Brompton M2R New owner - Questions about QR on seat post and folding

[bence8810]

Hi all,

I am brand new to Brompton's and brand new to this forum - 1st post here, sorry if I may sound silly.
I've been riding a Dahon Metro 2010 for about 3 years now, the reason why I bought it was so I could bring it with me to the small islands just south of Tokyo where I frequently go fishing / camping. The Dahon served me right but I always had my eye on a Brompton, not sure if it was the hype or the small fold that I wanted it but I am glad I got it.

p.s. I am also a film shooter and went through a few cameras before dropping the extra $$$ on a Leica and never looked back - I expect the same will happen to the Brompton.

So - the 2 questions I have - again if I overlooked something please bear with me. I watched videos and read threads / manual etc, still unsure what to do.

First of all the seatpost clamp, the QR thing. It is plastic and looks surprisingly cheap for the amount of $$$ (or Japanese yen rather) I dropped on this bike. I am having a hard time finding the balance between the clamp not tightening down the sleeve strong enough so the seat post goes in gradually over bumps and over-tightening the nut so that even with the clamp open, the seatpost won't slide in for folding.

I noticed that the plastic clamp sort of rotates beyond the central nut, I assume the plastic isn't strong enough and when the nut is tight, it starts slipping / over-turning. Picture below.
What do you guys do to sort this out? I read that adding an extra QR on the post will work but isn't the charm of the brompton simplicity and things just working out of the box? I read people sanding down the seat post etc, really not something I'd like to do as long as there is a better way like adding on a stronger lever / clamp that won't slip etc.



Second is the bumper / damper in the back between the main body and the rear triangle. I got the firm block and I am happy with the way it rides, I am 190cm and 82kg so it is under a heavy load but still feels firm and sporty, not at all wobbly. What I don't like / don't understand is the little play between the frame and the rear triangle even when in the locked position. If I lift the bike by the seat, there's a little play and the body moves first - a small gap is formed between the frame and the damper and then the back moves as well. It is perhaps only 5mm but still annoying, if i forget about it and just want to move the bike a little, it makes this clicking sound. I took two photos, first with the bike firm on the flat and the second with me lifting it, you can see there the gap. Is this normal?

Flat on the ground:



Lifted and showing gap:



Thanks a lot,
Ben

 

[ukoldschool]

Hi Ben,

I bought my S6 a few months ago and have experienced exactly the same 2 'issues' so you are not alone

For the quick release clamp, yes its plastic, but its a thick, quality plastic IMO so i'm not bothered about changing it, but mine did start to slip a bit.. I just tightened the nut up a qtr turn at a time until i hit the sweet spot between easy locking and tight post (its easy to tighten it too far so that its hard to close)

I also have the 'play' in the suspension block mechanism, and have thought a fair bit about reducing this but have come to the conclusion that there really is no need. Its there only when no weight is on the bike, and you cant feel it when riding, its also not unsafe as the mechanism is clearly 'locked' into place, so I've stopped worrying about it

 

[rogerzilla]

The efficacy of the clamp varies depending on how well the factory reamed the seat tube sleeve, or if they even bothered. The sleeves are also sensitive to how much glue is used - too much in between the sleeve and the seat tube, and they are effectively smaller. Take the bike back to the dealer and ask them to sort it out. Officially only the factory can ream seat sleeves but it's not rocket science. A new sleeve fitted to a well-cleaned out frame with an appropriate amount of glue often doesn't need reaming anyway. I did my own and the action of the QR is perfect. This is the part I'm talking about: https://brilliantbikes.co.uk/brompton-handlebars-and-seat-posts/503-brompton-seat-pillar-sleve.html

Your bike has the latch to prevent the rear triangle hanging down when the bike is picked up. It has no function when riding - don't worry about the gap. I remove the latch completely - earlier Bromptons are free to swing anyway.

 

[Pale Rider]

I fell off my Brompton with the latch open.

The bike ended up in the parked position, upright, resting on the carrier.

I was starfished on the road and recall looking up at my bike and a confused passer-by who had stopped to help.

He thought the bike had snapped in two.

 

[bence8810]

Hi all,

Thanks for the replies, I understand the back part has a little play and I won't worry about it since it sounds like it is normal. Indeed no issues with it what so ever when riding, I just didn't like the clinging sound it makes when picked up. Interesting to know that old ones didn't even have that latch holding the back in the locked position...

About the QR, I will keep looking and will also try to investigate which dealer sold the bike, I bought it 2nd hand.

Currently, I have the nut very tight so even with the QR open, I can't push the seat post back, yet with QR closed the post is still slipping under my weight. Perhaps it's time to go on diet . I'll clean the post first with alcohol and let it dry, clean the sleeve and see if that helps in any way.

If I don't manage to locate the dealer and I still have the problem, I might just go for a 2nd QR on the post and be done with it.

About the QR clamp, I am still worried about it despite non of you mentioning this as an issue.

Is this normal that the plastic slips on the nut? When I am tightening it down, the plastic keeps moving but the nut no longer turns. This isn't under extreme force or anything.

Thanks,
Ben

 

[FolderBeholder]

My 3 month old S6L also has seatpost “creep” but my wife’s does not. I am about 215# so I put the hurt on it.
She weighs significantly less!

I have been unweighting my saddle over bumps, transitions, and drainage shallows etc., which has minimized that.

I wish to avoid adjusting the QR bolt as there are plenty of horror stories of people over-doing that and damaging the seat post and the seat-tube (ovalizing it). I’m an over-doer! So before the warranty period is expired I’ll ask for an adjustment, but at the end of the day unweighting the seat over rough surfaces has all but eliminated it for me.

The suspension block “play” as you call it (I call it a rattle) is typical of both of our household’s Brompton’s and I consider it normal by design fwiw.

Enjoy your Brompton...I sure am enjoying mine.

 

[lazyfatgit]

As posted upthread, get your dealer to sort out the seatpost clamp. I'm 96kg and mine has never slipped.

The clip on the rear is just to make it convenient to lift the bike. I rarely have mine locked as if I'm not riding it I'll either flip the rear under so it's self standing while doing something off the bike or it's being folded.

 

[bence8810]

Thank you all for the answers.

I have now removed the seatpost, cleaned it as well as the tube with the insert where the post goes through.
I've also removed the clamping mechanism and cleaned it, checked and tried to understand it.

After putting it all back together, - drumroll - nothing changed, same problem.
However, I now noticed that turning the clamp backwards all the way actually works a lot better and totally tightens the setup without any slipping etc.
Is my clamp put together wrong? I didn't find a way to take it apart. I wish I could somehow turn it around, all my problems would go away immediately!

Any ideas?

Thanks,
Ben

 

[CaptainWheezy]

I had exactly the same problem on my wife's S6L. The seatpost clamp moulding doesn't fit tight enough around the nut, and when you tighten it a bit too much, the nut slips its original position and then doesn't apply enough clamping force to secure the seatpost afterwards.

You can see the problem if you look carefully at the photo you posted with the red line drawn around the nut. In your photo, on the bottom inside edge of the plastic that surrounds the hex nut, there is a little notch that protrudes towards the nut. This should be lining up with a notch that is cut into the nut, however on your clamp you can see the nut has slipped / rotated and the notch is now at the 1 o clock position.

I managed to get the nut back into its original position on my wifes bike, and tried all sorts of things (shims in the gap between the nut & plastic, epoxy resin etc), but nothing would fix it / prevent it rotating when tightening the clamp. I ended up having to buy a new clamp. Not expensive but also not impressed considering the bike had only done about 100 miles.

If your bike is still under warranty, get that part replaced.

 

[rogerzilla]

Bromptons are the smallest folder and parts availability is better than for other makes, but I'd never pretend they are particularly well made or good value. It's a £200 bike sold for £1000.

 

[ukoldschool]

what a load of bollocks /\/\/\

 

[rogerzilla]

I've owned three over the last ten years and still have a S3E-X. The components are cheesy, the frame is hi-tensile steel and the price has doubled, without justification, mainly because Cyclescheme facilitates it. But thank you for your insightful contribution.

 

[ukoldschool]

ok, could you please:

Explain then how they could be better made?
Show me a brand new British made £200 folding bike.......

You cannot justify whether something is good value as the concept of 'value' and how it relates to you is completely different to how it relates to me and to everyone else, therefore a pointless statement. As is the statement that the components are somehow 'cheesy'? like a bag of wotsits??

I would also love to hear why you believe that the frames should be made of something other than hi-tensil steel (the most commonly used material for bicycles to be made from across the globe), perhaps your engineering and/or road safety qualifications can assist with this? Perhaps your insight can outline the many benefits of why a company successfully making a product out of one material should change the way it does it to suit your wishes?

 

[bence8810]

You can see the problem if you look carefully at the photo you posted with the red line drawn around the nut. In your photo, on the bottom inside edge of the plastic that surrounds the hex nut, there is a little notch that protrudes towards the nut. This should be lining up with a notch that is cut into the nut, however on your clamp you can see the nut has slipped / rotated and the notch is now at the 1 o clock position.

This is it, right on the money!
I managed also to turn the nut back to its place and now the clamp really is working but like you said, it won’t last for me either. It’s already made half a turn and if it does another half, it will lose its grip again.

I’ll just buy another clamp. What a shame indeed, poorly designed part I think.

I don’t know who the dealer is or if I had warranty, I got it second hand. I already emailed brompton to try and find out who sold the bike, I will then enquire there.

Thanks a lot, this really nailed it!
Ben

 

[ukoldschool]

I dont think the part is poorly designed, it looks like its been overstressed by poor maintanance?