Bicycle Mechanics - BB size for veloce triple
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I'm putting a veloce triple crankset on a Bianchi Cross Concept and don't know what spindle length square taper bb to get. Any suggestions?
06-27-07, 07:38 PM
It's an ISO square taper, that's for sure. The length will depend on which generation crank you have. If you give the model number to the tech guys on the Campy Only web site you will certainly get a definitive answer.
06-28-07, 03:19 AM
Record and Chorus have asymetrical BBs for triples that are 111mm. Assuming you have an English BB:
1. Record part number BB02-RE11BC
2. Chorus part number BB03CH11BC
Centaur, Veloce and Mirage come in 2 sizes:111mm - for doubles and 115.5mm - for triples.
Since these are not asymetrical, you'll need the the 115.5
3. Centaur part number BB6-VE5G
4. VELOCE PART NUMBER BB6-VL5G
5. Mirage part number BB6-MI5G
I list them all since they are no longer in production, your local shop may not have Veloce but might just happen to have a Chorus or a Mirage BB.
06-28-07, 04:46 AM
My Bianchi Veloce has a 111 mm BB spindle, and the seat tube is 28.6 mm dia. It came with a Veloce triple, and I've fitted both a 53/39 double and a 50/34 Compact double without having to change the spindle. I think the only time you might need the 115 mm spindle is if your frame has the wider (32 or 35mm dia.) seat tube.
Familiar with the concept of chainline?
06-29-07, 05:25 AM
I'm not certain if you were asking me or the original poster whether or not they were familiar with the concept of chainline. I, of course, can only speak for myself and , yes, I am familiar with chainline.
I suggested the 115.5 spindle length because I believe the bike in question has a 31.4 clamp dia for the FR Der. (in this it is possible I am incorrect, if so, I apologize to the poster for providing incorrect information).
As a side note: In 2006, Campagnolo was still offering seperate double and triple FR Ders. You will need to purchase one of these as well to swap over. The travel on your current double der just may not cut it and you may have difficulty getting up on the big ring.
Be careful not to buy a 2007 Fr Der because they have changed. For 2007 Campagnolo introduced Quick Shift (QS) which was basically a shortened throw on the FR EP lever and a change in the angle of the body of the FR der. The 2007 der with have a QS marked on the face of the der right next to the Veloce logo. It's quite easy to see.
Having never actually TRIED to mix the 2006 lever with the 2007 FR der, I can only assume that Campagnolo is telling the truth when the say they are incompatible.
There is also the issue of the capacity of your RR der. I triple crankset needs to suck up a lot more chain so you need a longer der cage to accommodate that. If you have a med or short cage now, you can buy a long cage (actually, it's the cage and pulleys) and swap it into your existing der body.
Back to chainline. Production frame makers build bikes already knowing what group will hang on them. Things like chainline and braze-on positioning are then factored into the design. Some frames don't always work well when swapped to a triple. You can usually solve any chainline issues that do arise, but it can be an inconvenience and require more than a few trips to your local shop (along with some additional purchases). I suspect the cross frame will be okay but it is something you should keep an eye out for if you just can't seem to get the shifting dialed.
Have you considered a compact crankset? That way you could keep your existing RR der and only have to change the FR der and crankset. You could keep your existing BB as well (and no nasty chainline issues!). Have a look at a gear inch chart and see if a compact can get you where you want to be.
I hope that helps (sorry about the bad news regarding the additional purchases...and possible suggesting the incorrect spindle length. I should have asked for more information.)
I'm not certain if you were asking me or the original poster whether or not they were familiar with the concept of chainline.
Asking Wil, who's post is immediately above mine.
But I could just as easily ask you. Why do you worry about the clamp diameter, yet never mention the desired chainline, when determining spindle length? A dérailleur is easily adjustable; a bottom bracket isn't.
I'd consider the chainline first, then consider the FD if it presents a problem.
06-29-07, 09:24 AM
A larger clamp dia means a larger dia seat tube which resultingly places the der further away from the centerline of the bike (which is the point from which chainline is measured). This moves the arc of the FR der further away from this point as well. That means that the spindle has to place the crankset at a point in space that is the optimal position relative to the travel of the FR der. So...clamp dia matters when considering the performance of the FR der. (NOTE:This is also the method Campagnolo uses in their design specs given to frame factories. These specs ARE DIFFERENT than Shimano. So, using a Shimano clamp and a Campagnolo FR Der can, in some instances, place the der in a position that significantly degrades shifting performance.)
To achieve optimal chainline, the relation of the crankset to the cassette then comes into play. Campy has a 43mm chainline (FSA uses 45 which is why the shifting on FSA cranks in a Campy set up always sucks). Frame factories know this. So when they build a bike that they know will have Campy on it, they adjust the frame build accordingly.
In the aftermarket, when consumers start swapping parts and Frankenbiking (I would like to officially introduce this word as a verb into contemporary lexicology) they encounter shifting wierdness and have to shim BBs, cut up beer cans and make sacrifices to the shifting Gods because what they are doing is running counter to what was engineered in the first place.
When I was a shop manager I approached these kinds of issues in the same way and from the same perspective. After working with frame factories and dealing with these kinds of issues every day I now see them from a different angle.
You question is entirely correct when asked from the position of a consumer or someone in the aftermarket who is having to adapt to the situation as it is given. From that perspective I would probably approach it in the same way. I guess, from my perspective, I approach these kinds of questions knowing how these things were engineered and what considerations were given at the time.
Ultimately, we're both going to arrive at pretty much the same conclusions but we're going to approach it from a slightly different angle. Given a bike, a BB, a couple of wrenches and enough Doritos to choke a horse, we'd both end up encountering the same problem in the end.
Relative to my previous post more important issues remain regarding compatibility of components and the outlay of ducets. One solution sidesteps the chainline issue entirely. I strongly recommend looking at a compact crank. If the desired gear inches required can be thus achieved, I feel this would be the most prudent course of action.
That's about enough BS for anyone. I'm going to bed.
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