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What kind of shim - fitting a stem to seatpost for stoker bar

daniel_bdaniel_b Posts: 9,248
edited April 2017 in The workshop
Morning all,

I need to adapt our Kona Minute to carry my nearly 4 year old daughter - we have a Yepp Seat at present, but she is soon to be too big for it.

I have bought one of these (Yet to fit)
bobike_junior-classic.png

But realise I now need to fit a 'stoker' bar of sorts, for her to hold onto.

The Seatpost is a 27.2mm one, so it would appear the 130mm stem I have just ordered should do the job.
It's a 1 1\8th" which equates to approx 28.6mm.

So my question is, what can I use as a shim to make the seatpost big enough to get a nice solid fitment with the stem?
I have used innertubes for lights and so on before, but this will be taking more weight, and it has to be completely safe, can;t have it rotating at all - are there any off the shelf shims I can buy, do I need to cut up some aluminium cans, and use enough layers to get up to the desired thickness?

The other end will just take a normal set of chopped down flat bars I have lying about, so that's no issue.

Thanks in advance,

Dan
Felt F70 05 (Turbo)
Marin Palisades Trail 91 and 06
Scott CR1 SL 12
Cannondale Synapse Adventure 15 & 16 Di2
Scott Foil 18

Posts

  • daniel_bdaniel_b Posts: 9,248
    Felt F70 05 (Turbo)
    Marin Palisades Trail 91 and 06
    Scott CR1 SL 12
    Cannondale Synapse Adventure 15 & 16 Di2
    Scott Foil 18
  • Nick PayneNick Payne Posts: 288
    That should be fine - you might need to chop the length down, as the shims are usually around 100mm long and the height of the clamp part of a stem is less than half of that.

    Easiest way to reduce the length is to have the seatpost out of the frame, clamp the shim and stem around the bottom of it so that the bottom of the stem and seatpost coincide, with the excess length of the shim protruding, and hacksaw off the excess and clean up the cut.
  • daniel_bdaniel_b Posts: 9,248
    Thanks Nick for taking the time to reply.

    I have the shim now, so will be looking to fit in the next few weeks - thanks for the handy tip re cutting :-)
    Felt F70 05 (Turbo)
    Marin Palisades Trail 91 and 06
    Scott CR1 SL 12
    Cannondale Synapse Adventure 15 & 16 Di2
    Scott Foil 18
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