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Discussion Starter · #1 ·
This is happening a lot. The Lurcher has a pressfit 92 bottom bracket shell and I've replaced a gritty SRAM BB with a Token BB. I'm on my second X9 crank because the last ones threads got shreaded as a result of this problem. The instructions say to tighten to 40NM, I don't have a torque wrench so have to guess at the torque when tightening.

When I tighten it firmly to what feels sensible the crank does not spin freely, so I loosen it a bit until it does. Maybe I'm over doing it but I'm being pretty cautious. I've followed all instructions to the letter and checked that I'm using the correct spacers but when I disassembled it this evening I found that the wave washer had sort of mashed the plastic washer (with the lip that half covers the chain ring hex bolts) that fits tightly on the spindle on the drive side. This damage can't be right.

It just feels like this system was thrown together by a bunch of clowns, I never had this problem with screw in bottom brackets, it's become an expensive farce. I will never buy a frame with a press fit BB again.

Can anyone give me a definitive answer about the spacers I should be using with this frame, especially whether I need the wave washer.

Thanks
 

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The Fastest of Bananas
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I have a lurcher, but I am using a SLX crank.

My BB has one 1mm spacer on the drive side. I used red locktite gel on the BB, and tightened the crank until it takes out all of the play in the cranks laterally.

You dont need to tighten it any further, as it will just drag and damage things. The method is to tighten until it is right. If you go to tight, and then back off, things wont have the right torque.

Tighten until it feels good (no play, no drag), if you exceed this, back way off and start over.
 

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Did the Token BB come with instructions? The Lurcher BB is 89.5 and should have a 2.5 mm spacer. SRAM instructions show the spacer on the drive side between the crank and BB - not between the BB and BB shell like Shimano does it.
The Token BB fits both Shimano and SRAM so I assume you had to add a sleeve on the non-drive side to bush the bearing down in size.
The SRAM non-drive side crank is meant to be tightened quite tight - 48-54 Nm. If the crank has too much friction then you should play with spacers, not leave the arm loose.
 

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Trail Tire TV on blogger
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...... If the crank has too much friction then you should play with spacers, not leave the arm loose.
what he said.. if it's a GXP crankset..? (not all SRAM cranks are GXP so make sure)

if it is, and you are tighten down and it's binding you have the wrong type or setup of the BB. GXP has no pre load like Shimano/other cranksets.. it uses the races only on the non-drive side and traps the race it's self not pinching the bearings/balls. Using converters to go from a shimano type to the GXP isn't a great idea as the GXP is a straight contact and the others are usually angular contact. Get a proper BB for the frame/crankset.

I've repeat it time and again here.. look into Real World Cycling's BB.. they make one with the proper fittings for just about any combo of frame to crankset and use the correct style bearing for the cranks without goofy adaptors and other issue causing crap. Can also get the basic BB for around 50 bucks but have options for better bearing in many steps and price ranges. As well as about the best customer service of any bike part company I've dealt with yet.

Understanding the difference between the Shimano and Sram's GXP style of mounting is key to figuring out your issues..

Trail Tire TV: Sram's GXP Bottom Bracket, how it differs from others
 

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Discussion Starter · #5 ·
Thanks for the responses.
Yes, the token came with instructions.
Yes, it's GXP.
The sleeve was on the drive side, and the wave washer was was a tight fit when I did the original install so I should have know there was going to be problems. The mashed sleeve doesn't look like it's particularly integral to the crank, more of a dust cover, might offer a smoother interface between the spacers and the end of the spindle.

I'll call On One I think and see if they can make any sense of it.

Thanks for the input.

Mark
 

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Discussion Starter · #7 ·
OK I think I've figured out what's been going wrong, you know this drive side dust cap / seal / top hat washer type thing that got mashed by the wave washer? I don't think it should have been there. I think it was a drive side seal from the original SRAM bottom bracket I installed but when I disasembled the crank the seal was wedged up against the spider and came away on the spindle and I just assumed it was supposed to be there. I've read a few threads and looked at some pictures of the crank on Google and the seal that was on mine doesn't seem to be there on any of them.

This is the offending part (not mine), is this part of the crank assembly or part of the old bottom bracket?

Yellow Bicycle accessory Machine Bicycle part Steel


Thanks for looking.
 

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Trail Tire TV on blogger
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I believe so, but I haven't used any of the wavy washer style.. that's a new thing... mine just has a seal that kinda grips on the lightly raised lip.. look at your picture, you'll see the shiny area is just ever so slightly raised, my seals have a "gripper" edge so when it slides on over that area it stays in place I know the newer Sram newer BB's used the wavy washer I think to just hold the seal in place as it's not supposed to be tight against the spider like a shimano.
If you get like the Real World Cycling/KCNC and a few others the wavy washer isn't needed as the seal holds properly on it's own. Though i think with some of the newer press fit-to-GXP may use it. you need to look at the manual for your BB brand/manufacturer..
 

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Discussion Starter · #11 ·
A pretty unfortunate sequence of events lead to this point and if I've had this problem then I suspect others have too.

when I first installed the cranks it was on a different frame using the threaded bottom bracket that ships with the X9 cranks. I bought the Lurcher frame and a GXP presfit BB but when I took the crank off the old frame that seal came with it and I didn't realise that it was part of the bottom bracket and not part of the crank. So I went and put it on the Lucher and five months later the crank arm falls off the threads on the theads on the spindle are shagged and I'm scratching my head.

To replace the shagged spindle I bought a secong hand crank off ebay and swapped over the chainrings. This is the unlucky bit: when the second hand crank arrived it had the same seal up against the spider. "There's that crappy seal that gets mashed by the wave washer again" I remember thinking.

The moral of this boring story is, if you're swapping your SRAM cranks from a threaded BB to a Pressfit and you see that f#@king seal up against the spider, remove it.
 
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