[LOUISSSSS]

i have a new bike coming with a full Rival drivetrain w/ compact crankset. Coming from mountain biking, i'm used to not cross chaining. Does the same apply with Rivals?

Can I use the largest chainring in the front with the largest cog in the back? What about smallest chainring in the front with the smallest cog in the back? When doing this, how do i avoid the chain rubbing on the F. Derailleur?

sorry i'm a noob with road drivetrains, i only have a SS/FG bike.

 

[asad137]

On my Rival bike with compact crank, I can get all 10 rear cogs while in the big ring without rubbing (using the big ring trim feature for the front derailleur). I only use the big-big combination for short periods of time though (such as if starting from a stoplight).

When in the small ring, I cannot get the 2 smallest cogs without the chain rubbing against the big ring (not the derailleur cage). Some bikes may be able to get all of them without rubbing, but it depends on the chainstay length which determines the chain angle (longer chainstay = less severe angle). Also, I think (but haven't rigorously proven it to myself) that with a smaller tooth difference between big and small rings you have less likelihood of rubbing (i.e. a 53-39 or 52-38 would be less likely to rub than a 50-34). I'm not 100% sure on that last point because a couple of different factors come into play, but I'm not particularly interested in working out the geometry right now

Asad

 

[LOUISSSSS]

I'll have a 50/34, so i may have some rubbing of the chain on the 50t ring when on the small cog in the rear?(depending on chainstay angle/length?

But when riding on the 50t ring, i can ride at the largest cog in the rear without any damage to the chain?

 

[asad137]

I'll have a 50/34, so i may have some rubbing of the chain on the 50t ring when on the small cog in the rear?(depending on chainstay angle/length?

Possibly. You might rub in the two smallest cogs. It all depends on the bike.

But when riding on the 50t ring, i can ride at the largest cog in the rear without any damage to the chain?

I don't know about no damage. People say that cross-chaining is bad. It probably won't rub on the derailleur, but it's also probably not great for the chain, according to the conventional wisdom.

Asad

 

[Clueless Morgan]

I have to say I'm new to this Rival set. My only real problem is I get messed up with on the trim position all the time. Most often thinking I've down shifted only to find I'm only in the trim position. Also if running with big ring in front and one of the bigger cog's in back with the trim position on the FD and then start to pick up speed and want to upshift the rear, I want to be able to go straight back to full outer ring on the FD. As I see it, you have to cycle through the inner position first unless there's some trick I don't know about.

inner ring -> outer ring -> trim position -> inner ring -> outer ring -> trim position ->

being the cycle you have to got through?

 

[skyliner1004]

what is this "trim position" you're talking about? is it the "intermediate" between the small and large chainring in the front where i'd put the FD so i dont rub on it when cross chaining?

 

[Clueless Morgan]

what is this "trim position" you're talking about? is it the "intermediate" between the small and large chainring in the front where i'd put the FD so i dont rub on it when cross chaining?

Yes, exactly. A light tap goes from the big chainring to the intermediate or trim position. A larger tap is supposed to skip over the trim position and drop all the way down to the small chainring. It would appear that the purpose is for large chainring to large rear cog combination but not really usable for small to small because you only get to that position by being in the large chainring to begin with.

 

[paul l]

Morgan, you don't have click down to the small chainring to cancel out the FD trim, it's one of the features I like. If you have clicked in the FD trim (i.e. to minimise chain rub when using big ring and bigger easier rear sprockets) but then want to go back up the block (i.e. into the smaller higher geared sprockets) then just push the left shifter inwards as if you are changing up. This will cancel out the FD trim.

Hope this helps

 

[Clueless Morgan]

Morgan, you don't have click down to the small chainring to cancel out the FD trim, it's one of the features I like. If you have clicked in the FD trim (i.e. to minimise chain rub when using big ring and bigger easier rear sprockets) but then want to go back up the block (i.e. into the smaller higher geared sprockets) then just push the left shifter inwards as if you are changing up. This will cancel out the FD trim.

Hope this helps

Ah, thank you. I stand happily corrected, as that's just what I was looking for. I rode up and down the block trying this and it does work. I look at the documentation from SRAM, and there's no real instructions on using the shifter; mostly just installation, and so on. Under "Use" it just advises you not to cross chain. You would think if you were the new kid on the block with a new way of doing things, you'd spend a lot more effort explaining how your system works and why it's so great.

It seems my trim position needs adjusting, but it won't adjust any further in the correct direction. LBS guaranties adjustments for life, so might as well let them fix it.