Help with technical terms please

[Simond S]

I am getting my new bike this week, a Moda Stretto. It is coming with a 53/39 chainset.

http://www.eurobike.uk.com/details.aspx?p=322

I currently have the same bike that the shop loaned me while mine was being biult (3 months!) and it is fittted with a compact chainset. 50/34

As I am getting on well with the bike i was hoping to have it built with a compact, but Moda won't have any until the new year.

I am looking at a few on eBay and they appear to have "Mega Exo / GXP fitting (not BB30)" or "BB30"

what does this mean please, and would anyone know what size crank would be supplied with the bike? I have bought the 56 frame.

Many thanks

[ewenm]

Sounds like two different types of bottom bracket. You'll need to know which type of bottom bracket your bike comes with.

Edit: See this: http://www.thehubsa.co.za/forum/topic/86644-bb30me...

[Simond S]

Thank you,

The one I borrowed had the GXB, definately didnt look anything like to push fit in the photo.

Are they fairly easy to swap over? I want to try the full size but conscious that I may need to change it myself to save the shame of admitting I cant cycle up hills!

[shalmaneser]

Simond S said:

Thank you,

The one I borrowed had the GXB, definately didnt look anything like to push fit in the photo.

Are they fairly easy to swap over? I want to try the full size but conscious that I may need to change it myself to save the shame of admitting I cant cycle up hills!

It's very easy to change the cranks from compact to standard, you don't need to worry about changing the BB.

[anonymous-user]

Terminology: the bottom bracket is the thing that screws into the frame, left and right side, and acts as the interface between the frame and the crankset (crankset = pedal arms, front chainrings and the axle between them. The bottom bracket has a hole, or tunnel for that axle).

Bottom brackets come in a variety of standards. You have to have a crankset that matches the type of your BB - a BB30 crankset won't go into a GXP bottom bracket.

If you have a GXP BB, get a crankset that is GXP compatible. If in doubt , ask the bike store which you have.

When switching from 53/39 to 50/34 there are two things to watch out for (apart from BB compatibility). First, you will need to lower the front mech - the thing that shifts the chain from large to small ring. Secondly, you will need to shorten the chain - otherwise it will drag on your chainstay. Neither of these jobs are difficult if you know what you're doing, but the second has high potential for fk uppery (getting the chain too short). Your bike store might be the best place to have that done.

[Buffalo]

Just a word re_FSA mega exo BB. I have that on my Kona and it has started to get noisy after only a few rides (notably on sandy material). I did some research on t'internet this morning and there are a lot of reviews that suggest the BB may not last the course. Up to you whether you decide to get one but I have some doubts on mine and the reviews I read didn't put my mind at rest.

[Busa mav]

The length of the cranks is also another dimension that needs to be specced correct.

[Simond S]

Thanks for the help chaps.

I got lucky and won a chainset last night for £82, the LBS guy was actually at my house watching it with me and will swap it over / sort chain if required. If i dont need it he'll hold it for the next person that does!

I did for some reason leave the shop with a new saddlebag full of lezayne tools and a pump, so and extra £70 of goodies for me. Happy Christmas

[Rocksteadyeddie]

Your chainset will usually have the crank length printed on the inside of it. As others have said a doddle to change. 5 mins work with a 5mm allen key. You will have to lower your front mech but IME can often get away with the chain length (do check).