gitaneusa.com :: View topic - Replacement Derailleur options for 5 gear freewheels?

lanteca

I have an early 1970's Interclub. I would like to know if the modern derailleurs (that mostly seem to be rated for 9-10speeds) will work on a 5 speed freewheel - and that are decent quality ( not the Shimano Tourney line) I have a Pro-Compe freewheel, largest cog has 34 teeth. Chain wrap capacity is 38, & with a Sakae 3 cog crankset. I'm getting a new chain, and the gear teeth are in good shape. Currently there's a 1980's era Suntour derailleur w/ some fairly worn teeth. Have friction Campy shifters on the downtube. Any suggestions as to which nice quality modern derailleurs (as in $40-100 range) that work on these older type bikes? I'm getting a lot of variable input from bike store mechanics... Also, what kind of new chain (many say 8 or more speeds on package) will work? Please share advice/ experiences. Thank you!

vanhelmont

Hi Lanteca,

You are going to need a really long cage derailleur with that freewheel, and a triple. If the Suntour is in good shape, other than the pulleys, what I would do is change the pulleys. You probably won't gain anything performance-wise by changing it, unless you want indexing or something.

I replaced a Nuovo Record front derailleur with a low-end '80s Suntour alpha-3000, and the bike shifted noticeably better (I didn't expect any difference, but wanted the NR elsewhere).

If you really want or need to change, a Shimano LX will handle the 34t cog, and wraps 45 teeth of chain, which would be the total front and back difference.

Somebody correct me if I'm wrong, but I think the links on an 8-speed chain are the same width as on a 5/6-speed, but the pins don't stick out on the side so that they can handle the closer spacing of 7 or 8 speeds. You can use an 8-speed chain. I wouldn't use a 9 or 10 speed chain on a 5-speed freewheel. I just use whatever 6-speed chain the bike shop has, I think the current one I've got is Giant and seems to work fine.

verktyg

Chains designed for 9 & 10 speed cassettes may be too narrow to work well on older 5 speed sprockets.

SRAM (formerly Sedis/Sachs) makes very good chains. They made 3 models that were designed to work with 5, 6, 7, and 8 speed sprockets.

The PC-48 chain was their least expensive and you can still find them for ~$10. The PC-58 chain had nickel plated side plates and was more expensive ~$20 and the PC-68 was lighter, full nickel plated and even more expensive.

Here's a link that shows the PC-48:

http://wheelworld.com/itemdetails.cfm?ID=4059

The PC-48 was recently replaced by the PC-850 model chain with different side plates for easier shifting.

This is the PC-850 chain:

http://wheelworld.com/itemdetails.cfm?ID=5716

The PC-870 has replaced the PC-58 chain. Here's some info on those chains:

http://harriscyclery.net/itemdetails.cfm?ID=2581

No recommendations for or against above vendors, just good pictures on their websites.

I've used SRAM PC-48, PC-58, PC-850 & PC-870 chains and have been happy with all of them. They shift everything I've put them on very well.

If the parallelogram and cage is still tight on your old Suntour derailleur you could replace the jockey wheels. They're pretty cheap. You aren't going to find a much better long arm derailleur for friction shifting than the old Suntours.

Most derailleurs made after the late 80s were designed for index shifting on wider freewheels/cassettes. They will work fine with friction shifters except the shifter cable barrel that wraps the cable is usually too small in diameter to work well with newer index derailleurs. When you try to shift to the largest rear sprocket the shift lever can be pulled all the way back to where it's parallel with the down tube.

Huret Duopar rear derailleurs show up on eBay occasionally. A nice one can run as much as $100 used.

http://velobase.com/ViewSingleComponent.aspx?ID=42FE7685-2CF0-4168-9D48-082F8D20D4A0&Enum=108&AbsPos=8

http://velobase.com/ViewSingleComponent.aspx?ID=A4A8610A-62A4-4069-BAC3-D15A860A8D97&Enum=108&AbsPos=9

I have a Duopar on my touring bike. It handles a 13-32 6 speed freewheel with 50-46-30 chainrings and never skips a beat even under load. Suntour and Shimano had teams that tried to get around Huret's patent on their Duopar.

Chas.

lanteca

Ok - this is helpful. The chain info is great. I did find my SunTour Vx-GT on the VeloBase.com site. I'm not sure how to replace the jockey wheels however. From what the shop mechanics could tell, there is a tight spring inside the cylinder which the allen bolt holds the front jockey wheel to, and it would be very labor intensive to get that spring back in there. Then, there's the issue of obtaining the correct replacement jockey wheels... I'm including front & back photos of mine. The date stamp is WI, (Sept. 1980) The photos on VeloBase are good too. (http://velobase.com/ViewSingleComponent.aspx?ID=FC9AB947-7DA8-4836-8A27-4E2648EFFB19&Enum=108&AbsPos=241)

Thanks to all for your help.

verktyg

Does your old derailleur shift OK? Over the years there have been many derailleurs that used round jockey wheels. Unless there are some broken teeth if it still shifts well, there's probably no need to replace the upper wheel.

If you want a derailleur that will swap with your old one, Suntour Cyclone GT derailleurs show up on eBay all of the time. They work about the same as the Vx-GT.

http://cgi.ebay.com/Suntour-Cyclone-GT-R-Derailleur-Late-70s-Early-80s_W0QQitemZ270303511447QQcmdZViewItemQQptZCycling_Parts_Accessories?hash=item270303511447&_trksid=p3286.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318
http://cgi.ebay.com/NOS-SUNTOUR-CYCLONE-M-II-FRONT-AND-REAR-DERAILLEURS-NEW_W0QQitemZ330287251207QQcmdZViewItemQQptZCycling_Parts_Accessories?hash=item330287251207&_trksid=p3286.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318#ebayphotohosting

Chas.

Paul Wiseman

If you do decide to replace the derailleur, try to pick up an older model. Like Chas has said, the Suntour models are truely Supurbe! (ha, ha, ha...... Embarassed

ok, so it was a lot funnier after 3 glasses of a lovely Coonawarra shiraz - syrah for the francophiles among us).

Some of the modern derailleurs have a narrower space between the plates that hold the jockey wheels to go with the narrower chains. You dont want a chunky 8 speed chain constantly grinding away at the 10 speed derailleur.

Cheers.

verktyg