Smallest Ring on a double set

[Turkeytickler]

Does anyone know smallest number of teeth a double chainset can handle - Ive got a shimano 9sp set
at the mo with 39 on the bottom.....I want to avoid converting the whole thing over to triple if I
can.... but I want to get up the hills in the etape next year too!! I was thinking of putting 27-12
on the back but whats going to fit on the front?

tia

Chris

--
Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/

 

[Anonymous]

"turkeytickler" <[email protected]> wrote in message news[email protected]...
> Does anyone know smallest number of teeth a double chainset can handle - Ive got a shimano 9sp set
> at the mo with 39 on the bottom.....I want to avoid converting the whole thing over to triple if I
> can.... but I want to get up the hills in the etape next year too!! I was thinking of putting
> 27-12 on the back but whats going to fit on the front?

Not necessarily a helpful answer, but apparently since Tyler Hamilton used one in the alps this
summer, it's become legit to use a 110mm BCD double chainset, which afaik can handle down to a 34
tooth chainring.

cheers, clive

 

[H. van Beek]

"turkeytickler" <[email protected]> schreef in bericht news[email protected]...
> Does anyone know smallest number of teeth a double chainset can handle - Ive got a shimano 9sp set
> at the mo with 39 on the bottom.....I want to avoid converting the whole thing over to triple if I
> can.... but I want to get up the hills in the etape next year too!! I was thinking of putting
> 27-12 on the back but whats going to fit on the front?
>
> tia
>
> Chris
>
> --
> Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/

I bought a 50/34 chainset of FSA this summer. I did it to avoid a triple. It was rather expensive ¤
360. But very nice carbon.

 

[Peter B]

"turkeytickler" <[email protected]> wrote in message news[email protected]...
> Does anyone know smallest number of teeth a double chainset can handle - Ive got a shimano 9sp set
> at the mo with 39 on the bottom.....I want to avoid converting the whole thing over to triple if I
> can.... but I want to get up the hills in the etape next year too!! I was thinking of putting
> 27-12 on the back but whats going to fit on the front?

http://www.shimano-europe.com/cycling/ Provides details of gear mech capacites. But to save you the
trouble I've already checked and they state a 14 tooth max front difference, say 53/39, and 29 max
capacity which after deducting the 14 at the front leaves 15 at the back = 12/27. So theoretically
you can't go smaller at the front, in practice you quite possibly can if you are careful with chain
length and avoid extreme combinations of front and rear gear selections.

E.G. At the moment I'm running an 11-19 cassette and a 46/43/24 triple with a short cage RSX rear
mech on my winter bike (purely because the mech was kicking about and I'm too tight to buy new
long cage mech) so have a difference of 30 teeth and it works but I can only use the biggest 3
rear cogs with the 24 front.

Another, better imo, solution, which I've used, is to go to an mtb cassette with a 32 cog on the
cassette (11-32 in my case). You will need an mtb rear mech, which road shifters will operate, to
keep the top jockey clear of the sprocket but a cheapish model Deore at £19.99
<1> will probably cost no more than a new chainring and is more than up to the job. The downside to
this is the wider spacing between ratios but the upside is that it should (will) work
flawlessly.

<2>http://www.chainreactioncycles.com/categories.asp?numcats=2&category1=gear+m
echs+rear_Rear%20Gear%20Mechanisms&category2=Gear+Mechs+Spares_Spares

Pete

 

[Dave Larrington]

turkeytickler wrote:
> Does anyone know smallest number of teeth a double chainset can handle - Ive got a shimano 9sp set
> at the mo with 39 on the bottom

130 PCD double clangers - such as current Shimano road chainsets - can have a 38 as the smallest
ring. As someone else has pointed out, FSA now do one which will go down to a 34 (at a price); for a
bargain approach to the same kind of thing, Stronglight 86 mm PCD cranks go down to 28. In the dim
and distant pre-mountain bike era, when dinosaurs walked the earth and triple chainsets were strange
and exotic, my touring bike ran a Stronglight 99 with a 28/42 double. These days it has a
Stronglight 80 with a 28/44...

--

Dave Larrington - http://www.legslarry.beerdrinkers.co.uk/
===========================================================
Editor - British Human Power Club Newsletter
http://www.bhpc.org.uk/
===========================================================

 

[Dave Kahn]

"Peter B" <[email protected]> wrote in message news:<[email protected]>...

> Another, better imo, solution, which I've used, is to go to an mtb cassette with a 32 cog on the
> cassette (11-32 in my case). You will need an mtb rear mech, which road shifters will operate, to
> keep the top jockey clear of the sprocket but a cheapish model Deore at £19.99
> <1> will probably cost no more than a new chainring and is more than up to the job. The downside
> to this is the wider spacing between ratios but the upside is that it should (will) work
> flawlessly.

This is definitely the way to go if you want to avoid fitting a triple. You will probably need a
couple more links in the chain too.

--
Dave...

 

[Ian]

Dave Kahn scribed with passion and wit:

> "Peter B" <[email protected]> wrote in message news:<[email protected]>...
>
>> Another, better imo, solution, which I've used, is to go to an mtb cassette with a 32 cog on the
>> cassette (11-32 in my case). You will need an mtb rear mech, which road shifters will operate, to
>> keep the top jockey clear of the sprocket but a cheapish model Deore at £19.99
>> <1> will probably cost no more than a new chainring and is more than up to the job. The downside
>> to this is the wider spacing between ratios but the upside is that it should (will) work
>> flawlessly.
>
> This is definitely the way to go if you want to avoid fitting a triple. You will probably need a
> couple more links in the chain too.
>
> --
> Dave...
Or the SRAM 11-34.

--
Ian

http://www.catrike.co.uk

 

[Arthur Clune]

Peter B <[email protected]> wrote:

: But to save you the trouble I've already checked and they state a 14 tooth max front
: difference, say 53/39, and 29 max capacity which after deducting the 14 at the front leaves 15
: at the back = 12/27.

Shimano road kit will cope very nicely with 50/34 and 12/27 though. That's a little over the
recommended, but it does work by all accounts.

It's 2 teeth over capacity at the front (16 v 14) and the total difference is 31, also two over.

Search the google archives of rec.bicycles.tech for the phrase "50/34" and you'll find a long, long
thread about this. I think it's a nice setup and I'm thinking about running 34/50 and 13-26 (campag)
for La Marmotte this year.

Arthur

--
Arthur Clune http://www.clune.org "Technolibertarians make a philosophy out of a personality defect"
- Paulina Borsook

 

[David Martin]

On 9/12/03 3:55 pm, in article [email protected], "Arthur Clune"
<[email protected]> wrote:

> Peter B <[email protected]> wrote:
>
> : But to save you the trouble I've already checked and they state a 14 tooth max front difference,
> : say 53/39, and 29 max capacity which after deducting the 14 at the front leaves 15 at the back =
> : 12/27.

> Search the google archives of rec.bicycles.tech for the phrase "50/34" and you'll find a long,
> long thread about this. I think it's a nice setup and I'm thinking about running 34/50 and 13-26
> (campag) for La Marmotte this year.

So where can I find a shimano compatible 34 tooth ring then? I seem to be able to get up most things
on the 39 but there are the occasional few and it would be nicer to have a closer set of ratios.

Then again the road bike is running a mixture of Ultegra cranks (vintage 199x where x<4),
Shimano sante' mechs, downtube leavers and brake levers (the brakes were not the best so the
calipers got changed for RSX in 1998) and a seven speed rear wheel (open4cd on ultegra). Old but
still going nicely.

..d

 

[Pete Biggs]

David Martin wrote:
>> Peter B <[email protected]> wrote: Search the google archives of rec.bicycles.tech for the
>> phrase "50/34"

http://groups.google.com/groups?q=rec.bicycles.tech%3A+50%2F34&ie=UTF-8&oe =UTF-8&hl=en

>> and you'll find a long, long thread about this. I think it's a nice setup and I'm thinking about
>> running 34/50 and 13-26 (campag) for La Marmotte this year.
>
> So where can I find a shimano compatible 34 tooth ring then?

You mean: "where can I find the cranks that take a 34T ring?". 38T is the smallest size that can
possibly fit Shimano double road (130mm) cranks.

~PB

 

[Pete Whelan]

Peter B wrote:
> "turkeytickler" <[email protected]> wrote in message news[email protected]...
>
>>Does anyone know smallest number of teeth a double chainset can handle - Ive got a shimano 9sp set
>>at the mo with 39 on the bottom.....I want to avoid converting the whole thing over to triple if I
>>can.... but I want to get up the hills in the etape next year too!! I was thinking of putting
>>27-12 on the back but whats going to fit on the front?
>
>
> http://www.shimano-europe.com/cycling/ Provides details of gear mech capacites. But to save you
> the trouble I've already checked and they state a 14 tooth max front difference, say 53/39, and 29
> max capacity which after deducting the 14 at the front leaves 15 at the back = 12/27. So
> theoretically you can't go smaller at the front, in practice you quite possibly can if you are
> careful with chain length and avoid extreme combinations of front and rear gear selections.
>
> E.G. At the moment I'm running an 11-19 cassette and a 46/43/24 triple with a short cage RSX rear
> mech on my winter bike (purely because the mech was kicking about and I'm too tight to buy
> new long cage mech) so have a difference of 30 teeth and it works but I can only use the
> biggest 3 rear cogs with the 24 front.
>
> Another, better imo, solution, which I've used, is to go to an mtb cassette with a 32 cog on the
> cassette (11-32 in my case). You will need an mtb rear mech, which road shifters will operate, to
> keep the top jockey clear of the sprocket but a cheapish model Deore at £19.99
> <1> will probably cost no more than a new chainring and is more than up to the job. The downside
> to this is the wider spacing between ratios but the upside is that it should (will) work
> flawlessly.
>
> <1>http://www.chainreactioncycles.com/categories.asp?numcats=2&category1=gear+m
> echs+rear_Rear%20Gear%20Mechanisms&category2=Gear+Mechs+Spares_Spares
>
> Pete
>
>

going the other way you can get a 55T ring working with a 38T inner on a shimano road chainset OK.

--
Pete

interchange 12 for 21 to reply

 

[Terry]

> turkeytickler wrote:
> > Does anyone know smallest number of teeth a double chainset can handle - Ive got a shimano 9sp
> > set at the mo with 39 on the bottom

I used to have 14 to 32 7sp and 42/52 with ordinary short cage 105 rear mech and front mech and that
worked fine for several years, except perhaps for a short breaking-in period for new chains and
cassettes.You might try just getting a SRAM cassette up to 32 or 34, see if it works, then if
necessary get a long cage mech. TerryJ

 

[MSeries]

Terry wrote:
>> turkeytickler wrote:
>>> Does anyone know smallest number of teeth a double chainset can handle - Ive got a shimano 9sp
>>> set at the mo with 39 on the bottom
>
> I used to have 14 to 32 7sp and 42/52 with ordinary short cage 105 rear mech and front mech and
> that worked fine for several years, except perhaps for a short breaking-in period for new chains
> and cassettes.You might try just getting a SRAM cassette up to 32 or 34, see if it works, then if
> necessary get a long cage mech. TerryJ

This depends on your chainset in particular its PCD. My Sugino has a 110mm PCD and currently has a
36 tooth inner chain ring.