MTB Front derailleur with 50T big ring.

As long as the FD is for a 48t big ring, give it a try. 😉
If no good, try a FD-R453 for Flat bar bikes with 30/39/50 cranksets. 🙄

I was just considering tonight whether to use a 50 or 48 for LittleJackie's next bike, I have a Sugino XD 160mm 30/38/48 crankset ready for her. If I use the 48 tooth I can use a FD-CO51 front derailleur with MtB shifters. 🙂

gclark8 said:

As long as the FD is for a 48t big ring, give it a try. 😉
If no good, try a FD-R453 for Flat bar bikes with 30/39/50 cranksets. 🙄

Ta for that. That's what I was planning on doing if nobody had reported any experiences.

Let me know if you give the 50T ring a go and how it works out.

n

I sat down tonight to put the 50t on the Sugino spider.

No go! 🙄

The outboard pin on the Shimano Chainring is between the mountig bolts. The pin on Sugino is in line with the mounting bolt in the crank arm.

See pix:

gclark8 said:

I sat down tonight to put the 50t on the Sugino spider.

No go! 🙄

The outboard pin on the Shimano Chainring is between the mountig bolts. The pin on Sugino is in line with the mounting bolt in the crank arm.

See pix:

Does the pin have to be behind the crankarm?

Because if it doesn't, I'd simply consider filing it off, or just leaving it sticking out (not that I am suggesting you do so George!)

n

nerdag said:

Does the pin have to be behind the crankarm?

Because if it doesn't, I'd simply consider filing it off, or just leaving it sticking out (not that I am suggesting you do so George!)

Yes, it stops the chain getting stuck behind the crank arm if it comes off. As it is for a lady, I prefer to leave in all the built in safety features.

We had a talk about it tonight, she is OK with 30/38/48 and a FD-CO51 Front Derailleur on the bike. 😉

nerdag said:

This is one for the alfeng's and gclark8's of the world!

I know that Shimano say that you shouldn't use anything bigger than 48T with their MTB front derailleurs, but has anybody actually tried to go larger (say up to 50T)?

If so does the shifting still work, and is there are degradation in shifting quality?

Intended setup is a Sugino XD Series 26/36/50 with a Deore top pull FD (frame cables are routed from above). If it was bottom pull frame, I'd simply switch to a road FD, but alas, this is not so. I'm not keen on getting the pulley under the FD that some CX racers use either, since that's an additional cost I don't want to incur if it can be avoided.

Any suggestions in the affirmative or otherwise appreciated.

n

NB: the Sugino is originally a big ring of 46, but I'm hoping that I can swap that with the 50T ring on a surplus compact crankset I have here, and then use the 46T steel ring on a fixie!

FWIW. I currently have an 8-speed XT (737?) front derailleur [it's what I had handy] mounted with a 52/39 crankset (see attachment) ...

It works fine FOR ME ... WITH both a set of 105 9-speed/triple-capable STI shifters (3-clicks to shift/trim because the plates of the 8-speed front derailleur cage is a little wider than a 9-speed cage -- it is always better to match the front derailleur to the chain AFTER matching the chain to the cassette) AND equally-well-or-better with the Campagnolo ERGO shifters that are pictured on the bike ...

BTW. Those are older, STEEL 8-speed rings (I figured that since I have them, I might as well use them) which lack the amenities of ramping & pinning ... no problem!

BTW2. I know that a Shimano Ultegra/6503 ROAD front derailleur can handle a 52/36/28 without any difficulty when used with a Campagnolo shifter ... and, the ONLY (AFAIK) sub-standard (IMO) front derailleur that Shimano designed-and-released was the original, early-80s Deore front derailleur (I have one!). My impression is that ALL OTHER Shimano front derailleurs are EQUALLY GOOD as another if they are matched to the chain.

Other than cosmetics, I don't see why George has a problem with the location of the pin. I've certainly mounted the "wrong" Campagnolo chainring on Record cranks ... just locate the pin at ~4 o'clock (if the arm is pointed downward toward 6 o'clock).

So, I would suggest that you CAN successfully mate a 52t chainring with your front derailleur & other chainrings; but, I suppose that it might not work for you if George's concern is your concern, too; OR, if the cycling gods choose not to smile upon you.

Alf,

I have to do it "by the book" as the bike is brand new and being coverted to Flat Bar configuration for the client. Once the conversion is complete, It will go back to the selling dealer for pre delivery inspection before being released to the customer.

I would prefer to use Shimano Cranks and Chainrings, but they don't sell 160mm (30/39/50 or 30/42/52) cranksets in Aust.

I have offered the client a compact double using Shimano 34/50 9 speed rings and Trager 160mm arms, she declined. 🙄

gclark8 said:

Alf,

I have to do it "by the book" as the bike is brand new and being coverted to Flat Bar configuration for the client. Once the conversion is complete, It will go back to the selling dealer for pre delivery inspection before being released to the customer.

I would prefer to use Shimano Cranks and Chainrings, but they don't sell 160mm (30/39/50 or 30/42/52) cranksets in Aust.

I have offered the client a compact double using Shimano 34/50 9 speed rings and Trager 160mm arms, she declined. 🙄

FWIW. Well, if cost is no object, then a 50t Campagnolo mostly-110BCD, "compact" chainring can be modified to fit the Sugino crankset -- apparently, the "hidden" bolt hole is offset ever-so-slightly and would simply need to be elongated for the chainring bolt to fit -- probably, less than one minute's "labor" with a rat tail file.

BTW. I think that the "pin" in question is threaded into the chainring as often as it is simply riveted ... so, it can be removed from the chainring by unthreading OR by "brute force" (i.e., tapping it out from the backside with a nail-set "punch" OR a nail) AND THEN a new hole can be drilled & tapped in the proper location to accept a "pin" whose end is threaded (of course, THAT's more effort than I would bother with for myself).

Shimano definitely has some of the best chainrings ... and, cranks!

Thanks for your help, gents.

n

You need to make sure that you are not exceeding the RD capacity, unless you NEVER accidentally shift big-big or small-small. Don't want to kill the RD.
I don't see that the problem with the anti-jam pin is a big deal, provided that you pay careful attention to the upper limit screw of the FD.
Obviously, don't forget to see whether you need to elevate the FD on the seattube.

nerdag said:

I know that Shimano say that you shouldn't use anything bigger than 48T with their MTB front derailleurs, but has anybody actually tried to go larger (say up to 50T)?

I've done it. I used a barcon friction shifter with it and it shifted OK but not as slick as some other bikes that I've owned.

The biggest issue was the arc of the derailleur cage. Derailleurs that are designed for smaller chainrings have a smaller diameter arc so you have to mount them real high on the seat tube to keep the heel of the cage from dragging on the chainring. The simplest solution is to use a road front derailleur but then you might have to deal with the up-pull vs. down-pull issue.

Retro Grouch said:

..... The simplest solution is to use a road front derailleur but then you might have to deal with the up-pull vs. down-pull issue.

Like I said earlier:

Quoted post said:

......try a FD-R453 for Flat bar road bikes with 30/39/50 cranksets (and MtB Shifters).

However, I just tried the 50t chainring up against the 48t FD-CO51 Front Derailleur. The arc of the FD is ok for the chainring, providing the seat post is fairly steep. (67-71degrees chain stay to seat post angle)

I have an 10sp ultegra front derailleur working perfectly on a top pull mtb frame, i just made a little plate that goes where the screw that holds the cable currently is and then I put a thread through this plate so the cable can be attached to it.

xenith said:

I have an 10sp ultegra front derailleur working perfectly on a top pull mtb frame, i just made a little plate that goes where the screw that holds the cable currently is and then I put a thread through this plate so the cable can be attached to it.

What shifter are you using?

artemidorus said:

What shifter are you using?

im using a sram XO twist shifter (the version with all the trim settings as some xo twisters only have the 3 indexed postions)

xenith said:

im using a sram XO twist shifter (the version with all the trim settings as some xo twisters only have the 3 indexed postions)

Shimano MTB front shifters are said not to work well with Shimano road FDs - it is of interest that the SRAM one does work. Does it work well?

artemidorus said:

Shimano MTB front shifters are said not to work well with Shimano road FDs - it is of interest that the SRAM one does work. Does it work well?

yes it works perfectly, the sram xo twist shifters are the best to use as they have all of the trim positions in them

xenith said:

yes it works perfectly, the sram xo twist shifters are the best to use as they have all of the trim positions in them

I can upload a picture of that adapter i made if it is of interest to you?