Stem hinge - Brompton

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Kell

Veteran
The hinge on my Brompton's stem has a habit of getting stuck.

By which I mean, I'll ride to the station and attempt to fold my bike down when I get there. But sometimes, even though it's fully loosened off, the clamp gets stuck to the hinge.

To release it needs leverage. So a multi-tool screwdriver for example. it's not a horrible situation, but sometimes when I'm hustling for the train, taking time to get a tool out my bag is additional hassle and time.

There is significant paint rub and I suspect that the oxidization of the two parts is the issue. It's worse when it's wet.

Anyone experienced this? If so how did you solve it?

If not, how would you attempt to solve it?
 
Location
Essex
When the clamp is done up, there should be a gap between the bottom of the clamp 'c' and the two plates. They're designed to wear to preserve the frame, and overtightening or simple wear and tear will make the clamp splay over time so it could be that more surface area is in contact than is ideal.

First port of call, I think would be to clean both surfaces thoroughly and make sure there's no grippy crap in there and that the mating surfaces are smooth. If, when its done up the clamp is starting to bottom out then it's time for a £7 replacement hinge clamp plate or an upgrade to a whizzy, aftermarket self-extracting one :smile: SJS do them for a bargainacious £154.99!!
 
OP
OP
Kell

Kell

Veteran
I did replace them a while back with black edition ones. But the bike is now 9 years' old so they could be due another replacement I guess.

Brompton recommend every 5 years IIRC.
 
OP
OP
Kell

Kell

Veteran
Just checked - it was five years ago.

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Looks like it's time for some new ones.

Don't think I'll be spending £155 quid though.
 

gizmo1994

Senior Member
Location
France
I have just had exactly the same on the wife's Brompton. The hinge clamp stuck down on folding (which doesn't happen often as the bikes sit, ready to go by the front door). We resorted to hitting the clamp with a knife handle from the drawer and that would dislodge it usually. I took off the hinge clamps and just cleaned then in the washing up water, along with the contact points on the frame. It is now really free and comes off easily.
 

wafter

I like steel bikes and I cannot lie..
Location
Oxford
I put a smear of grease on the jaws to.prevent sticking.

Lubrication is probably the answer; personally I prefer Dr. Wafter's patent paste-wax (softened, squishy paraffin wax) as It doesn't retain contamination..
 
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neilrichardson55

Active Member
Location
Hemel
Talking of clamps (on my non busted bike) i do use a small amount of silicon grease to help it. but i have lost quiet alot of paint from this area
has anyone else repainted it >? ive got some rust killer and paint and some 2 pack lacquer to try and keep some paint on lol, anyone else tried ? is it worth doing ?
 

wafter

I like steel bikes and I cannot lie..
Location
Oxford
Talking of clamps (on my non busted bike) i do use a small amount of silicon grease to help it. but i have lost quiet alot of paint from this area
has anyone else repainted it >? ive got some rust killer and paint and some 2 pack lacquer to try and keep some paint on lol, anyone else tried ? is it worth doing ?

Tbh I don't think any form of surface finish is going to last long in areas of actual contact; especially coatings like paint / powder coat rather than oxide finishes.

As picky as I am I think it's unreasonable not to expect loss if finish in this area and really all should be good as long as this doesn't invite corrosion that damages the surrounding finish.

If you have rust, personally I'd just treat that with phosphoric acid / a chelating agent and apply a bit of "mobile" protection to the area afterwards like a wax or oil.
 
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