Elvish Legion

Would it be easier/better to let a bike shop convert a bike from a triple crank to a double? It will cost me 100 for them to do it or 80 for me to buy the part and do it my self.

Elvish

sydney

If you have to ask,the answer should be obvious.They may try and sell you more stuff than you really have to have.

Elvish Legion

I was asking because I have never done it before and I am unsure of how tough it would be. I think I may just end up having them do it and feel better knowing its done right.

Elvish

sydney

Unfortunately there is no guarantee that will always be the case.

capwater

The part? More than just cranks are needed. You'll need a new bottom bracket and while not a must have a new short cage rear derailler. They are going to do all this for $100? Even 105 level cranks are close to $80 just for parts. A BB will run 35 - 40 bucks, the derailler about 40 also.

Elvish Legion

So 100 is a good deal then?

Elvish

citizen560

What "part" are you referring to?

It depends on what you're getting for that money. They may just remove the smallest chain ring and then adjust the limits on your front derailleur - instant double (although not exactly proper), in which case $100 would seem to be a huge ripoff. What exactly are you getting for $100?

Why do you need the double?

kea423

Parts? I converted my triple to a double by removing my "granny" ring. I just make sure to keep my head out my a$$ when shifting so I don't drop the chain. I did it to lose the extra weight of a ring I don't use. Now if you want to go to a double and change your ring sizes then you'll need more parts as someone above has pointed out.

-dan

meb

Most people go from triple to double to get a narrower Q factor which will be easier on the knees and place the leg in a more perpendicular line to the pedals which is a more efficient stroke. There are also a few weight wennie motives in saving the weight of the granny.

capwater

Bet you started flying up those hills without the drag of all that extra weight! C'mon, we all know you did it because a double looks cooler than a triple........ (fyi, I did it too on my first real bike. Problem is the long cage rear der is a dead giveaway!)

capwater

Tell ya what mate, go back to the shop and ask them exactly what they are going to do for $100 complete with a parts list. Don't accept the "$100 triple to double conversion special" line as sufficient. As I previously posted, you're not going to get a proper conversion for that price unless they are talking about some used parts they have lying around. Also, what level of components are we discussing here? I just built a 105 bike snagging parts as cheap as I could off eBay and catalog retailers (cranks $60, rear derailler $30 & BB $30). A shop would be hard pressed to meet those prices just for the materials let alone a lobot charge. More info needed!

yakes_md

Is this question the same as the one that you posted on the 'Road Cycling' Forum?

https://www.bikeforums.net/road-cycling/118051-crank.html

If so, why did you post it in two places and why did you present the question differently each time?

capwater

All this discussion for a Bianchi Brava with a 8 speed Sora? If you want a bling factor a double on that bike ain't gonna cut it. It isn't even worth taking off the granny......

Just ride it as is.

DogBoy

I disagree with the "if you have to ask" philosophy. If you don't know something you have to ask (or read) about how to do it. You can't know it without asking, so hey, if you want to learn how to wrench your own bike, and can see changing bottom brackets & cranks again in the future then do it yourself. If you prefer to let someone else mess with it, pay the shop.

As others have said, you need to know what is included in the $100. The work involved is (assuming you don't change the rear derailleur):

Remove pedals, Remove current cranks, remove bottom bracket, install new bottom bracket, install new cranks, install pedals, adjust derailleur limit screws, adjust derailleur cable tension.

If you are also changing the rear derailleur: Break the chain, remove derailleur, Install new derailleur, thread chain, reconnect the chain, adjust limit screws, adjust tension, adjust B-angle screw. (assuming your derailleur hanger is not damaged)

This should take an experienced wrench about 30 min (45-60 with rear), so a "fair" labor charge is somewhere around $30 - $40 ($60-$80). These may actually be a bit high. A full build at my local LBS only costs $100, but I'm not sure if that is only if you buy the frame/components through the shop.

If you do it yourself, you will need the proper tools. If you don't have them already, it will be comparible in cost for you to do it yourself vs having the shop do it. For example, you will need the following tools:

Bottom bracket tool (of the type to match the bottom bracket currently on the bike & the one you are installing. They may be different). ~$15 ($30 if you need 2 types)

Ratchet or crescent wrench to utilize the BB tool (Assume you have one)

Pedal wrench: ~$10-$15

8mm crank-bolt hex wrench. (you need a longer handle to get the torque right). ~$5

Grease (for the threads of the pedal & BB (depending on the type, you need anti-seize compound for a ti BB). Item on hand or you need to buy a tub. ~$5-$10???

Screwdriver (to set limit screws). Item on hand

5mm hex wrench (to adjust the derailleur cable at the front derailleur) ~$1-$2

Good maintenence manual (Zinn or similar) ~$15

Maybe (probably) a torque wrench: ~$50 ??? Just a guess.

So the decision should not be based on cost, since they will be similar. It should be "do you want to do it yourself to learn more about my bike?" or "do I just want it done and I'll probably never do this again." If the former, by all means do it yourself. If the latter, have the shop do it.

sydney

The Zinn reference is the short story. www.paktool.com repair section also has the whole drill.

juicemouse

As if his bike isn't "worth it" or something? Please...

It's his bike. He should do whatever the hell he wants to with it! I don't like the immediate assumption you made that he's doing this to impress others.

capwater

If it ain't about bling why not do the cheapest "triple to double" conversion out there .... just don't shift into the granny chainring?

He came asking opinions, we have provided them. If he was hellbent on replacing parts, he would have done it already. Still don't think the $100 covers anywhere near everything for the conversion.

Cheers!

sydney

Not shifting to the granny is not the same as having a double with a 39 if his triple is one on the more traditional types witrh a 42 middle.and the chainline will blow too. The cheap way to do it 'about right' is to just ditch the granny and use a shorter BB,along with a generic 39 ring to relace the middle.