Road Cycling - Ah Yes, another Newbie in need of advice.

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conductor15
04-04-04, 10:58 AM
Hi all, not only am I a newbie to the Forum, but also a newbie to the world of road cycling. I got tired of riding my mountain bike on the roads when I couldn't get out to any good single track and so I took the plunge and purchased an entry level road bike. I live near Edmonton, Alberta, Canada, and the snow has just left and I've had the new ride out three times. I purchased a GT ZR 4.0 with upgrades to Shimano 105 front and rear derailleurs. I love the ride, extremely smooth and the shifting is incredible, even compared to my XTR equipment MB. The question I have is I want to upgrade my Cranks and bottom bracket as well.

I need some help. The bottom Bracket is listed as a VP-BC73. According to the VP web site the BB is 68mm x 110.5mm with square tapered ends. The crankset is a Tru Vativ Touro 52/42/30. I would like to upgrade to at least a Shimano 105 or equivalent. What make and model of BB and cranks go together and would work for my set up? It is a triple 24 speed with a 105 rear derailleur and a 105 front derailleur. One other thing I noticed, on the VP web site, this BB is listed as a MB BB, not a road bike. Is it really a 68mm x 110.5mm. Most road bike BB's seem to be 118mm. I really don't want to send it to my mechanic and lose its use for a few days while he pulls it apart and orders the parts I decide on. Does anybody out there know it the BB is truely a 68mm x 110.5mm?

Advice on BB and Cranksets to upgrade to would be greatly appreciated.

Thanks
Conductor15

demoncyclist
04-04-04, 01:01 PM
A well stocked LBS shouldn't have to order the parts. If you want them to install the new parts, let them figure out what the right parts are. That's what you are paying them for. They probably already know what will work right anyway. If you want older 105, the new cranks may fit on your existing BB anyway. If you want brandy new stuff, you are going to have to switch to an octalink BB and crankset.
conductor15
04-04-04, 01:11 PM
A well stocked LBS shouldn't have to order the parts. If you want them to install the new parts, let them figure out what the right parts are. That's what you are paying them for. They probably already know what will work right anyway. If you want older 105, the new cranks may fit on your existing BB anyway. If you want brandy new stuff, you are going to have to switch to an octalink BB and crankset.
Thanks Demon. Do you know is there anything wrong with the reported BB size, could it be a 68 mm by 110.5mm? I was thinking of buying the parts myself.

Thanks
Conductor15

khuon
04-04-04, 01:28 PM
Thanks Demon. Do you know is there anything wrong with the reported BB size, could it be a 68 mm by 110.5mm? I was thinking of buying the parts myself.

I'm guessing your bike is ca. 2000. At the time, there were few road triples in the Shimano lineup. Also, you have a TruVative crank which is probably an MTB crank with road sized chainrings. In order to get the chainline correct, they probably had to mate a MTB sized BB spindle. Also remember that your setup is square taper. Things change a bit when you start talking about splines. I think that if you're upgrading to a Shimano 105 series splined triple crank (FC-5505) and go with a Shimano BB-5500 in a 118.5mm splined spindle, you should be okay. Of course I would definately recommend taking it to the LBS to make sure that things line up correctly.