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I have an old, second hand road bike but in good condition. I'm doing a lot cross country cycling and the struggling uphill with the current gear set up.

This is what I have:

  • Sora RD 3300 derailleur (total capacity: 29T; largest sprocket 27T; front chainring tooth difference 14T)
  • Sora Flight Deck 2x8 shifters
  • CS-HG50 12-23t cassette
  • 52/42 chain rings
  • Hub: don't know

what I've been considering is:

  • Only replace the smaller chain ring to a 39T (or do I need a whole new chain set?)
  • Only replace the cassette to another 8 speed or 9 speed (if hub compatible) up to 25 or 27t
  • Replace both cassette and chain ring(s)

    1. What is the most effective and cost effective way to upgrade this set up?
    2. Would the shifter and the derailleurs work with a 9 speed cassette as long as I stay on max tooth range?

Thanks!

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No, your derailleur won't work with 9 speed casette. Well, it could work on 8 sprockets of the 9, but that won't help you.

You certainly can buy a new 8 speed casette from the Claris line (or MTB) but you cannot take just any, you cannot go over your derailleur capacity and over the largest sprocket size supported so you are out of luck for the modern 32T casettes. Unless you find a good deal on a more recent 8-speed RD (like the new Claris 11T-32T, however, it is also sold as 11-28T, 12-25T, 13-26. The 28T is one tooth over your RD but might still work.).

Changing one chainring should work, check it is a compatible one. That would be cost-effective. If you have the Sora 3300 FD, it has the capacity of 15T, so with 52 big ring you can go to a 37 small ring.

Otherwise, you could always buy a whole new crankset, for example, a compact one (50/34), those are the most common and certainly would bring you a better gear range. But I am not sure about the 16T difference with your front derailleur. There are two versions of RD3300, one is SS and one is S GS. One supports the front chainrings difference of 14T, the other 22T. If you have the GS (total capacity 37T), you are good to go, but with SS (total capacity of 29T) the shifting might have some problems.

Again, better to take an 8-speed one from the Claris range, or an older 8-speed Sora. But, buying a new crankset will be the least cost-effective. Unless you find a good deal on something older (but better unused).

This kind of crankset would be a good candidate https://sprockets.uk.com/shimano-rs200-8-speed-compact-chainset-black-170mm-34-50t/ (I mean RS200, this specific 170 mm might be too short for you). But for the SS version the difference is officially too big.

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  • Also the FC-A070. The rear derailleur capacity probably won't be an issue, even with the SS. I wore out the 50t chainring on my SRM, and couldn't find a proper replacement, but had a 53t handy. It ... works. It actually works. A 53/34 crankset, an 11-28 cassette, and an RD-7800 (best shifting 10-speed RD ever). Of course the bike's an old 10-speed AL Neuvation with probably 40,000 miles on it, but it's a good trainer bike. The 53-11 combo makes for good "hills" on a trainer. Apr 19 '20 at 15:54
  • Yeah, the front shifting sucks - but it's an FSA crankset, so that's baked in anyway. Apr 19 '20 at 15:56
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What would be most effective? I've made up a table from Sheldon Brown's gear calculator page with your 52-42, and approx 11-23, but extended down to 34 on the front and to 28 on the back.

Putting a 28 on the back with your 42 would drop the gearing down from 48.2 gear inches to 39.6, which is a start. However, just by installing a 50-34 chainset, you would achieve a lower gear than that (39.0 inches) even without changing your cassette. Then by changing the cassette you can go lower still.

When you know the gearing you want to achieve, you can then assess what would be most cost effective, but that sort of depends on your budget. I think you need to start with deciding the gearing you want, then see how much it costs to achieve. There are some good compatibility pointers in existing answers.

Check out the chart and the web page, you can make your own charts to explore what would happen if you make changes. Another website: https://www.bikecalc.com/gear_ratios is also useful to do this, you can see what cadence you would be riding at a certain speed/gear as well. So if you know you can pedal uphill at (say) 60 rpm, you can see what speed that would be in a certain gear.

SheldonBrown.com gear calculation chart customised

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Judging from the equipment you listed, this is probably from the early 2000s or thereabouts. The gear ratios in fashion in that era emphasized fairly closely-spaced gears. Some roadies (including my younger self!!) might have dismissed big cassettes (i.e. lower, easier gears) as "pie plates" meant for tourists and unsuitable for real men. This was ultimately counterproductive for many cyclists! Current generation equipment, including entry-level groups, frequently comes with a much wider gear range, which it sounds like you would appreciate. There are, unfortunately, some limitations as to how much lower gearing you can get.

(Note: a previous version of this answer forgot that the OP specifically said that the max cog size of his RD was 27t. The answer has been modified.)

The most cost-effective way to get lower gears is probably to change just the rear cassette. 12-28 tooth 8s cassettes exist and are fairly cheap (I believe about US$20 online, possibly $35 or so from a shop, plus installation). . You stated that your max cog size is 27t. Shimano's specifications tend to be conservative, and a 28t rear cog is very likely to work. This should lower your lowest available gear by about 19% (when calculating gearing in gear-inches).

To get even lower gears, you could likely go up to a 12-32 cassette, but you would also need to change the rear derailer. That cassette would produce something like 29% lower gearing in the biggest cog. A 12-30 cassette also appears to exist. However, both exceed the maximum sprocket size by quite a bit, and they also exceed your rear derailer capacity. You could look for a rear derailer compatible with your shifters that has the correct maximum cog size and enough capacity. For the record, your crankset uses 52-42 = 10t of capacity. A 12-32 cassette would use 32-12 = 20t of capacity. That configuration uses a total of 30t, or 34t if you change to a 39t inner ring. You might also explore an item like Wolf Tooth's Roadlink to extend the capacity of your current RD, but I'm not sure how this item works with 8s drivetrains.

The trade-off with all these cassettes is that the gaps between gears will be bigger. On group road rides, this is likely to be annoying. In that use case, you want to be able to produce your optimum cadence at the group's current speed. That type of riding does favor more closely-spaced cogs on the rear. On solo rides, this is a matter of individual preference, and it may be totally irrelevant to you.

Your crankset can accommodate a 39t or 38t inner chainring. This reduces your gearing by something like 5%. Inner rings are also cheap. Your front derailer can shift the resulting 14 tooth gap, although that affects rear derailer capacity also. You physically can't mount an inner ring smaller than 38t on this crankset.

Further modifications to the bike are possible. You could upgrade to a more modern compact crankset with 50/34 chainrings, or even 48/32. However, this almost surely requires a new bottom bracket, unless you found a square taper compact crank that fits on the square taper spindle you have - many square taper cranks may need a different spindle length to achieve optimum chainline. You could search on Google if you desired; there may be some cheap options, but many of the ones you find may be expensive. You could even get a 10s or 11s group second hand, although it will be used. Changing the group either needs you to get the tools and to learn how to install it, or it requires you to pay a shop to do this, so it is a relatively expensive option. By this point, it would probably be more cost effective to get a new second hand bike. The second-hand bike market has quite low prices, especially for rim brake bikes. This is because the latter have been superseded by disc brake bikes. However, and this is coming from someone who has one of each, rim brakes are more than adequate for road bikes in almost all conditions.

Last, I hope you come to enjoy cycling more and more. As you ride more, you will get stronger. Even if a 28t big cog is a little overgeared for you right now, chances are it will become less and less so.

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  • 1
    The total capacity is one thing but the biggest possible sprocket size is another. The total capacity also concerns the cranks. The info I can find about RD 3300 is the max cog size 27T, at least the short cage one. Some sites seem to say 28T.
    – Vladimir F
    Apr 18 '20 at 14:27
  • @VladimirF You’re right, and he even said the max cog size was 27.
    – Weiwen Ng
    Apr 18 '20 at 20:52
  • a square taper compact crank that fits on the square taper spindle you have Tourney FC-A070 Assuming the chainline works, anyway. It's listed as a road crankset, so it should. A bit of searching shows it can be found for as little as $33+shipping. Apr 19 '20 at 15:41
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The single most cost effective way to improve your climbing is to upgrade the engine (you) but that takes time and effort.

If you leave 8 speed, the costs go up quickly because the shifter needs replacing, and possibly the rear mech and freehub and wheel and then its getting to new-bike costs.

I'd suggest this order

  1. Upgrade cassette to a 28 tooth max but stay in 8 speed. Get a new 8 speed chain. Since your bike is described as "old" there's a good chance both are worn anyway.
  2. IF that is insufficient for your hills, then look at a replacement inner cassette. Keep the old one unless its really worn, to let you revert. Your spider and bolt pattern will limit the lowest toothcount you can use.

Another option is simply Chill. Relax. Ride the hill at your own speed. Get fitter while doing so. Cost is $0 but large in time. Ignore those who ride pass you on the climb. Compete with yourself, not with all of Strava.

If you really want to tip money into the black hole of upgrading, be aware that there's a slippery slope.

An 11 speed cassette may not fit on your freehub, so you're probably limited to 10 speed. Doing that will need a new cassette (obvs!) and a new 10speed chain. You may require a new chaintool/multitool. Your right shifter must be changed, and you might choose to replace the other to make them the same. Its possible the rear derailleur may need replacing too.

Its wise to replace your gear cable inners and outers with new ones given the bartape is off to change shifter levers. So get some new bartape while you're at it.

If you want 11 speed, then the rear freehub might be all that needs swapping, if you can get them for your wheel hub. Otherwise its a new hub and rebuild your wheel onto the new hub, or a complete new rear wheel. At this point you might elect to replace both wheels to make them look the same. And BOOM you're up in the 4-digits cost for a simple upgrade.


But its not all horror stories either. I used an old MTB as a parts donor for one bike, and upgraded from a 1x6 to a 3x8, going from janky sub-tourney grade components to mostly Deore level. That involved reuilding the rear wheel using the existing spokes, onto a freehub-based hub.

End cost of that upgrade was almost $0, the most expensive thing was a replacement cut-off wheel for a grinder.... I had to cleave the old 6 speed freewheel in two to save the spokes. The old hub was useless, in that case. But it took a good month to complete.

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