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I recently bought a used bike which has a shimano alivio 8 speed gearset. When I look at the drivetrain, it really looks small to me. Below are the size of them in terms of the number of teeth:

chainring: 24t,34t,42t

cassette: 11-23T.

Is this combo ok? From what I read this is not the standard no of teeth for chainring and cassette? Are their any drawbacks of using this combo?

EDIT

It's a hybrid bike (Specialized Sirrus) and has 700*32 wheels on it. As for my riding style I mainly ride it on the road, pavements and bicycle trails.

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    You should tell us what type of bike it is, including the wheel size. That sounds close-geared to me and lacking at the top end but I mainly ride a hybrid on road. It might be sensible for mtb use, but may be missing something at the bottom end there. – Chris H Nov 29 '15 at 12:49
  • It's ok. The cheap hybrids now come with this small chainring. It started from 27.5" and 29" mtbs. Later on you can switch it to any chainrings you want. – Alexander Nov 30 '15 at 16:17
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I read that as you already have a bike with this gearing, you're asking if its okay, not whether it will fit and work.

You might want to recount the teeth on the big ring. 42 is not impossible, but 44 would be more common based on the other two.

Assuming this is your 11-23, 11-12-13-15-17-19-21-23, and that you're on a 700 wheel with 23mm tyres, then Saint Sheldon says this at http://www.sheldonbrown.com/gears/

Little Middle Big chainrings

4.2 5.9 7.3 (metres of forward roll per complete pedal revolution, 11 tooth)

3.8 5.4 6.7

3.3 4.6 5.7

2.9 4.1 5.0

2.5 3.6 4.4

2.2 3.1 3.8

1.9 2.7 3.3

1.6 2.3 2.9 (same, but for the 23 tooth gear)

So its a road bike with a granny gear for steep hill climbs. The 42 chainring limits your top speed a little, and the 11 tooth rear will have mechanical loss of efficiency compared to a 12 or 13 tooth.

There is nothing wrong with your combination. Use and learn what you want, and where you struggle. Personally I have a 25 in the rear and a 22 on the front, and I still struggle with steep 20% grades.

Once its a bit more worn and you know what you want, then replace the chain and cassette with a range to suit your riding needs.

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    The 23 tooth biggest sprocket wastes most of the benefit of the granny chainring. I've got a comparable bike with 28-38-48 x 11--32. I've ridden up 1:3 on that, and don't quite spin out coming out of a descent at 60km/h. That's more like hybrid gearing. – Chris H Nov 30 '15 at 6:51
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There are a few things you need to check when you select a cassette+chainring wrt the derailleurs:

1) Can the front derailleur take it? The front derailleur has a certain number of teeth it can shift between chainrings, and a largest and smallest cog rating.

2) Can the rear derailleur take it? It needs the capacity to be sufficiently high for the chainring+cassette combo, appropriate largest sprocket (and smallest sprocket, if specified).

Both need to have the same type of cable pull as your shifters.

3) Is the cassette compatible with my wheel? Campagnolo cassettes don't fit on Shimano freehubs, for example. And if you put a Campagnolo wheel on a Shimano system, the spacing of the cogs may cause problems.

If all these are OK, you're fine technically, but you may want to change the gearing, for the type of riding you do.

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Yes that is narrow cassette that would be more for flat roads

They may have done that because that is all they had as that set up does not make much sense for that bike. It may also have low capacity derailleur so they had to keep ratios tight.

That bike currently comes with 11-32T cassette and 48/38/28T chainrings

If you need a lower gear now then get a bigger cassette now otherwise wait for it to wear out and then get a bigger.

If you need a higher gear you may need to switch out both the 24 and 42 as the derailleur may not have the capacity for 24 to 48.

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It is a narrow range road cassette. The chainrings are very small, with a more common 11-30 cassette most of the gear combinations would be too low to be useful unless you ride in the mountains. The narrow range produces more gear combinations in the useful range, and 22/23 lowest gear is still extremely low by road standards.

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