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Just how stuffed is my drivetrain?


Rudi Pollard

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What frame is that lapa? You can measure the bb shell size , pity, I'm in CPT i could give you some spacers, I've got enough for your next 10 builds too... B)

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As you can see in this internet pic, the TREK frame does not have the exterior BB cups

 

http://www.switchbackmb.com/contentimages/Trek_Superfly_2.jpg

 

 

Yeah just noticed your link was for pressfit bb. I remember a while back I had a similar issue on a frame I used. There is a spacer about 5mm think that slides over the spindle right up to the back of the spider to make up the clearance between the chainring and the frame. I never had that in and the chainring was sitting to close to the frame as well. Trying to find a pic for you to illustrate....

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What frame is that lapa? You can measure the bb shell size , pity, I'm in CPT i could give you some spacers, I've got enough for your next 10 builds too... B)

 

Its a Trek Superfly with the BB95 as per the link I posted earlier.

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Yeah just noticed your link was for pressfit bb. I remember a while back I had a similar issue on a frame I used. There is a spacer about 5mm think that slides over the spindle right up to the back of the spider to make up the clearance between the chainring and the frame. I never had that in and the chainring was sitting to close to the frame as well. Trying to find a pic for you to illustrate....

 

Here is a pic... This one has two "spacers" on the spindle but you can play around with only one at first and see what the clearance is like.

post-7810-0-18977900-1395732778_thumb.jpg

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Here is a pic... This one has two "spacers" on the spindle but you can play around with only one at first and see what the clearance is like.

 

That looks like the rubber band I use for my garmin mount... :blush:

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on my merida o.nine, my 42/28 also runs pretty close to the frame.

 

when I had 42 qrings on and a little mud. I didnt have enough clearance and always use to touch the frame, luckily only the plate on the chainstay.

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I'd say, if you dont experience any bad chain suck, you dont have to replace your whole drive train, do you know how irritating it is when you do have chain suck and all the components look fair.

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Guest Smimby

That looks like the rubber band I use for my garmin mount... :blush:

 

My NINER has the same spacing between chainring and stay

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That looks like the rubber band I use for my garmin mount... :blush:

 

 

Lol yeah I know it does look like an o - rings but its actually hard plastic. If you were to use rubber there it would not serve any purpose as you would actually compress it when you tighten the crank.

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Lol yeah I know it does look like an o - rings but its actually hard plastic. If you were to use rubber there it would not serve any purpose as you would actually compress it when you tighten the crank.

 

Haha ya I figured that much. Now just to find a shop who have those spacers for me. What are they called?

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Okay so I have found the spacer and installed it on the Drive side to move my chainline out a bit, but now I have a new problem.

 

If I tighten the Crank the suggested torque setting it barely moves. If I loosen it a bit it works nicely, but I am not sure how safe this is.

 

There is no play in the crank with the slightly loosened setting. Am I looking for trouble or should I be okay?

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Okay so I have found the spacer and installed it on the Drive side to move my chainline out a bit, but now I have a new problem.

 

If I tighten the Crank the suggested torque setting it barely moves. If I loosen it a bit it works nicely, but I am not sure how safe this is.

 

There is no play in the crank with the slightly loosened setting. Am I looking for trouble or should I be okay?

 

Tighten to required torque and a fraction back as you say should not cause any problems. Just check it from time to time.

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I agree with the shops, the spacing is alright. The press fit BB needs a tapered/stepped spacer to run on the inner race of the BB bearing. I use one when I run a 36 tooth on my DS frame.

 

Chain suck should never be a problem, as the guide/protector plate should be enough to keep the chain from sticking in the small ring.

 

On a 34 tooth have 3-4 mm clearance, on the 36 its 1-2mm, I run a 1.5mm stepped shim to prevent the 36 from grinding on the plate. Don't forget as your suspension squats, the chain stay moves away from the chain ring. Your clearance looks like a 3-4mm.

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Jeez. "That's why I don't ride in the rain / off the tar / when the wind blows / if it's raining somewhere / if there is a breeze / if the sun is shining / if the sun isn't shining"... :wacko:

 

Buy a steel cassette. It's cheap. It weighs maybe 80g more than your expensive one. That's a mouthful or two of water or 1/5 of a good dump.

 

Buy steel granny and middle ring - they weigh... who gives a toss... more than expensive ones and last way longer.

 

Go ride your bike.

 

If your drive train is stuffed but not hassling you, leave it until it does. Why spend money when you don't need to?

Edited by davetapson
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First off, your drivetrain's shot. Somewhere in the tech section there's a document called "Everything you ever needed to know about chains" or some such. Find it and read it, especially the bit about how to measure chain wear. If you know when to change a chain, you may never have to buy another set of cogs again.

 

Second, if that spacer makes your BB seize, it's not meant to be there. Don't compromise on recommended torque just to make it work - you'll either wreck the bearings or the spline, and then it's time for a new crankset too. If the chainring doesn't rub on the stay, there's enough clearance.

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I service my own bike, so I know when to change chains etc. This excessive wear was caused by all the mud riding the last few months.

 

I had to change the chain now as well as the jockey wheels which was completely shot, so I just want ahead and changed everything.

 

Ill check the spacing without the spacer again, but if its 1mm its a lot...

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