changing compact chainring sizing

[tubbylee]

hello,i have just ordered my new bike from wiggle ,a focus cayo and am waiting on its arrival,it is a compact 50/34,the 34 seems a bit small to me but i will give it a try, at the moment i ride a sirrus elite with 48/38/28 i find the 38 is ideal for me on the sirrus for all my cycling(except for downhills where i would use the 48)my question is i see there is a 38 chainring available for my compact crank can i just simply change the 34 for a 38 or will this cause shifting issues thankyou

 

[MichaelM]

You won't have any problems if you change the inner.

 

[Smokin Joe]

I'd go for a 36 inner, gives you a lower bottom gear and the gap between the rings gives a nice spread of gears.

You're right not to want 50/34, it's a pain in the arse to use.

 

[gbb]

You can go right up to 40T on the inner lee. Ive always fitted Stronglite Durals, moderately cheap (IRO £15 to £20) and they last well.
Remember to re-situate the dog fang if you've one fitted.

 

[VamP]

You're right not to want 50/34, it's a pain in the arse to use.

This is what I've got. In what way is it a pain in the arse? Not being funny, genuinely curious.

 

[endoman]

The Cayo has 27 teeth I think max at the rear, I know my hybrid has I think 32, Alivio, I think I would struggle up the hills round me with a 38, 27, although I got home last night without using my 28 ring up some decent hills, but had to use the 32. Hard work.

Hopefully my Cayo arrives today :-)

 

[Pottsy]

I happen to agree with Smokin Joe. I changed the inner on my road bike chainset to a 36. The gap changing between chainrings seems a lot more manageable and only really needs a simultaneous 1 or 2 gear change at the rear derailleur and not the 3 that used to be needed.

 

[Smokin Joe]

This is what I've got. In what way is it a pain in the arse? Not being funny, genuinely curious.

As Pottsy said above, the gap between the 50 and the 34 is too big needing two or three shifts on the cassette with every front change.


My bikes run 50/36 and 48/34.

 

[HLaB]

I couldn't do it, I'd say the same as lee but learn to spin; my road bikes are 39/53 and 38/52 btw but I was speaking to somebody in the club the other week he's on a 34/50 and did the Etape Caledonia (81 miles) in 3h 39 mins , to compound it his kid had an accident the day before and he had spent most of that in A&E and only slept a few hours

 

[bobones]

hello,i have just ordered my new bike from wiggle ,a focus cayo and am waiting on its arrival,it is a compact 50/34,the 34 seems a bit small to me but i will give it a try, at the moment i ride a sirrus elite with 48/38/28 i find the 38 is ideal for me on the sirrus for all my cycling(except for downhills where i would use the 48)my question is i see there is a 38 chainring available for my compact crank can i just simply change the 34 for a 38 or will this cause shifting issues thankyou

Play with this http://www.gear-calculator.com/# to see how much difference it would make. I'm not convinced it's worth changing from the 34.

 

[VamP]

Play with this http://www.gear-calculator.com/# to see how much difference it would make. I'm not convinced it's worth changing from the 34.

Great tool, thanks!

I agree with you, not worth changing IMO.

 

[Deleted member 1258]

My Kilmeston came with 50/34, I changed it to 48/42 http://www.dotbike.com/p/3593
Big improvement, as others have said the gap between 50/34 is to wide, I tried riding it with the 50/34 and couldn't get on with it

 

[Jenkins]

My Boardman Team Carbon also came with a 50/34. Within two weeks it was running a 50/36 as the original gap was too wide. The new combination seems just right for my style of riding.

 

[rockyraccoon]

Play with this http://www.gear-calculator.com/# to see how much difference it would make. I'm not convinced it's worth changing from the 34.

Excellent tool. Thanks for the link.

I also have replaced to a compact but the gap changing between chainrings/cassette is just too much.

What should I be looking at, technically speaking? More space between the cogs widely distributed and greater gear steps?

 

[bobones]

Excellent tool. Thanks for the link.

I also have replaced to a compact but the gap changing between chainrings/cassette is just too much.

What should I be looking at, technically speaking? More space between the cogs widely distributed and greater gear steps?

Can you post your setup from www.gear-calculator.com? (copy and paste the URL at the bottom after setting up your current cassette and chain rings).

For example, here's a comparison of my 50/34 with 8 speed 11-32 against 50-36

I don't see any improvement myself: my lowest gear isn't as low, there's still a 2 cog jump when moving from big to little ring (or vice versa) for the next gear in sequence, and the spacing is less even. Now subsitute a 38 for the 36 and there's only a 1 cog jump but my lowest gear is worse again. The whole point of me getting a compact was for the lower bottom gear!

I'm perfectly happy shifting front ring because I know what to expect. I can get up to 20mph on the little ring without cross chaining so I'm not leaping about from ring to ring on the flat. When I move ring I usually want a big shift either because I'm starting a descent or approaching a hill. Even if I just want the next gear in line it's a single swipe with the right shifter to move 2 cogs up the cassette or 2 sharp clicks to move down. Hardly the bane of my existence.

Saying that those with 10 speed cassettes might have a 3 cog jumps from time to time which would be more onerous.