Di2 rear cassette
Discussion
Moaningroadie said:
Try just buying the cassette first - I have run a 32 on a short 105 mech and short DA mech (both mechanical). Shimano say it can't be done but it can on some bikes - depends on rear hanger position, frame geometry, etc.
This. Depends what you run up front. I have 50/34 with a 32 on the back and it works fine with a short cage I can even go big/big without issues. On my other bike I have 52/36 and it still works but I have to consciously make sure I never go big/big. If you had a triple then you would definitely need a long cage, regardless.That may, or may not actually help. The 'short cage' is a max 28, medium 32. Thing is, cage length is a not-quite-adequate way of categorising them:
The longer cage length allows it to wrap more chain, and so handle more gear *range*
In order to accommodate a larger (32t) sprocket, you have to move the nearer jockey wheel radially out from the axle.
Changing the side plates will achieve the wrapping part, but *probably* not the increment in max sprocket size. It might do, but I'd be surprised - it would need to move the pivot location of the side plate arrangement.
First thing I'd ask is what you have up front.. you can go to 34 front, 28 rear without changing expensive electronic gubbins.. unless there's something special going on that ought to be more than enough.
The longer cage length allows it to wrap more chain, and so handle more gear *range*
In order to accommodate a larger (32t) sprocket, you have to move the nearer jockey wheel radially out from the axle.
Changing the side plates will achieve the wrapping part, but *probably* not the increment in max sprocket size. It might do, but I'd be surprised - it would need to move the pivot location of the side plate arrangement.
First thing I'd ask is what you have up front.. you can go to 34 front, 28 rear without changing expensive electronic gubbins.. unless there's something special going on that ought to be more than enough.
Standard compact 50/34. The thing is I need to have the added range at the back simply because I need the scope to be able to spin faster and lessen the stress on ze ticker - and I need to do it before I get back on the bike because I know that frst thing i'm going to do, as all cyclists do is 'see how much you can do'.
I need to limit my heart rpm (so to speak) as the speed limiter that was a beta blocker has now been removed. So, it will be very much a case of me, a HRM and easier gearing that will mean I can still do what I want to do, but without the (immediate and medium term) risk of over reving the engine.
Really, it's just a bit of forward planning on my part.
I need to limit my heart rpm (so to speak) as the speed limiter that was a beta blocker has now been removed. So, it will be very much a case of me, a HRM and easier gearing that will mean I can still do what I want to do, but without the (immediate and medium term) risk of over reving the engine.
Really, it's just a bit of forward planning on my part.
Noted - unless a) you have prior experience that tells you otherwise, or b) you're planning riding up the side of an alp.. I'd give it a try as is. You might be surprised just how low 34/28 is in reality.
Also don't assume spinning faster is easier on the ticker - for the same effort a lower cadence will tend to trash your legs and lower the HR, a higher cadence up your HR and easier on the legs. Granted on a proper hill smaller gearing will allow you to ride slower/lower effort, but in your position I'd be avoiding significant climbs.
YMMV obviously, just my thoughts.
Also don't assume spinning faster is easier on the ticker - for the same effort a lower cadence will tend to trash your legs and lower the HR, a higher cadence up your HR and easier on the legs. Granted on a proper hill smaller gearing will allow you to ride slower/lower effort, but in your position I'd be avoiding significant climbs.
YMMV obviously, just my thoughts.
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