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Single ring conversion(7 posts)

Single ring conversioncxer
Feb 27, 2003 1:13 PM
OK, a few questions on converting to single 44 on Ultegra crankset.
I am thinking of sandwiching the ring with 2 spot chainguards with the chainring in the "big ring" position, one guard replacing the small ring and the other guard sitting outboard of the big ring.
Is this ok? I guess the only support for the outboard guard will be the chainring bolts since there is no spider arm to rest on.

Also, where do you get the proper long chainring bolts or does anyone know the correct length?

Another concern is that the clearance from the chainring to chainstay is really tight. I have a 109.5 Ultegra BB. Should I go wider on the BB? To be honest, right now it doesn't look like a guard would clear the inner ring area. Maybe a 3rd eye instead?
Thanks guys
re: Single ring conversionflyweight
Feb 27, 2003 1:43 PM
A typical double guard set-up uses the ring on the outer spot with a guard inside and another spaced outside. You can get longer bolts and spacers from Cyclocrossworld.com or have your shop order them from QBP. You may or may need a longer BB spindle, that all depends on your frame. Make sure it's not too close because it can strike the stays when the frame flexes during hard efforts such as sprinting up hills.
re: Single ring conversionjhr
Feb 27, 2003 1:50 PM
Parts and/or kits are available at cyclocrossworld.com. Their site notes that some bikes may require triple bottom brackets (118.5). I think most people run the guards and ring as you described (chainring in outer/big ring slot). Gullickson runs an outerguard with a 3rd eye (I'm sure others do too). I have used a 3rd eye on my double (all bikes, road and cross) and can't say enough good things about them. They are great (best 50grams of chainstay/bb insurance you can buy)!

jhr
3rd eyecxer
Feb 27, 2003 2:35 PM
The only downside is I saw someone that got their chain jammed under the 3rd eye and couldn't pull it back on the ring. Maybe it flexed or was mis-adjusted?

Guard+big ring+3rd eye sounds pretty easy- won't have to change the BB.
I'll try QBP- cyclocrossworld is expensive.
3rd eyefeathers mcgraw
Feb 27, 2003 8:16 PM
Look at the ngear jump stop before you get the third eye. More substantial, more adjustability.
That Was Me...triangleforge
Feb 28, 2003 12:55 PM
I had a problem with my 3rd Eye -- in the last lap of the last race of 2002. I crashed and somehow the chain got yanked beneath the plastic 3rd eye. It took me about a minute to get the chain back on -- which was no fun considering the guy who was two points behind me in the series (and bumped me from 10th to 11th in the final tally) was about 40 seconds behind me when I went down and passed me for good as I stood there tugging at the chain. I had it set up as directed -- next to the chain with very little clearance to keep the chain on the chainring -- but I've heard some say they've had good luck using it as a "catcher" -- the unit doesn't keep the chain on the ring, but keeps it from falling all the way to the BB shell. If you're running a double, you might then be able to shift it back on, but if you're single, I don't see any real advantage, as your chain's still off and you need to get it back on by hand. Might make it easier to do it while you're coasting, I guess.

Mine really was a freak occurance, but it did prompt me to go to a double-guard set up when I opted this year for a single ring set up. If I were to use a chain minder, I'd look closely at the Jump Stop unit, which looks a lot stouter than the 3rd Eye.

As for the double guard set up, I don't have a whole lot of clearance off the chainstay (MAYBE 2mm, probably a little less) with splined Shimano 105 double cranks, a triple BB, and a 2mm spacer on the "fixed cup" side of the BB. It's worked without a hitch despite the close tolerance, but if I get some free time, I'll probably file or grind a radius on the edge of the inner guard ring where it comes close to the chainstay, just to get a little more air between the two.

Cheers!
I'd recommend this setup...1x1 Speed Craig
Feb 28, 2003 2:26 AM
Check out my 1x8 MTB. The drivetrain works great, and I haven't had any problems with the chain derailing. I haven't used a 3rd eye, but I'd highly recommend the N-Gear Jump Stop.

Craig
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