Can anyone give me info about the Huret " Rival " racing rear derailleur ? I have it on my Peugeot PGN10. Not sure about the front derailleur, but I think it is the same. I want to put a 32 teeth sprocket on my Helicomatic freewheel to get a better climbing gear, but I am not sure that the deraiilleur can handle it. I am assuming that I would have to get a longer chain. My current setup on this twelve spd. is 13-15-18-21-24-28. I would like to change to 13-15-18-21-24-32. Any advise on doing this with the " Rival " derailleur ?
The Huret Rival had published limits of 30T maximum cog size and 28T maximum chain wrap. Bicycling magazine tested the Rival and found the maximum cog size to be correct, but that the stated maximum chain wrap was slightly conservative and that it could actually handle 30T.
It would appear that you cannot use the desired 32T, but you could go to 30T. Depending on the size of your small chainring, you may also be able to use a smaller version to obtain your desired gearing. A change to 30T should not require an incease in chain length unless it already set up with the absolute minimum chain length. Even then, it would only be a problem if you rode in the large/large combination, which is not recommended due to the extreme chain angle. If you can push the bottom of the cage forward by inch with the chain on the large/large combination, then there should be no problem.
However, always the test changes to gearing with the bicycle in a stand or the wheel supported off the ground. Use light hand pressure to turn the cranks slowly and check all the gears, If there's a problem, the derailleur will put up a fuss and you can back off before you break something. If you test it on the road, while riding, the load will probably be too heavy and youyr response to slow to prevent breaking something in the event of an incorrect set-up.
BTW, Bicycling judged the shifting performance of this derailleur to be "excellent".
Thanks for the info - the cranks on my PGN10 are Sugino 52-42 with 144BCD. I don't think I can go to a lower inner chainring, but perhaps I'm mistaken about that. Several people have suggested changing to a triple setup, but I don't really want to mess with triples. I want to keep the basic integrity of the bike as it is - just get a little better climbing gear for my middle aged legs. A 30 tooth cog should do it unless I can change that inner chainwheel. Is it a possibility ?