Stem hinge - Brompton

[Kell]

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?

 

[Specialeyes]

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 SJS do them for a bargainacious £154.99!!

 

[Kell]

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.

 

[Kell]

Just checked - it was five years ago.

Looks like it's time for some new ones.

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

 

[rogerzilla]

I put a smear of grease on the jaws to.prevent sticking.

 

[gizmo1994]

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.

 

[Kell]

Thanks for the responses.

Ordered some new hinge clamp plates and will give the frame a bit of a clean.

 

[annedonnelly]

Mine started doing that. I gave it a good clean - removing the clamps to do it properly - and it's been fine since.

 

[wafter]

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..

 

[T4tomo]

Mine started doing that. I gave it a good clean - removing the clamps to do it properly - and it's been fine since.

ditto with mine, I could release them by thumping the clamp, but cleaning the clamp plates cured it. Mine will be 20 yeas old next year, although it hasn't been used much in past 5 years.

 

[neilrichardson55]

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]

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.

 

[404 Not Found Anywhere]

to bottom out then it's time for a £7 replacement hinge clamp plate or an upgrade to a whizzy, aftermarket self-extracting one SJS do them for a bargainacious £154.99!!

gone down to a real bargain of £124.99! I think I’d better get two sets, one to match the JK bars on my S6L and the second set to fit to my new whizzy G-series (😆)