Seatpost sleeve......... I find it difficult to understand how a 'pre-reamed' sleeve is an improvement over a 'standard' unless it's supplied with a more generous clearance such that it will be 'correct size' once glued in place - this suggests (to me anyway) that its service life is likely to be less than that of a 'standard' sleeve. If I was looking to replace the sleeve my plan would be as follows - please feel free to add comments (good or bad) or advise that I'm totally wrong if you wish...... It's all good discussion if we can resolve 'problems' and help each other. Being a self-confessed 'skinflint' I'd be looking for a low-cost solution but without compromising the result, so I won't be reaming the bust with a broomstick and sandpaper!
1) Look at any videos where others show how they've achieved it, and any instruction manuals.
2) Source a new (non-pre reamed per my opening comment) sleeve and the correct adhesive.
3) Source an adjustable hand reamer with enough range of adjustment for the job.... and a vernier calliper if I didn't already have one
4) here's the difficult one..... source a 'fitment' tube (or even a broomstick
) slightly smaller in diameter than the seatube (no more than 0.2mm smaller)
If the seat quick release adjustment nut has ever been tightened I'd slacken it off.
I'd then try a 'dry run' without adhesive to ascertain what I'm dealing with.....
a) Having cleaned out any residual plastic or glue from the area, fit the sleeve in position and try the seatpin for fit - it may not fit of course.
b) Try the smaller 'fitment' tube - If it fits (hopefully only just), carefully try the quick release to see if it will clamp the tube, but if the tube is a loose fit don't tighten the QR to its full tightness otherwise there is a risk of deforming the seat tube.
c) If the fit is reasonable, go ahead with removing the sleeve and refitting with some glue and insert the 'fitment' tube and tighten teh quick - release. Leave for the specified time for glue to dry.
d) remove 'fitment' tube and check if seatpin will fit (very unlikely of course).
e) Adjust reamer to size using the 'fitment' tube as a guide - making the reamer a slightly bigger diameter (maybe 0.05mm or even less) and ream the sleeve.
Repeat until there is minimal clearance which gives the correct 'feel' when the seatpost QR is tightened (ie. not too tight)
The above relies on the fitter being careful, having lots of patience and confidence to do the job. For the price of an adjustable reamer (maybe less than £30) it will be cheaper than (the fear of) someone else doing the job, with the satisfaction of DIY.
Indeed! I think the idea of the pre-reamed insert is that it forgoes all the buggering about with tooling; presumably at the cost of fit and as you suggest potentially service life.
It seems that what typically kills these is abrasion from contamination, so if that problem could be resolved (extended mudflap, better seatpost tube design) they should last a lot longer.. although mine is now also showing significant cracking at the point where it flares out at the top to locate in the groove in the frame.
Your suggestion sounds potentially workable, although I can think of a few potential issues:
- A typical adjustable reamer probably has parallel flutes which are likely to get snagged in the slot in the seatpost bush
- A typical reamer lacks any form of guide; as is used with the "proper" one to centre it seatpost tube at the bottom during reaming
- Finding a suitablely size "fitment tube" would probably be pretty difficult as it would be (to my knowledge) no standard metric size. You could bodge one by using shim around something smaller
- The "proper" adhesive is bloody expensive; so forgoing the Brompton reamer would only be part of the battle
On top of that I really want to find a better solution than glueing the bush in, since it's ruined the finish in my frame and is now inviting corrosion
For the time being mine's holding OK with the lashed-up red bull can - were it not so shafted I suspect that bonding a piece of more resilient shim (like brass or stainless) into the worn bush could probably be a pretty permanent solution..
In other news like a puppy sh*tting in my slippers, this week the Brompton has made me aware that it requires further attention. This thread is dedicated to the memory of another half-a-Saturday sacrificed upon the altar of self-propelled traffic-avoidance..
Putting the bike away after the last commute of the week I noticed the rear tyre was flat, so that was today's first job.
The usual, numbingly familar process was begun - bike inverted, rear wheel off, washed in the sink, stripped, inspected, patched, reassembled.. turned out to be a small puncture corresponding to a small cut in the tyre. Contamination apparently gone (although I ought to give it a really thorough check) and it all went back together OK.
The spectre of worn brake pads has been looming for a while; the final push to sort it out coming on Wednesday night when I failed to stop in time when something braked suddenly infront of me. No harm done and mostly my fault but the cack brakes certainly didn't help..
Thanks to the stupid Brompton's stupid design changing the pads meant having the wheels off, so off came the front one too which was also washed - in the process finding a piece of glass stuck to it; the removal of which may have prevented another puncture.
Even though the bike has only done five commutes since it was "functionally" cleaned over the holiday, it's already caked in shite again. The brake calipers were dry-brushed to remove the worst of it, then the pad assemblies unbolted and the mounting areas on the calipers cleaned locally with a wet toothbrush and rag as I could't face washing the whole thing again.
Pads and carriers after a wash - arranged as you'd find them looking down on the bike with the front to the right of the image..
Pad wear is uneven - straight on the front but the NDS pad has seen more wear; while the rear NDS pad has worn reet on the piss; maybe due to poor alignment from the factory.
In addition the carriers had suffered a little - I'm a bit baffled by the rub on the top of the rear carrier - being pushed with a flat, gritty tyre perhaps?
The bottom rear edge of this carrier had also been slightly nicked thanks to both its wonkyness and my failure to replace the pads sooner. Were I not well-beyond caring this would irritate me; with things as they are... meh.
The pad inserts were removed from the carriers and everything cleaned again. Old pads with new posh replacements that I'd pragmatically sourced some months ago; IIRC to bulk out an order for some other stuff:
The new pads look pretty nicely made; as they should for a fiver a piece..
Everything went back together with arguably appropriate adornments - paste-wax on the mating faces of the threaded bosses and between the washers, synthetic grease on the inserts to get them back in the carriers, mineral oil on the threads..
While in bits I took the opportunity to look at the front caliper, which has begun creaking loudly during use. Seems this was due to the crusty return spring sliding against one of the arms; probably due to the presence of accumulated grit. This was largely resolved by dry-brushing with a toothbrush then lubing with a bit of silicone oil; since the spring appears to bear against a synthetic insert in the arm.
Really the brakes probably want fully stripping, cleaning and lubing.. but that's not a job for today.
Once the pads were back in and the cable adjustors on the brake levers slackened right off the wheels were refitted; deflating the tyres to get them between the pads thanks to the utterly inexcusible lack of provision of any form of cable tension release fort this purpose
Tyres inflated and the brake shoes were aligned as best as possible then nipped up - trying to get them as parallel to, and centred within the rim as possible. The back was especially irritating due to my lack of apparently necessary go-go-gadget arms to operate the brake lever and manipulate the pads at the same time. Eventually I settled on actuating the lever with an elastic band which proved pretty handy - applying enough force to push the pad into contact with the rim while still allowing it to be moved about
Finally the front caliper bolt was slackened off to allow the pads to be centralised about the rim.
Other random points of note.. when the wheels were off I found a bit of slop in the rear hub bearing but nothing that caused particular concern (rightly or wrongly). I believe these aren't a whole lot of fun to adjust..
I also found that front wheel bearings are still rumbling; I'll have them to bits at some point but suspect there's not a whole lot that can be done.
After last week's damp conditions the not-long-rewaxed KMC chain is looking tatty again; although it's not squeaking so I'll run it until it is...
Measuring this last night with the vernier suggested that it's about 0.35% worn so probably has about another 900 miles in it until it hits 0.5% wear at around 3k miles... not a terrible innings since Brompton recommend they're replaced at 2k miles and I've heard many stories of them failing much, much sooner.
Both the original SRAM chain and KMC E8 EPT appear to be wearing at similar rates. It seems chain wear is governed primarily by the quality / hardness of the chain, and that that as a rule chains for more speeds typically seem to be made to a better standard. Once these two are dead I might look into fitting an 11sp chain, since the boggo KMC X11 on my CdF seems to be lasting forever (admittedly an apples-to-oranges comparison given differences in drivetrain and operating conditions) but IMO it's worth a go.
The sprockets still look OK; the 13T starting to show some slight "undercutting" of the teeth. This is presumably because it's wearing at a faster rate than the chain is elongating (since I'm running two so the effective rate of elongation is is half what it would be with one chain); so the typical migration of the contact patch up the teeth is slower. I suppose it'd probably be prudent to get a spare set in, just in case..
I also noticed a fair coating of brass deposits on the fork hook where it rubs against the brass frame-saver plate on the back end when folded - the mind boggles at the state the frame would be in were it not for this additional protection!
As usual after a morning of verbal abuse the bike charmed its way back into my affections on a quick (short, not fast) run to grab some more eggs for a well-earned early afternoon "breakfast".
Unsurprisingly the brakes feel immeasurably better now - I think due to a combination of much shorter lever pull (I was getting close to the limits of adjustment and had left the pads with plenty of clearance as they'd worn to allow easier wheel removal), more favourable caliper arm angles, clean rims and new shoes. I've heard good things about the Swiss Stop items - can't say as I really noticed a difference today over how I remember the less-worn original items, but then they're probably not fully bedded in yet (a process I might have forgotten to consciously carry out..)..
Anyway, while (as always) not as I want it at least the little bugger's serviceable again. For now...
