Changing to a larger chainring

[Edge540]

One for the tech guys out there. I have a Anthem 29er with a 11-36 cassette and 2x10 (24-38)chainrings. In order to get more top end for when I do road work is it possible to swop the 38 chainring to a 40 or 42. Would it work and if so how much difference would it make speed wise? Your comments would be appreciated. Thanks

[droo]

You'll have to swap both rings out, SRAM rings work in pairs. The set you're after is a 28-42.

[River Rat]

Droo is not wrong as that is what Sram recommend namely a14 tooth difference between chainrings. But I have managed to get 16 tooth gap to work so you could simply swap out the big chainring. You just need to have patience in terms of gear setting and you will most likely have a problem with the big chainring and the 36 t combo because of chain length.

[Traverse]

What the heck are you doing with a 24? I just replaced my wife's Anthem x 29 er's inside chainring with a 26 and no problemo, she's also using a sram crankset. The jump from 24 to 40 will be quite huge, rather go 26-39 or 28-42 assuming it is sram, isn't your Anthem using Shimano?

[Edge540]

It's the standard setup Shimano 24-38 as supplied when new. If I up the small chain ring I'm guessing I'd loose my granny gear which I so dearly love ( not all that fit )   I'm quite happy with the current setup for going up Tokai etc but I've been conned into doing the Argus (sorry that should be CTCT) hence the need for longer legs on road.

[JXV]

Standard Shimano 2x setup is a 26 - 38 afaik. There is also a 24-38 set avail. The two 38 rings are not the same. Dunno what longer options there are for Shimano but someone will tell us.

[ACM]

Depending on your specific FD, the jump from 24 to 40 might be too big. Then the chain will get trapped between the bottom of the FD and the 40T not allowing the chain to climb to the 40T.

 

Stick to 38T and just keep contant cadence :-)

[Edge540]

Depending on your specific FD, the jump from 24 to 40 might be too big. Then the chain will get trapped between the bottom of the FD and the 40T not allowing the chain to climb to the 40T.

 

Stick to 38T and just keep contant cadence :-)

Seems like this may be the way to go. Will do a few long rides and see how it goes

[Lone_Ranger]

I'd recommend changing to a big ring just for race day. I find that I don't use my small ring at al for the Argus, as it's too light for the road. Even my big ring(44) is too small for road cycling. I'm on a 26er btw, so 44 is still usable on the mountain.

[Edge540]

I'd recommend changing to a big ring just for race day. I find that I don't use my small ring at al for the Argus, as it's too light for the road. Even my big ring(44) is too small for road cycling. I'm on a 26er btw, so 44 is still usable on the mountain.

Thanks L_R. That sounds like a plan

[PeterF]

With a 38 x 11 at a cadence of 100rpm you will be doing about 47.7 km/h.  Do you really need to go faster?  Chances are that with a 42 on the front, you will spend more time on the 12 or 13 at the back and actually go the same speed as with a 38 x 11.

[Lone_Ranger]

With a 38 x 11 at a cadence of 100rpm you will be doing about 47.7 km/h.  Do you really need to go faster?  Chances are that with a 42 on the front, you will spend more time on the 12 or 13 at the back and actually go the same speed as with a 38 x 11.

To answer your question, YES you really do need to go faster.

 

At 47.7km/h on the downhills the roadies will drop you like a hot potato. Even the slow ones.

[Edge540]

Thanks PeterF. To get to 30/35 kph it seems like I'm pedalling myself into the ground. Wouldn't want to keep that up for anything longer than necessary. I seriously doubt I'd ever be able to get to even 35 on the flat for any distance.