Granny gear for 2016 CAADX 105

jimbop · Post by **jimbop** » 15 Jul 2018, 1:11pm

hi all - i ride a 2016 CAADX 105 and i decided i wanted a broader range of gear and easier climbing so I changed the small chainring from 36 tooth to 34 and the cassette from 28 tooth to 32. I'm a beginner rider and my legs are still pretty weak plus I'm going to try going bikepacking, which will involve hauling some weight and probably more off-roading. The upshot is that i'd like a really really easy granny gear to help me climb but i'm not sure if i can just put on an even smaller chainring without having to change anything else?

mattsccm · Post by **mattsccm** » 15 Jul 2018, 2:33pm

I'll assume that the chainset is a compact so 34t is the smallest that's possible. (I think that a 33 is technically possible but I have never seen one).Actually its the 110 BCD that allows a 34.
The only thing to do without a new chainset is bung on a cassette with an even bigger bottom gear. If you have a short arm rear mech then you are lucky that the 32 is working. Any thing bigger will require a long arm mech. I suspect that a 34 is an option if not a 36. Probably a new chain as well.
Some of us run smaller chainsets. I have used a 28/42 MTB double with no problems although it's a SRAM one and just maybe is different to a Shimano one. There are super compact chainsets out there but they are rare and don't solve all your issues.
Finally I am assuming that you don't swap the chainset and BB to a square taper set up. That will give more choice although some people will see that as a retrograde step. Some will see it as an improvement.

jimbop · Post by **jimbop** » 15 Jul 2018, 3:00pm

mattsccm wrote:I'll assume that the chainset is a compact so 34t is the smallest that's possible. (I think that a 33 is technically possible but I have never seen one).Actually its the 110 BCD that allows a 34.
The only thing to do without a new chainset is bung on a cassette with an even bigger bottom gear. If you have a short arm rear mech then you are lucky that the 32 is working. Any thing bigger will require a long arm mech. I suspect that a 34 is an option if not a 36. Probably a new chain as well.
Some of us run smaller chainsets. I have used a 28/42 MTB double with no problems although it's a SRAM one and just maybe is different to a Shimano one. There are super compact chainsets out there but they are rare and don't solve all your issues.
Finally I am assuming that you don't swap the chainset and BB to a square taper set up. That will give more choice although some people will see that as a retrograde step. Some will see it as an improvement.

Thanks for all the info. I know literally nothing - my friend helped me along with Google. The cassette I got was the biggest shimano one that was an option at the online shops I checked. Yeah - my friend was kinda surprised that the short arm mech worked but it does beautifully. What sort of money does a new chainset run to? I'm trying to find a job at the mo so a new cassette wasn't too spendy and my mate had the chainring spare

Happy to buy another cassette and long arm mech if that's the cheapest option and a new chainset is too spendy.

I'm a trendy consumer. Just look at my wobbly bog brush using hovercraft full of eels

jimbop · Post by **jimbop** » 15 Jul 2018, 3:07pm

This article says I could run an Ultegra 34 cassette or even a 40 cassette if I change to a medium arm Ultegra mech. Interesting.

http://road.cc/content/feature/213519-s ... es-how-get

I'm a trendy consumer. Just look at my wobbly bog brush using hovercraft full of eels

jimbop · Post by **jimbop** » 15 Jul 2018, 3:22pm

And this is interesting - Wolf Tooth Roadlink https://www.wolftoothcomponents.com/products/roadlink

I'm a trendy consumer. Just look at my wobbly bog brush using hovercraft full of eels

Brucey · Post by **Brucey** » 15 Jul 2018, 3:51pm

chainset

https://www.spacycles.co.uk/m2b0s109p3383/SPA-CYCLES-Super-Compact-Chainset-with-Zicral-Rings

add ~£15 for a suitable BB

gear ratios for 44,26 double onto 11-32T cassette compared with 50,34 double onto 11-40T cassette here

http://www.ritzelrechner.de/?GR=DERS&KB=26,44&RZ=11,12,14,16,18,20,22,25,28,32&UF=2215&TF=110&SL=2.6&UN=KMH&DV=gearInches&GR2=DERS&KB2=34,50&RZ2=11,13,15,18,21,24,28,32,36,40&UF2=2215

you can see that the supercompact double gives you lower gears if that is what you want, and there is the possibility of a 24T chainring if 26T isn't small enough.

cheers

NetworkMan · Post by **NetworkMan** » 15 Jul 2018, 4:22pm

Jimbob admits he's not a super strong rider so there's surely no disadvantage in having a square taper bottom bracket. A small weight penalty perhaps but that's about it. If it were me I'd have a triple every time but that would mean a new STI shifter I suppose. Can anyone confirm that? Otherwise a Spa XD2 at £35 and a BB for about £10.
What about a cheap friction downtube shifter for the front and keep the STI for the rear. The advantage of a triple is that most of the time you run on the middle ring so hopefully the front changer won't be needed much.

jimbop · Post by **jimbop** » 15 Jul 2018, 4:24pm

NetworkMan wrote:Jimbob admits he's not a super strong rider so there's surely no disadvantage in having a square taper bottom bracket. A small weight penalty perhaps but that's about it. If it were me I'd have a triple every time but that would mean a new STI shifter I suppose. Can anyone confirm that? Otherwise a Spa XD2 at £35 and a BB for about £10.
What about a cheap friction downtube shifter for the front and keep the STI for the rear. The advantage of a triple is that most of the time you run on the middle ring so hopefully the front changer won't be needed much.

Defo want to keep the shifters where they are for speed/convenience and also because downtube will be obscured with a bikepacking frame pack but good thinking regardless.

jimbop · Post by **jimbop** » 15 Jul 2018, 4:33pm

Brucey wrote:chainset

https://www.spacycles.co.uk/m2b0s109p3383/SPA-CYCLES-Super-Compact-Chainset-with-Zicral-Rings

add ~£15 for a suitable BB

gear ratios for 44,26 double onto 11-32T cassette compared with 50,34 double onto 11-40T cassette here

http://www.ritzelrechner.de/?GR=DERS&KB=26,44&RZ=11,12,14,16,18,20,22,25,28,32&UF=2215&TF=110&SL=2.6&UN=KMH&DV=gearInches&GR2=DERS&KB2=34,50&RZ2=11,13,15,18,21,24,28,32,36,40&UF2=2215

you can see that the supercompact double gives you lower gears if that is what you want, and there is the possibility of a 24T chainring if 26T isn't small enough.

cheers

Very interesting indeed.
So the two main options are:
1) Keep my existing 11-32 cassette and change to a super compact chainset ~£65 and a new bottom bracket ~£15. Total ~£80.
2) Change to an Ultegra medium arm rear derailleur ~£65 and new cassette such as the Shimano SLX M7000 Cassette 11-40 ~£60. Total £125.

In terms of flexibility and being able to change my gear setup, which requires the least work to swap between my current setup and granny setup?

NetworkMan · Post by **NetworkMan** » 15 Jul 2018, 4:48pm

Brucey will advise but you might need a new triple front changer for the super compact option. The difference between the two rings may be too much for a double, perhaps not though - Brucey's suggestion is only 2T bigger in chain ring difference 18T versus 16T.

LinusR · Post by **LinusR** » 15 Jul 2018, 5:43pm

I have a 2016 CAADX (with Tiagra shifters and mechs). I changed the rear mech for a longer arm and installed a 34 inner chainring and run a 34 rear cog. You can even fit a 33 tooth inner ring (I've done this on another 110 BCD crankset). But 34 on the front and 34 on the rear gives you a pretty low gear, though I doubt it will do for heavy touring. A saddle bag will be ok.

You might even be able to run a 36 - but this might only work with Tiagra. I'm sure someone else will tell us. [edit] sorry didn't read the above with regard to the Ultegra mech suggestion.

[edit] A post above suggests changing to a square bottom bracket. Won't work. The CAADX uses the BB30 bottom bracket standard, not a threaded BB.

[edit again] whoops, apparently there's a converter http://www.chainreactioncycles.com/fsa-bb30-threaded-adapter-b3119-/rp-prod129935

jimbop · Post by **jimbop** » 15 Jul 2018, 9:22pm

LinusR wrote:I have a 2016 CAADX (with Tiagra shifters and mechs). I changed the rear mech for a longer arm and installed a 34 inner chainring and run a 34 rear cog. You can even fit a 33 tooth inner ring (I've done this on another 110 BCD crankset). But 34 on the front and 34 on the rear gives you a pretty low gear, though I doubt it will do for heavy touring. A saddle bag will be ok.

You might even be able to run a 36 - but this might only work with Tiagra. I'm sure someone else will tell us. [edit] sorry didn't read the above with regard to the Ultegra mech suggestion.

[edit] A post above suggests changing to a square bottom bracket. Won't work. The CAADX uses the BB30 bottom bracket standard, not a threaded BB.

[edit again] whoops, apparently there's a converter http://www.chainreactioncycles.com/fsa-bb30-threaded-adapter-b3119-/rp-prod129935

All good input. Apparently the 105 groupset is the only one not to support 34t cassettes, which is why people end up (if i have understood well) going for an Ultegra mech and cassette.

Post by **slowster** » 15 Jul 2018, 11:36pm

I am planning to buy and fit a Spa Super Compact double to a bike using 105 STI levers, and as per the comments above, I am anticipating that I may encounter problems with the front derailleur/shifting.

Like the OP's bike, mine currently has a 46/36 chainset, and with the chain on the small ring the current front derailleur (Microshift Arsis model) is already only 2mm above the chainstay. I know that this distance would be greater with a standard Shimano double front mech, e.g. Ultegra, but I have already bought a CX70 front derailleur which is intended for 46/36 cyclocross chainsets and should be better than a standard mech for even smaller chainsets like the Spa Super Compact double.

I intend to buy the smallest version of the Spa Super Compact double, i.e. 40/24, and I think that even with the CX70 front derailleur that inner chainring size might prove to be just too small for the front derailleur to be positioned low enough. If so, I intend to buy either a 26 or 28 tooth replacement from Spa for £11 plus postage. In other words, I am steeling myself for a bit of trial and error to get it it to work, and I think the OP might need to be prepared for a similar experience.

I expect it to be worth it because the gearing range will be so much better, and therefore I am willing to persevere.

OP, do have the requisite tools (or can you borrow them)? If you have to buy the necessary tools both to remove the existing external bottom bracket, as well as to install a square taper bottom bracket, that would obviously increase the cost. That said, you would probably want to have the relevant tools anyway for whatever bottom bracket and chainset you decided to use on your bike. If you went down the square taper route, you would eventually at some point want to remove the chainset, so you would then need a crank extractor tool as well, but you can buy generic versions of that tool quite cheaply.

Lastly, if you do order the Super Compact double, make sure you include everything you need in your order, because Spa charge postage on orders below £50. So don't forget to include a pair of crank bolts in your order for example:

https://www.spacycles.co.uk/m2b0s173p3395/SPA-CYCLES-Crank-Bolts

EDIT TO ADD:

OP is your bike 10 speed or 11 speed? That might influence what changes you make. For example, I think that the chainrings Spa supply with their Super Compact double chainset are nominally 9/10 speed, so if your bike is 11 speed, you would need to check if the chainrings would be suitable for use with an 11 speed chain.

jimbop · Post by **jimbop** » 15 Jul 2018, 11:57pm

slowster wrote:I am planning to buy and fit a Spa Super Compact double to a bike using 105 STI levers, and as per the comments above, I am anticipating that I may encounter problems with the front derailleur/shifting.

Like the OP's bike, mine currently has a 46/36 chainset, and with the chain on the small ring the current front derailleur (Microshift Arsis model) is already only 2mm above the chainstay. I know that this distance would be greater with a standard Shimano double front mech, e.g. Ultegra, but I have already bought a CX70 front derailleur which is intended for 46/36 cyclocross chainsets and should be better than a standard mech for even smaller chainsets like the Spa Super Compact double.

I intend to buy the smallest version of the Spa Super Compact double, i.e. 40/24, and I think that even with the CX70 front derailleur that inner chainring size might prove to be just too small for the front derailleur to be positioned low enough. If so, I intend to buy either a 26 or 28 tooth replacement from Spa for £11 plus postage. In other words, I am steeling myself for a bit of trial and error to get it it to work, and I think the OP might need to be prepared for a similar experience.

I expect it to be worth it because the gearing range will be so much better, and therefore I am willing to persevere.

OP, do have the requisite tools (or can you borrow them)? If you have to buy the necessary tools both to remove the existing external bottom bracket, as well as to install a square taper bottom bracket, that would obviously increase the cost. That said, you would probably want to have the relevant tools anyway for whatever bottom bracket and chainset you decided to use on your bike. If you went down the square taper route, you would eventually at some point want to remove the chainset, so you would then need a crank extractor tool as well, but you can buy generic versions of that tool quite cheaply.

Lastly, if you do order the Super Compact double, make sure you include everything you need in your order, because Spa charge postage on orders below £50. So don't forget to include a pair of crank bolts in your order for example:

https://www.spacycles.co.uk/m2b0s173p3395/SPA-CYCLES-Crank-Bolts

EDIT TO ADD:

OP is your bike 10 speed or 11 speed? That might influence what changes you make. For example, I think that the chainrings Spa supply with their Super Compact double chainset are nominally 9/10 speed, so if your bike is 11 speed, you would need to check if the chainrings would be suitable for use with an 11 speed chain.

Mine's an 11 speed. It's a bit of a black art this stuff isn't it!! It would be simpler (in my mind) to go for a new rear mech and cassette, particularly if the new mech would also work with the 11-32 cassette installed at the moment because that way I might be able to just swap cassettes to move from bikepacking/steep/off-roading mode to unladen/less hilly/road mode. The only negatives being cost and I read that cassettes such as 40t weigh a lot more so the overall solution might be heavier than changing the chainset? I don't have any specialised tools but a friend about 20 mins cycle from me does.

I'm a trendy consumer. Just look at my wobbly bog brush using hovercraft full of eels

Brucey · Post by **Brucey** » 16 Jul 2018, 10:41am

do bear in in mind the following

1) if a hanger extender is fitted, shift quality is often surprisingly good, considering, (to start with) but once the chain gets a little bit baggy, the chickens may come home to roost and you can find that having the guide pulley so far away from the smaller sprockets is not such a good recipe for slick shifting.

2) Between the hanger extension and the 40T sprocket you will need a chain that is quite a bit longer than you might use on an 11-32T cassette. The long chain may not work perfectly with the usual setup.

3) It is a very good idea to keep a separate chain with each cassette, so that you don't end up running a worn chain on a newer cassette (noisy and fast-wearing) or vice-versa (which causes the chain to skip)

Also consider that you could do some other different things or choose differently for other reasons, e.g.

a) buy different chainrings for the new chainset, so that you can convert from one setup to another just by changing those

b) that there may be inherent differences between setups meaning that you will spend more time running cross chained or double-shifting on one vs another

Needless to say there are those who would suggest that there is another entirely different solution which is that you flog your shifters, chainset etc and just get some new stuff which will allow you to run a triple chainset at the front. Two setups in one, no need to mess about with it....

cheers

Cycling UK Forum