kevntri

I need some help....
I have a Specialized Allez sport triple. I want to switch it over to a double.
Specs say square taper 68mm 118.
It is a 9 speed. I would like a 105 or better. I am thinking about Ebay for cost reasons.
I am totally confused on what to look for????
If I get a crank that is not a square taper and need a bottom bracket, What do I buy size wise.
Is it 118?

I may not be asking the right questions, but the LBS was no help

dr1445

check here for the crankset you are interested in.
www.sheldonbrown.com/bbsize.html

operator

You choose your crankset. And then you find out which bb length you need. Not the other way around. This is easy as pie.

mikeybikes

In general, the cranks determines the size of the bottom bracket. Look at the specs for the cranks you buy.

DOS

If you buy shimano 105 or better, the BB you will need will likley not be square taper unless they are quite old. If you buy modern cranks with intergrated spindle, the external cups will come with; no BB decisions to be made.

shelbyfv

Jenson has nice 105 doubles on sale for $20. You would need the correct octalink bottom bracket, 68/???.

operator

It's 109.5 for the doubles.

kevntri

I ordered that crank from Jensons...Thanks. I also got the correct BB.
One more question????
I have Tiagra STI flightdeck. They are for my triple.
Is it OK to just adjust the stops for the double? They have the two place click adjustment on the middle ring?

DOS

They'll work with the double.

kevntri

What about my front derailer? I see designated double and triple on ebay. Can I use my current one?

DOS

Yes. You can use a triple fd with double cranks without problem. Thgere are two types because a double FD will not work well with triple cranks; the cage isn't big enough to deal with the extra chain ring. However, the larger cage of a triple FD does not inhibit shifting with a double crankset.

Panthers007

Yes. You just set the set-screws to only allow the double-crank. A triple FD works for a double - but a double FD won't likely work on a triple-crank. The set-screws allow you to control the range of shifts to match the new crankset.

Here a Copy & Paste regards installation of the FD. Feel free to boost it and hand it out:
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Take the cable off the FD. Now install it from scratch as per Park Tool Repair:

https://www.parktool.com/repair/readhowto.asp?id=75

And BicycleTutor:

https://bicycletutor.com/adjust-front-derailer/

When you have it properly trimmed and are ready for the cable - a new one wouldn't hurt - you want to pull the cable taut - not too tight, taut. Then apply 48 to 60 inch-pounds to the pinch-bolt. Then put it through it's paces.

It's always easier and faster to install a FD from square-one, than it is to make adjustments with it already attached. This tends to fix one thing - while throwing another out of kilter. Start fresh. You'll get it.

Adding an inline barrel-adjuster can solve many problems with the cable coming loose - or being too tight.

Barrel Adjusters:

https://www.biketoolsetc.com/index.cg...rrel-Adjusters

kevntri

Got the 105 (170) crank for $22 and the BB for $21....

My buddy has a crank puller for the square taper. Do I need any other special tools?

reptilezs

u need a splined crank puller or button/shim for the old puller. you dont need a puller to install cranks though

operator

No he doesn't. He's pulling a square taper crank.

kevntri

Everything is on....
I am having trouble with the F/D
My LBS says I need a double F/D
The Triple has a bend in the cage that is rubbing on high gear.
Is there any trick to adjusting?