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This is a continuation from my previous topics:

determining the rear fork spacing of giant escape 2 2013

rear wheel cassette hub and speed set compatibility question

Summary: My bike's (giant escape 2, 2013) rear wheel was stolen and I am trying to determine what specifications do I need for the new rear wheel. It is a second hand bike (police registered) with some parts replaced.

Here is the information I gathered:

  • Speed set is Shimano tiagra 10x2
  • Rear fork internal spacing is 135mm
  • Front set: 52x36 (standard is 50x34 but this is a XL large bike so that is why I assume).
  • Rear cassette: Unfortunately I do not have this information but a look at the following page Shimano Tiagra HG500 says that available ranges are 11-25T, 11-28T, 11-32T, 11-34T. I checked the Derailleur which looks like a GS and the max and min specifications for it are 34T (Front double), 28T (Front double) Shimano tiagra derailleur GS

My question is among some potential candidates that I see online (see below), there are some options with with 11-36T rear cassettes and 11-28T rear cassettes. My most likely guess is that mine was 32T or 34T. Would that mean that I should prefer 11-28T just to be on the safe side?

Candidate 1

Candidate 2

Thanks

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    It really depends on the lowest gear you need. If you need a 32 or a 34 to get up hills, you need it. What kind of riding do you do? Flat? Hills? Shimano's specifications are really conservative. If the specifications say a 32t cassette will work, a 34t one will almost certainly work just fine, and even a 36t one will likely work well enough to be usable. Nov 24, 2022 at 15:24
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    Not sure, but you seem to be mixing up a few things here. Are you asking about cassettes or the whole rear wheel? You do realise one of those candidate wheels you've linked is for Disk Brakes while the other is Rim brakes. Maybe your better solution is taking your bike to the LBS and let them source the parts. As for what size cassette, really that depends on your situation and what sort of climbs you're doing
    – Hursey
    Nov 24, 2022 at 21:14
  • @Hursey I am looking for rim brakes. I thought for the second one there was an option to select no disc brakes (no disc rotor option) however since I never used disc brakes I am not %100 sure if no disc rotor means rim breaks. Thanks for pointing out that though I will ask the vendor. I am asking for the whole wheel with the cassette. I am mostly using it for daily commute on flat roads. Honestly I am just trying to go for the cheapest possible option since the bike itself is quite old by now.
    – Sina
    Nov 25, 2022 at 13:12
  • @AndrewHenle Daily commute, mostly flat.
    – Sina
    Nov 25, 2022 at 13:18
  • do you have any pictures at all of your bike?
    – njzk2
    Nov 26, 2022 at 14:19

1 Answer 1

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Because you have a GS cage derailleur--this is Shimano's medium cage length but the largest available on road rear derailleurs--you can be assured of the system having enough chain wrap capability to handle the 52/36 chainrings paired with an 11-34 cassette. Chain wrap is the ability of the rear derailleur to take up the chain slack between the amount of chain needed to wrap around the 52t front and 34t large cassette sprocket versus the chain required to go around the 36t front and 11t rear.* The slack must be taken up by the sprung derailleur cage and this capacity is directly related to the cage length. The "total capacity" of a derailleur is a function of the cage length. The Tiagra GS cage has a TC of 41t, and you'll be dealing with a max TC of 39t depending on the cassette choice.

I see in the comments your commute is mostly flat. The 52/36 front makes for some big gearing ratios. This is why the sub-compact, 50/34 or even smaller large chain wheels with tooth counts in the high 40's have become more popular. Us mere mortals are a market force. Anyway, some factors in the choice of cassette include frequency of the need for a lower gear, such as a hilly route or gravel section. The balancing factor to a wide range cassette is the closer gearing steps of a narrower range cassette. Note that on an 11-28 cassette the gearing goes up by a single tooth count in the 5 highest gears, then the spread is two teeth at the low end. This narrower range allows better fine tuning of your gearing allowing for a consistent, efficient cadence.

Regarding wheel selection, your requirements are 700c (622-19 is a standard sizing for a 700c road wheel. The "19," a measure of the inside diameter of the rim can be different within a range, say 18-21, and still fit a common, 622-32 road tire which is what the Escape 2 came stock with. After size, you'll need your choice to be rim brake compatible. Sometimes "machined sidewall" will be a phrase used. Hub consideration is next. it appears the Escape 2 used a standard 10mm QR axle. The other option is that your frame requires a 12mm through axle which will require that standard of your hub.

*An experienced cyclist will for the most part not find themselves in either of these gear combinations. This causes a extreme cross chaining to occur in the drivetrain which saps watts, induces extra wear into the drivetrain components, and is foolish in the sense that an identical or even more favorable gear ratio can be found using the other chainring in combination with a different cassette cog. The result will be a quieter, more efficient chain line in a system that's going to last longer.

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  • An experienced cyclist will for the most part not find themselves in either of these gear combinations. FWIW, I've done more than a few races with a cassette chosen such that I could stay on the large chainring the entire race, cross-chaining be damned. And I learned that from some very experienced racers. Doing that totally eliminates the risk of dropping the chain or getting caught with the chain on the small chainring when it's time to go. Nov 25, 2022 at 21:17
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    @Andrew Henle I too, find myself in 50-32 often enough. Really with modern doubles with 11 speed chains that tolerate the lateral forces, it's fair to say cross chaining is a bit of non-issue today. My perspective mentioning that in the answer was to, I guess, be apologetic of the explanation of the two gearing extremes. A person seeking such information may be knowledgeable enough to have heard of the "evils" of cross chaining and while.wondering about that lose sight of total capacity discussion.
    – Jeff
    Nov 25, 2022 at 22:15

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