Shimano 9 speed 12/34 upgrade to 12/36 opinions

[gmcampy]

The Fargo has Shimano 9 speed 12/34 in place with Deora level RD. Harris says a Shimano HG-61 12-36t can be used if teh B tension screw is lengthened. Any one have any success with the idea, LBS is not sure if this will work an I hat to spend $$ for a "maybe" solution.

Thangs Glenn

[eddief]

you will have no problem. Sounds like a fairly typical LBS.

[gmcampy]

you will have no problem. Sounds like a fairly typical LBS.

Not sure of the RD model, but I will post later after I pick the bike back up. LBS "better" than most but they are concerned it will not shift smoothly.....its a gravel bike with bar end shifters, smooth shifting is a bit of an oxymoron, LOL

[Ti Designs]

The longer screw really isn't rocket science, nor should it cost much to tell if it's going to work. The answer to that question depends a lot on the dropout of the bike, otherwise I would just tell you how to make it work. The answer is simply to rotate the derailleur back from it's upper pulley and see how far back it needs to move in order to give you a half link clearance between the upper pulley and the largest cog.

I'm including a few pics of my own angry - er, I mean cross bike. This is a set-up I've used many times, looking at all of the details of all of the parts being used. The b-tension screw is what you're really interested in, note that I've run an allen head 4mm screw in backwards. The larger head of the screw means I can run it out well over 1cm without the screw head getting past it's stop on the dropout tab. In this set-up, using a 7703 derailleur, I've swapped the large upper pulley for a much smaller XTR upper pulley, which allows clearance for a 34T large cog.

[biker.caliente]

@Ti Designs:

Very ingenious in using a smaller upper pulley and an M4 screw with the larger allen head for B-screw. I had no luck with inserting the B-screw backward, even with a longer one. The mushroom head of the screw kept sliding off the dropout tab. I think I will give this a try.

Also, do you know many teeth is in the XTR wheel pulley that you use? Do they come any smaller than 10t?

Cheers,

[Ti Designs]

When you start pushing the limits you exit the simple "just use this" answer and it gets tricky. The pulleys also need to be the same width, and if you move the cage out too far either the chain will start dropping inside the cage or the inner cage will make it to the spokes. There is a smaller pulley available, but it means using a lathe to make it work to my standards. The other option with a replaceable dropout hanger is to machine a slightly longer one - that assumes you have a milling machine...

[Ken Robb]

Would a smaller chain ring work for you?

[gmcampy]

Would a smaller chain ring work for you? Currently a triple with 24 on the small ring, so Im not too sure Ican get much smaller. Just need a loaded/climbing bail out gear for gravel riding thus the 36.

[Ken Robb]

Currently a triple with 24 on the small ring, so Im not too sure Ican get much smaller. Just need a loaded/climbing bail out gear for gravel riding thus the 36.

Wow! I have a 52-42-30 front with 11-34 cassettte and another with 48-38-28 and 13-29 cassette and I can barely spin the cranks fast enough to maintain enough speed to stay upright. You are the "tempo man"!

[gmcampy]

Wow! I have a 52-42-30 front with 11-34 cassettte and another with 48-38-28 and 13-29 cassette and I can barely spin the cranks fast enough to maintain enough speed to stay upright. You are the "tempo man"! LOL, I only hope to never need the gear but with a 65# bike/gear and 20% grades its inevatable. and it will still only be a grind I bet

[oldpotatoe]

The Fargo has Shimano 9 speed 12/34 in place with Deora level RD. Harris says a Shimano HG-61 12-36t can be used if teh B tension screw is lengthened. Any one have any success with the idea, LBS is not sure if this will work an I hat to spend $$ for a "maybe" solution.

Thangs Glenn

Yep, those longer b limit screws might be $.50..HUGE $$....Most 'LBS will do it for free BUT, I have installed more than a few 9s Deore rders, with 10s shifters, onto 11-36, w/o mucking with/swapping the b limit screw..no problem..not sure why a 9s 12-36 would be any different.

Just make sure the chain is the proper length..just long enough for big-big..no longer, certainly no shorter. .