# MTB shifter with 50/34 compact crank and road FD........



## Andyman_1970 (May 17, 2004)

*NOTE: *This was posted over on roadbikereviews, but DIRT BOY suggested I post this over here as some of the member are running road FD's with MTB shifter pods.

The situation:

I purchased a Giant TCX frame (with geometry to match my MTB) this spring to build into a flat bar road/cross bike (similar to NINO's "winter bike" that was the inspiration for mine). It's set up with XT FD and RD and shifters with an Ultregra 12-27 cassette (all 9 speed), I have about 300 miles total on the bike. I had previously been running a 48/32 MTB crank and this week installed a compact 50/34 road crank.

My first ride on it was not bad, other than adjust the limit screws I didn't change much about the FD when I switched to the compact road crank. I did notice the tendency to throw the chain off the big ring if I was not careful shifting. So in an effort to alleviate this, I spend well over 3 hours last night trying to adjust the FD to prevent throwing the chain off the big ring.:mad2:

I had researched several threads on here yesterday and used the Part Tool website and their instructions just to make sure I'd covered all my bases. The strange thing is, I can get the FD to shift from the small to large ring on the workstand, but when I ride it I cannot get the FD to shift up to the big ring (without throwing the chain off) even when pulling the cable rather than using the shifter.

After a very exasperated evening I thought I would check on here for any recommendations.

After some research on this today, I've found the following threads that seem related to what I'm dealing with (using MTB shifter on a road crank):

The 16t jump on my crank seems to have exceeded the FD's capacity (12t according to Shimano) and the closer chainline vs. the MTB crank make me think that is also an issue.

http://forums.roadbikereview.com/showthread.php?t=45846&highlight=flat+bar

Sheldon seems to say on this thread that using a MTB shifter with a road FD is doable.

http://forums.roadbikereview.com/showthread.php?t=778&highlight=flat+bar

One poster says he uses XTR shifters and Ultegra triple crank and FD with no problems.

I know also from my research on here the MTB shifters pull a different amount of cable than a STI shifter (MTB shifter pulls more).

Here's my question:

I know from previous threads that MTB shifters have a different cable pull than a road STI shifter. The Shimano R440 shifter and FD combo are supposed to be used with each other. I know in my attempt to use a MTB FD with a compact road crank I am pulling too much cable to get my shifter to index (thus the problem throwing the chain off the big ring). I also know that the R440 FD and XT FD have different chain line requirements (43 for the 440 and 50 for the XT). So I'm wondering if because my crank is now at a road chainline rather than the previous MTB crank chain line if that is ultimately the culprit.

I checked the Shimano site and the R440 FD seems to have the appropriate chainline requirement and teeth capacity to accommodate a road compact crank. So I'm wondering if a R440 FD (or any road FD, Ultegra for instace) will work with my XT shifter pods or do I also need to get the 440 shifters as well&#8230;&#8230;.. If I can get the road FD (be it R440 or other) to work with my XT shifter pods would be preferable to having to get new shifters as well.

Any comments or recommendations are welcomed&#8230;&#8230;&#8230;&#8230;.


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## Ultra Magnus (Jan 13, 2004)

Check the FSA website. The make a 16t jump FD specifically for their compact road cranks. Just a guess. I've never done what your doing, but have thought of that gearing combo for a commuter.

BM


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## smudge (Jan 12, 2004)

If you're throwing the chain to the outside, you should be able to prevent that by adjusting the H limit screw. In doing so, you're more likely to experience problems with trim adjustment. Take your #2 phillips with you on a spin around the block and turn in the limit screw according to your experience. I've often found that things aren't often as they seem in the work stand.

When you have the FD height set properly above the big ring, are you having any problems with chain rub when you drop to the 34t?

Another option would be to get a compact FD and run a gripshift on the left side (for the trim)


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## Andyman_1970 (May 17, 2004)

smudge said:


> If you're throwing the chain to the outside, you should be able to prevent that by adjusting the H limit screw. In doing so, you're more likely to experience problems with trim adjustment. Take your #2 phillips with you on a spin around the block and turn in the limit screw according to your experience. I've often found that things aren't often as they seem in the work stand.
> 
> When you have the FD height set properly above the big ring, are you having any problems with chain rub when you drop to the 34t?
> 
> Another option would be to get a compact FD and run a gripshift on the left side (for the trim)


I spent 3 hours last night adjusting and re-adjusting the H limit screw with no success on the road actually riding the bike. That's the confounding thing about this problem is that I can get it to decently (not perfect mind you) shift while the bike is on the workstand, but once I think I have it adjusted I test ride it and all the FD does is push the chain against the inner face of the big ring and grind.

Funny you mention taking the screw driver with you&#8230;&#8230;&#8230;.I did that very thing as well, making 1/4 turn adjustments until it would shift to the big ring, which when I found that point, would throw the chain over the big ring every other shift.

Needless to say that was a very frustrating 3 hours last night&#8230;&#8230;&#8230;..LOL

In the interim (so I can actually ride) I'm putting on a 3 year old Bontrager Race compact MTB crankset with the little ring removed until I can iron out this shifting problem with the road crank.

I'm wondering if the combination of only having a 12t capability of the FD and the MTB shifter pulling more cable than a STI shifter is making this set up so finicky&#8230;&#8230;&#8230;..if not impossible to adjust.

I'm wondering if a thumb shifter like this:

http://www.bikemannetwork.com/biking/p/LD8764

Would help the problem, or at least get this combination into a position where it can actually be adjusted. I could just set my limit screws (theoretically) and not have to worry about the indexing for the FD&#8230;&#8230;&#8230;&#8230;&#8230;it might also give me some trimming capability. Since they are so cheap I thought about trying that approach before buying a road FD.

Sheldon Brown suggests slightly bending the forward edge of the inner plate of the FD to improve upshifts&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;so that too may be a possibility.


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## nino (Jan 13, 2004)

Andyman_1970 said:


> I spent 3 hours last night adjusting and re-adjusting the H limit screw with no success on the road actually riding the bike. That's the confounding thing about this problem is that I can get it to decently (not perfect mind you) shift while the bike is on the workstand, but once I think I have it adjusted I test ride it and all the FD does is push the chain against the inner face of the big ring and grind.
> 
> Funny you mention taking the screw driver with you&#8230;&#8230;&#8230;.I did that very thing as well, making 1/4 turn adjustments until it would shift to the big ring, which when I found that point, would throw the chain over the big ring every other shift.
> 
> ...


hi,
funny but if i'm reading right you don't mention what parts you are actually using or at least it's so confusing i don't get it...so: which front derailleur? which rear derailleur? which chain? what shifters?what cassette?what BB size?

anyway - i've mixed about all shifting components from MTB to road and vice versa , 9s., 10s...if it's shimano it works! i've not encountered any problems with XT shifter pods and Dura Ace derailleurs (f+r). i never heard about different cable pull between road and MTB and i don't think that's true seeing my shifting works flawless.

just give me the needed info on your parts and i should be able to help or at least locate the probleem ( i hope).


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## Andyman_1970 (May 17, 2004)

nino said:


> hi,
> funny but if i'm reading right you don't mention what parts you are actually using or at least it's so confusing i don't get it...so: which front derailleur? which rear derailleur? which chain? what shifters?what cassette?what BB size?
> 
> anyway - i've mixed about all shifting components from MTB to road and vice versa , 9s., 10s...if it's shimano it works! i've not encountered any problems with XT shifter pods and Dura Ace derailleurs (f+r). i never heard about different cable pull between road and MTB and i don't think that's true seeing my shifting works flawless.
> ...


Hey Nino,

My apologies for the lack of info.

Current setup is: XT FD and RD, with CN-7701 chain, Ultegra 12-27 cassette and FSA Energy compact road crank (50/34t).

Before I installed the FSA crank, I had a Race Face 104 BCD 48/32t crank (Prodigy forged, MTB crank) and had no shifting issues.

**EDIT** I think in my OP the confusion may have come from parts I proposed to install to fix the problem I outlined - I proposed using a road FD with the compact road crank I have installed. Again, my apologies for the confusion and if I was not clear. 
Thanks for your help.


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## nino (Jan 13, 2004)

*hmm...*



Andyman_1970 said:


> Hey Nino,
> 
> My apologies for the lack of info.
> 
> ...


what BB lenght? with 2x9 you should use a 108mm axle lenght. that's the typical roadie lenght which is about 5mm shorter than MTB (typically 113 on HTs, 118 on FS).

but i'd say it must be the rings or FD. you should try a road derailleur in the front. biggest MTB rings go up to 48t. seems unlikely to me that it shouldn't work on a 50t but you never know.

does the problem happen regardless of the position of the chain on the cassette? i mean does it happen if you are in the lowest or highest gear in the back as well?


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## Andyman_1970 (May 17, 2004)

68x108 is the BB


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## nino (Jan 13, 2004)

*get a roadie FD!*



Andyman_1970 said:


> 68x108 is the BB


then i'd say it's the derailleur. get a roadie derailleur! NO compact derailleur!!! these don't work any better than the regular ones. in fact, they are worse!


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## Andyman_1970 (May 17, 2004)

nino said:


> but i'd say it must be the rings or FD. you should try a road derailleur in the front. biggest MTB rings go up to 48t. seems unlikely to me that it shouldn't work on a 50t but you never know.


I was thinking the same thing, 48t is not that much bigger than 50t.

The Shimano site says the XT FD is "good" for only a 12t jump, so that made me question the FD. However, with the Race Face FD, it was a 16t jump just like the FSA crank, and the RF crank had no issues.



nino said:


> does the problem happen regardless of the position of the chain on the cassette? i mean does it happen if you are in the lowest or highest gear in the back as well?


The problem is independent of chain position on the cassette.


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## Andyman_1970 (May 17, 2004)

nino said:


> then i'd say it's the derailleur. get a roadie derailleur! NO compact derailleur!!! these don't work any better than the regular ones. in fact, they are worse!


Thanks for the advice I'll order a roadie FD today................

Thanks Nino...........:thumbsup:


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## FooFighter (Jun 3, 2006)

*YES! Road FD*

They are made to make the jump from 39 to 50+ - and make sure you ordered a DOUBLE FD, not a triple....

And get the ruler out and measure your chainline just to be sure.


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## Nigel (Jan 13, 2004)

Generally, the rule with this situation is that you cant go past a 12 tooth jump.


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## Andyman_1970 (May 17, 2004)

Nigel said:


> Generally, the rule with this situation is that you cant go past a 12 tooth jump.


I thought the same thing but with the 48/32t Race Face crank I was previously running I had no problems adjusting the FD to operate properly with the Race Face crank. I did notice that on the FSA road crank the outer chain ring (and inner one) are futher inboard (towards the centerline of the bike) than the Race Face crank, indicating their chain line is different.

I wonder if the shorter chainline of the FSA crank was outside of the operating envelope of the XT FD, that in combination with the 16t jump?

I plan on reinstalling the FSA crank tonight and doing one more attempt at adjusting the FD. Should that fail I'm going to visit the LBS and see if they have any 9 speed double FD's in their spare parts box.


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## Spin Cycle (Nov 6, 2004)

*from shimano web page tech tips*

FC-R700 Compact Cranks

Compact specific technology: 
Shimano Compact cranks get an additional set of sub-pins to further regulate the shifting process. This maximizes shifting performance and ensures compatibility with traditional Shimano road racing double front derailleurs despite the massive 16-tooth jump between chainrings.

Compact specific chainrings mean that you don't need to worry about compact specific front derailleurs! Any 10-speed double front derailleur will be compatble with the FC-R700.


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## Andyman_1970 (May 17, 2004)

Spin Cycle said:


> FC-R700 Compact Cranks
> 
> Compact specific technology:
> Shimano Compact cranks get an additional set of sub-pins to further regulate the shifting process. This maximizes shifting performance and ensures compatibility with traditional Shimano road racing double front derailleurs despite the massive 16-tooth jump between chainrings.
> ...


The drivetrain I'm running is 9 speed, I'm not sure the FC-R700 is compatable with a 9 speed system...............plus I would like to avoid buying another crank if I don't have to.

But thanks for the info................


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## Spin Cycle (Nov 6, 2004)

Andyman_1970 said:


> The drivetrain I'm running is 9 speed, I'm not sure the FC-R700 is compatable with a 9 speed system...............plus I would like to avoid buying another crank if I don't have to.
> 
> But thanks for the info................


I wasn't suggesting a new crank just that shimano states that there FD will cover the 16 tooth gap of the compact set up .............


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## Andyman_1970 (May 17, 2004)

Thanks for the info...........

**UPDATE** I found a used XTR M952 FD in my spares box and thought what the heck I'll try it.

I've not been able to fine tune the adjustment yet, but the initial ride on it (in the driveway) looks very promising............


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## Andyman_1970 (May 17, 2004)

*Sucess!!!!!!!!*

The XTR M952 top swing, top pull (the cables on the Giant TCX CX bike are routed on the top tube) worked perfectly. It was a bit finiky to adjust, it seemed like small changes in cable tension had a huge effect.

Thanks for all your responses, suggestions and help in this matter..........

Andy


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