Sprocket famine

General cycling advice ( NOT technical ! )
Roy A
Posts: 46
Joined: 28 Dec 2015, 7:41pm
Location: West Midlands

Re: Sprocket famine

Post by Roy A »

Bompton sprockets are 3/32 and usually use 8 speed chains, which precludes 1/8 versions.
King of Mercia, Giant Defy, Raleigh MTB, Brompton M3L & S6L
PhilD28
Posts: 352
Joined: 26 Sep 2016, 8:31am

Re: Sprocket famine

Post by PhilD28 »

Roy A wrote: 10 Oct 2021, 4:29pm Bompton sprockets are 3/32 and usually use 8 speed chains, which precludes 1/8 versions.
If it’s a simple 3 speed hub without a chain tensioner what’s the problem using an 1/8” chain on 3/32” sprockets. I’ve ridden 1000’s of miles with 1/8” chains on my Rohloff 3/32” sprocket. The chains are cheap and often last longer than 3/32” chains.
Roy A
Posts: 46
Joined: 28 Dec 2015, 7:41pm
Location: West Midlands

Re: Sprocket famine

Post by Roy A »

Brompton use a chain tensioner.
King of Mercia, Giant Defy, Raleigh MTB, Brompton M3L & S6L
PhilD28
Posts: 352
Joined: 26 Sep 2016, 8:31am

Re: Sprocket famine

Post by PhilD28 »

I have no experience of Brompton chain installs, but looking at the tensioner it appears to have enough space to run an 1/8" chain. Maybe someone has tried it?
Tompsk
Posts: 195
Joined: 6 Nov 2014, 9:35am

Re: Sprocket famine

Post by Tompsk »

rogerzilla wrote: 6 Oct 2021, 2:39pm Wouldn't most Brompton owners want a 1/8" 14T sprocket?
I can't speak for most Brompton owners but mine has 1/8 sprocket and has the original Brompton chain tensioner. My Brompton is a rather ancient SRAM 3 speed model (which runs very well) so the OP may be out of luck with their bike in terms of choice if their (possibly) later Brompton has a narrower tensioner or if they have the 2 sprocket set up.

The OP could try a short ride with a 1/8 chain on their bike to check if this is a way forward.

I went for a 15 tooth sprocket for the lower gearing. IIRC it was about £3 + postage from Bridgewater (so I bought 2 at the time as same postage).

1/8 seem to be in stock for 13, 14 & 15 teeth:
https://www.sjscycles.co.uk/sprockets/s ... cp-hsl852/

Edit: Add link
User avatar
Audax67
Posts: 6001
Joined: 25 Aug 2011, 9:02am
Location: Alsace, France
Contact:

Re: Sprocket famine

Post by Audax67 »

Don't know squat about Brommies, but I just looked up Ultegra cassettes at my usual supplier: since March 2020 an R8000 11-spd has gone from 65€ to 89€.

My current one has >5000 km on it. <gulp>

Fortunately I switched to wax lube around the same time last year and it hasn't been ground up by road gunge.
Have we got time for another cuppa?
gxaustin
Posts: 890
Joined: 23 Sep 2015, 12:07pm

Re: Sprocket famine

Post by gxaustin »

Feeling smug with spares for everything - and I had enough bits to make 2 bikes up over lockdown :D
Mind you I'm about to fit my only spare chainwheel, but the old one lasted 25,000 miles.
Costs have gone mad and availability is worse.
rmurphy195
Posts: 2199
Joined: 20 May 2011, 11:23am
Location: South Birmingham

Re: Sprocket famine

Post by rmurphy195 »

Stradageek wrote: 7 Oct 2021, 8:37am
Tinnishill wrote: 5 Oct 2021, 1:54pm Having tried eight online retailers (including Brompton's own website) I found only one shop had an example in stock; they wanted a fiver for the sprocket and a tenner for the post.

I used my bus pass for the first time in 18 months and took the hour long bus trip into the nearest city and spent the afternoon walking round bike shops; the fifth one had one (yep, one) in stock and wanted £14 for it. I bought it.
Welcome to the wonderful world of the capitalist free market economy where you are encouraged to sell anything for as much as you can get away with.
As opposed to a government official deciding whther or not you should have it - with or without his/her commission. Or indeed the governement deciding whether the product should be available at all to certain classes of people.
Brompton, Condor Heritage, creaky joints and thinning white (formerly grey) hair
""You know you're getting old when it's easier to ride a bike than to get on and off it" - quote from observant jogger !
Stradageek
Posts: 1657
Joined: 17 Jan 2011, 1:07pm

Re: Sprocket famine

Post by Stradageek »

rmurphy195 wrote: 24 Oct 2021, 3:06pm
Stradageek wrote: 7 Oct 2021, 8:37am Welcome to the wonderful world of the capitalist free market economy where you are encouraged to sell anything for as much as you can get away with.
As opposed to a government official deciding whther or not you should have it - with or without his/her commission. Or indeed the governement deciding whether the product should be available at all to certain classes of people.
You're assuming that the only alternative to unbridled capitalism is communism, how about socialism/controlled capitalism?

I often ponder a new UK where private rents are controlled to match council rents having seen so many of my friends endlessly moving house as the landlords raise the monthly rents by £200 every year with complete impunity. Such controls exist, and work, in the economically struggling Germany https://www.ft.com/content/efe1f74c-3c1 ... 303f70fcff :D

I could go on but this would constitute serious 'thread creep' :lol:
Carlton green
Posts: 3645
Joined: 22 Jun 2019, 12:27pm

Re: Sprocket famine

Post by Carlton green »

The FT link is unfortunately behind a pay wall. Yes, it would be serious ‘thread creep’ but not an uninteresting diversion.

My ‘vote’ would be for ‘socialism/controlled capitalism’.

Sprocket famine? Well there might be a shortage of parts at the moment, my policy is to buy parts well in advance of when I’m likely to need them. Occasionally I do get caught out or have to make do with another solution, but normally there’s something in my store of bits.
Don’t fret, it’s OK to: ride a simple old bike; ride slowly, walk, rest and admire the view; ride off-road; ride in your raincoat; ride by yourself; ride in the dark; and ride one hundred yards or one hundred miles. Your bike and your choices to suit you.
simonhill
Posts: 5226
Joined: 13 Jan 2007, 11:28am
Location: Essex

Re: Sprocket famine

Post by simonhill »

Makes my spare Surly seem like a good idea. Not planned as it was inherited, but nice to know that every replacement part is sitting in my lounge.

Rides well on those dry sunny days when I take it out.
Post Reply