Cycling UK Forum

Chris Jeggo wrote: ↑7 Jun 2023, 8:09am Replace rim if thinner than 1mm.

Maybe 1mm is too conservative. If it is thinned down to 0.5mm anywhere, then for sure the replacement is a must, I usually acted by 0.7mm.

SteveGray wrote: ↑31 May 2023, 1:37pm Applying my school physics, a longer lever will spread the work over a longer distance and reduce the force needed to change gear, resulting in less pain I hope.

Has anyone invented a reliable lever extension ?

Initial thoughts are copper water pipe, flattened to fit closely over the existing lever.

Below you have exactly the solution you envisioned, a Sunrace thumb shifter with a short piece of an alu tube, flattened at one end, put onto the lever to make it longer, and covered with heat shrink. This has worked on my Brompton for about 3 years now. The need for a stronger than normal torque applied resulted from the complicated cable routing on the folder and the front derailleur shifting over a big gap between rings.

If the culprit is a stubborn Loctite that might have been put in excess, then a flooding with acetone, so that it could get into the thread area, might help.

The offer on AliExpress has operating instructions towards the bottom of the description:

https://www.aliexpress.com/i/3256801644138939.html

Once a given link wears just a bit more than other, the link in front of it will start to wear in an accelerated fashion and then the next. This is because a worn link disrupts sharing of the load between the links. I.e., the chain is principally unstable with respect to the development of uneven wear. E.g., a worn quick link put on a chain will start ruining the links that are in front of it.

Same, here, the lightly (106) studded Nokians became my least used tires since I got Conti TopContact Winter, in particular with lamellas. I only turn to the heavily (240) studded Nokian/Suomi when it gets really rough. By the way, Conti Winter I, that had no lammellas, but just winter rubber formulation and some glass shards embedded, rather than studs, have also been good.

Congratulations on this turning into a success.

Mick F wrote: ↑14 Sep 2022, 11:17am As for the clearance question, I've just measured.
In 34inner and 30t big cog (bottom gear) there is 21mm of space below the chain to the inside bottom of the cage.
I swapped over to the forbidden 34inner and 12t smallest cog, and there was still 12mm of space.

Thanks. This sounds more than enough for an extra 3T drop in the size of the smallest ring (3*.5*25.4mm/(2*pi)=6mm). Of course, the chain vibrates, so the still remaining space is very welcome. I should be getting that mech then.

The cracking can depend on mounting and stress points that the mounting can produce. Otherwise, some brittleness can be good. I witness a friend taking off into the air when his mudguard locked the front. That mudguard was made from a very resilient plastic and lacked safety releases. If it were made from brittle plastic, it might have saved his fork, helmet and laptop and spared the visit to an emergency room. Maybe safety releases could have been sufficient, but double protection may be good too.

Mick, in the testing, could you check how far the chain is above the bottom of the cage when on the smallest 34T ring? My uses require as large capacity as 30T, hence my interest whether there as any extra space left.

As to shiny vs dull, in my experience the shiny cages are more rigid and then brittle, limiting the degree they can be tweaked to a specific configuration on the bike just by bending.

Thanks.

Mick F wrote: ↑11 Sep 2022, 7:16pm I've released the spring, and going to fit the mech and experiment with where the chain sits on each ring with respect to the mech.

Have you released the spring before and managed to reengage it? I tried it with a mech that was broken and anyway condemned, but, under home conditions, all I ended up with were a couple of gashes in my hand. Is there some good method for reengaging the spring?

I would suggest looking into non-studded Conti Top Contact Winter https://www.continental-tires.com/bicyc ... r2-premium. These tires take care of most of my winter needs. I turn to studded tires only when there is a heavy build-up of snow an/or long stretches of ice develop.

531colin wrote: ↑10 Sep 2022, 8:42am Love to see some pictures, just to be nosey!

cycle tramp wrote: ↑10 Sep 2022, 9:48am You don't half hide your light under a bushel! Any chance you feel like writing a thread for this forum about your super hero ability (or even an article for the cuk magazine?... sign if only there was a magazine with the title 'bicycle mechanics' on the newstands)

OK here are a few photos. When the mech is on a bike, it is hard to take a photo that reveals much.


This one, in my memory, is the one I used for double on Brompton.


This one is a peak into the current triple on Brompton, 50-34-20. Most of the cage is completely remade. I usually add a bottom lip to the rear plate and narrow the channel for the chain towards the bottom of the cage building up material on the inside of the top plate. The cage may be cut and made longer.


This one is a peak from the side. You can see the soldered on bottom of the cage.

One significant derailleur I rebuilt, not here, is for shifting over 4 rings. All my shifting is indexed.


This is the miniature torch I use when the amount of metal I need to heat begins to overwhelm the soldering iron.

531colin wrote: ↑9 Sep 2022, 8:24amI might favour silver soldering a bit of stainless in place, rather than drilling and bolting. Forming the cage to make it narrower or turning the mech. a bit to "toe in" the front might risk chain rub on the big ring, although "toeing in" is easy to try and can be easily reversed if it doesn't work.

I am routinely modifying front mech cages to optimize shifting with different rings, increasing capacity, adapting to different chain width, etc. The general strategy is of silver soldering stainless steel pieces. The chain swipes away the solder it rubs against, but the soldered on pieces stay and work just as effectively as the regular cage. Right now I am riding a Brompton with 50-34-20 rings shifted over with a heavily modified Suntour mech, I think XC Pro.

In any case, the repair of the cage here would be relatively trivial compared to what I normally do. The procedure is forgiving. If the piece you added does not work well, you melt the solder, modify the added piece and try again. You can put pieces on top of pieces, cut cages, make them longer and so on. My front shifts end up being nearly as smooth as in the rear and this no matter whether the rings match or have any pins or ramps.

I quickly terminated reading the reviews as I got afraid that their somber content could push me into depression

All these batteries are just differently packaged collections of 18650 cells that may well come from the same manufacturer.