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Derbi Rabasa 1970

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Derbi/53 cm/1970?


Recromed fork after a crash in the city. It had to be reenforced/Stock


Stock/Cheap one


Olimpo front/Olimpo


It's my first build. it was abandoned in the garage at home. Had been sitting there ever since I remember and when the guy who owned the parking lot left, he gave it to me for free. I need as many information as you guys can give me because I'm quite new in this. I'd like to know more about the bike. I wonder if the Crankset will brake with the whole going forward/backwards all the time. Is it possible to convert these oldies into a square Crankset? Should I do it or leave it stock? What do you think of the Gearing? I've read somewhere that it would be better to have an unpair relation like 52x17, should I do it?

Thanks again

People who friended this bike Bella butter, CONDENADO

Hi friend, by the looks of

Hi friend,

by the looks of it you have a cottered crankset and it will have a cup & cone bottom bracket. Cup & cone bottom brackets need to be overhauled annually by replacing the bearings and regreasing them, more or less depending how many miles you put on it and riding conditions, such as rain. Taking off the cranks & installing them to do this is going to be a pain because to install the crankarms you have to drive a small pin into a hole.

If you wish to do this then that is fine. From a maintenance stand point you'd be better off to replace the bottom bracket with a sealed square taper bottom bracket, as they never need maintenance. The new bottom bracket will have to have the same spindle length as the old spindle so you should take the old spindle with you to a shop, or just have the shop install the bottom bracket if you do not have the tools.

Of course if you do this you will need a crankset that will fit onto the bottom bracket. A cotterless crankset will be lighter & you will be able to change chain ring sizes. You could buy new or just buy used via Ebay or Craigslist, of course it has to be compatable with a square taper bottom bracket.

Cycling guru Sheldon Brown says "If you want to get the maximum life from your chain & sprockets, select even numbered sizes when available" You should choose a gearing that is comfortable for you and appropriate for where you ride, this is different for everybody.

I hope this helps, Billy

Wow Billy, thanks a lot,

Wow Billy, thanks a lot, this has been a lot of help!
I hope you enjoyed the bike, and if not, please, tell me so too, I'd like to know different opinions. the web page you sent me it's amazing! that'll help too!
Derbi Rabasa is a Catalan brend that use to produce bikes and motorcycles, they still produce motorcycles but I don't believe they are into bikes anymore...

Take care and thanks again!

Hi friend, sounds like you

Hi friend,
sounds like you are having fun with your build, and you have a frame that you don't see everyday. The only thing I would change is replace the quick release on the seat post to a binder bolt, or a nut & bolt. As the quick release makes it very easy to steal your seat & seat post. I'd adjust the saddle so it is level too, but if it is comforatable the way it is for you then leave it. Finally, lining up the logos on the side of the tires with the valve stem shows attention to detail.

The threading for the bottom bracket, whether it is French, English, or Italian, will dictate the type of threading of the bottom bracket you install, if you choose to do so. Again, if you have a bike shop install the bottom bracket they can determine this.

With the threaded headsets I like to cut a piece of mountain bike inner tube and stretch it over the bottom cup of the headset. The reason for this is the bottom cup can pick up dirt from the tire & can transfer it to the grease & bearings. When you overhaul threaded headsets the top headset is usually clean & the bottom headset is dirty, because the bottom cup is the only one exposed to dirt. The only thing is you have to take the fork off to be able to get the piece of inner tube on, but it works great.


"The only thing I would

"The only thing I would change is replace the quick release on the seat post to a binder bolt, or a nut & bolt."
Well, I find binder bolts cleaner to look at, but I actually got a quick release because what I usually do is untie the seat post and get it lock right next to the bike with a chain that holds everything together (wheels and frame and seat post) and then the whole thing using a U lock.
Thanks again for the advise on the Threaded headsets!

Another question. My Chain ring might be slighly bend...I realise the bike makes a constant sound due to it. Will it cause me any problem on a long term basis? Because I tried my best in realinging it, but seems like I did not get it completely. How should I do it? thanks!

Guillem (Which actually is the Catalan name for William)

Hi Guillem, you could try

Hi Guillem,

you could try using a adjustable wrench to bend the chain ring. If you are trying to get it precise then put a nylon zip tie around the seat tube to extend out to the chain ring & that would give you a truing guide, like truing a wheel. If your crank isn't one piece then you should trying tightening the chain ring bolts too.

The issue with the noise may have to do with the chain line not being completely straight or a loose bottom bracket. You can check this by grabbing the cranks and rocking them back the forth to see if there is any play in the bottom bracket. I'd do this first, then tighten the chain ring bolts, and then align the chain ring. If the noise doesn't go away then it could be the chain line.


thanks, I'll try all that,

thanks, I'll try all that, I'll see what it comes with. Thanks again!

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