# Crankset for PF86 BB?



## RaptorTC (Jul 20, 2012)

*Play in PF86 crank setup*

Hello,

So the crankset on my cross bike has developed some vertical play that I can't get out no matter how I try to torque the bolt. Originally I thought the play was part of the pedal/cleat interface so I didn't think much of it and kept riding. Eventually the crank worked itself loose enough to determine that was definitely the problem and I managed to tighten it enough to get home with a multi tool. Cranked it back down when I got home, but there is still a bit of vertical play, meaning that if I pull my feet up and down I can feel it move a bit.

Anyway, I fear that I've worn down the crank interface by riding it with this bit of play and I may need to just get a new crankset. Unless anyone has any tips to getting this play out as I feel like riding it this way is just going to make it worse and worse. I've always used your average threaded bb so I'm not quite sure as to what exactly what I'm looking for. Is PF86 essentially the same thing as BB86, so could I just throw your average Shimano crankset in there and be good? The crankset that is on there now is an Oval 730, which just has one bolt on the end of the crank instead of the pinch bolts on the side like Shimano. 

Anyway, thanks. I just don't understand why we need a million different kinds of BB's...


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## bikerjulio (Jan 19, 2010)

Not knowledgeable about PF86, but are you sure it's the crank moving within the bearing, or is it the whole bearing moving?

I'd be more inclined to think it's BB wear than actual wear on the crank spindle.

Tried to look up your crank, but the Oval site does not list it. I assume it's supposed to be Shimano compatible?


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## 007david (Dec 24, 2007)

First, PF86 and BB86 are the same thing. As for the crank, I'm not sure about the 730, but I just recently got a Norcom Straight which came with the 720 and it had a SRAM/Truvativ GXP spindle. If you pull the crank and the NDS bearing has a smaller inside diameter compared to the DS (22 vs 24mm), then a SRAM crank or GXP press-fit BB is your pick. That being said, SRAM recommends using a wavy washer when using a press-fit BB, so if the 730 has that interface, I might try that first since it's going to be fantastically cheaper than a BB or crank.


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## bikerjulio (Jan 19, 2010)

If you are running a GXP crank in a Shimano BB, you will get movement on the NDS because a GXP requires a smaller diameter NDS bearing as David alludes to. GXP crank requires a GXP BB.


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## RaptorTC (Jul 20, 2012)

I'll have to check it out for sure when I get home, but I'm pretty sure I remember seeing what was probably a wave washer on the drive side when I pulled it apart and greased it up last night. So maybe it is a Sram style spindle. I'll check the bearings to see if they're different sizes/moving. The bike only has like 600 miles on it so I'm hesitant to think the BB is already showing that much wear.

Thanks for the suggestions!


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## RaptorTC (Jul 20, 2012)

So I measured it when I got home. Sure enough, drive side was 24mm and nds was 22mm, so its a GXP setup.
Am I correct in thinking that this little guy in the middle of the spindle is the wave washer? I've never seen one before, but this surely looks wavy and like a washer.


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## bikerjulio (Jan 19, 2010)

Yep. That's what a wave washer is.

So, if you have a Shimano BB, then problem solved - it's the wrong one and will give the symptoms you have.

Get a GXP BB and all will be well.


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## RaptorTC (Jul 20, 2012)

It is a GXP bottom bracket though since I measured the DS being bigger than the NDS. Pretty sure I just rode it loose for too long, thinking the problem was in the pedal. I don't think the BB is the problem as I tried tightening the crank down outside of the bike and it still had that play and no matter what I tried doing I couldn't develop any play. 

I'll probably run it by the LBS to be sure, but I'm pretty sure the crank is the problem. I've heard of riding a square taper setup loose causes the "hole" in the crank arm to wear down. My best guess is that something along those lines happened here.


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## bikerjulio (Jan 19, 2010)

> I don't think the BB is the problem as I tried tightening the crank down outside of the bike and it still had that play and no matter what I tried doing I couldn't develop any play.


If you have the wrong BB, then tightening a GXP crank will not fix the problem.


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## RaptorTC (Jul 20, 2012)

I'm pretty sure I have the right BB though. I measured the diameter of the inner diameter of the bearings and found them match what was posted above for GXP. 

Unless I'm confused and there is a different way to tell?

Sorry, I don't mean to be difficult here, just trying to understand it all. Makes me really enjoy the simplicity of the external BB setup on my road bike.


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## bikerjulio (Jan 19, 2010)

You have not really explained the history of how this crankset and BB got together.

A normal PF86 BB is intended for a Shimano type spindle.

If a GXP type spindle is put in you will get exactly the problem you are describing.

The bike would require a specific GXP BB to be installed for it to work. Was this done?


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## RaptorTC (Jul 20, 2012)

I'm riding the bike with the configuration it had when I bought it. That's why I'm hesitant to think that there is the wrong BB in it. Also, I didn't have this problem when the bike was new. I've done a century on it and had no problems then. This has developed in the last 70 or so miles.

Bike/specs HERE

Maybe vertical play wasn't the right way to say it. Essentially what happens is you can hold one crankarm still and move the other one a wee bit each way along the axis of pedaling. It takes a bit of force to do this, but its noticeable when pedaling (and I originally thought this was a cleat/pedal interface problem) Almost as if the splines of the spindle and the crank are not matching up perfectly. Other than that there is no play in the system. Nothing side to side or up and down or anything else.


EDIT: 

Sorry, its BB86. Sorry for any confusion I caused here. I guess I saw press fit and immediately stamped pf into my brain.


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## bikerjulio (Jan 19, 2010)

OK if you bought the bike new then we have to think it's the correct BB.

I'd go back to thinking it's just BB wear, especially seeing as it a cross bike covered in dirt!

Just get an LBS to install a new PF 86 GXP BB (or do it yourself, it's pretty simple).

FYI GXP was introduced originally by Truvativ, now owned by SRAM.

Here's what you need wiggle.com | SRAM BB86 GXP PressFit Team Bottom Bracket | Bottom Brackets


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