Cx gearing

Jterrier

I am sure this topic has been done to death but.

My bike has a 44t with a 10-42 at the back. This gives me a massive range, meaning i dont have to prolapse myself going uphill or simply stall and run like others. I like it. But it is heavy and the gaps are wide. I also rarely stray into the bottom half of the cassette, prb because the chainring is quite large. So i am thinking of saving weight and closing it down a bit; a 38t with an 11-36. The idea being to retain the climbing range but smooth the differences in cadence between cogs, and maybe try and spend more time at the bottom so i can go upwards plenty of times for hills (i seem to make major gains there, as lots of people seem to have such hard narrow gearing that they either kill themselves / stall / get off and run).

Does anyone have any experience of this, does it make sense? Its also an excuse for spanky new lighter wheels that are tubeless and dont have an xd driver.

VamP

I'm sure it's been done to death too, but 38 front with 11-28 (32) seem to be the combos most of single ring users favour for racing.

I have been using 38t - 11-28 for years, but just tried 11-32 and while I doubt I'll use the 32 much in racing, it's actually pretty useful for sighting laps, when I want to take it easy.

Jterrier

VamP wrote:

I'm sure it's been done to death too, but 38 front with 11-28 (32) seem to be the combos most of single ring users favour for racing.

I have been using 38t - 11-28 for years, but just tried 11-32 and while I doubt I'll use the 32 much in racing, it's actually pretty useful for sighting laps, when I want to take it easy.

I think maybe you are stronger than me. If my lowest gear was 38/28 i think i would be running half the lap ;-). Maybe thats the problem. I need to get stronger.

robertpb

My bike came with the same gearing, I just changed to a 38 chainring, gives a much better set of gears for me plus the steps between each gear is less.

But I use my CX on MTB trails not racing

tgotb

VamP wrote:

I'm sure it's been done to death too, but 38 front with 11-28 (32) seem to be the combos most of single ring users favour for racing.

I have been using 38t - 11-28 for years, but just tried 11-32 and while I doubt I'll use the 32 much in racing, it's actually pretty useful for sighting laps, when I want to take it easy.

Yep - 38 x 12-32 for me (I'm a bit more of a spinner than most).

trek_dan

38 with 11-32 for me too.

tgotb

If you don't need the 38x11 highest gear, you can also get similar ratios by going down to a 34t chainring and smaller cassette. That will presumably save you a very small amount of weight, but might also give more flexibility in your choice of rear mech (all other things being equal, shorter cages are generally better.)

Chris James

I've now got 34/27 bottom gear on my cross bike and last year raced on 34/25 (same as 38/28) which was okay but I found it a little hard going on very muddy hilly courses.

Jterrier

TGOTB wrote:

If you don't need the 38x11 highest gear, you can also get similar ratios by going down to a 34t chainring and smaller cassette. That will presumably save you a very small amount of weight, but might also give more flexibility in your choice of rear mech (all other things being equal, shorter cages are generally better.)

So, say a 34t with 11-25. Hmm. Although can you buy a 5 bolt 110bcd narrow/wide 34t...?

fat daddy

Jterrier wrote:

[
So, say a 34t with 11-25.?

be careful with that .. 34t -11t is fine off road, But I have just gone from 34t 11:42 to 38t 11:42 as on the road the 34t was just spinning too fast as soon as you hit a descent of any size ... If you are happy just cruising on the road then fine, but if you are wanting to comfortably hit above 26mph then I would recoment the bigger chain ring.

all depends on you and your routes though ... but get out on your bike and set the gearing to the same inchage and see what it would feel like

34t was too small for me on the road

Jterrier

Heres a detail kicker. Will a shimano 11-32 11spd cassette work with a rival 1 rear mech (back end is qr) and will the spacing and mech tune go out of whack (wheel and freehub change too, see above)

Underscore

Jterrier wrote:

TGOTB wrote:

If you don't need the 38x11 highest gear, you can also get similar ratios by going down to a 34t chainring and smaller cassette. That will presumably save you a very small amount of weight, but might also give more flexibility in your choice of rear mech (all other things being equal, shorter cages are generally better.)

So, say a 34t with 11-25. Hmm. Although can you buy a 5 bolt 110bcd narrow/wide 34t...?

Yep, I've got one of those from Superstar (with an 11-28 cassette). Note that their new Raptor rings will only fit in the outer position, however, but there are a few discontinued CX I/O rings that will fit in either position...

_

othello

Jterrier wrote:

So, say a 34t with 11-25. Hmm. Although can you buy a 5 bolt 110bcd narrow/wide 34t...?

Get them from Superstar, especially as they are selling off their original range at discounted prices. Really good rings.

joey54321

While on the subject; what is the difference between SSC's I/O ring and the new raptor ring?

Underscore

The Raptor ring is 12 speed compatible and the tooth shape is not symmetric so it can only go in the outer position, whereas the old I/O could be flipped and put in the inner position (as I have done).

_

joey54321

Why do you have to 'flip' it to mount it on the inside?

I have one of the I/O rings awaiting my attention to strip my bike down to 1x groupset.

ChrisSA

joey54321 wrote:

Why do you have to 'flip' it to mount it on the inside?

I have one of the I/O rings awaiting my attention to strip my bike down to 1x groupset.

The chainring has recesses where the bolts hold it on to the crankset. You can run it whichever way round you want, but your single-ring thickness bolts may not work if the recesses are inwards.

Supernaut

42 with 11/32 here. I occasionally think about putting 38s on for brutal courses (I have the 38s in the garage ready) but never seem to get round to it!

joey54321

Another question in a similar vein:

With SRAMs mechs being compatible across MTB and Road shifters is there much of a difference between the 2.1 mechs from the MTB side and the 1x mechs on the road side? Are they similar just badged and marketed differently?

Underscore

ChrisSA wrote:

joey54321 wrote:

Why do you have to 'flip' it to mount it on the inside?

I have one of the I/O rings awaiting my attention to strip my bike down to 1x groupset.

The chainring has recesses where the bolts hold it on to the crankset. You can run it whichever way round you want, but your single-ring thickness bolts may not work if the recesses are inwards.

That's interesting - when I spoke to SSC about this, they stated that the Raptor ring could not be installed in the inner position and that I should send the ring back...

_

trek_dan

joey54321 wrote:

Another question in a similar vein:

With SRAMs mechs being compatible across MTB and Road shifters is there much of a difference between the 2.1 mechs from the MTB side and the 1x mechs on the road side? Are they similar just badged and marketed differently?

Yup. In my experience the older 10 speed MTB ones seem a lot more robust too. Although SRAM are phasing out the X7 / X9 mechs which is a shame.