Is this feasable

pictit

At present my gearing is :
105 Long Reach 9 speed rear mech
52/42/30 chainset
12-25 9 speed cassette.

What I'd like to do :
Deore Hollowtec 48/38/26 chainset
11-32 cassette or the nearest to the 32 I can get.
<b>Would the 105 rear mech 'handle' the 11-32 </b>given I would be reducing by 4 teeth on the chainset?.
I figure my only other option for similar gearing would be to keep the current chainset but go for a Deore rear mech and 11-34 cassette

nmcgann

No, the biggest rear sprocket the 105 mech is rated to handle is 27T. You need a MTB rear mech.

Neil

pictit

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by nmcgann</i>

No, the biggest rear sprocket the 105 mech is rated to handle is 27T. You need a MTB rear mech.

Neil
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Drrrraaaaaaaaaat!![:(][:D]

maddog_2cp

and the front mech may not shift too well with the smaller rings either....

You can sometimes stretch to 28,29 teeth with a roadie mech but 32 is usually too far, even if you tweak the tension screw to the max.

You could go for a 11-34 cassette, mtb mech and keep your existing chainset.....

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Drop bars are a historical accident...... discuss</font id="purple"></font id="size1">

Gary D

pictit,

I have a similar set up on my Tricross which I converted from a double. It has a Deore 48/36/26 Chainset, 105 long cage rear mech and triple front mech and an 11/28t cassette. It still has the Sora shifters (8 speed).

The good news is it works perfectly![:D]

What I did find was that the chain length was fairly critical. It is nothing to do with the fact you are reducing the number of teeth by 4. It is down to the overall difference in teeth numbers which you are not actually changing on the front ring.

I know it is not quite the set up you are seeking, but with a 26 front ring and a 28 rear it is very low geared. I certainly find it OK and I am still overweight and unfit.

When I was trying to figure out if my conversion was feasible, one of the things that became clear was that the specs that Shimano quote are fairly conservative and can be tweaked a little. I didn't try my set up with a 30T cassete but my opinion is that it would probably be pushing it too far. I can actually get the full range of chain/cassette combinations if I wanted (but I don't). With a bigger cassette, you would run the risk of wrapping the rear mech around the cassette if you accidentally changed to the big/big combination. Not good!

I hope this helps.

Gary.

Must try harder....

John C.

I run 26/42/52 front(so you could just change the inner ring) with a 12-32 rear(home made from a 12-25 with big jumps of 21-25-32, I took out the 23 ring and replaced it with the 32), this is controlled with a deore XT rear mech and a tiagra front mech, I now use campag centaur levers but the old shimano sora gear changers managed without any problems.
Hope this helps a bit, good luck .

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