Play in Brompton front frame hinge..

[wafter]

As if there wasn't already enough, my cup runneth over with anxiety fuel

Short story is that at around 3.3k miles / 3yrs old / maybe 200 folds there's noticeable play in the hinge pin at the front of the main frame.

I'm pretty certain this wasn't present when I got it so it's evidently developed during my ownership. Further, the nature of the play seems somewhat odd / concerning since movement can be seen between the top end of the hinge pin and the top part of the frame's front section.

Delving a bit deeper it seems that the hinge pin is fitted from underneath and retained by a spline that's driven into the lower / outer / front portion of the frame; meaning it's intended to remain rotationally static relative to the frame's front section and rotate within the centre portion of the hinge that's attached to the rear of the frame.

Hence, since the pin and frame in the area of play do not rotate relative to each other this movement can't be due to wear enountered during folding.

the hinge pin has a counterbore in the top end that apparently acts to centre a drill / punch when it the pin is removed; I'm wondering if this has maybe allowed the pin to collapse inward somewhat during use and cause this play..

Is anyone else seeing anything similar on their bikes?

This seems like an odd failure mode and I'm concerned about its ongoing effect on the bike..

Unfortunately like many other areas of the bike this doesn't seem like a great solution - while I'm possibly missing something, I don't see why the pin has to be single-use and retained using a method that effectively damages the frame when something like a shoulder bolt could be used instead; allowing more straightforward and reversible fitting / removal..

 

[rogerzilla]

There's a kit to replace these, and it can be done at least twice in the bike's lifetime. As with all Brompton specialist tools, the kit is expensive if you can get them (Brompton do seem to have restarted tool sales to end users, though) so it is probably cheaper to go to a dealer - if THEY have the kit.

Alot of things on a Brompton are not especially user-friendly. I have the rear hinge tools and the seatpost sleeve tool, but not the hinge kit.

 

[wafter]

There's a kit to replace these, and it can be done at least twice in the bike's lifetime. As with all Brompton specialist tools, the kit is expensive if you can get them (Brompton do seem to have restarted tool sales to end users, though) so it is probably cheaper to go to a dealer - if THEY have the kit.

Alot of things on a Brompton are not especially user-friendly. I have the rear hinge tools and the seatpost sleeve tool, but not the hinge kit.

Thanks and yes, I'm aware of the replacement options. My issue is really that it appears to have "worn" very quickly in a seemingly unconventional way, while also if I go the conventional replacement route after only one year of use the frame will be scrap in 2-3 more years.

 

[rogerzilla]

If it's not normal wear but a manufacturing defect, you should contact Brompton (they'll probably insist you take it to a dealer). I think there's a high probability they'll claim it's normal wear to fob you off.

 

[FrankCrank]

Hey Mr Wafter, I hope you haven't been sneaking off to the BMX park and doing all sorts of jumps and whatnot

 

[wafter]

If it's not normal wear but a manufacturing defect, you should contact Brompton (they'll probably insist you take it to a dealer). I think there's a high probability they'll claim it's normal wear to fob you off.

Thanks - that was exactly my thought and my fear is that I'll get some muppet claiming wear and tear because they either don't understand the problem or have an agenda in not dealing with the issue properly..

Also, I suspect that even if they admit it's a defect the outcome will be the same - replacement of the pin with the next size up, with all the invasive work, grief and loss of one of the frame's four lives that this involves..

Hey Mr Wafter, I hope you haven't been sneaking off to the BMX park and doing all sorts of jumps and whatnot

lol - obviously not, although I do wonder how it's happened as I can't see it being wear for the reasons above, while equally regardless of how it's loaded a steel pin shouldn't just become sloppy inside a steel hole... either the pin has got smaller or the hole bigger; again can't see how either could happen legitimately.


I guess I'd better contact Brompton and brace myself for the ensuing battle..

 

[wafter]

Since this is clearly a significant issue that's likey going to drag on ad infinitum, I've updated my main thread on the bike with my latest findings..

 

[wafter]

Quelle surprise, Brompton have got back to me with the old "they all do that mate" fob-off.

When I have the mental fortitude I'm going to press them to provide feedback from the thier technical department about the specifics of this failure as I imagine the response so far just came from a muppet reading from their "hinge wear" crib sheet.

I'm also tempted to seek the input of a shop, but of course that's only going to be as good as their competence and the logistics won't be straightforward.

I know it's a pain, but is anyone else with a brompton able to confirm whether, when during folding the hinge pin remains static with the front portion of the frame or rotates with it, please?