make a clean landing in the fields on the far side of the river.
    Alas Anthony the sturdy steel-mesh fencing erected above the parapet means you now bounce back into the road looking like a fly after it has been swatted.

    Which makes life much easier for the recovery team.
    Last edited by Graham Breeze; 08-05-2021 at 09:32 PM.
    "...as dry as the Atacama desert".

  2. #22
    Admin brett's Avatar
    Join Date
    Jan 2007
    Location
    Cononley
    Posts
    3,385
    Another hour spent on WH Smiths on the Grove?

    Quote Originally Posted by Graham Breeze View Post
    As if on cue...Cycling Weekly this week,

  3. #23
    I've got a TDF (Tour De Fer - some similarities to the CDF but more touring orientated) and I really like it. My other bike has a compact 105 chainset and I was told it's fine to cross the chain from big ring to big sprocket as it was designed to be able to handle that - I took that with a big pinch of salt and don't. But I have found myself occasionally losing count and finding the chain at a greater angle than I would normally like without any obvious Ill effects (except maybe not immediately apparent wear and tear).

  4. #24
    Quote Originally Posted by Mark G View Post
    I've got a TDF (Tour De Fer - some similarities to the CDF but more touring orientated) and I really like it. My other bike has a compact 105 chainset and I was told it's fine to cross the chain from big ring to big sprocket as it was designed to be able to handle that - I took that with a big pinch of salt and don't. But I have found myself occasionally losing count and finding the chain at a greater angle than I would normally like without any obvious Ill effects (except maybe not immediately apparent wear and tear).
    I think chains are an engineering miracle. Obviously they stretch and I've just changed my SRAM on the ADV after 1400 miles but at 20 - who cares?, but more than once as I have been standing on the pedals inching up a 25% climb, forty miles from home I have prayed "chain, chain please don't let me down now!
    "...as dry as the Atacama desert".

  5. #25
    Senior Member Marco's Avatar
    Join Date
    Apr 2009
    Location
    Flat SE Staffordshire
    Posts
    441
    Quote Originally Posted by Graham Breeze View Post
    SRAM produces a 12 speed cassette including a 10-tooth socket and is now releasing chain rings to the public with up to 56 teeth. Because the smaller sockets are less efficient than those closer to the spokes there is a case that using a really big front ring means you can keep away from the smaller and less efficent sprockets but achieve the same ratios. It's the straight chain thing.
    When Franco Moser broke the world hour record in 1984 the Italians did a lot of research into the efficiency of different sprockets, and found that a 15 tooth sprocket was the smallest one that was efficient. As a result he used something like a 57 x 15 gear with an oversized rear wheel.

    The Italian research discovered that with sprockets smaller than 15 tooth because the chain was turning through a greater angle between each tooth, as the sprocket got smaller, this led to a corresponding increase in friction. Or to put it in English, a 60 x 15 gear will have less friction (but more weight) than a 56 x 14, which in turn would have less friction than a 52 x 13 and so on.

    If you want to see how fast you can go downhill, if you spin a gear of 52 x 13 up to 180rpm, (which is considered to be as fast as you can possibly pedal), on 700c x 25mm tyres you will reach around 57mph. Around 35 years ago, sadly before accurate speed measuring equipment was available, I achieved something similar on the A52 Ashbourne - Derby road riding one metre behind an Irish fish van (which looked more like a removal van) with a very bad gearbox. It was great until the road went upwards and I lost the tow and got hit by the turbulence you would expect from 3 metres behind something of that size going over 50mph. Not recommended

    In short, stick to 52 x 13 or 48 x 12 and spin your legs, (which will help your downhill fellrunning technique), and save your pennies
    Last edited by Marco; 09-05-2021 at 12:35 PM.

  6. #26
    Senior Member Marco's Avatar
    Join Date
    Apr 2009
    Location
    Flat SE Staffordshire
    Posts
    441
    Quote Originally Posted by Mark G View Post
    ... My other bike has a compact 105 chainset and I was told it's fine to cross the chain from big ring to big sprocket as it was designed to be able to handle that - I took that with a big pinch of salt and don't. But I have found myself occasionally losing count and finding the chain at a greater angle than I would normally like without any obvious Ill effects (except maybe not immediately apparent wear and tear).
    Last autumn one of my mum's neighbours bought a well-equipped 2400 bike from the Lancashire company named after the river. Carbon frame, carbon wheel rims (but with calliper brakes), 105 equipment and a compact 50/34 chainset.

    As I have said, many times, it's very flat around here with the occasional short hill that rarely exceeds 1 in 10. It means for fit, and experienced, cyclists the 50 tooth chainring is all you need. For a newcomer, however, the hills are too steep for the big ring

    I saw his bike after he'd ridden it four times, and less than 100 miles, and there was a visible loss of metal from the outside of the front chainring, which was the result of the shearing action of the chain in the big chainring to biggest sprocket. Based on what I saw, if he continued riding the bike in this way he'd need a new front chainring after 500 miles. He told me that he didn't use the 34 chainring because it was too small. I did wonder why, when spending this amount of money, he didn't specify a 42 inner ring.

  7. #27
    Quote Originally Posted by Marco View Post
    When Franco Moser ...
    Francesco!

  8. #28
    Quote Originally Posted by Marco View Post

    If you want to see how fast you can go downhill, if you spin a gear of 52 x 13 up to 180rpm, (which is considered to be as fast as you can possibly pedal), on 700c x 25mm tyres you will reach around 57mph. Around 35 years ago, sadly before accurate speed measuring equipment was available, I achieved something similar on the A52 Ashbourne - Derby road riding one metre behind an Irish fish van (which looked more like a removal van) with a very bad gearbox. It was great until the road went upwards and I lost the tow and got hit by the turbulence you would expect from 3 metres behind something of that size going over 50mph. Not recommended

    In short, stick to 52 x 13 or 48 x 12 and spin your legs, (which will help your downhill fellrunning technique), and save your pennies
    Being 100 years old I have stopped chasing fish vans and just want to get up climbs. The smallest gear on my road bike (say 19 lb) is 34/29 and on the ADVenture bike is 32/32 (but 24 lb). The ADV feels clunky and is heavier and I don't really like riding it (I really bought it as my winter bike) but I have concluded that the lower gearing means that even with the extra weight and clunky tyres it should provide an easier ride up steep hills. Pity really because it just doesn't cut quite the same dash as the Italian! (I know I should do a timed comparison but my remaining time on this earth is short!).
    Last edited by Graham Breeze; 09-05-2021 at 04:16 PM.
    "...as dry as the Atacama desert".

  9. #29
    Master mr brightside's Avatar
    Join Date
    Jul 2009
    Location
    Loving it in the Pilates Studio
    Posts
    6,568
    I knew it wouldn't be long before this thread became a new tributary of the grand tidal estuary of factual cycling chat that is 'todays bike ride'.

    As i've been skimming i've noticed someone saying its ok to strain the chain on a 105. Personally, i'd throw the lot in the bin and go SRAM as i've been woefully disappointed with how 105 shifts; especially on the rings. I could scarcely believe my senses when the weather warmed up and i got back on the Colnago which is fitted with DA7800, it was like going from a Trabant to a 5 Series.
    Can't climb for toffee...

  10. #30
    Master mr brightside's Avatar
    Join Date
    Jul 2009
    Location
    Loving it in the Pilates Studio
    Posts
    6,568
    Any news on the TdeY after Mr Verity's surprise departure?
    Can't climb for toffee...

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •