[ginntonic75]

i have a trek y33 from 1996....... i bought a new crankset and the one they shipped was off another trek but it is a 68X113. i think i need a 73X113. the bottom bracket is an es-71. i looked up some info and they say this is also a 73 but the one i have is labelled a 68. will this work?

 

[Bikinfoolferlife]

Put the gin down and try again. What are you talking about, the crankset or the bb you got with your used crankset? The crankset will work with both 68 and 73 bb shell widths, but the bb's are slightly different even though they both have 113 spindle lengths. The frame's bb shell width determines which bb to use, get out your ruler and figure it out...try www.sheldonbrown.com/chainline and www.sheldonbrown.com/bbsize.html for help

 

[Speedub.Nate]

Probably not, but you can try.

But first things first, I'd really recommend a 118mm ES71 for that setup. I'm not saying for sure the 113 isn't going to work, but I've had some trouble with those in the past due to the wide shell.

Just out of curiousity, what size seat tube / derailleur clamp does that bike take?

By installing a 68x113 into a 73mm shell, you're going to end up with your chainrings stuck out an extra 2.5mm -- essentially what you'd have with a 118mm spindle.

But on the other side of things (the non-drive side), that crank arm is going to be sucked in an extra 2.5mm.

Not only will that result in a net 5mm imbalance to your Q-factor, but you may find your non-drive crank arm is pulled into the bottom bracket adapter, preventing the crank from spinning freely.

If you're adventerous, and don't think you'd mind the 5mm imbalance much, give it a shot. But I'd really recommend a 73x118mm ES-71 for that bike, especially if you have a 34.9mm (1-3/8") seat tube/derailleur clamp diameter.

 

[ginntonic75]

wait

Probably not, but you can try.

But first things first, I'd really recommend a 118mm ES71 for that setup. I'm not saying for sure the 113 isn't going to work, but I've had some trouble with those in the past due to the wide shell.

Just out of curiousity, what size seat tube / derailleur clamp does that bike take?

By installing a 68x113 into a 73mm shell, you're going to end up with your chainrings stuck out an extra 2.5mm -- essentially what you'd have with a 118mm spindle.

But on the other side of things (the non-drive side), that crank arm is going to be sucked in an extra 2.5mm.

Not only will that result in a net 5mm imbalance to your Q-factor, but you may find your non-drive crank arm is pulled into the bottom bracket adapter, preventing the crank from spinning freely.

If you're adventerous, and don't think you'd mind the 5mm imbalance much, give it a shot. But I'd really recommend a 73x118mm ES-71 for that bike, especially if you have a 34.9mm (1-3/8") seat tube/derailleur clamp diameter.

i would put the gin down--- but it is too damn good!! you seem to knoew the bike well! you are correct on the seat tube. it is a 34.9. i have not taken the old bottom bracket out ( yet) . i emailed trek to find out what size i need and they say that i should have a 73 by 113 down there. i understand that if i do a 118 that the cranks will be out an additional 2.5 mil on each side but is that going to affect anything? can i drop it in and go or am i going to have to do alot of adjustment? obviously my granny gear is going to be affected more so than the rtop ring....correct? if it helps i am replacing the front derailer at the same time along with the cssette and chain. once this is done the bike will weigh under 20 pounds and that is with computer ,lock out, and bar ends.

 

[Speedub.Nate]

I don't like it when bike companies give spindle length recommendations. Instead, they should stick with recommending chainlines, because there are too many variables when picking a spindle length.

Remember that splined hollow spindles weren't around in '96, so are they telling you 113 specifically for your setup, or 113 based on what square taper crank was originally spec'd with the bike?

Keep in mind that Shimano 113 square = 118 Octalink / ISIS = 126mm LX 572 Octalink = 122mm old-school Shimano square = .....you get the picture.

A 118mm ES71 will get you a 50mm chainline, which is within range of proper front shifting and will ease your shifts into granny on any bike with a 35mm derailleur clamp.