Lowering Gearing and compatablilty

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Timuk
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Joined: 17 Feb 2015, 5:04pm

Lowering Gearing and compatablilty

Postby Timuk » 6 Jul 2015, 6:17pm

Hi folks - would like a bit of technical advice on lowering the gear in on my bike for some loaded touring.

Currently have a Salsa Vaya 2 (2014 model) with pretty standard Shimano 105 ten speed triple chainset (with 105 drop bar brake/shifters) and 12-30 cassette.

Initially I have already changed the smaller chainring from the 30 tooth it came with to a 26 tooth ring from Spa cycles (cost £10)

This is fine for most of the day tours I do from home to the Moors and Dales of North Yorkshire. However I did a quick test run at the weekend with my bike loaded up and I think I could definitely do with a better set up for a multi day loaded trip I have planned in August

What the best way would be to go?

As I see it there are a 2 options :

1 New chainset - maybe something like the Spa 46,36,24 (£100) - plus new bottom bracket I guess?
2 New cassette with a lower range - I understand that 10 speed 105 shifters will work with Shimano xt 11-36 10 speed cassette and 10 speed chain with a 9 speed xt rear derailleur in place of the current 105 one. (Total cost around £70)

I really like the neat 105 shifters and so want to keep using these

Not sure what will be smoother, be easier for me to fit or what other parts I will need to make it work.

Option 1 seems expensive for little gain so I am favoring option 2 however I am not sure exactly how option 2 would work - I guess I "lose a gear" somehow - no problem if its the highest one!
(tbh I dont really know why my bike came with such high gearing - I hardly never have need for the highest gear - if I'm going that fast I'm freewheeling :-)


Any pointers on how this all works would be great - many thanks

Brucey
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Re: Lowering Gearing and compatablilty

Postby Brucey » 6 Jul 2015, 6:27pm

is it not possible to fit a 24T chainring to the extant chainset?

Also your 'option 2' does not involve 'losing a gear' you still get ten gears with a 9s MTB mech and 10s shifters.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

freeflow
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Joined: 29 Aug 2011, 1:54pm

Re: Lowering Gearing and compatablilty

Postby freeflow » 6 Jul 2015, 6:32pm

What do you mean by a better setup?

reohn2
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Joined: 26 Jun 2009, 8:21pm

Re: Lowering Gearing and compatablilty

Postby reohn2 » 6 Jul 2015, 6:39pm

I would think the existing chainset will take a 24t inner ring(74mm BCD?)
And the 105 rear mech will handle a 32t biggest cog,so for another tenner for and inner ring and £35 for a 11-32 cassette and chain, you'll get your gearing a lot lower than present.
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beardy
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Re: Lowering Gearing and compatablilty

Postby beardy » 6 Jul 2015, 8:02pm

I understand that 10 speed 105 shifters will work with Shimano xt 11-36 10 speed cassette and 10 speed chain with a 9 speed xt rear derailleur in place of the current 105 one. (Total cost around £70)


It doesnt have to be an XT rear dérailleur but it does have to be a "shadow" rear dérailleur as the XT dérailleurs without the shadow designation only go to 34 teeth.

freeflow
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Joined: 29 Aug 2011, 1:54pm

Re: Lowering Gearing and compatablilty

Postby freeflow » 6 Jul 2015, 9:02pm

For option 1 you could try a deore triple chainset which means you don't need to change the BB or in fact anything else.

http://www.chainreactioncycles.com/shim ... prod108982

Before you dismiss this out of hand I'd say that I'm happily running an XT 771 triple chainset (44/32/22) with Ultegra 6603 STI and 6703 front mech with 12-36 cassette and XT shadow 9 speed rear mech.

Bonefishblues
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Joined: 7 Jul 2014, 9:45pm
Location: Near Bicester Oxon

Re: Lowering Gearing and compatablilty

Postby Bonefishblues » 6 Jul 2015, 9:26pm

Might assist, I asked a similar question last year:
viewtopic.php?f=5&t=90006&hilit=Gearing+down

pickerd1
Posts: 36
Joined: 31 Mar 2014, 5:05pm

Re: Lowering Gearing and compatablilty

Postby pickerd1 » 7 Jul 2015, 8:53am

If it helps my present set-up is ...

24-36-46 rings (on 64 / 104 bcd 4 arm crank)
12-30 10 speed cassette
105 10 speed & triple STI levers
Tiagra 4603 front derailleur
105 med cage rear derailleur

This works really well

I also have used a 9 spd RD M591 rear derailleur - this was also ok and has a long cage if you want to increase the size of your cassette. Note: 9 spd MTB rear derailleur works with 10 spd STI levers.

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cycleruk
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Location: Lancashire

Re: Lowering Gearing and compatablilty

Postby cycleruk » 7 Jul 2015, 9:18am

My long cage 105 rear mech' is happily running an 11/34 cassette.:-
http://www.merlincycles.com/shimano-slx ... 49512.html

This quite surprised me as I was expecting a clash. Maybe down to the hanger length but I don't know.
I did buy a Deore 9 speed mech' ready but it's still in the box.
The 24T granny ring will fit in place of the 26T and with a 34T cassette is about a 19" gear.
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Timuk
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Joined: 17 Feb 2015, 5:04pm

Re: Lowering Gearing and compatablilty

Postby Timuk » 7 Jul 2015, 3:53pm

Thanks for all the replies

Before I order a new cassette just wanted to check - how do make absolutely sure my 105 mech is the long cage variant?

Had a close inspection and it says 5701 - further up the mech there is a stamp "LC" - so I am guessing that means long cage - and therefore a 11-34 will work? (notwithstanding these cassette seem to be universally described as MTB only)
11-32 would probably be ok with a 24 tooth chainring if this wont work well

Also - does it matter that these shimano "MTB Cassettes" say you need a HG-X MTB Chain? - Will a simple Sram or KMC 10 speed chain not work? (assuming the current KMC chain is not long enough)


I will also get a 24 tooth small chain ring and hope I can adjust the front mech properly to change smoothly 50-39-24 (seems a big jump to me!)


Thanks again all

fatboy
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Location: North Hertfordshire

Re: Lowering Gearing and compatablilty

Postby fatboy » 8 Jul 2015, 9:41pm

I run 50 39 24 on my Sora chainset with Sora front mech and I run 48 38 24 on my tourer both work fine and didn't need any adjustment of the front mech. The shifts from 24 to 39 aren't the crispest but it's good enough for me. CJ described the shifting from middle ring to small ring as falling with style! I tried a 22 ring on my tourer but that was a step too far.

Good luck
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Eldog
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Joined: 18 Aug 2015, 2:07pm

Re: Lowering Gearing and compatablilty

Postby Eldog » 29 Nov 2015, 7:01pm

Hope nobody minds if I jump in on this topic. I've just obtained a Cannondale Synpase Sora that I want to use on a LEJOG and hence get some lower gearing to help with the hills! My very knowledgable buddy has change the set up to a triple (52 42 32) with a large ring 34 cassette on the back. This is resulting it some quite clunky gear changing, particularly on the front. He is now suggesting putting a SRAM set up with a 34 54 compact on the front with a 36 large ring cassette on the back. Is this a good option compared to the triple or indeed, are there any other options to make the hills a little easier. Would be grateful for any advice. Ta.

BigG
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Location: Devon

Re: Lowering Gearing and compatablilty

Postby BigG » 30 Nov 2015, 5:48pm

I was surprised about the restriction to a 34 tooth rear sprocket claimed for pre-shadow XT rear mechs. I run a 761 with a 40 tooth sprocket without problems. Going to 41 teeth did give some difficulty - not changing onto the big sprocket but a reluctance to change off it. This was cured by filing down some teeth on the big sprocket "W cut" style to make the shift easier. Of course, the length od drop on the gear hange makes abig difference. Mine is a standard Campag horizontal drop-out.

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Lowering Gearing and compatablilty

Postby Brucey » 30 Nov 2015, 9:50pm

BigG wrote:I was surprised about the restriction to a 34 tooth rear sprocket claimed for pre-shadow XT rear mechs. I run a 761 with a 40 tooth sprocket without problems.....


blimey.... I've seen people struggle with 36T using those mechs, and 40T needs about 8mm more clearance than that.... :shock:

cheers
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BigG
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Joined: 7 Jun 2010, 4:29pm
Location: Devon

Re: Lowering Gearing and compatablilty

Postby BigG » 1 Dec 2015, 8:20pm

CIMG0576.jpg
CIMG0574.jpg
My 40 tooth is on a 6 speed freewheel. I don't have a photo handy. However, I use a 41 tooth on an 8 speed (9 speed spacing on a 7 speed freehub) with an identical rear mech. I attach pictures. The shiftmate is to allow use of my Suntour Command Shifters. The lateral movement of the mech in this case over the full width of the cassette is 30.5 mm (7 x 4.35 mm) and just 27.5 mm on the 6 speed (5 x 5.5 mm). A characteristic of the slant parallelogram system is that the jockey cage drops as the mech travels inwards and I would expect that a 9 speed cassette would have the guide sprocket at least 4 mm lower than on my 8 speed when in bottom gear (7 mm lower than on the 6 speed). This should allow an additional 2 teeth. I have had to file down some of the teeth (4 pairs) on the 41 tooth sprocket to allow the change onto the next 34 tooth one to work reliably and quickly. This should not be necessary with a 9 speed cassette and would remove the need for filing the teeth. I attach pictures of the system both in large ring/large sprocket combination and in small ring/large sprocket pairing. Both function perfectly well although the chainline on the former is not good. These photos were taken when I was using a 47/43/17 chainset. That was merely an exercise to see what was possible. I also replaced the normal 11 tooth tension sprocket with a 15 tooth one to give more chain wrap. I have since reverted to 45/41/19 chainset which gives a little more chain slack in the large/large combination. Both were safely rideable in all gear combinations and changed gear reliably. Only the rear was indexed. Indexing such a wide ratio front is probably not possible.