New seat post clamp - to stop slippage.

[RegG]

Pull the post out (remove the saddle, pull it out from the bottom) and degrease it and the sleeve with meths or similar. A bit of grease or oil on the post can cause slippage. If this doesn't work, tighten the nut just enough to prevent slippage when you bounce on the saddle.

Thanks for that...... we will give it a try.

 

[sdawila]

I am currently having this issue !, I purchased the bike brand new and today it is not even 3 weeks old and I have already broken the seat post clamp. after bringing the bike back to the store where I finally got it replaced for free at the end. Guess what ?, I broke the replacement after 2 rides (around 60 Km). I still use the bike but the bike cant be folded since I secure the seat post clamp manually by twisting the bolt with a spanner.

Brompton is not my first folding bike, my first folding bike is the Dahon Vitesse D7 and I still have it and loving it, folding and unfolding the bike is not new thing to me, but I was blamed by a Brompton distributor in Jakarta that I folded and opened the bike in an incorrect way and oh boy it did insult my experience for commuting daily by a folding bike for a year plus. Long story short, I am not a happy customer and I am not going back there for the same problem.

Maximum bike payload is 110 Kg. and I weight 92 Kg. what do I do next to overcome this problem ?

 

[rogerzilla]

Which part broke? The lever?

 

[sdawila]

the lever looks good as new but it does not do the job when you tighten or loosen it. This happened both to the old and the replacement ones.

 

[rogerzilla]

I wonder if they've redesigned them in poor materials? It sounds as if the cam has rounded off or something.

 

[Kell]

Where did you get it done @Kell ?

Got mine done at Saddle Safari in Marlow.

It’s where I bought it from.

I’ve left the second clamp on for now too as it adds about half a second to the the fold/unfold time. And hopefully will stop me over tightening in the future.

 

[sdawila]

I wonder if they've redesigned them in poor materials? It sounds as if the cam has rounded off or something.

I have just discussed with long term brompton owner about this issue, more or less about the seat post clamp material, according to him, the stock seat post clamp does the job better than the 3rd party branded ones that cost a lot.

It seems like I’m facing a dead end if I’m stucked with another replacement which will brake after few rides.

 

[RegG]

I have just discussed with long term brompton owner about this issue, more or less about the seat post clamp material, according to him, the stock seat post clamp does the job better than the 3rd party branded ones that cost a lot.

It seems like I’m facing a dead end if I’m stucked with another replacement which will brake after few rides.

I've had a reply from Brompton re the seat post slipping on my daughters 3 week old Brommy.....

We've been advised to return it to the dealer for adjustment and, if that doesn't work, Brompton say they will have it back to the factory to rectify it. Trying to do it ourselves could invalidate the warranty.

I've no idea how the warranty works in Indonesia but I would suggest an email to Brompton to see what they say.

Good luck.

 

[rogerzilla]

I have just discussed with long term brompton owner about this issue, more or less about the seat post clamp material, according to him, the stock seat post clamp does the job better than the 3rd party branded ones that cost a lot.

It seems like I’m facing a dead end if I’m stucked with another replacement which will brake after few rides.

The Brompton seat clamping arrangement is a fairly unique hybrid of an old-fashioned steel frame seat lug (the type that has "ears" for a binder bolt or short QR skewer) and the separate collar type of seatclamp found on most modern frames. Not many off-the-shelf clamps would work very well.

 

[sdawila]

I've had a reply from Brompton re the seat post slipping on my daughters 3 week old Brommy.....

We've been advised to return it to the dealer for adjustment and, if that doesn't work, Brompton say they will have it back to the factory to rectify it. Trying to do it ourselves could invalidate the warranty.

I've no idea how the warranty works in Indonesia but I would suggest an email to Brompton to see what they say.

Good luck.

well thanks for the respond. Turned out our problem is the same. on my way to work this morning I decided to stop over to one of the Brompton workshops owned by friend of a friend just to obtain a way out from this seat post clamp headache. According to one of the technicians the seat post clamp material is far poor compared to the previous version/batch. He had actually weighted both the new stock clamp and the old ones, the old ones in indeed a lot tougher and weight almost double than the new ones. He suggested to get the titanium replacement for a power user who'd rather abuse the bike for more than 120 km weekly. The stock ones are great for weekend rider but not for user like me.

 

[rogerzilla]

Brompton do tend to use customers as beta testers. They've had a few notable failures over the years: aluminium seatposts and cracking M-type bars spring to mind.

Much of the specification is also suspect. The hinges and clamps are well made but a hi-ten steel frame is a bit cheap on a £1000 bike and there are some really cheesy components that you'd expect on a £200 bike.

They do fold smaller than anything else but you're mostly paying for the brand (and London labour costs).

 

[sdawila]

To update the issue, i finally found a cure. I’ve ordered a titanium seatpost clamp from ebay and it will take sometimes to arrive in my possession. While waiting for it to get to me, i ended up buying a alloy seatpost clamp which cost lots cheaper than the original ones. It did look good and paid it, installed it and it is a cure for my problem. But....

The slipping issue is still happening but it’s not as bad as it was. I will try to borrow someone’s seatpost just to see if the gravity of this mess is actually the seatpost.

 

[bikegang]

We have worked with KCNC with this aluminum CNC machined Groovy seatpost, test ride pretty convincing and will lose -140 g in the process... iso certified to 120kg.

 

[rogerzilla]

Brimpton tried an alu seatpost after they discontinued their own titanium one. I think it marked too readily - it didn't last long as a product.

 

[sdawila]

Brimpton tried an alu seatpost after they discontinued their own titanium one. I think it marked too readily - it didn't last long as a product.

The slipping issue is still happening. The first problem I have I thought it was the defected seatpost clamp but it turned out I still have the same problem after replacing the clamp with a titanium. Does anyone reckon if I replace the seat post with a titanium one would end this problem ? or should I replace the shim first ?