Replacing BB and crank

Quoted post said:

Originally posted by Antti
Well, I have a small puzzle to solve.

I have 2002 Jamis Durango SX, which was good enough with it's default setup until now. I've decided to upgrade some parts, including crankset.

Crankset that I chose is M572 (2004 model, octalink). This crank needs ES51 BB.

Now, the puzzle is:
Current BB is Tien Hsin BB-7700, 110mm spindle (seems to be cheapest thing money can buy 🙂 ) with Alivio crankset. I want to replace it with above mentioned M572 and ES51. What will it do with my chainline? Somewhere in cyclingforums archives I found message from Hecubus saying that 121mm ES51 spindle is about equal to 113mm standard spindle, because the 572 cranks have a much deeper bore.

Speaking about chainline ...
I'm going to replace rear cassette also. In default configuration there is 8-speed cassette which I believe is SRAM 5.0. I want to replace it with LX 9-speed cassette.

What do you think, will this mixture work? 11mm seems somewhat big difference for me to just jump over. 121=113 equation would leave me with 1,5mm difference on each side ...

Current BB spindle length has nothng to do with it and was matched to the crank that was on the bike.The the m572 crank has a BB spindle length spec. Ues that. No puzzle. You need a 9 speed shifter and chain to go with that 9 speed casette.

Quoted post said:

Originally posted by boudreaux
Current BB spindle length has nothng to do with it and was matched to the crank that was on the bike.The the m572 crank has a BB spindle length spec. Ues that. No puzzle.

This is a lot of, how to you put it?, hooey! The guy is asking about what it'll do with the chainline and that is why the spindle length and how far a crank will sit in it matters.

Quoted post said:

Originally posted by boudreaux You need a 9 speed shifter and chain to go with that 9 speed casette. [/B]

Doesn't take a genius to figure that one. :p

Quoted post said:

Originally posted by dennis dee
This is a lot of, how to you put it?, hooey! The guy is asking about what it'll do with the chainline and that is why the spindle length and how far a crank will sit in it matters.



Doesn't take a genius to figure that one. :p

A new crank with the correct spindle even to it's longer will do nothing to the chainline will not do a thing to the chainline. It will be the same as before. You are just trying too hard without having a real clue. 🙄

Quoted post said:

Originally posted by boudreaux
A new crank with the correct spindle even to it's longer will do nothing to the chainline will not do a thing to the chainline. It will be the same as before. You are just trying too hard without having a real clue. 🙄

Oh my, strike 2 boudreaux! Definitely not true. Not all spindle/crankset/chainset have the same tolerances when installed.

Quoted post said:

Originally posted by dennis dee
Oh my, strike 2 boudreaux! Definitely not true. Not all spindle/crankset/chainset have the same tolerances when installed.

Well,both current shimano and campy stuff is designed around proper chainline when the crank is matched to the proper spindle. Stick a crank speced for a 121 spindle on a 110 or 113 spindle, and I think you willl find out about 'tolerances'. As I said, the the BB spindle length that was ok for the old crank ISN"T ok for the new one he's considering. There is no 'puzzle' as he indicated. Just the reality that the crank he wants to use is designed around a LOT LONGER spindle length.

Gonna have to agree with Boudreaux on this one. Manufacturers spec bracket length / cranks to maintain chainline.

For MTB's, its typically 47-50mm ( http://www.sheldonbrown.com/chainline/ )

A given crank may require a longer spindle due to the configuration of the taper or amount of beef in the spider/crankarm buildup ( http://www.sheldonbrown.com/bbsize.html )

Quoted post said:

Originally posted by dobber
Gonna have to agree with Boudreaux on this one. Manufacturers spec bracket length / cranks to maintain chainline.

For MTB's, its typically 47-50mm ( http://www.sheldonbrown.com/chainline/ )

A given crank may require a longer spindle due to the configuration of the taper or amount of beef in the spider/crankarm buildup ( http://www.sheldonbrown.com/bbsize.html )

I know what you mean and generally that will be the case but not necessarily so for all crank/spindle/chainring sets. We are talking minute tolerances here measured in millimeters.

For instance. A late Campy Record crank meant for a 10s or 9s requires a 102mm spindle. The SAME crankset when used for an older 8s requires a different spindle length and a different chainring to maintain the chainline as meant by Campagnolo. Sure it will still work, but flawlessly? For anal retentives, i doubt.

Quoted post said:

Originally posted by dennis dee
I know what you mean and generally that will be the case but not necessarily so for all crank/spindle/chainring sets. We are talking minute tolerances here measured in millimeters.

For instance. A late Campy Record crank meant for a 10s or 9s requires a 102mm spindle. The SAME crankset when used for an older 8s requires a different spindle length and a different chainring to maintain the chainline as meant by Campagnolo. Sure it will still work, but flawlessly? For anal retentives, i doubt.

Well, the way I read the book, the 9 speed record,chorus cranksets are listed as also 8 speed compatible using the same 102BB. So, then tell me,what spindle would you use to manintain this so called perfect chainline? Campy list no options for this alleged mismatch. In ACTUAL PRACTICE, which I suspect you are likely short on, I have found that minute differences and a few mm off spec in 'the perfect chailnine' makes no practical difference, with all due respect to the 'ARs', and 'Campys line', assuming that is even what you are quoting from again. Where you really get into trouble is if the mismatch places the chainrings where the FD has inadequate travel, or the rings end up too close to or hitting the chainstays. Being seat of the pants makes life alot easier.

Quoted post said:

Originally posted by dennis dee
Sure it will still work, but flawlessly? For anal retentives, i doubt.

Long on idle speculation in an attempt to make a point ....EH?

Quoted post said:

Originally posted by boudreaux
Well, the way I read the book, the 9 speed record,chorus cranksets are listed as also 8 speed compatible using the same 102BB. So, then tell me,what spindle would you use to manintain this so called perfect chainline? Campy list no options for this alleged mismatch. In ACTUAL PRACTICE, which I suspect you are likely short on, I have found that minute differences and a few mm off spec in 'the perfect chailnine' makes no practical difference, with all due respect to the 'ARs', and 'Campys line', assuming that is even what you are quoting from again. Where you really get into trouble is if the mismatch places the chainrings where the FD has inadequate travel, or the rings end up too close to or hitting the chainstays. Being seat of the pants makes life alot easier.

Eureka you said it! PERFECT CHAINLINE! This is exactly why campy released the 102BB even if the spider is essentially the same (the 111BB just didnt cut it).

Funny you talk about speculation. Yet you say all spindle/crankset/rings tolerances are created equal - how speculative is that.

Quoted post said:

Originally posted by boudreaux
In ACTUAL PRACTICE, which I suspect you are likely short on...

Speculation again. If you have lots of ACTUAL PRACTICE? where did it all go then? :eek: tsk, tsk

Quoted post said:

Originally posted by dennis dee
..... even if the spider is essentially the same (the 111BB just didnt cut it).

" Essentially the same"...that might be the difference right there,assuming you even know what you are talking about. And as for 'perfect chainline': something to rant and write about, and the terminally ARs to worry about.