Replacement bolt?

[Jevans92]

I have a Dunlop doubledisc26 Mountain bike. Recently i was cycling down the road when my derailleur fell off suddenly. The derailleur was on a bolt which is screwed to the frame. When i looked there is nothing on the end of the bolt to keep the derailleur on. I am guessing i need a new bolt with a nut or something similar on the end, but i can't find one. The derailleur says 'Power index system' but i can't find any information anywhere which could point me where to buy a new derailleur bolt. In fact, i can't anything at all on who made the derailleur.

I am unsure of where I can go with this now and would really appreciate some help. Someone suggested i just see if a shimano derailleur would be compatible but i need one which has a bolt the same thread size to screw back into the frame again. Possibly one which can go straight onto the wheel bolt?

Sorry if i haven't described my situation very well, but any suggestions/advice would be great, thanks!

[trevgbb]

this is a common problem, and if your RD is a known brand, your LBS (local bike shop) will probably have them in stock, but check the condition of the thread in the bracket or take your bike to them and they will advise you.

[nfmisso]

Pictures would help a great deal.

Cheapest, fastest is to get a new RD. I believe that this one would work:
http://www.amazon.co.uk/Shimano-Tourney-Rear-Derailleur-RDTX31G/dp/B00131P6EK/

based on the pictures here:
http://www.amazon.co.uk/Dunlop-DISC26-Mens-Dual-Suspension/dp/B001HN6QG6

Please note that the bike in the Amazon link is equipped with a rear derailleur that is several generations out of production - possibly as much as ten years.

[Jevans92]

Thanks for the suggestions! I took it to the bike shop and the guy there said the derailleur was indeed outdated and didn't have any suitable bolts for it. Instead i ended up with a new derailleur.

Thanks again for your suggestions!