Bash ring and chain guides

[chrisga]

Wonder if any of you knowledgeable chaps could help. Thinking of changing my outer chainring to a bash ring as dont really use it that often anyway. That seems totally simple and fairly obvious. While looking though ive spotted some chain guides that "appear" to be little rollers that sit right down and behind the chainring. Do these do much as surely they are on the side of the chainring where the chain is leaving the cog, not going on to it? And if so do any of them work on a double chainring setup or are they purely for single chainrings?

[chrisga]

Thanks Pablo, thats a great help. I'm struggling to figure out how the roller works as the chain moves though. Or is it wide enough for when chain is on granny and in middle?

[chrisga]

Thanks Matt, I'm thinking about converting to a double with bash ring setup though. I've got the bash ring sorted, understand thats just a remove outer chainring and replace with whichever bash ring, just making sure pcd of bolts is the same as crankset.

I'm just trying to understand how the chain guides work that ive seen below and behind the chainrings. Oviously the front mech will still need to be above. If you can still shift between two chainrings at the front, are they worth it?

[chrisga]

Thanks Ally thats fantastic. Those pics are way better than anything i could find online. I get it now, the stepped roller was the bit that was confusing me.

How do you think the roller helps? Is it just that it keeps the chain under more tension? Kind of like a new age DCD (Dave's chain device) like I used to have on my really old mtb back in the day?

[chrisga]

Thanks Ally my DC was red, of course it went well with the purple of my trek 970 and the RC35's adorned with mint sauce stickers. Hey i was young.....

Anyway, back to the chain guide thingy, I might give one a go on the enduro. Thanks for your help guys!

[chrisga]

Already in my faves

[chrisga]

Ally M, sorry to drag up an old topic, but you gave me some good advice before. i think im about to take the plunge and buy a double chain device and bash ring as per your pics above. Well i was, right up until i got thinking about chain lines. I have an XT triple crankset on my bike, and if i remove the outer ring the chain will still work across all gears when on the old middle ring as thats presumably central to the cassette. But if im moving to a double presumably i will spend more time in little ring (i will change middle ring from 32 to 36t), but wont this chainring be too far to the left to get the small cogs on the cassette? Surely it would be better if i could move my chainrings toward the outside ring slightly to try to centralise them. Is there an easy way of doing this and does anyone bother? I dont want to have to buy some double specific cranks if I can help it. I realise they will still work but would be nice if they were "right" if you see what i mean.

[chrisga]

Thanks Pablo and Ally, its more chainline than cross over of ratios i was thinking about. Is there a way of spacing the right hand crank out so that the gap in between the granny and middle ring is where the middle ring used to be?

Anyone got a 36t chainring (preferably black) with bolt spacing to fit a 2008 XT crankset that they dont want need anymore that I could buy?