What's the problem here? *pics* SRAM Spider Content

[kppolich]

Is the crank arm shape out of whack or the spider bent? The 3 torx bolts aren't able to tighten all the way down due to the crank arm not fitting in the cutout on the spider. This causes massive chain ring wobble when installed. I've used other spiders in the past and this crank arm used to be used with a Quarq on my CX bike, but going back to a standard spider as I prep the bike for sale. What is your guess?

Crank Arm: SRAM Force CX1, GXP if that matters
Spider: SRAM 110BCD hidden bolt

*pics* as promised.

[dddd]

No, it doesn't look bent, but the splined hole in the spider sure isn't settling down over the crank's splines!

Try to ID the point of interference (look for localized contact abrasion), and if the inside dimension of the opening in the spider can be strategically relieved with a file to ease the fit, there should at least be absolutely no resulting adverse affect on the flat alignment seating surfaces interface that keeps your chainring running straight in plane.

I would advise not tightening the bolts forcefully against parts that won't easily fit together.

[kppolich]

Can any SRAM experts chime in on whether or not there is a difference between force, red, apex, and rival spiders?

[glepore]

Never mind...

[kppolich]

Originally Posted by glepore

Never mind...

thought you had something there til i googled. Non hidden bolt on both...

[batman1425]

I'm presuming that there's no debris, gunk, etc on the splines of the arm and around the base that might be getting in the way/binding as you are trying to snug things down?

The first thing I do with tolerance fit problems is to clean both mating surfaces very well. Sometimes what doesn't look like a lot of gunk can make a big difference and my understanding is that the sram spider crank interface is supposed to be a particularly tight friction fit.

After cleaning, I would try reinstalling but tightening the bolts in a star pattern, gradually snugging it down evenly in the event it is a binding problem.

If still no joy, you could try warming up the spider with a heat gun to give you a bit more space to work with to get it on there.

[quickfeet]

SRam made different spiders for s900 cranks, you may have one of those. It’s stupid, the crank arms are barely different. I had to buy three spiders once. Even the same crank with a different generation won’t fit. You are hitting in two places near the top of the spider which is why only one of the bolts is flush.

[dddd]

I've used brush-on White-Out to detect clearance issues as when trying to determine where to grind metal off of to make a very old rear derailer travel fully across a newer, wider stack of cogs.

The good thing with this spider is that it only transmits torque in one direction, so the fit on the splines doesn't need to be absolutely slop-free.
So as long as the amount of metal needing to be removed were very small, I would consider a bit of metal removal using a "rat tail" or "chain saw" file.
It almost has to be a tiny amount of metal given that the spider went 90% of the way on, only the taper or "draft angle" of the splines should be interfering I would think(?).

[jtbadge]

I have a spider from a Force 1 GXP crank. PM me if you want it.

[batman1425]

Originally Posted by quickfeet

SRam made different spiders for s900 cranks, you may have one of those. It’s stupid, the crank arms are barely different. I had to buy three spiders once. Even the same crank with a different generation won’t fit. You are hitting in two places near the top of the spider which is why only one of the bolts is flush.

IIRC- the deal with the current s900 crank and associated spider is that they are the previous design where all 5 bolts are visible, instead of the newer hidden bold design with the 5th bold blocked by the DS arm, which is different than the integrated spider Red cranks that had the threaded insert in the back of the crank arm. All of the new sram cranks (save for the s900) including those pictured here are "hidden bolt".

That said - I've seen folks do the s900 spider to other sram crank conversion:

https://www.bikehugger.com/posts/cur...er-conversion/

I suspect this is a tolerance incompatibility issue. A spider on the small side of spec with a spindle on the large side. Its supposed to be a friction fit to begin with. Not a lot of room for variance.

[quickfeet]

It’s not supposed to rely on friction fit, the spiders just slide on and you use lock tight on the bolts. I’ve had the exact same thing happen, the crank arms are likely hitting the spider at about 2 and 10 o’clock positions.

[batman1425]

Originally Posted by quickfeet

It’s not supposed to rely on friction fit, the spiders just slide on and you use lock tight on the bolts. I’ve had the exact same thing happen, the crank arms are likely hitting the spider at about 2 and 10 o’clock positions.

I don't mean that friction alone will hold it on, only that the tolerance between these parts is a friction fit. I've seen some where it takes quite a bit of effort to separate them.

[kppolich]

After a call with SRAM and a visit to my local shop we have an idea. This spider is from an aluminum crank (rival 22) which is shaped just a tad different. SRAM did confirm that the crank arms with Force 22 and CX1 are identical besides branding.

They did also confirm that the spiders are the same for Force 22 and CX1 as well. It did not matter if they were two ring fronts or single chain ring CX1s.

Big shout out to the new local shop Emerys in Milwaukee for the help. Brent talked to me for about an hour about all things bike related. Pretty cool having an Olympic medalist a mile from your house!

[loxx0050]

Originally Posted by batman1425

IIRC- the deal with the current s900 crank and associated spider is that they are the previous design where all 5 bolts are visible, instead of the newer hidden bold design with the 5th bold blocked by the DS arm, which is different than the integrated spider Red cranks that had the threaded insert in the back of the crank arm. All of the new sram cranks (save for the s900) including those pictured here are "hidden bolt".

That shouldn't make a difference. I've got a non-hidden bolt Quarq Elsa spider and swapped out cranks arms with a Force 1X crank I picked up on ebay that was hidden bolt (for the spider). Fit perfectly fine and everything was flush.

But yeah, that was an interesting tibit that a Rival spider is slightly different. You'd think they'd keep them the same to save on production and tooling costs.

[kppolich]

Also still unsure if the S900 spider is also different than the Red/22/CX1 or not.