Calling Brompton Techs

[digital kid]

Hi I need to change the rear frame on my Brompton - I managed to bend mine (don't ask!). Can someone run me through the procedure of changing the rear frame - from pulling the crank wheel to changing the bush/hinge that the rear frame pivots on. I am no novice but this will be my first attempt at changing the frame. I spent 10mins the other day trying to loosen the bush/hinge allen key but that is bloody tight (it bent the allen key!) and I assume that this may need to be drilled out? also the crank seemed to be very very tight when I undid the crank nuts, are there any tips for removing this? or do I need to be more manly..?

Thanks muchly in advance

[Ugly]

To remove the cranks you will need the correct crank puller, not too expensive from any half decent bike shop.

The pivot bolts are fixed with loctite and will probably need drilling out, a pillar drill is useful to ensure that you drill accurately.

getting the bushes out is tricky on my brompton one side dropped out the other needed pulling out with an old pair of long nosed pliers bent outward at the end.

when refitting use loctite to ensure the bolts stay in place

I got all the bits from St John Street Cycles, if you are doing this much work it's also worth thinking about new chain and sprocket(s) cables etc and get the bike nicely overhauled for summer

Brompton have a technical support service that may be useful

good luck

[rogerzilla]

There is no need to take out the bushes unless they are worn. Try undoing the bolts first - sometimes they will come out, sometimes one comes out which saves drilling that one. Otherwise, drill off the heads and then remove the stubs from the shaft with molegrips afterwards. Remove and grease the shaft and obviously use new bolts with strong Loctite when refitting.

I would advise against replacing the bushes yourself anyway - the correct procedure is to pull out the old ones, press in the new ones and then ream them in situ using the special Brompton tool which costs over £100. *Sometimes* you can get away without the reaming, but you don't know until you push in the shaft and find it's slightly too tight. Cyclecare (Earls Court Road in London or Purton near Swindon) did the whole job on one of ours last year for £45, although that also included retapping the BB shell which I'd slightly messed up when removing a recalcitrant BB cartridge.

I'm not hugely impressed by the rear hinge, and I'm sure they could use 7mm needle bearing cartridges with a minimal redesign.