Customising a Shimano HG50 Tiagra/Deore cassette
I've never been able to push a really big gear; anything much over 100" is not much use to me. There must be plenty of people who can as, for instance, most off-the-peg 'sportive' bikes – a growing market these days – come with 12T or even 11T as the smallest rear sprocket. But paired with a large chainring of 50T or more this gives a top gear which, for me, is redundant.
Shimano CS-HG50 Deore and Tiagra cassettes with HG53 chain. At the time of writing available for less than £50 online including delivery.
My latest bike wasn't quite off-the-peg: most of the components were swapped on to a 51cm Kinesis Racelight T2 2010 frame from a 54cm Ridgeback Horizon for delivery on Chrismas Eve. I am not going to blame anyone else for my newest bike having a few compromises. And I should have pressed the bike shop for a woman's saddle (the Ridgeback-branded components were replaced with a range of others) so that Mrs Bailey might use the bike in the summer. By which time I would have broken in the Brooks B17 standard saddle she bought me for Christmas, and put it on the Ridgeback Panorama I hoped to get in the summer. Well, plans change and I'm unlikely to get another bike this year. Instead I've slightly adapted this 'winter training bike' Kinesis in to a light tourer/Audax bike. I've added a pannier rack for a rack bag and a week ago I fastened on the fittings for a handlebar bag. But the most significant change has been to the rear cassette. I don't think compromise is the right word here. No, customise is the right word. This is an account of the simple steps required to swap a Shimano Tiagra 11-25 HG50 cassette for a Shimano Deore/Tiagra custom 13-34 cassette.
My original Tiagra cassette went like this: 11/12/13/15/17/19/21/23/25. The two biggest gears were bigger than anything I was able to push with the 50T chainring even on long descents. And at the other end the 30T inner ring on my Sora triple chainset gave me a gear that let me manage the biggest hills locally, but I didn’t feel I would comfortably cope with on longer, steeper hills, say, during day rides in the Yorkshire Dales carrying the gear I like to take with me. My Sora triple is a standard 50/39/30.
After a few calculations on the Tiagra and Deore HG50 cassettes available for me to buy online I settled on these two:
Tiagra 13/14/15/16/17/19/21/23/25
Deore 11/13/15/17/20/23/26/30/34
Broken up they would become 13/15/17/19/21/23/26/30/34
Apart from at the very top end – which I don’t use much anyway – there are no big jumps. And now when I’m using the big chainring I can make use of the 21T sprocket (giving me my preferred option of an inch gear in the mid-sixties) that wasn’t previously available to me from the large chainring.
The six largest sprockets on a Shimano HG cassette are held together by retaining pins. They will need to be removed.
After drilling out or grinding off the heads of the retaining pins they will come out easily. I used an automatic centre punch, but be careful that there are no burrs left on the edges of the rivet head or you may break the plastic spacers.
Taking off the existing cassette requires a chain whip and a locknut tool.
Slot the new sprockets and spacers on to the freehub. HG sprockets will only fit in one position because of the splines on the freehub body. If you break up two cassettes to customise your gearing some of the functionality of the HyperGlide system will be lost (the ramped edges that aid with downshifts will no longer be in synch). In practice I haven’t found this to be a concern.
Reuse the retaining pins if you wish. However, they are mainly for convenience during initial assembly, and your locknut is there to keep the cassette in place. Ideally, you should use a torque wrench to tighten the locknut.
If you use a large rear sprocket as big as my 34T, you may need to change the rear derailleur. I had a spare Deore mech, which can be picked up online for about £25. With 50/39/30 chainrings and 13-34 cassette I have a range of gears from about 104” to 24”.
My Kinesis Racelight T2 2010. I had, briefly, considered replacing the chainset with a MTB version. However, there are compatibility issues with STI levers and mountain bike chainsets and front derailleurs.
I’ve had to shrug off comments from sixty-something blokes in my local group; two about being able to get up brick walls and another about dinner plates. I’m not bothered. At the moment I’m neither fit enough nor light enough to cope with really steep hills without the option of a couple of gears below 30”.
My original cassette gave me a top gear of approximately 124" and a bottom gear of 32", a difference of 92". My custom cassette has a top gear of 104" and a bottom gear of 24", a difference of 80". So not only do I have narrower ratios between gears, I can now make use of them all.
Interesting. I did wonder why you didn't fit a different chainset but I suppose that would be more expensive. On compatibility: our Panoramas came with STI levers and Tiagra front mechs, then the rest is Deore. It works okay but the STI front lever has four positions. I've never worked out why, as my MTB lever has three and that bike has a Deore front mech (I'm not too well up on this sort of thing).
I have a set of wheels I bought purely for touring, and the Deore XT cassette is 11-34 compared to the 11-32 plain Deore that came with the bike and which I use most of the time (I've since rebuilt these wheels with new rims and spokes). So with a 48/36/26 chainset my touring range is 118" to just over 20" and my normal range is 118" to 22".
Incidentally, you couldn't really customise a Deore XT cassette because it's built on a one-piece spider for lightness.
For info: with the bike fully loaded (weighing about 75lbs in all, plus me at 11 stone) my cruising speed on the flat is about 14 mph, using the highest gear of 118". Sandra never used her big chainring on tour. At the other end of the scale I use the 28-tooth sprocket with the 26-tooth chainring (25") to get up to my house at the end of every local ride.
With the touring wheels on, my Panorama will definitely climb a wall.
Online tool: CycleSeven bicycle gear inch calculator »
June 5th, 2010 at 11:04 am
To travel at 14mph on my 50T chainring I would expect to be on the 21T rear sprocket, approximately a 63” gear
I did think of changing to the Deore, or XT, MTB chainset – the 44/32/22 model as opposed to what Shimano calls the Deore/XT in its ‘trekking’ range: 48/36/26. (A 48T large chainring would still give me a whopping 118” gear at the top end, and the 26T inner ring would only have given me a gear 4” lower than I already had.)
But this would also probably mean a new front derailleur because the outer chainring at 44T is likely to be too curved for the Sora triple front mech. So I might have needed a new front mech, but what about STI levers and mountain bike (ie 44/32/22) chainsets? I understand that there are compatibility issues between STI levers and mountain bike chainsets/front derailleurs and the amount of pull required. Hence my decision to go for a cheaper, less drastic solution.
June 5th, 2010 at 6:12 pm
Sorry Chris. Thinking about it, I may have got that wrong about using my highest gear fully loaded on the flat. I did use the highest gear at times though, and on the unloaded bike on the flat, I do sometimes use the highest gear. I've read about compatibility issues with MTB and road components but not really looked into it yet. My tourer has a Tiagra road mech with an MTB chainset but this has changed to all Deore on the current model.
I might add a box to my (our) gear inch calculator so that speed can be fed in as an alternative to cadence.
June 5th, 2010 at 6:49 pm
I had a Dawes Galaxy for years and I like a big low range. I just got a mountainbike 42,32,22 chainring and used that with an 11-32 (I think) cluster and that gave me what I wanted. I next went full MTB for touring, adapting a racing front suspension MTB for touring, raising and shortening the handlebar reach, fitting a carrier and fitting high-pressure slick tyres. It's doing the same thing, actually, giving us what we want rather than what the bike manufacturers think we might want!! One advantage of the MTB approach is that you can fit tyres of such width that pinch punctures are eliminated. I've never got a pinch puncture on an MTB.
June 8th, 2010 at 5:45 am
Very interesting.
I've a Campag Chorus triple 53/42/30 with a Campag 13/14/15/16/17/19/21/23/26/29 – 10sp cassette. Top gear of 108" and bottom of 27". Gives a range of 81"
The bottom gear is low enough for me to get up the steepest of hills, and the top gear is ok for powering along the flat. I cannot imagine a better set of gears than I have. They are slick and quiet, change easily and quickly, and almost feel like silk.
Was it cheaper to buy two cassettes than to buy a couple of replacement cogs? It seems a waste to do this. In the past, I had a Suntour Ultra freewheel and you could buy many different cogs. I had a bag of different ones to suit my riding for different occasions, and it was easy to swap them over as all you needed was a couple of chainwhips to unscrew the stack and screw on others. Each cog was not particularly expensive.
These days, it's possible to buy Campag sprockets as spare parts, perhaps you can't do this with Shimano? Other than that, Highpath Engineering supply sprockets in all different sizes for both S and C setups.
Either way, you seem to have come up with an ideal set of ratios.
Well done!
June 17th, 2010 at 9:31 pm
Hi, Mick. In the olden days it was easy to pick up sprockets for Shimano IG [edit: Uniglide] cassettes. But apparently there are so many permutations with HG (they are ramped differently depending on the intended size of the sprockets either side of them) and I couldn't be bothered to spend too much time looking for stuff online. So I used Chain Reaction Cycles and bought two cassettes that gave me exactly what I need right now including the 13T smallest cog and its locknut.
The other sprockets aren't wasted. As I get fitter I may come down to a smaller large sprocket and use the intermediate sprockets from my stockpile.
Thanks for the information on Highpath Engineering, though. I've bookmarked their site.
June 19th, 2010 at 9:45 am
Wow, what a coincidence. I am doing pretty much exactly what you have done to get my perfect audax bike with gears from 25" to 105" using a 13-32 (from a 13-25 and an 11-32), with a 52-42-30 chainset.
Maybe there is a demand for this kind of custom cassette – see you on Dragon's Den.
August 6th, 2010 at 12:47 pm
Nice write-up.
You would have noticed that misaligning adjacent sprocket ramps results in slower shifts. Fix is to grind down one side of the wide HG spline tab on some of the sprockets so that these can be re-oriented on the freehub with ramps appropriately offset.
In your case you could retain the 17/19/21/23 Tiagra sequence and grind tabs off and re-orient all others, although it'd be slightly simpler to retain the Deore 23/26/30/34 sequence.
September 2nd, 2010 at 2:06 pm
I wonder if the good people on the previous posts can help me. I have a Trek 1.5 Triple (50-39-30), with an SRAM 11-26 rear cassette, and a Shimano Tiagra rear dérailleur. I read that I could use a Shimano 11-34 rear cassette on my group set, and have purchased one. I have fitted the cassette and attached a new chain. Now, when I change to the 2 lowest gears (30 and 34), I get a grinding noise from the err derailleur, almost as if the upper jockey wheel is too close to the largest cogs. Adjusting the B screw doesn't seem to make any difference. What am I doing wrong?
December 10th, 2011 at 4:28 pm
Are you using a long cage rear derailleur? Usually you have to change the derailleur if you are fitting a much bigger cassette. Is the new chain longer than the original to take into account the larger 34 cog?
December 10th, 2011 at 6:03 pm
Forget the above I see it's already been mentioned. doohh.
December 10th, 2011 at 6:04 pm
Don't know if this is any use, but my rear mech (Shimano XT) has a screw at the back. I've never adjusted it but it looks as if it can be tightened to swing the whole mech further back to pull the jockey wheel away from the casette. I think one of my sons had this same issue and we fixed it this way.
December 10th, 2011 at 11:54 pm
Hi, Simon. I'm not sure where you have read that, as technically you don't have a group set as such. You (or whoever put this mix together) have SRAM and Shimano in the same drive train. I suppose that's fine, but your problem would appear to be the Tiagra rear mech. You don't say whether you are running a 9 or 10 speed cassette, but either way you have exceeded the maximum capacity for the rear derailleur. I'm pretty sure the 9 speed Tiagra rear derailleur had a capacity of 27T (for the largest rear sprocket). The 10 speed long cage Tiagra rear derailleur (RD-4600-GS ) takes a maximum rear sprocket of 30T. So either way you have exceeded the manufacturer's stated limit. In reality these stated limits can be exceeded a little bit. But why risk it? As Jim says, this is mentioned in the original post.
If you must go with 11-34 try a Shimano Deore (or LX or XT) rear derailleur as these are designed for the job.
[edit: just had another thought: are whichever shifters Simon is using compatible with both SRAM and Shimano rear cassette spacings? Over to you, Simon...]
December 11th, 2011 at 10:16 am
We had the same problem on the tandem with our 11-34 cassette. Bertrand changed our Ultegra rear derailleur to a Deore XT and all is fine now.
December 11th, 2011 at 3:09 pm