Chain rings.



G

Gaz

Guest
Hi, I have a Shimano Sora equiped Orbea with 52/42 chain ring. I
cannot ride on the 52 ring unless I'm going down hill with the wind
behind me :). I like to ride in the Downs around Goodwood on my other
bikes but can't on this one. Is it possible to change these for a
lower sized rings. If so is it easy to do myself.
 
D

del

Guest
On Monday 16 Jul 2007 15:20 Gaz, wrote:

> Hi, I have a Shimano Sora equiped Orbea with 52/42 chain ring. I
> cannot ride on the 52 ring unless I'm going down hill with the wind
> behind me :). I like to ride in the Downs around Goodwood on my other
> bikes but can't on this one. Is it possible to change these for a
> lower sized rings. If so is it easy to do myself.


You need to build up to it not replace it!
Ride on the Downs but gradually use the bigger gears and in time you
will be using the 52 ring almost exclusively and wonder what all this
fuss was about.
Ride on,
--
del :cool:
 
On Jul 16, 3:20 pm, Gaz <[email protected]> wrote:
> Hi, I have a Shimano Sora equiped Orbea with 52/42 chain ring. I
> cannot ride on the 52 ring unless I'm going down hill with the wind
> behind me :). I like to ride in the Downs around Goodwood on my other
> bikes but can't on this one. Is it possible to change these for a
> lower sized rings. If so is it easy to do myself.


you wont go much, if any lower without getting a compact crankset.
You should be able to use more or less any manufacturer rated for the
right number of sprockets on the cassette (are you eight speed?). You
will likely need a new bottom bracket and a crank-puller and BB tool
if you don't have them already. All of this can be found pretty
cheaply if you stand by for bargain spots from the hive mind

hth
james
 
S

Stan Cox

Guest
Gaz wrote:
> Hi, I have a Shimano Sora equiped Orbea with 52/42 chain ring. I
> cannot ride on the 52 ring unless I'm going down hill with the wind
> behind me :). I like to ride in the Downs around Goodwood on my other
> bikes but can't on this one. Is it possible to change these for a
> lower sized rings. If so is it easy to do myself.
>

They are easy to change. I would leave the 52 alone & change the 42 for
a 39. You might be surprised how much difference the 3 teeth make. Just
make sure to fully tighten them or they might come loose I bend. What
cassette do you have on?

Stan Cox
 
S

Simon Brooke

Guest
in message <[email protected]>, Gaz
('[email protected]') wrote:

> Hi, I have a Shimano Sora equiped Orbea with 52/42 chain ring. I
> cannot ride on the 52 ring unless I'm going down hill with the wind
> behind me :). I like to ride in the Downs around Goodwood on my other
> bikes but can't on this one. Is it possible to change these for a
> lower sized rings. If so is it easy to do myself.


Fit a 'compact' chainset. The only Shimano compact I can find is over a
hundred quid, which is probably not what you want to pay; other compact
chainsets should work but you may need to change the bottom bracket as
well.

--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; MS Windows: A thirty-two bit extension ... to a sixteen bit
;; patch to an eight bit operating system originally coded for a
;; four bit microprocessor and sold by a two-bit company that
;; can't stand one bit of competition -- anonymous
 
G

Gaz

Guest
On 16 Jul, 17:21, Stan Cox <[email protected]> wrote:
> Gaz wrote:
> > Hi, I have a Shimano Sora equiped Orbea with 52/42 chain ring. I
> > cannot ride on the 52 ring unless I'm going down hill with the wind
> > behind me :). I like to ride in the Downs around Goodwood on my other
> > bikes but can't on this one. Is it possible to change these for a
> > lower sized rings. If so is it easy to do myself.

>
>
> What
> cassette do you have on?
>
> Stan Cox


I have a 24/13 7 speed cassette. How much can I cross the chain? If
I'm on 42 ring can I safely use 5th or 6th sprocket or on 52 use 2nd
or 3rd?
 
N

Nigel Cliffe

Guest
Gaz wrote:
> On 16 Jul, 17:21, Stan Cox <[email protected]> wrote:
>> Gaz wrote:
>>> Hi, I have a Shimano Sora equiped Orbea with 52/42 chain ring. I
>>> cannot ride on the 52 ring unless I'm going down hill with the wind
>>> behind me :). I like to ride in the Downs around Goodwood on my
>>> other bikes but can't on this one. Is it possible to change these
>>> for a lower sized rings. If so is it easy to do myself.

>>
>>
>> What
>> cassette do you have on?
>>
>> Stan Cox

>
> I have a 24/13 7 speed cassette. How much can I cross the chain? If
> I'm on 42 ring can I safely use 5th or 6th sprocket or on 52 use 2nd
> or 3rd?


Smaller work across the largest six without issue. Largest five if being
cautious.
Larger should work across the smaller six, five would be more sensible.



My suggestions for your gearing issues:
Front; cheapest change would be to go to 39+52, only one ring to change.
39+50 might work better for you (two rings)

Then its more complicated, you could change the rear to 13-26 or 13-28, but
you will loose the closeness of some of the ratios, which is a loss on a
performance oriented bike (less of an issue on a chugging tourer style).
Or you could change the front to either a compact (34+50) or a triple.
Stronglight are a source of fairly cheap cranksets, Spa Cycles in Harrogate
are one mail-order source.
All of these more complicated changes might require a longer rear derailleur
(a triple certainly would, plus new front derraileur, plus new shifter,
forget it !), and changing the front might require a new bottom bracket,
depending on what is available.


- Nigel

--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/
 
S

Simon Brooke

Guest
in message <[email protected]>, Gaz
('[email protected]') wrote:

> On 16 Jul, 17:21, Stan Cox <[email protected]> wrote:
>> Gaz wrote:
>> > Hi, I have a Shimano Sora equiped Orbea with 52/42 chain ring. I
>> > cannot ride on the 52 ring unless I'm going down hill with the wind
>> > behind me :). I like to ride in the Downs around Goodwood on my other
>> > bikes but can't on this one. Is it possible to change these for a
>> > lower sized rings. If so is it easy to do myself.

>>
>> What cassette do you have on?

>
> I have a 24/13 7 speed cassette. How much can I cross the chain? If
> I'm on 42 ring can I safely use 5th or 6th sprocket or on 52 use 2nd
> or 3rd?


If you can't use the whole width of the cassette without problems
something's wrong. Yes, it isn't a good idea to run in the big/big or
small/small combinations, because it accelerates chain wear, but it should
not cause any problems if you do. If you're having a particular problem at
one end of the range it's possible that your bottom bracket is the wrong
length.

--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; all in all you're just another click in the call
;; -- Minke Bouyed
 
On 16 Jul, 18:28, Simon Brooke <[email protected]> wrote:
> in message <[email protected]>, Gaz
>
> ('[email protected]') wrote:
> > Hi, I have a Shimano Sora equiped Orbea with 52/42 chain ring. I
> > cannot ride on the 52 ring unless I'm going down hill with the wind
> > behind me :). I like to ride in the Downs around Goodwood on my other
> > bikes but can't on this one. Is it possible to change these for a
> > lower sized rings. If so is it easy to do myself.

>
> Fit a 'compact' chainset. The only Shimano compact I can find is over a
> hundred quid, which is probably not what you want to pay; other compact
> chainsets should work but you may need to change the bottom bracket as
> well.


Is there some reason why he can't fit, say, 39/48 or a 38/46 rings
to the existing chainset? If Shimano don't make them, surely someone
else does? Stronglight & TA both make 130mm BCD 'rings and I thought
they were sold as "Shimano compatible"...

I must be missing something, here... Does this chainset have unusual
compatibility requirements?

Cheers,
W.
 
D

Dave Larrington

Guest
In news:[email protected],
[email protected] <[email protected]> tweaked the Babbage-Engine to
tell us:
> On 16 Jul, 18:28, Simon Brooke <[email protected]> wrote:
>> in message <[email protected]>,
>> Gaz
>>
>> ('[email protected]') wrote:
>>> Hi, I have a Shimano Sora equiped Orbea with 52/42 chain ring. I
>>> cannot ride on the 52 ring unless I'm going down hill with the wind
>>> behind me :). I like to ride in the Downs around Goodwood on my
>>> other bikes but can't on this one. Is it possible to change these
>>> for a lower sized rings. If so is it easy to do myself.

>>
>> Fit a 'compact' chainset. The only Shimano compact I can find is
>> over a hundred quid, which is probably not what you want to pay;
>> other compact chainsets should work but you may need to change the
>> bottom bracket as well.

>
> Is there some reason why he can't fit, say, 39/48 or a 38/46 rings
> to the existing chainset? If Shimano don't make them, surely someone
> else does? Stronglight & TA both make 130mm BCD 'rings and I thought
> they were sold as "Shimano compatible"...


No reason whatsoever. I've got a 105 triple on one bike - 130 mm BCD - with
38 and 49 T Stronglight rings.

--
Dave Larrington
<http://www.legslarry.beerdrinkers.co.uk>
Frozen gorillas can be used to control the temperature of a warm
and stuffy room.
 
D

Dave H.

Guest
"Gaz" <[email protected]> wrote in message
news:[email protected]
> On 16 Jul, 17:21, Stan Cox <[email protected]> wrote:
>> Gaz wrote:
>> > Hi, I have a Shimano Sora equiped Orbea with 52/42 chain ring. I
>> > cannot ride on the 52 ring unless I'm going down hill with the wind
>> > behind me :). I like to ride in the Downs around Goodwood on my other
>> > bikes but can't on this one. Is it possible to change these for a
>> > lower sized rings. If so is it easy to do myself.

>>
>>
>> What
>> cassette do you have on?
>>
>> Stan Cox

>
> I have a 24/13 7 speed cassette. How much can I cross the chain? If
> I'm on 42 ring can I safely use 5th or 6th sprocket or on 52 use 2nd
> or 3rd?


A 24 tooth - 42 tooth top climbing gear is suitable for a racer, but not
very good for the rest of us.

You can change the cassette for very little money. A slightly smaller
chainring up front won't do much for you.

http://www.jbarrm.com/cycal/cycal.html
Try this handy online calculator.

High end cassettes have several of the largest gears mounted together on
aluminum carriers. The cheapest cassettes are assembled from loose steel
cogs and bolted together. They can be used as found, or taken apart and
assembled into custom cassettes, or you can just take off a larger cog and
add it to your current cassette (giving up a smaller cog to make room).

A set of 39/53 chainrings will take a 13-30 cassette (13-15-17-19-21-24-30).
Your 42/52 front rings should work with up to 32 teeth in the back. To get
anything easier would require a new front crankset, a compact or a triple.

You might need a new chain to wrap over the largest gears front and rear. I
have used cassettes this large with standard short cage Shimano road
derailleurs. The 13-30 has better gear ratios, less of a jump to the last
gear with a 39t front, but offers the same top climbing ratio as a 32t with
a 42t up front.

Dave H.
======
 

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