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?

[Pablo16v]

The little roller is a chain tensioner that takes up some of the slack in the chain and stops it falling off the chain rings or jumping down from the middle ring to the inner when the going gets rough. It's mostly used with a double and bash set up but they are also included on chain guides for use with single ring set ups as used by downhillers and freeriders, again to keep the chain nice and toight.
Unless you're constantly bothered by your chain dropping off I'd just go with a bash guard on it's own and remove 3 or 4 links from the chain. You won't need to stretch it over an outer chain ring again so it can be run slightly shorter.
On my bikes I run a bash guard on my hardtail and a bash + tensioner (a Blackspire Stinger) on my full suss. I have no need for a chain guide. Both bash guards are Race Face Atlas.

[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?

[Matt106]

Not many chain guides about for triple chainring to be honest. However check out this one, it gets great reviews and could be what your looking for?

http://www.chainreactioncycles.com/Models.aspx?Par...

I run a gamut chain device on my race bike and its great, chains never come off, its super light and has stood up to a few crashes

Have a browse through the Chain Reacton website im sure you'll find something.

[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?

[a11y_m]

chrisga said:

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?

Absolutely worth it IMO - I run Blackspire Stingers on two bikes. One is twin-ring plus bash, the other bike is twin-ring but no bash. The Blackspire only has a roller to tension the lower section of the chain, meaning the front mech is free to move the chain between rings. The roller is "stepped" - there's two parts of it the chain runs on and it just moves from one part to the other depending on what ring you're using. The e.thirteen DRS works similarly to the Blackspire Stinger.

A picture probably helps more than all I just typed above lol:

[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?

[shalmaneser]

chrisga said:

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?

Just ups the tension really and gives you more chain wrap so the chain doesn't bounce off from the bottom.

[a11y_m]

shalmaneser said:

chrisga said:

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?

Just ups the tension really and gives you more chain wrap so the chain doesn't bounce off from the bottom.

Ha, I had a purple DCD back in the day - started with a silver one but then they brought out the anodised colours and I had to have a purple one!

Just what shalmaneser says: ups the chain tension and gives more wrap around the chainrings, meaning less chance of the chain abandoning ship over lumpy terrain at speed. I'd got used to no chain flap on my singlespeed and hub-gear MTB and quickly got fed up jumping back onto geared bikes. The chain device goes a good way towards helping IMO.

[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!

[a11y_m]

Totally O/T, but at the mention of Mint Sauce I remembered about this site: http://homepage.mac.com/pfellows1/thisiswhy/index....

[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.

[Pablo16v]

There will be a x-over of gear ratios so you won't (and shouldn't) use the smaller cogs at the back while you are in the granny ring. Once you get to 4th or 5th (on a 9 speed cassette for example with 22/34 up front) you should change to the middle ring and 2nd to get a similar ratio.
I'm not sure if that's explained clearly but you can find a ratio calculator here

http://www.sheldonbrown.com/gears/

[a11y_m]

Pablo16v says it all really - I've not had any problems with chainline whatsoever. I've found I'm using the smaller cogs MORE than before, in either of the front rings. When I ran a triple I'd maybe only use the top 4 cogs on the cassette with the granny ring, but now I probably go as far as the 6th or 7th cog. Yes, there is still overlap but I reckon I now use more of the cassette than before.

I very much doubt I'll ever go back to triple rings. Ideally I'd like a 38t on my full-susser and will perhaps do that once the 36t is more worn. I'll also be changing the 22t to a 24t once the 22t is gubbed.

Currently:
full-susser (pictured earlier): 22t-36t with a 32-11t cassette
hardtail: 26t-40t with a 34-11t cassette

[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?