Author Topic: Brompton rear triangle  (Read 418 times)

Brompton rear triangle
« on: November 30, 2017, 12:59:16 am »
Having discovered yesterday that I've managed to snap the chainstay on my Brompton, I'm looking for a solution ...

Fairly obviously, I can pay £150 to a dealer for a new rear triangle, then the same again (well, more or less) to have it fitted and the bike serviced. While that's all very well, I quite like the idea of being a bit more self-sufficient, and of not spending three hundred quid - while the Brom is useful, and very nice to have, I don't really use it a huge amount and could nearly always find another option, plus I've got better things to do with three hundred quid ...

How practical is it to get hold of a rear triangle (dealers say publicly that they may only sell them along with fitting, and I haven't tried to convince one otherwise; ebay only has 3rd-party Ti ones at £500; I can't immediately find a s/h one), and then fit it myself? (I know a couple of people here have replaced rear bushes, with varying reliance on the official tools - I'd probably do that job at the same time simply because it's probably getting close to necessary.)

Or, frame repair? I've not spoken to anyone yet, but is brazing a Brom chainstay fairly close to the lug at the bottom bracket end practical? Sensible? Will I die horribly?

Kim

  • An appetite for the epic, but no real stamina
Re: Brompton rear triangle
« Reply #1 on: November 30, 2017, 01:01:40 am »
Try Kinetics.  He's in the business of replacing Brompton rear triangles with posh custom ones that take Rohloffs and such, so presumably has a supply of standard ones (some probably very lightly used) kicking around.

http://www.kinetics-online.co.uk/
Watching the TV without subtitles is like riding up a hill without using the gears :)

Re: Brompton rear triangle
« Reply #2 on: November 30, 2017, 01:13:55 am »
Thank you. Emailed.

(I'd spotted that yesterday, and meant to email him, and completely forgot in my enthusiasm to crowd-source a solution here.)

(On another note, I stuck this in OT Knowledge by mistake - can I move the thread myself (and if so, how?) or do I need to ask a mod?)
Moved almost before I'd asked ... Thanks.

Re: Brompton rear triangle
« Reply #3 on: December 01, 2017, 09:15:13 pm »
Try fitting the spindle without reaming the new bushes.  It often works, according to the local dealer.  If tbe bushes do need reaming, you'll need to have a dealer do it but it's a very quick job.
Never tell me the odds.

Re: Brompton rear triangle
« Reply #4 on: December 06, 2017, 03:08:50 pm »
OK, new-to-me rear triangle sourced, and shortly to be on its way to me from Kinetics - Kim, thanks again for the nudge in Ben's direction.

What else should I be checking, buying and planning to do/renew once it arrives? Suggestions, instructions and offers of help welcome ...

(LWaB's already offered use of tools, and http://www.shanecycles.com/brompton-hinge-repair/ seems a usefully coherent guide to bush and spindle replacement.)

LittleWheelsandBig

  • Whimsy Rider
Re: Brompton rear triangle
« Reply #5 on: December 06, 2017, 03:19:47 pm »
Your major hassle is removing the existing bolts. Drilling can be easy or a real pain (using the same sharpened drill!). drossall had some good advice in another thread.

While the bushes were out, I fitted SS grease nipples to the Bromptons I've done.
Wheel meet again, don't know where, don't know when...

Re: Brompton rear triangle
« Reply #6 on: December 06, 2017, 03:55:36 pm »
This thread https://yacf.co.uk/forum/index.php?topic=23380.0, yeah?

I have an impact driver. I have decent drill bits. I have a range of taps. I shall order a bush'n'spindle kit. Anything more to get? (I may have some grease nipples in stock, but it'll probably be easier to order new than find any that are concealed in the cellar.)

Where did you put the grease nipple - central on the hinge housing? Facing backwards to avoid the weld?

Did you decide it was worth cross-drilling the new spindle to make subsequent removal of the bolts easier?

LittleWheelsandBig

  • Whimsy Rider
Re: Brompton rear triangle
« Reply #7 on: December 06, 2017, 04:29:05 pm »
Where did you put the grease nipple - central on the hinge housing? Facing backwards to avoid the weld?

Did you decide it was worth cross-drilling the new spindle to make subsequent removal of the bolts easier?

Yes. Oriented to avoid getting knocked when the bike was folded but easily accessible by grease gun

No. I figure that the bushes will never need to be replaced again but that a grub screw in the grease nipple threads would be enough to lock up the spindle, if required. Somebody else just used a large flat washer and nut clamping onto the outside of the rear triangle on the 'loosened bolt' side and that was sufficient to let the tight bolt be removed.
Wheel meet again, don't know where, don't know when...

Karla

  • car(e) free
Re: Brompton rear triangle
« Reply #8 on: December 06, 2017, 04:42:46 pm »
Looking at that Kinetics site, I noticed there is a bike called a Moulton TSR 2.  Does it have wings?
Latest tour journal: Bucharest to Berlin

LittleWheelsandBig

  • Whimsy Rider
Re: Brompton rear triangle
« Reply #9 on: December 06, 2017, 04:49:27 pm »
That was why the Moulton got that model number. Alex admired the aircraft and the bike was titled to match. The other TSR designations had to follow the TSR 2.
Wheel meet again, don't know where, don't know when...

Karla

  • car(e) free
Re: Brompton rear triangle
« Reply #10 on: December 06, 2017, 04:56:51 pm »
Aah, I did wonder.
Latest tour journal: Bucharest to Berlin

Re: Brompton rear triangle
« Reply #11 on: December 06, 2017, 10:36:02 pm »
The method of cutting away the plastic bush and hacksawing through the spindle was so easy that I wouldn't worry about making provision for needing to remove the bolts again. You're not meant to re-use them anyway. I spent far longer faffing around, planning, and going carefully to make sure I didn't make a mistake (with someone else's bike) than doing the actual job. Once you've done it once, you'd see it as a quick job next time - provided of course you have borrowed LWaB's tools!