Rear cassette with 105

adscrim

Veteran
Location
Perth
What length is your rear mech? Ideally you'd have at least a medium cage rear mech with a 32 cassette. There is no problem running a 32 tooth cassette with the chainset if your mech is capable of handling it.
 

Osprey

Veteran
Location
Swansea
I'm running a 30 tooth cassette on a medium rear mech and was told by the lbs not too go bigger. Having said that, its plenty low enough for the hills. Is this for your Roubaix or your n+1.
 
OP
philinmerthyr

philinmerthyr

Über Member
For the N+1. I was thinking about a triple but there are none left in the sales in my size.

The new Defty Advanced 2 with 105 and disc breaks looks good for £1400 and a 34/30 easiest gear would be ok.

For now though I'm at the Liberty Stadium to see the Ospreys beat the Dragons.
 

davester65

Growing Old is Compulsory...Growing Up is Optional
Probably not, if the rear derailleur is a 105 ss (10 spd 5700) then max sprocket size is 28t on both the ss and gs rear derailleur (info sourced from Shimano website)

If you want to run a really low gear for hill climbing then the new 5800 11spd 105 gs rear derailleur will run up to a 32t sprocket, but be careful if you're thinking of doing upgrades, 10spd and 11spd shimano components are not usually cross compatible. (ie. you can't use an 11spd rear mech with 10spd STi's or vice versa)
 

bpsmith

Veteran
Gear ratio for 34 x 32 is 1.06, for 34 x 30 it's 1.13 and for 34 x 28 it's 1.21. Basically the 32 over the 30 is as much a step as going for 30 over a 28, so actually worth it if you need that extra gear.
 
OP
philinmerthyr

philinmerthyr

Über Member
Gear ratio for 34 x 32 is 1.06, for 34 x 30 it's 1.13 and for 34 x 28 it's 1.21. Basically the 32 over the 30 is as much a step as going for 30 over a 28, so actually worth it if you need that extra gear.
Being around 20st and living in the Brecon Beacons I need all the help I can get. Thinking of getting the new Defty Advanced 2. It looks a superb bike with 105 chainset and disc brakes. I think it will take a 12/35 11 speed cassette but have emailed Giant to check.

image.jpg
 

PaulSecteur

Specialized fanboy
Have a look on the back of the rear derailieur, you should see one of these numbers...

5600....32 wont work
5700....32 wont work
5701....32 will work
58xx....32 will work

The length of the derailiure is to do with the front chainset. A tripple needs a long one to take up the extra slack.

A double will work with long or short, but best With the short one... which they call the medium.

Hope that helps.
 

SpokeyDokey

Into my 64th
Moderator
Have a look on the back of the rear derailieur, you should see one of these numbers...

5600....32 wont work
5700....32 wont work
5701....32 will work
58xx....32 will work

The length of the derailiure is to do with the front chainset. A tripple needs a long one to take up the extra slack.

A double will work with long or short, but best With the short one... which they call the medium.

Hope that helps.
Is 32 recommended for 5701 or is it something you have tried and was ok?

Reason I ask is that I have 5701 and just switched 12-28 to 12-30 and when I checked 30 was the max'.
 

PaulSecteur

Specialized fanboy
Is 32 recommended for 5701 or is it something you have tried and was ok?

Reason I ask is that I have 5701 and just switched 12-28 to 12-30 and when I checked 30 was the max'.
i think the specs says something like 32 is ok with medium and a 34-50 chainset. With a triple the say 30 max, but i ran a 32 on mine with no problems.
 
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