Can I have an even more compact crankset?

[michael.chaseling]

Hi all,

I was wondering whether I could change out one or both of my chainrings on my compact for smaller ones. The reason is that the jump from the smaller to the bigger ring is too much to be useful. I find it a little impractical where I ride as I very rarely need the highest gears.

When I am picking up speed, I change up on the back gears until I start cross chaining and rubbing on the front derailleur. Then when I shift to the bigger chain ring, I find I then lose cadence and feel like I need to ride harder and faster. I only change up to avoid the rubbing and cross chaining, not get a dramatic increase in speed, so a smaller outer ring would make sense right?

There are also a lot of hills where I live, and at least once per ride, i find the lowest gear is not quite low enough.

I ride mostly to the pub and back etc so I don't ever need to race flat out.

What do you reckon?

[Derny Driver]

What size are your chainrings? 34 and 50?
And what is your cassette, in teeth numbers?

I would think that 34 -46 chainrings with an 11-28 would be good for you.

[Bentnose]

I use a 34/48 tooth as I don't like the big gap.

[MattyK]

Don't waste money on a pub bike. Do what everyone else does and shift the rear sprocket down 2 or 3 gears when you upshift the chainring. And vice versa.

[RonK]

when I shift to the bigger chain ring, I find I then lose cadence and feel like I need to ride harder and faster. I only change up to avoid the rubbing and cross chaining, not get a dramatic increase in speed...

Makes no sense at. If the small ring is so low you have to change to the big ring, smaller will just make it worse.

Sounds like you need a bigger small ring.

[bychosis]

MTB crankset without using the big ring?

[Derny Driver]

when I shift to the bigger chain ring, I find I then lose cadence and feel like I need to ride harder and faster. I only change up to avoid the rubbing and cross chaining, not get a dramatic increase in speed...

Makes no sense at. If the small ring is so low you have to change to the big ring, smaller will just make it worse.

Sounds like you need a bigger small ring.

Ron I think what he means is that once he gets to the 34-11 and is crosschaining he wants to change up to avoid that. When he changes chainrings he ends up in the 50-11 and the cadence is too low. Even if he knocks it back a couple of cogs the gear is still too big and cadence too low so he feels he has to speed up. He would need to change back 5 cogs to the 50-16 to find an equivalent gear to the 34-11 he was comfortable on. By replacing the 50 with something smaller he can minimise the difference or even just ride everywhere in the big ring.

[Baalzamon]

Save your money and learn to shift better. Change to the big chainring earlier say middle of the rear cassette and if necessary drop 2 gears off the rear then as speed picks up continue to downshift.

[mitchy_]

when I shift to the bigger chain ring, I find I then lose cadence and feel like I need to ride harder and faster. I only change up to avoid the rubbing and cross chaining, not get a dramatic increase in speed...

Makes no sense at. If the small ring is so low you have to change to the big ring, smaller will just make it worse.

Sounds like you need a bigger small ring.

Ron I think what he means is that once he gets to the 34-11 and is crosschaining he wants to change up to avoid that. When he changes chainrings he ends up in the 50-11 and the cadence is too low. Even if he knocks it back a couple of cogs the gear is still too big and cadence too low so he feels he has to speed up. He would need to change back 5 cogs to the 50-16 to find an equivalent gear to the 34-11 he was comfortable on. By replacing the 50 with something smaller he can minimise the difference or even just ride everywhere in the big ring.

i beleive Ronk's angle on the situation is that if they had a larger small ring, they wouldn't get to the end of the cassette and need to upshift as quickly. however they would lose lower gears, which they may or may not be using.

it all depends on more info from the OP however. what rings and cassette he currently has will make all the difference.

[silentC]

Sounds like a job for a triple to me...

[Derny Driver]

i beleive Ronk's angle on the situation is that if they had a larger small ring, they wouldn't get to the end of the cassette and need to upshift as quickly. however they would lose lower gears, which they may or may not be using.
.

Yes good point, but the OP says the smallest gear isnt small enough so a larger small ring isnt an option.

[queequeg]

Well, on my commuter I run a CX chainset with 46/38 rings. I find this ideal for commuting. paired with an 11-32 cassette (or 12-32).
When I jump from the 38 to the 46 it is very quick, and I only have to knock it back one or two clicks after shifting up to maintain the same cadence.

[CXCommuter]

Well, on my commuter I run a CX chainset with 46/38 rings. I find this ideal for commuting. paired with an 11-32 cassette (or 12-32).
When I jump from the 38 to the 46 it is very quick, and I only have to knock it back one or two clicks after shifting up to maintain the same cadence.

I also love my 46/38 cross crankset coupled with 11 to 27 is great and capable of hitting 60km/h if needed (not often ). There should be planty of capability to go 46/36 or 48/36 for a better set up.

[Xplora]

Pub bike? Stop pedalling down the hills

[ValleyForge]

Sounds like a job for a triple to me...

Would seem the simple solution....

[harmonix1234]

Can you put a 36 / 48 combo on a 110 bcd compact crank?

[mitchy_]

Can you put a 36 / 48 combo on a 110 bcd compact crank?

yep. my CX is 36/46 on a 110BCD crank.

[harmonix1234]

Woo hoo! Git sum!

[Stephanebkk]

Don't waste money on a pub bike. Do what everyone else does and shift the rear sprocket down 2 or 3 gears when you upshift the chainring. And vice versa.

Agreed

[slowK]

On my old bike, I run 46/34 - replaced the 50T ring with a FSA 46T big ring on my SRAM Rival (34/50 110 BCD) cranks. The front shifting is actually worse, despite the smaller tooth difference - the ramps/pins/teeth shaping of the rings from two different brands are not directly compatible to encourage upshifts. Dropping from the 46 to the 34 is fine, but pushing back the other way is a bit sluggish. It shifts, but just not super quickly.

On the other hand, I run a 12-30 cassette on the back, so I pretty much just stay in the 46T front ring for most rides I do.

[Mulger bill]

On my old bike, I run 46/34 - replaced the 50T ring with a FSA 46T big ring on my SRAM Rival (34/50 110 BCD) cranks. The front shifting is actually worse, despite the smaller tooth difference - the ramps/pins/teeth shaping of the rings from two different brands are not directly compatible to encourage upshifts. Dropping from the 46 to the 34 is fine, but pushing back the other way is a bit sluggish. It shifts, but just not super quickly.

On the other hand, I run a 12-30 cassette on the back, so I pretty much just stay in the 46T front ring for most rides I do.

Did you drop the front mech to compensate for the smaller ring?

[slowK]

Did you drop the front mech to compensate for the smaller ring?[/quote]

Yep - did that. It shifts, but just not as quickly (probably an extra half pedal revolution) as the stock big ring. And the gearing is so much more appropriate for my riding that I don't mind at all.

[Bentnose]

Did you drop the front mech to compensate for the smaller ring?

Yep - did that. It shifts, but just not as quickly (probably an extra half pedal revolution) as the stock big ring. And the gearing is so much more appropriate for my riding that I don't mind at all.

There is a CX front mech available which is designed to work with the smaller big rings, don't know how much of a difference it makes.

[simonn]

Did you drop the front mech to compensate for the smaller ring?

Yep - did that. It shifts, but just not as quickly (probably an extra half pedal revolution) as the stock big ring. And the gearing is so much more appropriate for my riding that I don't mind at all.

There is a CX front mech available which is designed to work with the smaller big rings, don't know how much of a difference it makes.

Shimano CX-70 front derailleur. Ultegra level.

I've got two. One on my CX 46/36 crankset (Shimano CX-50) 105 5700 shifters and one on my audax bike 46/30 crankset (Sugino OX601D) with campy veloce shifters. Very snappy for both, but not sure if it really makes a difference...

46/30 rocks for anything except racing/fast group rides. 46 is low enough that you rarely have to change at the front, but you have super low gears (I have 13-29 cassette) for the super steep hills (I can do 20% seated). Will probably go a 12-30 cassette next time though (I already had a spare 13-29 cassette).

[Xplora]

I did my first ever 53/39 with a 11-23 on the weekend, including 3kms at 6-11%. 45rpm sucks but I had enough juice at the top to change up and attack (because I'm that guy). I had 40kms to warm up... and I've done more weights than I care to remember recently. I like to spin 90rpm no matter how flat or rolling the hills are, and 15 minutes of climbing vs 5 hours of bliss, I know what my knees preferred.

Audax is a different story - they can't make a low enough gear once you've passed 250kms, even 2-3% feels like 30% that far in.