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Small Chainrings

Stephen Willetts2023-08-25 10:52:39
I use a triple chainring set up with a 30t inner. I have just looked on several retailers websites none of which list these. Small these days seems to mean 40t - 38t presumably for modern solo set ups. Are 30t - 28t chainrings still available? 
Peter Herron2023-08-25 11:49:53
Yes definitely. Try Spa Cycles website. 
Lawrence McPhillips2023-08-25 11:52:35

Have a look here: https://www.spacycles.co.uk/m8b0s210p0/Drivetrain/Chainrings-Spa


Plenty of smaller rings carried by both suppliers - in four and five arm pattern and in most common BCD sizes.

2023-08-25 12:21:19
Depends where you are, always good to get face to face advice. It will depend on your current set up and BCD all chainsets have a minimum size. I would second Spa cycles but if you speak to Bob go easy on him he is just back from PBP.
Stephen Willetts2023-08-25 12:29:27

Problem solved.

I'm running 135 BCD for outer and middle, inner runs on 74BCD attaches to 5 sockets on the inside of the spider. I had been looking for 135BCD 30T which is impossible!

Thanks for the advice, I rang Spa Cycles, that's when the penny dropped!

2023-08-25 14:07:16
Gosh, I was looking at exactly the same issue this morning, (30T inner ring too large, 74mm BCD). Our current chainset is FSA with black rings, and they don't do smaller than 30T, but TA do black rings with 28, 26 or even 24T for 74mm PCD, which at 7%, 14% or 20% reduction will equate to one, two or three 'extra gears'. I've  ordered a 26T ring, on the basis that if we go too slowly we'll fall over! 
Garry Miller2023-08-25 14:34:25
Sorry if teaching granny to suck eggs, but be careful  not to push the capacity of your front mech. to far. Fitting smaller inner ring is great, but most front mechs will have a max differential between small and large ring of around 15 teeth or so. So with a 30 inner ring your max big ring would be circa 45 teeth. You can stretch these numbers a bit but expect changing issues if you are at the extreme of capacity.
Stuart Hibberd2023-08-25 16:53:15

If you have a triple chainset with the appropriate front derailleur then its capacity will be around 22T. Double chainset derailleurs will have a smaller capacity.

I run a triple with 50-39-26 and a campag racing triple front derailleur 22T capacity and it works fine. On my solo I have a 44-38-25 and a shimano dura ace derailleur 15T capacity and that all so works fine.

So the capacity figure quoted by the manufacturers is a guide but not the whole truth.

If you want a big range of gears you may need to stretch to capacity of your derailleurs.

Don't forget about your rear derailleur's capacity if you change the front chainring. The total capacity of my chainset and gears is 42T but my rear derailleur is rated for 40T.

Capacity is probably based on the gears and chainset being sold at the time. Take Shimano Tiagra gears 11-32 cassette plus 50-40-30 chainset giving a capacity of 41T and low and behold the capacity of a medium cage Tiagra rear derailler is .... 41T.