Author Topic: Maximum gear capacity / chain length  (Read 648 times)

Maximum gear capacity / chain length
« on: April 17, 2018, 04:18:59 pm »
I've entered Deano's Most Excellent off-road 100, but I'm a right fat fucker at the moment, so I need to gear my CAADX down from the 11-28 11sp cassette it comes with. I'm looking at a Shimano 11-42 MTB cassette, but I'm kind of concerned there won't be the capacity for that. The front has 46/36.

Am I right to be concerned?*

* About the gearing, that is - I know I'm right to be concerned about being a right fat fucker.


Re: Maximum gear capacity / chain length
« Reply #1 on: April 17, 2018, 04:32:47 pm »
Need to know what rear mech model and cage length Chris, but I doubt you'll get to 42 unless you've got an MTB mech on the back.

Re: Maximum gear capacity / chain length
« Reply #2 on: April 17, 2018, 04:35:29 pm »
Need to know what rear mech model and cage length Chris, but I doubt you'll get to 42 unless you've got an MTB mech on the back.

It's a 105 - it's all 105. Would it help if I measured it?

Re: Maximum gear capacity / chain length
« Reply #3 on: April 17, 2018, 04:41:16 pm »
you can get 42T sprocket capability by using a wolf tooth roadlink derailleur hanger extender (or similar) with a 105 long cage mech.

Total capacity may or may not be adequate...

cheers


Re: Maximum gear capacity / chain length
« Reply #4 on: April 17, 2018, 04:43:28 pm »
Sounds like 42 is probably a tad ambitious then.

Re: Maximum gear capacity / chain length
« Reply #5 on: April 17, 2018, 04:49:16 pm »
dunno, you don't have a huge chainring capacity to worry about and AFAICT the roadlink gizmo slightly increases the total capacity of the mech as well as the max sprocket size. I'd try it and see; with the chainset so you can use big-big the worst case is that you can't use the small-small combinations without the chain running slack, but you don't need to use those anyway.

cheers

cygnet

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Re: Maximum gear capacity / chain length
« Reply #6 on: April 17, 2018, 04:54:40 pm »
https://bicycles.stackexchange.com/a/51589  ;D for the SHOUTING

Sheldon says similar but more eloquently.

I Said, I've Got A Big Stick

Re: Maximum gear capacity / chain length
« Reply #7 on: April 17, 2018, 04:57:36 pm »
Need to know what rear mech model and cage length Chris, but I doubt you'll get to 42 unless you've got an MTB mech on the back.

It's a 105 - it's all 105. Would it help if I measured it?

Getting there  :)  what speed? short mech cage (SS) or long (GS), that'll be stamped on it.

If it's 11 speed and the GS mech, max, sprocket according to shimano is 32, who are notoriously conservative on spec, although I have heard tell of 36 being squeezed in, but then you're 4 teeth beyond the chainwrap capacity so little/little would be a problem, not a massive one, you'd know it wasn't happy by the racket.

x-post

Re: Maximum gear capacity / chain length
« Reply #8 on: April 17, 2018, 05:02:10 pm »
Small/Small is something I've trained myself out of - it could end up in a tangley mess on the tandem...  :hand:

Re: Maximum gear capacity / chain length
« Reply #9 on: April 17, 2018, 05:02:49 pm »
The alternative would be to downsize the chainrings, presumably a non-Shimano option would be needed.

I ran a 1x setup at the Yr Elenydd recently, and found the 42x11 to be more than adequate for the faster bits of riding (I freewheel in any case when going suitably fast!), and the 42x42 was good for the uphill bits. I'll be trying out a 36 tooth chainring if I make it up for Deano's ride.

So a chainring combination of 40/26 or similar might work ok for you, as an alternative option.

quixoticgeek

  • Mostly Harmless
Re: Maximum gear capacity / chain length
« Reply #10 on: April 17, 2018, 05:37:21 pm »
I've entered Deano's Most Excellent off-road 100, but I'm a right fat fucker at the moment, so I need to gear my CAADX down from the 11-28 11sp cassette it comes with. I'm looking at a Shimano 11-42 MTB cassette, but I'm kind of concerned there won't be the capacity for that. The front has 46/36.

Note that the rear mech of 105, Ultegra, and Dura Ace are interchangable (some rumour the Tiagra 4700 to also be interchangable). I think there is an Ultegra rear mech that will accept a 34 at the rear. I have the GS version of the tiagra 4700, and I have a 11-34 rear cassette.

Of all the parts that can be changed, the rear mech is relatively* affordable.

*for values of affordable
Quote

* About the gearing, that is - I know I'm right to be concerned about being a right fat fucker.

As a fellow person of substantial mass, I can recommend ambitious bike adventures as a way to lose weight. I lost 3.5kg in a single 7 day trip through Germany...

The alternative would be to downsize the chainrings, presumably a non-Shimano option would be needed.

I ran a 1x setup at the Yr Elenydd recently, and found the 42x11 to be more than adequate for the faster bits of riding (I freewheel in any case when going suitably fast!), and the 42x42 was good for the uphill bits. I'll be trying out a 36 tooth chainring if I make it up for Deano's ride.

So a chainring combination of 40/26 or similar might work ok for you, as an alternative option.

So on my frankenbike, which is based on a Genesis Vagabond, I couldn't fit my planned 50/34 front chainset on, so ended up with a mountain bike chainset. I have a Deore 40/28 on the front, with the matching front derailure, which is driven by tiagra 4700 shifters. Officially this is a combo that Will Not Work™, but the reality is, I've done 2760km on this setup and it's worked so far.

Even with a 28-34 bottom gear, I still struggle on some hills, but that's due to the aforementioned excess kummerspek, and I hope to resolve this in due course...

J
--
Beer, bikes, and backpacking
http://b.42q.eu/

LMT

Re: Maximum gear capacity / chain length
« Reply #11 on: April 17, 2018, 07:05:57 pm »
I currently run a 40/23 with a 11-46 on the rear with an Ultegra Shadow rear mech with a wolf link. No dramas at all and it will go large large (just). Not that I run it in that config.


LMT

Re: Maximum gear capacity / chain length
« Reply #13 on: April 17, 2018, 07:25:51 pm »
^ Yep, takes 5 minutes to fit and adjust.

quixoticgeek

  • Mostly Harmless
Re: Maximum gear capacity / chain length
« Reply #14 on: April 17, 2018, 07:29:39 pm »

Note, wolftooth have free delivery worldwide, if you spend $50. Given the exchange rate, if you want some other stuff from them, then it's going to be cheaper to get it direct (tho slower).

I like their B-RAD stuff, and their tools.

J
--
Beer, bikes, and backpacking
http://b.42q.eu/

Re: Maximum gear capacity / chain length
« Reply #15 on: April 17, 2018, 07:45:14 pm »
^ Yep, takes 5 minutes to fit and adjust.

 :thumbsup: Thanks!


jiberjaber

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Re: Maximum gear capacity / chain length
« Reply #17 on: April 17, 2018, 09:55:21 pm »
18bikes also supply wolf link (where I got mine).

Tiagra will take 36 (wot I has on my CdF, 10spd though but).

11 spd Ultegra (GS) will take 34 (HG800 currently on the Jack) but it sacrifices some jumps in the upper gears 11-20 area. http://www.chainreactioncycles.com/shimano-ultegra-r8000-11-speed-cassette-11-34/rp-prod161362


If you want to downsize teh crankset, absolute black do a sub-compact setup for Shimano hollowtech cranks, either 30/46 or 32/48  I am pondering the 32/48 but can't seem to get my head around what that gives me relative to what I have now... I'm thinking the spinner 30/46 might be more suited to Moor Gravel but unsure.....

https://absoluteblack.cc/oval-road-chainrings-30-46-and-32-48-for-110-4bcd/
Regards,

Jason

Re: Maximum gear capacity / chain length
« Reply #18 on: April 17, 2018, 10:03:46 pm »
How low are the gears on the tandem, Chris?

quixoticgeek

  • Mostly Harmless
Re: Maximum gear capacity / chain length
« Reply #19 on: April 17, 2018, 10:30:11 pm »
18bikes also supply wolf link (where I got mine).

Tiagra will take 36 (wot I has on my CdF, 10spd though but).

How much fettling and fiddling is needed to go from a 11-34 to and 11-36 cassette do you think? I'm going to replace my cassette after the next chain (hopefully in ≥2Mm time), and sticking an 11-36 would perhaps make the Ardennes a tad easier when fully loaded...

Quote

11 spd Ultegra (GS) will take 34 (HG800 currently on the Jack) but it sacrifices some jumps in the upper gears 11-20 area. http://www.chainreactioncycles.com/shimano-ultegra-r8000-11-speed-cassette-11-34/rp-prod161362


If you want to downsize teh crankset, absolute black do a sub-compact setup for Shimano hollowtech cranks, either 30/46 or 32/48  I am pondering the 32/48 but can't seem to get my head around what that gives me relative to what I have now... I'm thinking the spinner 30/46 might be more suited to Moor Gravel but unsure.....

https://absoluteblack.cc/oval-road-chainrings-30-46-and-32-48-for-110-4bcd/

I have not yet used any Absolute Black kit, but I've had some really interesting and helpful email exchanges with them in the last couple of weeks. Their customer service seems excellent. I'm seriously considering the 46/30 set on my next bike. I'm waiting to see if the rumours of a power meter compatible version is true.

If not, then FSA make a 46/30 crankset, tho it requires it's own bottom bracket... It does seem to be relatively cost effective as an option.

J
--
Beer, bikes, and backpacking
http://b.42q.eu/

jiberjaber

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Re: Maximum gear capacity / chain length
« Reply #20 on: April 17, 2018, 11:59:58 pm »
Fairly easy fit but there was an issue with the alignment of the cassette and the chain but after I'd reset the cassette back on the free wheel and retorqued it was fine.  I bought the MTB version and was worried I had created myself a problem in doing so but it was just not fully home.  I'll confirm which version I bought in the morning.

ETA: Shimano Dyna-Sys SLX 10 Speed Cassette Silver 11-36
Regards,

Jason

frankly frankie

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Re: Maximum gear capacity / chain length
« Reply #21 on: April 18, 2018, 08:32:36 am »
I currently run a 40/23 with a 11-46 on the rear with an Ultegra Shadow rear mech with a wolf link. No dramas at all and it will go large large (just). Not that I run it in that config.

23 --> 46   :o
"This is a complex subject, with a need for more than one highlighter pen."

Re: Maximum gear capacity / chain length
« Reply #22 on: April 18, 2018, 09:31:21 am »
I currently run a 40/23 with a 11-46 on the rear with an Ultegra Shadow rear mech with a wolf link. No dramas at all and it will go large large (just). Not that I run it in that config.

23 --> 46   :o

^  Surely that's gone past the stage where it's quicker to get off and walk (or do you just not like getting your feet wet :) )

Re: Maximum gear capacity / chain length
« Reply #23 on: April 18, 2018, 09:36:44 am »
I currently run a 40/23 with a 11-46 on the rear with an Ultegra Shadow rear mech with a wolf link. No dramas at all and it will go large large (just). Not that I run it in that config.

23 --> 46   :o

^  Surely that's gone past the stage where it's quicker to get off and walk (or do you just not like getting your feet wet :) )

I think LMT is a recumbentist and they're not the easiest things to push

jiberjaber

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Re: Maximum gear capacity / chain length
« Reply #24 on: April 18, 2018, 10:38:28 am »
Here's some comparisons on the absolute black I've been playing with.  This is comparing with a compact 34/50 matched with a HG800 11-34

For the 30/46 AB rings, thats sort of like having an 12-38 on a 34/50 :
http://www.ritzelrechner.de/?GR=DERS&KB=30,46&RZ=11,13,15,17,19,21,23,25,27,30,34&UF=2185&TF=80&SL=2.5&UN=KMH&GR2=DERS&KB2=34,50&RZ2=12,13,15,17,19,21,23,25,27,30,34,38&UF2=2161

For the 32/48 AB rings, thats sort of like having an 11-36 on a 34/50:
http://www.ritzelrechner.de/?GR=DERS&KB=32,48&RZ=11,13,15,17,19,21,23,25,27,30,34&UF=2185&TF=80&SL=2.5&UN=KMH&GR2=DERS&KB2=34,50&RZ2=11,13,15,17,19,21,23,25,27,30,34,36&UF2=2161

Obs tyre width has an impact on final feal (increase width, increases the gear-inches further etc)
 
Pros: lower gear, cool looking rings, opportunity to see if oval does make a difference etc
Cons: more expensive than a wider cassette (?), because of the offset bolts, no bolt covers when fitted, because of the offset bolts, may need a specific chain (according to AB but surely all chains still have the same dimensions so maybe not an issue?)

I am erring towards the 30/46 but still need to ponder where there is duplication on the gear-inches and how that impacts my synchronous DI2....

ETA: So a set of AB = £171 or a roadlink plus cassette = £77 (roadlink = £22, Cassette £56)
Regards,

Jason