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instead of triple rings, how about this setup?(13 posts)
|instead of triple rings, how about this setup?||rib-eye|
Aug 19, 2001 7:20 AM
|Situation: I ride about 100-150 miles a week "around town", and perhaps 3-4 times a month I ride Colo. mtns. I love riding the steep and high altitude stuff: passes, Mt. Evans, etc. But, for these extreme situations I frequently need the gears a triple provides. Other than that I prefer a double. I want to upgrade my current Ultegra triple or a full Dura-Ace group and thought this might be a reasonable way to do it.
In a nutshell, permanently mount a long cage XTR der. For normal riding I use a typical 12-23 or 12-25 DA cassette. For mtn riding I use a 12-34 XTR cassette. Actually I would probably use two rear wheels and not hassle with swapping cassettes on a single wheel. The 39/34 combo would actually give me a lower granny gear than what a triple typically provides. It seems like this should work just fine mechanically speaking since the long cage XTR will handle either cassette, although it might look a little odd on a road bike.
|re: instead of triple rings, how about this setup?||capnjim01|
Aug 19, 2001 7:34 AM
|Sampson bicycles offers this set up in one of their build kits and several other poster on this board have used similar equipment should work fine good luck|
Aug 19, 2001 8:28 AM
|You can also use a Ultegra or 105 long cage der, but replace the upper 11 tooth pulley with a 10 tooth and it will go up to a 32 in the rear. To use a 34 in the rear you will have to use a 9 speed MTB rear deraileur.|
|club: don't even need a long cage for a 34t||ub|
Aug 19, 2001 12:39 PM
|since you're running a double, you don't need the total chain capacity that you would if you had a 20-plus tooth span from big ring to granny up front. The 34 in back becomes an issue when you are using a granny gear, oftentimes when you're in the granny and the 34 in back, the chain is so loose it lets the rear derailleur cage point rearward, which rotates the upper pulley up and toward the 34 cog. When it's too close, it all but pinches the chain in between the pulley and the cog and causes a rubbing, grinding noise. In these cases (I run weird gearing on my MTBs including some with a 34 in back) if the B tension screw is insufficient to rotate the derailleur enough to provide the clearance, all you need to do is remove a couple of chain links so the cage doesn't let the upper pulley get too close to the 34 cog. I've got bikes with short-cage XTR and short-cage SunTour XC Pro derailleurs set up this way right now, and used to run an old 600 road rear with a 34 this way. The key is to NOT SHIFT INTO THE BIG-BIG with this setup. If you can handle that, everything is groovy. With the double setup you want, you will have no problems whatsoever, even without a super long cage rear derailleur. Don't believe it? Try it with your short cage rear before you buy a new one.|
|Excuse me for breaking in . .||12x23|
Aug 19, 2001 2:53 PM
|I can work an XT 11-32 cassette in with my D/A r. der.? Reason I ask is I was thinking about something like this for the Six Gap century in Dahlonega, Ga next month. I just figured I would have to get a mtb der. to make it work. If this is the case you've solved my problem.|
|I call foul||LC|
Aug 19, 2001 6:44 PM
|You may not intend to do it, but sooner or later you will toast a short cage road deraileur when you accidently get the wrong gear. The other option is to run it too loose, but that works too sloppy and your chain comes off all the time. The other problem is that the 34 actually rubs the upper pulley even with the B tension all the way in; 32 is the max you can push it.
A short cage MTB is about the same thing as a long cage road, but if you have a newer 11 tooth upper pulley on a road der then put in a 10 tooth or all you can use is a max of 29 cassette.
|like I already said||club|
Aug 20, 2001 5:21 AM
|if the B tension screw isn't cutting it, take out a pair of links and the upper cage won't rub the chain against the big cog. I have no problem not shifting into the big/big; if you do, then you need to stick with Shimano's rated specs.|
|club. Couple more questions please . .||12x23|
Aug 20, 2001 4:25 PM
|So if I understand, I can use an XT 11-32 9-sp with my D/A r.der. and 53x39 (double) up front? I would only be using this set-up for one century with a really steep climb and have no problem with a little big-big discipline. And, I can work it out with B tension and chain length so that it shifts well? Thanks.|
|You will have to watch your chain length (nm)||Mike K|
Aug 19, 2001 9:06 AM
|I use a...||Ron B.|
Aug 19, 2001 9:58 AM
|12 x 30 8 speed set up on my road bike with a 53 x 39 front set up. I use an LX derailleur and overall it works really well for hills. The gearing is a little spread out for riding flatter areas.
I so far have encountered no problems with this set up and recomend it as a cheaper alternative to going to a triple set up. I also think the front shifts better than a triple set up, based upon my wifes shifting on her triple.
I'd say go ahead and do it, but depending on your shape you may just want to go with a 11 x 32 set up.
|re: instead of triple rings, how about this setup?||Stickers|
Aug 19, 2001 10:27 AM
|I have an Ultegra triple 9 speed front, and an XTR 9 speed regular derailleur with a 12-34 XTR cassette in the rear. I need to spin on the long uphills, that's why I changed to a triple. Had an 8 speed double with XTR rear derailler and 12-32 cassette, it just wore me out on the climbs. Oh, don't get the rapid rise derailleur.|
|a bunch of great ideas...thanks all....nm||rib-eye|
Aug 19, 2001 3:00 PM
|53-38 / 12-34||Dog|
Aug 19, 2001 6:59 PM
|I have about the same thing on my Bianchi "climbing bike," one I've built specially just for climbing, but could be ridden normally.
I use 38 and 53 chainrings in the front, with a 12-34 XTR cassette and XTR medium cage rear derailleur. It works fine. I use a downtube shifter for the front, but the downtube rear shifter would not hold the XTR rear derailleur spring, so I use the STI.
You can climb a wall with this setup. Useful for those times you bonk but must keep going up 22% slopes.