Butthash

Hello all. As some of you may know, About a week ago I got a 1982 Ph8 from the local bike kitchen. The derailleur works fine on the smaller rear gears but as it goes up to the larger 2 or so cogs.
Do I need to replace my derailleur? if so, whst should I get if I'm on the cheap? Is there an easy fix? Tough fix? I am fairly new to derailleur qnd gear maintenance, as I used to mainly ride a singlespeed. If you need any further info, just lemme know, I am trying to get this baby to run as smoothely and efficiently as possible.

Thanks for your time and consideration+

Lascauxcaveman 

Pics are needed here, but if I am understanding your complaint, you need to either

(1) Adjust the 'B' screw on your rear derailleur to rotate the derailleur back a bit, effectively shortening the chain. (some older RDs don't have a B screw)
(2) move the rear wheel a little further back in the dropouts, effectively shortening the chain
or
(3) get a chain tool and remove a link pair from your chain, literally shortening your chain.

I guess what I'm saying is your chain is too long.

Aubergine 

jimmuller 

You didn't say which Suntour 7 you have. If it is one of the long cage (GT) versions where the guide pulley is inline with the cage pivot, shortening the chain won't help.

Butthash

Alright! thanks for the heads up. Here are some photos.

Vintage_Cyclist

That's not a Suntour Seven; that's a Simplex brand derailleur. The 'S' inside a sun is the Simplex logo. That's why pics are good.

It has a short cage, so you may need to finagle with the dropout positioning to get it to work with the larger cogs. Start with moving it farther back in the dropouts.

Butthash

RAD! thanks for the heads up. Totally good to know. The orher day I was calling them simplex but the brochure said it was Suntour for my model.
I will give that a try. Thankies!

base2 

...Or the large cog on the freewheel is too big. A longer derailleur cage would help with that.

Could it be a combination of one kind of derailleur on another kind of drop out? Isn't the b-screw nub clocked differently between brands? I thought one reason Shimano became dominant is they just used a screw making the clock position of the nub irrelavent. But I may be mistaken.

Since it just came from a bike kitchen, you wouldn't happen to know the component history? Did this combination work before & now it doesn't? Or is this a first run with this combination of stuff?

Dave Mayer

You own a Simplex derailleur set. Not Suntour. The model is likely: SX610.

I've used the same rear derailleur and found it almost impossible to make it work with a cog as large as 28. In order to do so, you need to have to exactly tune the chain length, and fuss for hours with the upper and lower pivot spring tensions. There is no B-tension adjustment.

Note that this derailleur is removed via a bolt from the back of the hanger. The front 5mm hex bolt is only used for adjusting the spring tension. If you try to remove this derailleur from the front, then you'll bust the spring, as happened innumerable times with these derailleurs.

My recommendation - as much as I grew up using Simplex, I would jettison this turkey derailleur, and install a real Suntour unit like a mid-cage VX. Or better, a workmanlike Shimano Deore unit from the 90s. Of course, you're chain is pooched, and should have been replaced in 1984 and every year since then. Refresh the shifter cables and all of the brake and shifter cable housings.

BTW: check you derailleur hanger to see if it is labelled: Simplex. If so, report back here; you may be in for a whole bunch of hurt.

Dave Mayer

Another thing: your chain and freewheel are likely ancient French units, such as Maillard or Atom. I used these for years, and they are truly horrible - in terms of shifting quality. A current 7-speed Hyperglide-like freewheel and chain will immensely improve your shifting.

Finally, check the front derailleur cage for something interesting.

Butthash

Can't find the "simplex" label, but I did find a starred "s" and on the top of the deraileur says SX610. (see below photos for referance)



Not sure if I can pull farther back in the drops or not.

Vintage_Cyclist

Some bike companies, like Peugeot, Raleigh and Fuji had their brand name put on parts they contracted for from component companies. The Simplex brand name would normally appear where the derailleur says Peugeot. This bike might have a Simplex-specific derailleur hanger bolt, which would make replacing the derailleur a problem solving exercise.

Lascauxcaveman 

You might; just remove the rear wheel and then remove the little inserts in the dropouts that prevent the axel from going further back. Then try putting the wheel back in, slid all the way back in the dropouts. That *might* be enough to use the big cog without the upper pulley grinding on it. But probably not.

If not, then shift the bike into the big/big combo, see if you have enough spring left in the rear derailleur to survive a 1" shorter chain, and if you do, get a chain tool and remove one link pair.

The advice of getting a new used long cage Suntour or Deore rear derailleur and a new chain is good advice, if you want better shifting and want to use the big cogs. You can try the above as a first step and move onto new parts if it doesn't work out.

The Golden Boy 

Re-read @Dave Mayer's post- if that is a 28 tooth cog- it will be difficult to get that derailleur to work with your bike.

Replace that derailleur, and the front derailleur (the chain has worn through the cage). Get an inexpensive Suntour set and you'll be in business for the next 30 years.

Butthash

Sorry to come at y'all with more questions, but here I go: Derailleurs. I want it to work and I want the price if the parts/repair to be cheap. Is a vintage suntour my only bet or are there more derailleurs I can go for on the cheap? I want the bike to function, but doesn't neccecerily need to be restored back to its OG beautiful Glory.
Thanks again for your time,
Io

lasauge 

If your frame has a standard (Campagnolo-type) derailer hanger then most any derailer will work - Suntour was mentioned specifically because old Suntour derailers are plentiful, cheap, and effective. The same can also be said of Shimano. The bike kitchen you got this bike from will almost certainly have a large bin full of compatible derailers.

The possible difficulty you may encounter is that your frame might have a Simplex -type derailer hanger, which means that the solution is just slightly more involved. You can diagnose which kind of hanger you have, and read about the possible work around solutions if that is the case, by reading this page here and comparing your bike to the pictures:
Derailleur Hangers Demystified

Butthash

Excellent! thank you, I will have to check.

noobinsf 

jimmuller 

You've gotten some pretty good advice. If the catalog listing said it originally came with Suntour then it most certainly would have compatible threads. Ride the bike over to your bike kitchen, see what they have, ideally a Suntour VGT Luxe or Vx-S (both long cage), or VT or Vx (both short cage), which are very good, bulletproof, not usually expensive. If you shift the chain to the BB inside the crank it will take the tension off the chain. Or even better, remove the rear wheel. Then you can remove the RD without even loosening the cables. This will let you check the threads in the hanger with an alternative RD.

It hasn't been said here yet but be aware that Suntour and Campagnolo hangers don't use quite the same threads. The Japanese RD's would have 1mm threads, Campy 26tpi. For the RD hanger a mismatched fit isn't perfect but is acceptable, though it may feel tight. Since it deforms the threads a tiny bit you shouldn't regularly swap back and forth.

Before you do any of this try again to tweak that 610 into working. Those Simplex derailleurs, especially the metal-body ones which don't wear out as quickly as the Delrin ones, can shift quite well. The 610 has a "horizontal" parallelogram which unfortunately places the cage and pulleys closer to the wheel axle. If you find a cheap 410, try it. I have a 410-GT (long cage) on my PFN-10 and it works great. We have another on our Peugeot tandem and it too works great.

jimmuller 

One more comment. I was looking at your pics in the Show Your French Bike thread. (Nice pics, nice bike.) Your have very little clearance between the rear tire and the ST. If that is how you found it then the bike definitely has some history. Either those tires are large for that bike (they look big) or someone put 27" wheels on when it originally had 700c. The wheel could be moved further back in the DO's to give more clearance while riding (not a big deal) but that won't make removing the wheel any easier.

wrk101

Price has more to do with WHERE you buy, rather than the exact model. At the co-op I volunteer at, you could get a nice set of front and rear derailleurs for $10. If you start shopping on eBay, you will pay that much just for postage.

Suntour products from that era are a good value choice, work well, and except for a couple of the highest level models, relatively cheap.

Butthash

Perfect! Thanks all! Now I just wait until broke isn't me, then I make a purchase and go. (Gonna be a while unless the kitchen has what I need, then I can just use points.

scozim 

Great timing - I'm dealing with this right now on my 84 PSV10 also. Exact same scenario. My dad's PSV ran the same derailleur with a 28t in the rear with no problems. I have the rear wheel all the way back in the dropout and barely have enough clearance. From what I remember it may not be possible to adjust the spring tension on these 610's but I find that would be short sighted on Simplex's part. Who knows. I was actually having trouble with the derailleur not rubbing on the 24t cog as well. Moving the wheel back fixed that clearance issue. Seems to me it's more of a spring tension issue.

My 84 PH10 has the same derailleur and a Helicomatic 13-28 6 spd on the rear. That has worked well since new also.

jimmuller 

I don't recall working on a 610 specifically but I have worked on various similar models. It is possible though a bit awkward to adjust the upper spring tension. (The lower spring too, I think, though I don't recall doing it lately.) After you remove the nut holding it to the DO you have to loosen another nut of sorts that sits between the derailleur knuckle and the DO. You probably have to do this by loosening the hex bolt at the outer end. Re-assembling and re-torquing everything almost requires three hands, or maybe four, and some good swear words. And some patience. You have to get everything pretty tight because the spring loading wants to unscrew the critical nuts. If you don't, it may come loose on the road. But it can be done. Look carefully and think deeply when you take it apart. When you re-assemble it think deeply about which way you are preloading the spring.

JohnDThompson 

In my experience, the SX6nn derailleurs outperform the SX4nn derailleurs. My Gitane tandem came with an SX410, and when it wore out I replaced it an SX660 onto which I mounted the long cage from the SX410 to handle the 30T freewheel.



The OP's dropout appears to have a quite thin hanger tab. If a SunTour derailleur is mounted, it may be prudent to use the thin nut SunTour uses behind their claw-mounts to secure the derailleur on the hanger.