newtttton

Hello,

Recently I learned the reason I struggle climbing hills is because my road bike is equipped with Shimano HG50 9 sp. 11-25T casette. The Rear Derailleur is Shimano Tiagra 4500 9 speed.

I was told upgrading to a more teeth casette would help alot. Researching I came across Shimano CS-4600 Tigara 10speed 12-30T at rei.com for $50. Are these casettes interchangable? Do i need a new chain? My existing chain is Shimano HG53 9 sp.

Thanks in advance for answering these questions for me!!

NOt sure if this information is irrelevant or required but the current Front Derailleur is Shimano Tiagra 4500 and the cracnkset is Shimano Tiagra Compact 34x50T.

Shimagnolo

10s cassette will work only if you change to a 10s righthand shifter.
And yes you would need a 10s chain.

Homebrew01

If you have a 9 speed Shimano system, you need a 9 speed Shimano cassette.
If you swap to a 9 speed with more teeth, then you'll need a longer chain.

ghsmith54

Probably your best and least expensive upgrade would be a 12x27 9 speed cassette and a new 9 speed chain. Although larger cassettes (more teeth) are available, using one would also require a new rear derailleur.

DOS

+1. With that derailleur, the max you can do on the largest rear cog is 27 teeth.

At risk of getting off topic, I discovered not long ago that dropping 10 pounds off my saddle made a lot more difference when it came to climbing than a few teeth either way on my cassette.

Camilo

If you want to make a truely significant improvement to your climbing gears, replace your cassette with a 9 speed 11-32 or 11-34 mountain bike cassette, and buy an inexpensive Shimano 8 or 9 speedmountain bike rear derailleur (either will work). You can get whatever level of MTB cassette, chain and derailleur you can afford, but the basic/cheapest ones (i.e. Shimano Deore) are just fine. Total cost, new will be about $30+$40+$15 = $85.(cassette/RD/Chain), cheaper if you can get the RD used. If your cables are in good shape, likely you won't have to replace it - my experience at least.

Yea, it's $85, but the net cost is ONLY the cost of the MTB derailleur ($40, or less if uesed), because you'd have to buy a new road cassette and 9 speed chain with the other strategy - and basic quality road stuff costs about the same as basic level MTB stuff.

This sort of conversion is becoming more and more common around where I live, especially for those who are being forced into compact doubles for road machines rather than triples. But even triple users sometimes to it if they need lower gears. My wife's road bike has a Tiagara road triple with 11-34t rear cassette and MTB RD, and she absolutely loves it, shifts perfectly. It's really increased her enjoyment of going up hill, making them a doable, enjoyable challenge rather than an ordeal.

This will give you a change you will really notice and enjoy and will work perfectly with your 9 speed road shifters. Replacing your current cassette with the largest road cassette gearing compatable with your current RD will be a small tweak (from 25t to 27t), not a big improvement. If you decide you don't need the gears later, you can easily swap back without replacing the chain.

For what it's worth, replacing a rear derailleur, cassette and chain is a very do-able yourself if you're into it. If you're not, probably a 1/2 hour job for a shop, billed accordingly.

JohnnyCyclist

No guarantee, but your RD might accept a 28t top cog. A Shimano RD on one of my bikes is "rated" as "27t max", but I put a 28t top cog cassette on with no problem.

SRAM offers an 11/28 9-speed cassette for cheap.

caloso

I would just do this. Those extra 3 teeth will make a huge difference.

shelbyfv

IMO Camilo has covered it. Deore or LX 9 speed RD, 9 speed 11-32 and 9 speed chain. Will work perfectly. Remember tho, the real reason the hills are difficult is that you are not strong enough.

JiveTurkey

OP, you'll probably need to screw in the B-screw all the way to keep the upper RD pulley from bumping against the cog when in the lowest gear (smallest chainring/largest cog).

If it still bumps, then try flipping the B-screw around so that the head rests on the RD hanger tab (the RD female threads need to be fully engaged still).

I'm running a 50/34 x 11-28 (10-speed) with a 105 RD and I needed to flip the B-screw and it works perfectly.

KevinF

The "huge difference" is about 11%. Which means if you're grinding along at around 60rpm, you'll now be grinding along at around 67rpm. If you really want to make a noticeable difference, you need to put a MTB cassette on, which can give you a gear that's 20+% lower.

I agree with DOS though that the only way to really make climbing easier is to climb a LOT and lose whatever weight you can.

caloso

You are correct. I guess I was considering it as a binary question, as in the difference between riding and walking. And I still think that getting a 28t cassette is still the cheapest and easiest solution.

newtttton

Thank you all for the generous reply. It helps a lot. Kudos to Camilo, I'll be researching for the mountain bike cassettes.

Camilo

Just as an aside - I'm the guy who recommended considering the MTB rear end and still do.... but that said, on my road-triple (30t chain ring) commuter, I have a Shimano 11-28 (could be a Sram, I can't remember; I got if off my wife's road bike when I converted hers to MTB stuff!).

Anyway, that 28t cassette works very easily with two long cage road RD's I have: a 9 speed Dura Ace and a 9 speed 105. (please note: I'm not saying the long cage has anything to do with it. The B screw/cassette clearance is the same whether the derailleur is long or short cage).

The 105 was on my wife's bike before I took it off and it had plenty of clearance. The Dura Ace is on my commuter, and I simply put the 28t cassette on there, did a tiny bit of tweaking with the B screw (it had a 26 on there before) and it was good to go. Both have very ample clearance with the B screw, I don't believe they're even maxed out. I even think I could get a 30 on there.

As for the gearing of my old 26t vs the 28 on my commuter: it is a pretty small difference. Really, only "one more low gear" maybe the same jump as from the 23 or 24t to the 26t that you already have. Fine for what I need for that commuter with the 30t front ring. If I had a compact double on the commuter, I'd want at least a 32 and would have done the MTB conversion.

Dave Mayer

I built a bike with 105 short cage rear derailleur with a set of 42-52 rings, and a 14-34 Megarange freewheel. Yes, a 34. Chain length was critical, and I had the B-tension screw was maxed, but it worked fine.

But to repeat a good suggestion made here: get a mountain bike cassette and a cheap (Deore is just fine) Shimano rear MTB derailleur. Plus you'll need a new (longer) chain.

newtttton

So I followed the recommendation and did the upgrade/change. It made an enourmous difference in hill climbing. Safe to say there's now no mountain that's unconquerable. Thanks. One minor problem though: When the bike is in the highest gear (biggest front sprocket and smallest at the rear) and I suddenly start backpedaling, my chain jumps (skipps.) We were able to replicate this on repair stand with my mechanic but he's clueless and couldn't figure it out. Problem happens ONLY in the smallest two or three rear cogs and big sprocket in the front. Pedal hard forward, suddenly stop and pedal backwards (or just jerk the pedal backwards) and you'll see the chain jump and skip. So far, we've lubed the chain good and confirmed there's no bad link. Any ideas? BTW, no such problem when pedaling forward normally.

NJgreyhead

Good you got it sorted out (mostly).
Also, you could have gone to a 12-30 cassette with your same rr der (and a longer chain, of course). See Sheldon Brown. Worked for me.