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Stuck seat posts and chain widths

by David9694
Sun, Jun 02, 2024 07:58
5

At last! a table detailing chain/ chain pin widths, courtesy of Hopkinson's cycles. I'd like to complete this with how/when drop out widths changed from 120 to 126, 130 and 135 mm. 

https://hopkinsoncycles.co.uk/bicycle-chains/

Also https://theseatpostman.com/service/ may be annoyed by the video on the Facebook feed of https://gcbikerepairs.com/collections/bike-servicing?page=2 - part of the secret seems to be out. 

If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.

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wtjs | 3 weeks ago
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Several interesting links here. I began with 9-speed when it came out as Ultegra- later, I could see all the chaos developing over 10+ speeds and resolved to stay out of it because 9 speed is really good and cheap. However, there's a lot of 12 speed about, so I may join one-day. I'm pretty sure I will never have a 13+ speed

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David9694 | 3 weeks ago
1 like

Here's a grab from the seat post video.  Doesn't look like they've used a lubricant?  Where can I get that clamping plate?? 

As you can see, the guy is standing on the work bench with a foot on the vice - made my Health & Safety self twitch a bit. 

BTW, I found this shop looking for a respray place as my options otherwise seem to be Argos, Sussex, Kent, hipster places in London, or oop north - central southern England is a bit of a desert.

https://gcbikerepairs.com/ See under ADDITIONAL SERVICES 

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David9694 | 3 weeks ago
2 likes

I have a lot of time for Hopkinson's as they sell a lot of the basics and the fiddly stuff.  

As well as drop-out widths, I find myself hazy about chainwheel compatibility. Unless there's more to it, then the same chainset will work whether it's 5 6 7 or 8s - right?  The widths of 9, 10, 11 and 12s chains are all the same, it seems - but was there really 1.4 mm of spare pin to trim off (9 to 12s)? 

But you also see chainsets sold with ratings that straddle different chain widths, e.g. 8-9 speed https://hopkinsoncycles.co.uk/product/sram-s600-chainset-42-32-22t-crank...

This is article focused on freehub issues, but there's some useful information along the way about cassette widths. https://www.slowtwitch.com/Tech/Cassette_How-To_-_Part_2_3257.html

 

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S.E. replied to David9694 | 3 weeks ago
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Apparently not all chain manufacturers follow the same rules, eg in the 5-8 speed range you could find widths from 7.1 to 7.8 mm. Then 9 sp might be 6.7 mm, 12 sp 5.25, ie slightly different than in your table.

That's why the speed number or range of speeds can vary for each chain, I guess.

So while the narrower chain should fit cassettes with less speeds, it might be more expensive, or not last as long... (I wanted to buy a Sram 12 sp for my 11 sp Shimano after reading excellent results, half the wear compared to all other chains, but they are also 2 x the price, so I just bought a chain checker instead for 7 €, and will keep using and monitoring my Shimano and Connex chains! I also had good results with KMC...

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Matthew Acton-Varian replied to David9694 | 3 weeks ago
1 like

Another point to make with 9 to 12 speed, is that that due to the narrower spacing between the sprockets on the cassette, the plates of each link are narrower each time you go up a gear option. This is how they have managed to get all the sprockets in 12 speed to fit in almost exactly the same space as 9 speed (although the 11sp+ HG/universal freehub body is 1.87mm longer than the first edition).

The thickness of the teeth profile will be uniform across 5-8 speed and 9 to 12 speed. This chart might need updating with road now being 12 speed and there are some 13 speed options out there (Rotor, and Campagnolo Ekar).

Unlike the rear, where the jockey wheels apply pressure to shift from the inside of the links, the front derailleur pushes the chain from the outside to move it, using different speed equipment can lead to slower and a little more imprecise shifting because of those subtle differences.

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