[knutso]

Hey all

I am monkeying around with a deore triple, some tiagra shifters, and a bolt on XT front derailleur. I have it running great with the 26-36 that came stock on the triple, but am wondering if yall could save me some headache as I buy some new gearing.

Am I right in thinking I can put a ramped 42t outter ring in the middle postion, with shorter bolts and a 28t on the inside?

1000 thanks

 

[Harold]

I bet you run into chainstay clearance issues.

 

[knutso]

I am gonna be glad if that is the only thing to worry about. I stuck a 44t in the middle to test the clearance and it was good to go. I am tempted to run the 44, but the bolt on FD only clears it by a hair and the jump down to 28 is a big one.

I am wondering if there is some offset or ring thickness factor to the equation that I am missing. Or can I just bolt an outter ring facing forward against the spider, as opposed having its back to it?

 

[frdfandc]

There is an offset to the chainrings. Not sure if flipping it would would work or not.

But an issue that may come up is the FD capacity. It probably on has a 16 tooth jump capacity. So the shift from the 28 to the 44 may not work. Just something to look into.

Sent from my SM-G930V using Tapatalk

 

[LyNx]

You're going to have several issues if you do this, even with a 42t ring.

First, the ring is designed to have the countersink for the bolt heads on the outside, when you put it on the inside the head will stick out, might cause an issue in shifting, might require longer bolts.

Second, the FD is designed to cover the size cogs it does in a certain position, it will not be raised high enough to clear such a big ring in the middle position.

Third, as said, FDs aren't designed for that big a jump between rings, I used to run 24/38 and that was pushing it in terms of what the FD could handle, but I knew that and took great care setting it up and in shifting.

Not quite sure why you'd want such a big ring, a 38t with a full cassette and 10 or 11t small cog should give you loads of top end gearing for roads etc, if that's your thinking.

 

[knutso]

Right on, thanks guys. Yall are making a shiny new XT 40/28 look more and more tempting.

 

[knutso]

Fwiw, FSA makes their pro mountain d-10 chainrings for this purpose, found a 42t that is offset to run as a big ring in the middle position.