Disaster with front derailleur grrrr

[johnnyb47]

Hi to all.
I hope your having a better evening than me.
Tonight the big plan was to replace my ageing 34 year simplex front derailleur with a new one. The pivots in it are really showing there age and the whole mechanism is feeling somewhat sloppy.
I was given a brand new Shimano xt derailleur with some shims so it clamp into the narrow tube which is 25mm.
After clamping it in place I wasn't over keen on the way it looked (it looks way to over engineered) and then soon realised the pedal arm was fouling the bolt that clamps the gear shift cable on it.
So off with it and back on with the original simplex.
The Simplex clamp is made of plastic and after 30 odd years of use , it snapped whilst I was tightening it up. :~(.
I was hoping of any suggestions on another one that would be suitable for my bike. The down tube is 25 mm so that would limit my options as to the clamp size and would like something a little more compact than the xt derailleur.
All the very best.
Johnny

 

[Hugh Manatee]

Suntour made superb(e) front mechs. This one http://www.ebay.co.uk/itm/suntour-s...212918?hash=item3aecc195b6:g:3jEAAOSwzIVZdf2j might not be the right size but, keep looking occasionally.

 

[davidphilips]

If you still have the shims then you could look at ebay and buy a derailleur with a different cable clamp and may even get one very cheap.

 

[johnnyb47]

Hi again.
Thanks for the suggestions. I've still got the shims from the xt derailleur. Thinking on a little ,,the down tube is not 25 mm as I first thought. The seat post I recently fitted was 25 mm so the external size is obviously going to be bigger. The Simplex has got 32 stamped on it which may suggest its 32 mm.
The xt derailleur is a 34.9 diameter clamp and fitted perfectly with the shims.

 

[davidphilips]

I may be wrong but a 28.6 front derailleur should fit they are used on a lot of steel framed bikes so it should not be to hard to pick one up, what i have found is that a triple front can be fitted and adjusted up to work on either a double or triple chainset.

Just be sure you buy the correct pull ie top or bottom cable pull some derailleurs can work with any.

 

[johnnyb47]

Thankyou David for helping me out. Tomorrow I will pop down to the local bike shop armed with both derailleurs and see if they can help me out.

 

[johnnyb47]

I've got it all sorted now. I bought a Shimano 105 derailleur with a band of 34.9.mm and used the shims that I already had. Its now working nice and smoothly and will hopefully do me for many years to come.
All the best.
Johnny

 

[johnnyb47]

I've just got back from a ride and the derailleur is suffering from an irritating chain rub on the side plates. I've adjusted it and re adjusted it to no avail. After nearly giving up hope on it, I noticed that the 52 chain ring was very slightly buckled and it was causing the chain to rub up against the derailleur,s side plate . The guide were the chain goes through the plates on the Shimano derailleur are a lot more narrower than the old agricultural simplex, so trying to comspensate for the slight buckle in the chain ring is impossible , so I got a pair of pliers on the side plates and opened them up a fraction and its now working nice and smoothly.

 

[si_c]

I use 105 5800 derailleurs on my old pug, but I also use a 105 chainset. It's well worth upgrading both derailleurs and the chainset imo if you just want to ride and aren't too worried about keeping it vintage.

One nice thing about the 5800 front I noticed was the swing arm was much longer and better shaped than the huret that came stock, which made shifting with the friction system that much nicer.

 

[johnnyb47]

I replaced the rear derailleur a few weeks back with a shimano. Its done a good few miles now and to be working well. I've got a long ride planned for tomorrow so I be able to give them a good test.

 

[si_c]

I replaced the rear derailleur a few weeks back with a shimano. Its done a good few miles now and to be working well. I've got a long ride planned for tomorrow so I be able to give them a good test.

It's also worth considering upgrading your wheels, if you get the rear respaced you should be ok going up to 10speed.