Cross Chaining

[Swordtail]

I've got a new Giant TCR 0 with a 50/34 up front. This leads to much bigger differences in gear ratios when changing between large and small than my 20 year old bike which has a 52/42 front chain ring. As a result I'm less inclined to change between the two, and would rather stay on the large chain ring and use the bigger rear cogs when I need to.

So, is cross chaining a problem these days with modern components (my old bike was 8 speed on the back, the new one is 10)? If it is, how many of the cogs on the back at the extremes should be avoided? Just the end cogs, or more than that?

Cheers!

 

[Scoosh]

I think it depends a bit on the set-up of your rear cassette.

I have SRAM 10-speed and can, with fine tuning of the gears, get 8/10 on the 34 ring and 9/10 on the 50. Beyond these, I can hear a bit too much scraping for it to sound OK.

 

[screenman]

Excessive bend in the chain for my liking. Only time I have snapped chains is when I have been on the extreme rings.

 

[Paulus]

Try to avoid using the large chainring and the largest sprocket on the back, and likewise the smallest chainring and the smallest sprocket. The chain will be at such an angle to the rings and sprockets with these combinations it will cause excessive wear to the chain and the teeth on the cogs. Even with modern materials, chains are still suppossed to run in straight, or near straight lines.

 

[HLaB]

I do most of my cycling on the large chainring and upped the cassette (lowered the gear) by 1 so its practical (I run a 38/52 and a 11-26) I found that by that way I rarely need the large/large combo and when I do I can drop into the small ring instead.

 

[fossyant]

I've moved my old 20 year bikes to 53 x 39 shift (even bigger drop) from 52 x 42, and it's still a quick jab - chain ring down and two shifts of the sprockets. Milliseconds with one hand - Oh and this is on down tube shifters - still faster than STI/ERGO doing this.

Most folk complain about 50/34 compacts. It seems folk don't know the 'wrap over' of gears.

 

[Garz]

Try to avoid using the large chainring and the largest sprocket on the back,

I would extend more concern these days with the larger cassettes that offer say 32t sprockets. If the range has 32t, 30t, 28t downwards then you would probably try avoiding the largest two or three when in the 50t chainring on a compact.

 

[MacB]

[QUOTE 1680906, member: 45"]I've got a ten speed with a single front ring and it's fine in all gears.[/quote]

Did you mess with the chainline at all, trying to favour either end of the cassette, or just aim for as close to middle as possible?

 

[Nebulous]

[QUOTE 1680906, member: 45"]I've got a ten speed with a single front ring and it's fine in all gears.[/quote]

What are your gear ratios?

In the 80's I had a 12 speed and have occasionally toyed with the idea of getting an old racer. However for using it around town I don't see the need for multiple front rings - so I have wondered about 6 or 7 gears. 10 sounds better though, and would cover most eventualities.

 

[cyberknight]

You could always change the inner ring to a 36 or 38 to give you less of a drop.

 

[Swordtail]

I was having problems with the front changer and have discovered Shimano deliberately put an extra "index" on the front changer so that you can "trim" the mech, moving it very slightly because it rubs at the extreme gears (big cog/big cog and small cog/small cog). This works quite well and seems to have been designed specifically to enable you to ride at cross chained gears without the chain rubbing on the mech. I wonder if this means it is ok to cross chain? It wasn't really the rubbing noise against the mech I was worried about, it's the angle of the chain, but if Shimano have designed something in to allow you to do it without the noise, it must be ok?!

 

[screenman]

I have as yet never read a bike manual that did not say do not use the extreme sprockets with the large and small chain rings, one of the most obvious reasons is excessive chain and sprocket wear. Now I am sure there will be some internet experts that go against that which the likes of Shimano, Campagnola, Giant, Trek, Specialized etc say. Now it would be nice for said experts to come on and tell us why they feel it is good to go against expert advice.

Happy to be educated and will certainly not be offended if proved wrong.

 

[Wankelschrauben]

I was having problems with the front changer and have discovered Shimano deliberately put an extra "index" on the front changer so that you can "trim" the mech, moving it very slightly because it rubs at the extreme gears (big cog/big cog and small cog/small cog). This works quite well and seems to have been designed specifically to enable you to ride at cross chained gears without the chain rubbing on the mech. I wonder if this means it is ok to cross chain? It wasn't really the rubbing noise against the mech I was worried about, it's the angle of the chain, but if Shimano have designed something in to allow you to do it without the noise, it must be ok?!

The same shifters are used on both triple and double chain ring set-ups, the fact you can trim the de-raileur on a double set up does not mean it was the manufacturers intention, rather a positive consequence of money saving design.

 

[Swordtail]

the fact you can trim the de-raileur on a double set up does not mean it was the manufacturers intention

This may be true but they do advocate it. The tech doc explains how to set it up. It also says:

"When the chain is in the position shown in the illustration,
the chain may contact the front chainrings or front derailleur
and generate noise. If the noise is a problem, shift the chain
onto the next-larger rear sprocket or the one after."

(http://techdocs.shimano.com/media/t...01/SI-5LW0A-001-ENG_v1_m56577569830671268.pdf)

You'd have thought it would tell you there not to cross chain because it wears out components, rather than just to avoid noise.

Mind you, even given all this, it still seems like a bad idea to me and to be avoided. Perhaps just the occasional very short stretch is ok.

 

[Garz]

Just put it down as a wise tip from users to extend the life of your components. Then theres the elitist that are embarrassed one has to use a 'compact' in the first place or even consider shifting into the 'lower ring'.