nebelppa

Can anyone recommend a vintage Suntour front derailleur for a 50-44-24 crankset? It's biopace.

I have a V-GT RD so hoping to stick to Suntour.

Alternatively, I could put a chainguard in place of the 50t ring and use smaller FD, huh?

Slightspeed

I'm very happy with a Suntour Cyclone II FD on my Super Course. It shifts my Sugino AT 32,40,50 triple very nicely with a Suntour VGT Luxe and a Shimano Megarange 6 speed 34 on the rear. I just bought a 52t chain wheel but haven't tried it yet with this setup. Suntour bar ends keep things moving. I love this set up.

smoothness 

you don't need to stay any particular brand with a FD. just make sure the cage fits well on the oblong side of the chainrings.

The Golden Boy 

With a V-GT rear- that's fancy, it would probably have been paired with a VX FD, stylistically it'll totally match a 1st gen Cyclone. I haven't used a VX- but I have used a 1st gen Cyclone on a triple down to 26, but not 24. I currently have one on a 28 granny triple- and it works great.





I don't know if that 24 is going to cause some problems, not a lot of FDs go that low... you might have to go with an ATB front derailleur- a Mountech or LeTech are about the best there ever have been.

When you go around looking at hobo bikes- you realize you can make pretty much anything work. But choosing components that work together- even if it's just a connection in your head, it's much more coherent as a build- even if it's just coherent to you. I have to have things match my idea, otherwise it bugs the crap out of me.

seypat

The Suntour BL works well.

verktyg 

Not sure of the model but it was a Suntour MTB FD from the early 90's. Handles 50-46-30T x 13-32T without a glitch.

There were a lot on log arm front derailleurs produced during the C&V era. Most of them worked well with granny gear triples, even Huret Alvit FDs.

1/2 step with a granny gear was popular way BITD in France: 50-46-26T with a 13-26T 5sp FW.

nebelppa

Thanks, all! I was doing some more poking around and realized there are really no vintage derailleurs with a capacity over 40t, so I think I'm gonna go compact double for now (replacing the highest chainring with a guard) and looks like I might need to go to different component set (V-GT only has 36t capacity according to specs). Cheers.

The Golden Boy 

I think you'll find bunches of folks who have used a 50-28 triple and a 13-30 or so rear end using Cyclones or similar.

nebelppa

True. I'll see if I can stretch things first. The capacities are very conservative I've read. Thanks!

verktyg 

Huh?

Biopace chainrings can have their own set of issues as far as FDs are concerned. I'm running Shimano Deore derailleurs on the bike below with 48-38-28T Biopace chainrings and a 12-28T cassette. I could easily go to to a larger rear sprocket or chainring but this setup gives me all I need.

I have a triple on one of my Bianchis: 50-40-30T chainrings and a 12-28T cassette. Again, I can go bigger.

40T shouldn't be a big problem for long cage FDs. A bigger issue is the seat tube angle vs. the arc of the derailleur cage.

A bike with a 75° seat tube angle and a derailleur designed to match the radius of a 52T chainring may not reach low enough at the rear of the cage to work with a 30T chainring, especially with the smaller cogs on the rear. See last picture.

Published derailleur capacities are intended as a guideline for a minimum range without complications. The manufactures have no control over chain stay lengths, chain lengths and so on so they go conservative.

By changing the chain length and or position of the hub in the dropouts you can easily exceed the published capacities.

Chas.

devinfan

I’m running a Suntour Mountech on my triple and it handles from 52 down to 28 without complaining.

John E

I use SunTour XC with 48-40-28 or 48-40-24 on my mountain bike. When I use the "vertical ascent" inner ring, I have to upshift slowly and carefully out of it, but everything works fine as long as I do so.

bbayer

Frank Berto's 'Complete Guide to Upgrading Your Bike' (1988) rates touring front derailleurs. The Suntour XC-9000 front derailleur is rated VG on shifting a 52xXxX triple crankset, and was measured to be able to shift to a front chainring smaller than 24 teeth. I have one on a bike with a wide range triple and it works well, matched with a Suntour Le Pree 3 pulley rear derailleur and a 12x32 Suntour freewheel.

nebelppa

thanks all.

fietsbob

I think my Specialized expedition had a high normal FD, ( in the mid 80s ) cable pulled it to low, spring pushed it to high.

top gear, both cables were slack, downtube levers forward 50-44-28 as I recall .





....

jcb3

+1 on the mountech.

3speedslow

Both Montech and the ARX will handle the triples.

AustinFitz

Sounds like the SunTour Le Tech. They were designed for triples, and were high normal. I just picked one up the other day.

The Golden Boy 

Nice!!!

Post that guy in the "derailleur eye candy" thread that's current now!

You don't see those LeTech RDs too often- and I don't think I've ever actually seen a LeTech FD in person.

AustinFitz

Thanks! I definitely will once I get it cleaned up.

Before acquiring these two I had never seen a front, or rear in person. That was part of the reason I went in search of them.

Both seem to have seen very little use, and are very close in manufacture dates, so I think they'll make a nice pair. The front is July of '83 and the rear is August of '83.

My initial impressions of the FD are that it's very similar to the Mountech FD just with a few extra bits to reverse the action. I've never used a high normal FD before, so I'm excited to play with it!

goodwrench84

I’m having issues with replacement front derailleur for my Fuji touring series III. I purchased it recently and found how much it was molested with a few replacement parts. Rear wheel, front & rear derailleur and both front and rear chainring’s and freewheel (FW). The front derailleur (FD) was a 2x. Like stated by previous post, the bottom rear of the FD doesn’t clear chain on the 24 gear when on the lower FW gears. I am not well versed on trial and error with replacement derailleurs when original parts are MIA, but it looks like the Suntours listed from previous posts, XC & XC 9000 are an option worth looking into.

philbob57

Biopace wasn't out before 1983. The V-GT could be 10 years older. I expect V-GTs were mostly paired with Vx and Compe-V FDs. I've used a Vx, Cyclone Gen 1, and Compe-V with a 45/42/28 triple, and I think they'd all work with a 26T small c'wheel (TA Cyclotouriste std) and probably with a 50/45/24 triple with round chainwheels, but the Biopace c'wheels are a question in my mind.

I think I'd go with Shimano ders, or at least a Shimano FD.

ShannonM

I'm running a Suntour AR double on a 45/42/30 half-step triple. I'm not sure I could run a 24T granny without chain drag. With the FD high enough to clear a 52? Not a chance.

If you drop your big ring to a 46 or 48, you'll find a lot more front derailleurs that will work.

The Golden Boy 

Can you post a pic?

goodwrench84

I failed to mention I did install a new front derailleur, Shimano Altus FD-M313-6 as recommended by a tec department from a bicycle online supplier, but it doesn’t quite match up or shift correctly. I am using a friction shifter for the front an index for the rear and have put a few miles on this bike yesterday after finishing her up. I can get all 3 chainrings, just not smooth. Plus, the inner guide hits the number 2 ring if positioned correctly as per outside guide tape. Future intentions of fenders and rack’s and trying some light touring in the future. As per 1984-86 catalog, both original derailleurs were SunTour Mountech, both MIA on my bike as purchased. I am still running the same rear that came with my bike, not sure what model but it is a SunTour. After researching and getting great insight on this thread, finding NOS is probably a good option. Thanks in advance for much welcomed guidance.


RD that came with bike.

Replacement FD

After some updates.

Before