Changing to smaller chainring gap

[Twilkes]

Are there generally any problems with switching a compact 50 chainring to a 44, to get 44/34 gearing?

Looking for a bike for my wife and there are some nice flat bar road bikes but she'll not make the most of a 50 for the riding we'll be doing, and a smaller gap will make switching between rings less of a hassle.

 

[lazybloke]

Pretty sure you'll have to move the front derailleur down close to the rings

 

[Twilkes]

Pretty sure you'll have to move the front derailleur down close to the rings

If it's just that kind of stuff it'll be fine, just making sure there were no compatibility issues.

 

[Ming the Merciless]

Check the BCD of the outer chainring of any bike you are looking at. Then check it’s small enough that you can get 44t rings with that BCD. The derailleur should cope fine.

 

[Juan Kog]

I run both my compact chain set equipped bikes with 46 outer rings . ( 46 x 11 is tall enough for me ) . As advised already, front mech will needed to be lower and cable adjusted. Spa cycles would be a good place to look for suitable chain rings. Your right , front changes are snappier .

 

[Twilkes]

It was more having less cadence difference between the rings, but yes I guess changes might be better too.

 

[Smokin Joe]

Swapping the 50 ring for a 48 on my last road bike was a massive improvement. Far fewer double gear shifts and sweeter shifting. With 11t sprockets becoming the norm now only racing guys need anything bigger.

 

[Twilkes]

I'm tempted to do that on my own bike, I like to keep pedalling on quick downhills, even if it's low cadence, and the difference between the 11 and 12 cog is very small, so 48-11 would likely be fine.

I also used to Frankenstein a 12-32 cassette by replacing the 11 and 12 on an 11-32 with the 12 and 13 from a 12-28 cassette, so it would save me having to do that again!

 

[Rusty Nails]

I am looking at doing this on a gravel bike...from 50T to 48 or 46T.

One problem I am wondering about is whether I can lower the front derailleur enough as I have a direct mount fitting. Has anyone had experience of this?

 

[T4tomo]

Direct mount. - don't they have a height adjustment built into them?

You can buy CX double chain sets 46/36. My OH has that on her gravel bike.

 

[LittleWheelsandBig]

Some front derailleurs have a minimum difference between chainrings = min. 11t or 13t. Other mechs are fine with a 10t gap. Some front derailleurs are long enough that a 44t big ring means the tail of the cage hits the chain stay when the seat tube angle is fairly relaxed or the bottom bracket is low.

 

[Tigerbiten]

I am looking at doing this on a gravel bike...from 50T to 48 or 46T.

One problem I am wondering about is whether I can lower the front derailleur enough as I have a direct mount fitting. Has anyone had experience of this?

The front derailleur moves up/down 2mm per tooth difference.
If you know how much adjustment there is, then you can use the above to workout how much you can alter your chainrings by.
You can shrink more but you run a greater risk of the chain being unshipped outwards on an upshift.
You also need to check that if you move the derailleur down the full distance that it then doesn't hit the chain stay.

Luck .........

 

[Ajax Bay]

Check the BCD of the outer chainring of any bike you are looking at. Then check it’s small enough that you can get 44t rings with that BCD. The derailleur should cope fine.

Agree. Spa Cycles gives you a good idea of what available for a high BCD (eg 130 or 135mm) - and they have 44t in silver or black.
The FD is designed for a 34-50 upshift so will do 34-44 even easier.
A braze-on (as opposed to band-on) FD may limit the amount you can drop (can be measured easily).
But the limitation is likely to be the tail of the FD cage (lowered by 12mm) impeded from shifting to the inner ring by the chainstay. OP can check this easily when inspecting a prospective purchase.

 

[Twilkes]

Is there any need to match brands/models of chainrings, or will any replacement chainring that fits do? I'm sure I read about Shimano chainrings being designed to work together to improve shifting smoothness, with the way the teeth are shaped etc, but is that absolutely necessary?

 

[ianrauk]

Swapped a 50-36 to a 46-36. I swapped out an Ultegra chainset for a CX50 cyclocross chainset
I originally did the change for my commuter/tourer and it makes a whole world of better difference. I'm no speed freak rather than a commuting and long distance plodder. And not having the massive gear change up front is a godsend. As @Smokin Joe said above, does any one really need any higher gearing other then those that are racing.
For my road bike, My Van Nick, I'm planning on going for the change too. I have a 11-25 at the back so the step down on the front with 46-36 will make for some nice close gear changes.