2021 Brompton C-Line Explore

[EltonFrog]

I am sure it was around £50 plus the sleeve

Seems reasonable, I don’t know how much the tooling costs, but I suspect more than that.

 

[rogerzilla]

The tool cost me £40 unused!

 

[wafter]

There are actually two types of bush in existence - pre-reamed and normal. Years ago I fitted a pre-reamed one after a respray and it works perfectly. However, other people have found it less satisfactory. My bike has the old Brompton Ti blue/black post and it no doubt has much higher friction than a chromed steel post.

If you want to come to Swindon and DIY using the Brompton tool for the price of the bush you can. I think they were about a fiver each and I bought a few. You will need glue (see above for my recommendation).

They recommend using an old Brompton seatpost to knock out the worn bush from below. This is something owners probably don't have, so it's a case of breaking it inwards.

https://www.brompton.com/support/bikes/c-line/bromptonacademy

Thanks - I'd be willing to try a pre-reamed insert if I could get my hands on one, but they don't seem available anywhere as a stand-alone item.

Ta muchly for the offer of using your gear; not sure how I want to go currently but I'll keep it in mind

I had a look at the process and it doesn't look particularly pleasant - probably a toss-up on the quality of outcome between inexperienced me treading very carefully and someone with more experience but less OCD..


I've not updated this thread for a while since the ownership experience has taken a bit of a nosedive over past months thanks largely to the seatpost and hinge issues...

A while ago the frame hinge pin was kindly sorted by Warlands under warranty; their position was that it wasn't "normal wear" and they'd never seen one fail in that way before.

However, despite my having sent Brompton a couple of videos of the defect they continue with the "la la la not listening they all do that mate" line; which is.... disappointing.

Anyway, the replacement pin was apparently the same 6mm diameter as the original while Warlands did a decent job; not without an amount of damage to the finish but realistically about as good as it could have been given the process and I'm very grateful for their assistance.



Today the bike got a necessary half-arsed wash as I needed to strip the external gear shifter mech as it'd become varying degrees of reluctant to shift from the 16T to the 13T sprocket; typically this was significantly worse in the wet or after fitting a newly waxed chain.

Since none of the shifter mech has seen any attention in my ownership I stripped and cleaned all the associated bits at the back end of the bike.

Disassembly proved less than straighforward and I ended up resorting to a useful video on Brompton's website. As unimpressed as I remain by many aspects of the company, I do appreciate thier willingness to supply both information and tools to facilitate owners working on their own bikes.

It was still a bit of a pig and didn't come to bits as anticipated; possibly due to an amount of grit that had made its way inside..

Once apart I found the shifter setup to be more complex than anticipated with quite a few bits - below is the sub-assembly that transfers the shifter cable's motion to the "chain pusher":

If anyone's using the above as a guide for reassembly please note I've got the cable stop (bottom-right-most-part) the wrong way around by 180 degrees - the hook should face towards the left of the image.

Off the bike the assembly still operated OK but was a bit rough and had been subject to varying degrees of muck ingress; hardly surprising given its location and the rear mudguard's limited abilities. After a thorough clean it went back together with moly grease on the internal spring / cable and a smear of paste wax on the external spring / guide.


The chain pusher itself also felt pretty rough; again not really presenting a lot of resistance but certainly not right. This was stripped to reveal the ally (I think) and plastic bearing inside; which contained a surprising amount of crap. Not sure if this was contaminated grease or all mud; regardless it was given a thorough clean and reassembled with silicone grease..

While the bike was in bits I also noticed more play in the front wheel bearings; having been cleaned and repacked relatively recently these were just nipped up to remove the slop.


All back together and a quick test ride found shifting to be very slick and snappy so I think the problem is resolved; however the real proof will be in the next soaking wet ride or fresh chain fitment.

It seems that the filthy chain pusher was most likely responsible for the poor shifting and given how closely all the parts fit together it's surprising that so much contamination found its way inside. I guess over so many thousands of actuations and parts rotating next to each other it can work its way in.

Maybe after the inevitable winter hammering I'll strip this assy again to see what it looks like / if anything can be done to protect it further; although my enthusiasm for the bike currently remains at a low ebb in the face of the avoidable issues encountered recently..

 

[rogerzilla]

The derailleur assembly is really Heath Robinson. The reason it's like that, with the huge springs, is because Brompton wanted a lot of slack in the operating mechanism, so you can initiate a shift when not pedalling (or stationary), although the shift won't actually complete until you start pedalling. The bikes are intended for use by non-enthusiasts who could be confused by the difference between a hub gear shift (best when freewheeling) and a derailleur shift (need to pedal).

The newer actuating mechanism that goes with the integrated shift/brake lever is worse than the old one as there is a sliding part that is known to jam if dirty or just in hot weather.

Changing the cable on either type is an experience you don't forget quickly.

 

[wafter]

The derailleur assembly is really Heath Robinson. The reason it's like that, with the huge springs, is because Brompton wanted a lot of slack in the operating mechanism, so you can initiate a shift when not pedalling (or stationary), although the shift won't actually complete until you start pedalling. The bikes are intended for use by non-enthusiasts who could be confused by the difference between a hub gear shift (best when freewheeling) and a derailleur shift (need to pedal).

The newer actuating mechanism that goes with the integrated shift/brake lever is worse than the old one as there is a sliding part that is known to jam if dirty or just in hot weather.

Changing the cable on either type is an experience you don't forget quickly.

Thanks - I'e found the hub shifter lever to occasionally be temperamental in returning to its original position, but other than the issue described above have found the gears to be pretty reliable.

I think the pusher itself seems pretty robust and well executed (sealing notwithstanding); while the upstream cable assembly is certainly "unique". Again sealing could be better (or for the hundredth time protection from the mudguards better) however I guess I can't complain too much after 3.7k miles and over a year's use in all weathers without any attention.