Mountain Biking - Chainline problem

I have 1999 Shimano XT cranks + a shimano UN51 bb . is it possible to adjust the chainline w/this setup? the crossover gear( big to big ) is way off . When I'm in the granny gear I only use the 3 largest cogs , so I'd be happy to give up the 5 smaller cogs. If it's not possible , what square taper BB's are available with the ability to adjust the chanline?

I'm not sure I understand your problem. Why are you in the big/big combination?

If the Big-Big combination is off, no problem (if everything is set up well, it likely will be off). That's why you have a middle ring and something to move the chain to it.

+1 to LowCel

Like stated above, I'm not sure what you are trying to accomplish but if you want to change your chainline, you will have to get a new BB with a different spindle width (depending on which way you want your rings to move).

Just don't x-chain.

Yeah, what everyone else said....

also, are you asking if there is an 'on the fly' adjustable BB spindle length BB? That would be interesting. :eek: Adjust the spindle out with a poploc type switch when you want to go small small, and switch it back left for the ''big big''

Or you could get a singlespeed....or just learn how to shift.

I'm not sure I understand your problem. Why are you in the big/big combination? the reason I use the crossover gear is , I'm often in the Big ring and want to make use of all 8 cogs . When I am using the granny gear , I never use the 5 smallest cogs. The way things are now, I have 6 gear combinations that I don't use . The Big - Big combo is a gear that is more likely to be used than the 22x11 or 22x12 . Those gears never get used.

Or you could get a singlespeed....or just learn how to shift.this is not my first rodeo ,there Bucko :D

Unfortunately that is just the way the bikes are designed. They aren't meant to be used with that gear combination.

Basicly with a 3x8 setup you should only use these combinations.
Big front - four smallest rear.
Middle front - six middle gears on rear (I don't follow this rule though)
Small front - four biggest gears on rear.

Unfortunately that is just the way the bikes are designed. They aren't meant to be used with that gear combination.

Basicly with a 3x8 setup you should only use these combinations.
Big front - four smallest rear.
Middle front - six middle gears on rear (I don't follow this rule though)
Small front - four biggest gears on rear.
I know that's how they are designed, that's why I want to change it a little. I think Phil Wood BB's allow it , now if I could only find one.

Here ya go. They have them at Cambria (http://www.cambriabike.com/ShopDisplayProducts.asp?ID=30&cat=Bottom+Brackets).

this is not my first rodeo ,there Bucko :D



It does sound like this is your first rodeo.
You should never even use the top three cogs when you are in your big ring. (Unless you have a double and a straight block)
All my Mtn bikes are set up with the chain too short to even get onto the top two cogs when I am on the big ring.
You need to use the gear combinations that give you the best chain lines and access to the best jumps from the middle ring.

Here ya go. They have them at Cambria (http://www.cambriabike.com/ShopDisplayProducts.asp?ID=30&cat=Bottom+Brackets).
Thanx lowcel , You Da Man .

It does sound like this is your first rodeo.
You should never even use the top three cogs when you are in your big ring. (Unless you have a double and a straight block)
All my Mtn bikes are set up with the chain too short to even get onto the top two cogs when I am on the big ring.
You need to use the gear combinations that give you the best chain lines and access to the best jumps from the middle ring.that's great for you man :rolleyes: . I use whatever gear combo that feels right at the time . Yes , I know that the crossover gear combo puts a lot of stress on components and wears out chains, chainrings, and cogs rapidly . I don't care . $hit breaks, you buy a new one. No big deal. thanx for your opinion

I see what you've got going, BoSoxYacht. Is it possible to accomplish virtually the same thing by upsizing your 2 bigger rings? I'm just wondering - I do think your solution is the better choice for many reasons, the least of which is the fact that you'll get to ditch the UN51 for a Phil Wood.

I see what you've got going, BoSoxYacht. Is it possible to accomplish virtually the same thing by upsizing your 2 bigger rings? I'm just wondering - I do think your solution is the better choice for many reasons, the least of which is the fact that you'll get to ditch the UN51 for a Phil Wood.
thanks gastro, the un51 has seen a lot of use and is still kicking . I've been wanting to upgrade for a while , But why , it's still smooth . It's time to get the 2 big rings replaced so I may just get new cranks + BB to match. I think I may have been a little hard on Worldwind . He prolly doesn't get much conversation at work and needs a little banter .

Thanx lowcel , You Da Man .

No problem. I still don't think it is the best idea but it doesn't really matter what I think, it's not my bike or my money. ;) I hope the phil wood bottom bracket works for your situation.

the best thing about this attempt is, like gastro pointed out , is a new Phil Wood BB . Phil's components are simply perfect .

I haven't yet encountered a situation where I would want to be cross-chained, nor can I imagine one.

Why shift the chain up to a bigger cog in the rear when you can simply drop into the middle ring?

I haven't yet encountered a situation where I would want to be cross-chained, nor can I imagine one.

Why shift the chain up to a bigger cog in the rear when you can simply drop into the middle ring?
less chance of a mis-shift in rough terrain is why I do it . The sport is not new to me Hank . I know how "to ride" , and I know how "I ride". Sometimes these are two very seperate techniques . BTW Hank , do you read the book or see the movie? Just curious.

I haven't yet encountered a situation where I would want to be cross-chained, nor can I imagine one.

Why shift the chain up to a bigger cog in the rear when you can simply drop into the middle ring?


exactly

+1

less chance of a mis-shift in rough terrain is why I do it .

I don't understand how being in that combo would reduce the chance for a mis-shift (or why you would be concerned about a mis-shift if your drivetrain is properly adjusted).

Being in the middle of the cassette offers more shifting flexibility, especially quicker shifts into easier gears when compared to being cross-chained. I can't think of any advantage to cross-chaining, other than having to run a longer chain which will give you more chain slap.


BTW Hank , do you read the book or see the movie? Just curious.

I've read the book a few times. I don't know of any movie adaptation.

I don't understand how being in that combo would reduce the chance for a mis-shift (or why you would be concerned about a mis-shift if your drivetrain is properly adjusted).

Being in the middle of the cassette offers more shifting flexibility, especially quicker shifts into easier gears when compared to being cross-chained. I can't think of any advantage to cross-chaining, other than having to run a longer chain which will give you more chain slap.



I've read the book a few times. I don't know of any movie adaptation.

if ur front derailleur is properly adjusted and ur teeth arent shot there is no chance of the chain popping off

very true, if ur mid cassette it is far faster/easier as well as less chance of a misshift

think about it.. if ur bigringing both.. and you need to shift rapidly.. ur screwed.. you have to send it down 3or 4 gears.. more of a chance to get chain skip..etc

i guess its personal preference.. and ur money...

as for me.. i'll stick to keeping my chain straight in the middle ring

And here I thought cross-chaining cause more mis-shifts and chain throws.

Sorry Hank , why I do this is not open for debate . I do this because it works for me. If you don't like it , then don't do it . This thread is a question about a chainline and BBs , not an inquiry about proper shifting techniques. Your opinion has been heard by all .Thank you very much

And here I thought cross-chaining cause more mis-shifts and chain throws.
Hence, why I wanted to adjust the chainline . Thank you for pointing that out, Captain Obvious. :roflmao:

If you want to do that why don't you just get a chain guide? You'll need a longer spindle anyways.

Sorry Hank , why I do this is not open for debate . I do this because it works for me. If you don't like it , then don't do it . This thread is a question about a chainline and BBs , not an inquiry about proper shifting techniques. Your opinion has been heard by all .Thank you very much

My, my, you're awfully touchy aren't you? The reason why I asked the questions is because your explanations don't make sense, froma mechanical standpoint or a riding standpoint.

So, if you do go ahead with this project you're going to need to pay close attention to the amount of clearance that you currently have between the teeth on your little ring and the chainstay bulge. If it's tight now, you have very little room to move the BB inboard.

Assuming that you have enough clearance, you also need to consider possible interference between the chain and your tire when riding in your lowest gear combo. This can definitely pose a problem, even with relatively narrow 2.1 xc-ish tires.

The old white bros bb was adjustable, there are a few on ebay now and then, but I don't think you need one.

If you want to do that why don't you just get a chain guide? You'll need a longer spindle anyways.


off subject, but, I'm totally with you on the no shimano, no sram thing, but what other brands would you use for derailleurs lets say.

If you want to do that why don't you just get a chain guide? If you get the right one, it will be cheaper than a Phil Wood BB anyways.I use front deraileurs because for my riding, I need them. I hate them , because they suck, but I still need them. Why would I want to make 2 shifts to get the ratio I want, when a click of the index finger will get me the gear ? As I said , "It works for me".

off subject, but, I'm totally with you on the no shimano, no sram thing, but what other brands would you use for derailleurs lets say.

I'm a singlespeeder.

I'm a singlespeeder.

why yes you are, I thought for sure you had gears on your bike, sorry.

I use front deraileurs because for my riding, I need them. I hate them , because they suck, but I still need them. Why would I want to make 2 shifts to get the ratio I want, when a click of the index finger will get me the gear ? As I said , "It works for me".

E.thirteen DRS(Dual Ring Security)

Remember this though even a longer BB spindle will effect how you ride and how the bike handles, every part on the bike except the grips have an effect.

You should try setting a singlespeed up, you'll find that a straight as possible chainline is king next to the proper chainlength. Also how do you know that you need all the gears, how many times do you really shift in the first place, you face less maitenance, the bike is quiet when being ridden and no real deraillieur lag to note.

also if ur moving the entire crank over.. there might be some complications with front derailleur shifting... maybe not.... just throwing that in though

also if ur moving the entire crank over.. there might be some complications with front derailleur shifting... maybe not.... just throwing that in though Which is why I mentioned a chainguide.

My, my, you're awfully touchy aren't you? The reason why I asked the questions is because your explanations don't make sense, froma mechanical standpoint or a riding standpoint.

So, if you do go ahead with this project you're going to need to pay close attention to the amount of clearance that you currently have between the teeth on your little ring and the chainstay bulge. If it's tight now, you have very little room to move the BB inboard.

Assuming that you have enough clearance, you also need to consider possible interference between the chain and your tire when riding in your lowest gear combo. This can definitely pose a problem, even with relatively narrow 2.1 xc-ish tires. Thank you for pointing this out, I haven't thought of that yet . Better check that out . :) As far as being touchy , I've seen tons of your posts and I feel that you enjoy belittling people that don't agree with you .No big deal . BTW I just checked and there's a centimeter of clearance . I run a 2.35 Nevegal in the rear . Surprising how much room there is. Maybe this is the wrong BB spindle length for the bike .?.?

I have 1999 Shimano XT cranks + a shimano UN51 bb . is it possible to adjust the chainline w/this setup? the crossover gear( big to big ) is way off . When I'm in the granny gear I only use the 3 largest cogs , so I'd be happy to give up the 5 smaller cogs. If it's not possible , what square taper BB's are available with the ability to adjust the chanline?

can you post a picture of the setup?

I've seen tons of your posts and I feel that you enjoy belittling people that don't agree with you .

Pot, kettle, black.

"I think I may have been a little hard on Worldwind . He prolly doesn't get much conversation at work and needs a little banter ."

If questioning people's goofy, illogical "facts" or practices is belittling, then so be it.

Enjoy your long-chained, cross chaining setup!

also if ur moving the entire crank over.. there might be some complications with front derailleur shifting... maybe not.... just throwing that in thoughthe sram X-Gen has lots of room on the low end ,not too much on th big ring . If I mash the 42x11 real hard it rubs , even with the high stop backed all the way out. I think the frame might have the wrong BB in it .

this is a derailleur adjustment issue it sounds like, not bb. the angle and height of the front der. is very important for the big ring.

Pot, kettle, black.

"I think I may have been a little hard on Worldwind . He prolly doesn't get much conversation at work and needs a little banter ."

If questioning people's goofy, illogical "facts" or practices is belittling, then so be it.

Enjoy your long-chained, cross chaining setup! Hank , He's an M.E. his clients don't have a lot to say.

i kno some one who only runs big ring up front .. 44 that is... with 11-34 rear.. i have said many times on rides its not too great... but hes at the level where it doesnt matter.. which is why hes shifting to a single ring 44 up front...

why dont u just go single ring in this case?

can you post a picture of the setup?not tonight , dead batteries. :mad: I hate when that happens

the 42x11 mashing is on a 6.5 mile (1800ft elevation) downhill. This only happens when I'm mashing the pedals ,not spinning it . It was said to point out how far away from the frame the set-up is . I'm not spinning that gear on flats.

this is a derailleur adjustment issue it sounds like, not bb. the angle and height of the front der. is very important for the big ring.when I put the front Der. on (Sram X-Gen) , the propaganda that came with it said something about the seatpost angle. Are there different front deraileurs depending on seat post angles ? there never used to be, but things change, I guess

You should try setting a singlespeed up, you'll find that a straight as possible chainline is king next to the proper chainlength. Also how do you know that you need all the gears, how many times do you really shift in the first place, you face less maitenance, the bike is quiet when being ridden and no real deraillieur lag to note.I do plan on setting up a SS fairly soon as a second bike . For the riding I do, it's just not practical to use as my only bike. To me that's like buying a sailboat instead of a motoryacht. We have the technology to go faster , longer , easier , so I'm going to use it. :D

when I put the front Der. on (Sram X-Gen) , the propaganda that came with it said something about the seatpost angle. Are there different front deraileurs depending on seat post angles ? there never used to be, but things change, I guess

I was talking about the angle relative to the chain, like if you are looking from the top.

I was talking about the angle relative to the chain, like if you are looking from the top. I switched the BB with another one I had on a hardtail frame that was lying around, Problem solved . it was about 4-5 mm smaller than the one I had been using. thanks for everyones help :)

Have tried using those Shimano BB spacers? I've been able to get away with some mis-aligned chainlines with these.

bikeparts.com has them.