UK and Europe · Public discussion

Brompton questions

Started by Tim Woodall · · Last activity · 10 posts · 444 views

This thread is locked and is currently read-only.

Thread navigation

Jump through the discussion

Go to the original post, the replies on this page, or the latest preserved contribution.

Thread details

What we know about this thread

Original section
UK and Europe
Published
10 September 2005
Last activity
16 September 2005
Original author
Tim Woodall
Posts
10
Discussion status
Public discussion
Total views
444
Views / 30 days
0
Topics

The navigation and discussion metadata provide context. Posts remain in their original chronological order.

Showing posts 1–10 of 10
Posts remain in their original chronological order.

Text size
  1. Some quick questions (I hope)

    1. Is there a source of bigger wheels for the rear of the rack. I've
    just fitted a new rear light[1] and it just catches on the floor as the
    bike is folded (once it's properly folded it's ok, it's as it folds and
    one day I'll clout it on the floor and smash the light.
    10mm more in diameter would be ok, 20mm would be perfect.

    2. See [1], would a couple of zeners help here if I clamped the voltage?
    And what voltage should I clamp it to 6VRMS[2]? SON hub dynamo -
    I'd rather buy a new light every couple of years than a new dynamo so I
    don't want to do anything that might damage the dynamo.
    I've ordered the "B&M Lumotech Plus round halogen dynamo front light with
    standlight" which might have this protection already built in? The
    "oval" won't fit with the front pannier AFAICT. My current light is the
    the same light but without the standlight

    3. How much play should there be in the joint that folds the rear wheel
    under the bike. I've definitely got some slight play there - maybe this
    is normal but if it's not I'd like to get it sorted before it gets any
    worse. (It's a very slight movement and you don't notice it while riding
    and can safely be ignored if it's normal but I've never noticed it
    before - all the fiddling around with the rear light made me see it
    today)

    Tim.

    [1] My old rear standlight light packed up after the front bulb blew and
    I didn't notice - it was all working at work when I left but not working
    by the time I got to Euston and the roads are so bright with
    streetlights there is no way to tell that the light isn't working.

    [2] A zener isn't going to be able to clamp it "RMS". It's going to look
    like a truncated sine wave (assuming that the dynamo puts out a sinewave
    which I haven't checked). Looking in an (old) maplin catalogue, it looks
    like there is 7.5V or 9.1V @ 1.3W

    --
    God said, "div D = rho, div B = 0, curl E = - @B/@t, curl H = J + @D/@t,"
    and there was light.

    http://tjw.hn.org/ http://www.locofungus.btinternet.co.uk/

  2. Tim Woodall said:

    Some quick questions (I hope)

    1. Is there a source of bigger wheels for the rear of the rack. I've
    just fitted a new rear light[1] and it just catches on the floor as the
    bike is folded (once it's properly folded it's ok, it's as it folds and
    one day I'll clout it on the floor and smash the light.
    10mm more in diameter would be ok, 20mm would be perfect.

    Lots of people, me included, have fitted skate wheels (Decathalon sell
    them in a range of diameters). They roll much better than the Brompton
    ones. Or you could get the new Brompton ones
    http://www.biketrax.co.uk/products.php?plid=m6b0s142p763

    Quoted message said:


    3. How much play should there be in the joint that folds the rear wheel
    under the bike. I've definitely got some slight play there - maybe this
    is normal but if it's not I'd like to get it sorted before it gets any
    worse. (It's a very slight movement and you don't notice it while riding
    and can safely be ignored if it's normal but I've never noticed it
    before - all the fiddling around with the rear light made me see it
    today)

    There is a little bit of play but the bearing does wear and need
    replacing before it gets too bad. Its quite a job though and probably
    better left to the shop. If you want the inside on how to successfully
    DIY ask on the Yahoo BromptonTalk group where several people have done it.

    --
    Tony

    "I did make a mistake once - I thought I'd made a mistake but I hadn't"
    Anon

  3. I submit that on or about Sat, 10 Sep 2005 14:45:35 +0100, the person
    known to the court as Tony Raven <[email hidden]> made a
    statement (<[email hidden]> in Your Honour's bundle) to
    the following effect:

    Quoted message said:

    Lots of people, me included, have fitted skate wheels (Decathalon sell
    them in a range of diameters). They roll much better than the Brompton
    ones. Or you could get the new Brompton ones
    http://www.biketrax.co.uk/products.php?plid=m6b0s142p763

    On which subject, I have a pair of the new wheels with 5mm bolts (my
    bike has 6mm bolts, I was supplied 4 wheels), if anyone wants them
    drop me a line.

    Guy
    --
    http://www.chapmancentral.co.uk

    "To every complex problem there is a solution which is
    simple, neat and wrong" - HL Mencken

  4. Can I also ask a question?
    Someone at works selling a 6 year old Brompton for 150 pounds, if
    resonable condition would it be worth that much?

  5. "NJF" <[email hidden]> wrote in message
    news:[email hidden]...

    Quoted message said:

    Can I also ask a question?
    Someone at works selling a 6 year old Brompton for 150 pounds, if
    resonable condition would it be worth that much?

    That's not really the question you should be asking - it should be 'if
    reasonable condition, would it be worth that little' :-)

    IOW yes - certainly for an L or T.

    cheers,
    clive

  6. NJF <[email hidden]>typed

    Quoted message said:

    Can I also ask a question?
    Someone at works selling a 6 year old Brompton for 150 pounds, if
    resonable condition would it be worth that much?

    Yes, at least.

    --
    Helen D. Vecht: [email hidden]
    Edgware.

  7. in message <[email hidden]>, NJF ([email hidden]'😉

    Quoted message said:

    Can I also ask a question?
    Someone at works selling a 6 year old Brompton for 150 pounds, if
    resonable condition would it be worth that much?

    Unless it's really ratty, bite his hand off.

    --
    [email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

    ;; Madness takes its toll. Please have exact change.

  8. "NJF" <[email hidden]> wrote in message
    news:[email hidden]...

    Quoted message said:

    Can I also ask a question?
    Someone at works selling a 6 year old Brompton for 150 pounds, if
    resonable condition would it be worth that much?

    Nah - a rip off. Give me his number and I'll ring him up and tell him ;-)

  9. Simon Brooke said:

    in message <[email hidden]>, NJF ([email hidden]'😉

    Quoted message said:

    Can I also ask a question?
    Someone at works selling a 6 year old Brompton for 150 pounds, if
    resonable condition would it be worth that much?

    Unless it's really ratty, bite his hand off.


    It was a bit grubby and needs the bars changing/bracing, collecting
    after payday (I.E. in October), £100!

    Thanks for all the advice, more questions may follow!

    Niel, aka badger.badger

  10. Tim Woodall said:

    Some quick questions (I hope)

    2. See [1], would a couple of zeners help here if I clamped the voltage?
    And what voltage should I clamp it to 6VRMS[2]? SON hub dynamo -
    I'd rather buy a new light every couple of years than a new dynamo so I
    don't want to do anything that might damage the dynamo.
    I've ordered the "B&M Lumotech Plus round halogen dynamo front light with
    standlight" which might have this protection already built in? The
    "oval" won't fit with the front pannier AFAICT. My current light is the
    the same light but without the standlight

    I haven't heard of anyone doing serious damage to a SON by
    mis-connection (but someone might correct me).
    Zeners should keep the voltage down at high speeds. The Lumotec will
    contain protection and I think the component I burnt out in mine was a
    ST BZW 04 6V4B or something like it. Anyway someone else had one of
    these in a headlight (of unknown manufacturer) according to
    http://www.cycling.org/lists/bikecurrent/archive/2004/2004-08/1093635840000

    The spec sheet at

    http://www.st.com/stonline/books/pdf/docs/2971.pdf

    talks about it being able to cope with 400W as peak pulse power
    dissipation but 1.7W "power dissipation on infinite heatsink T_amb =
    75oC". My supposition is that this should protect normal high voltages
    at high speeds - but that if you persist in trying to dissipate the
    total output of your SON through this little Zener when your 3W bulb
    has blown it won't hold out for ever. Eventually it will fry....... If
    you are good and switch off your dynamo/ replace your bulb reasonably
    promptly, the Lumotec should survive.

    Tim

Active in the last 60 minutes

Active in this thread

0 users · 0 guests ·0 bots ·0 total

No signed-in users are active right now.

No known search crawlers active right now.