[HarryTrauts]

For my indoor training, my preference is for rollers over turbo.  Obviously, my level of resistance is controlled by gear selection.  The issue I have is changing onto the big ring.  It’s unreliable and I’ve not worked out why.  The front mech is indexed to within an inch of its life and works perfectly when I’m out on the road.  On the rollers, however, it’s either a struggle to shift or sits rattling away on the little ring refusing to make the jump.

Does anyone have a similar problem and, more importantly, how can I solve it?

Thanks in advance.

Topic

[saladfunky]

Maybe due to the fact that

Maybe due to the fact that when on rollers it is difficul to ease off the power when changing into the big cog? On the road you can subtly ease the power if needed at that critical point to make the change. This may be that difference between the rollers gear change and the road gear change?? Maybe?  I use rollers lots and do find you need to really push the chain onto the big ring with quite a good nudge of the lever, moreso than I would when changing on the road. I am assuming you aren’t using DI2 mind ??  

[sizbut]

Maybe the lack of normal road

Maybe the lack of normal road vibration helping joggle the chain… super-glue some stones and other road grit to the rollers…

[HarryTrauts]

Thanks for the replies.

Thanks for the replies.

surly_by_name does make a good point that the front mech shouldn’t be affected by load and roller position, but it might still be a factor.  What’s confusing is that it’s intermittent.  Usually towards the end of a session so user error could be involved, as surly_by_name further suggests.

peted76 I need the small ring for spinning between intervals,  I’m afraid.

[surly_by_name]

CXR94Di2 wrote:

I can assume that when on rollers the wheels dont sit ontop but slightly behind and in front placing a different load on frame and altering the cable pull on the derailleur ever so slightly.  

Errrr …. what? Even if this made any sense at all, which it doesn’t, I believe OP is talking front mech, not rear mech. Front mech attached to down tube which sits between the rollers and won’t be affected by position of front and rear wheels.

OP: I’d guess its because you aren’t riding on rollers in same way that you do on road. On road I imagine you come off the power ever so slightly and potentially slow your cadence while you gently shift front ring so it goes shifts perfectly (because you’ve adapted to allow ensure that it does so). Its harder to do this naturally on rollers because the first time you do it you feel like you are going to come off the stupid things, so you fluff your shifting by pushing too fast or not modifying power/cadence, so no shifting.

[peted76]

I’d have never come up with

I’d have never come up with what CXR94Di2 says above! 

I will say posititional wise that your front wheel should be in line or ‘very’ slightly behind the centre of the front roller.

I have also had shifting issues on rollers in the past but I recall after a lot of time on youtube and me fettling about, I took it to my LBS who identified a slightly bent hanger in 30seconds flat, out came a pipe, a quick ‘gentle’ bend back (they are designed to break not bend) and I was cured!

The only time I shift into the little ring is to see how slow I can go keeping 90rpm cadence..  

 

[CXR94Di2]

I can assume that when on

I can assume that when on rollers the wheels dont sit ontop but slightly behind and in front placing a different load on frame and altering the cable pull on the derailleur ever so slightly.  

[Author]

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