[Bataivah]

I've been thinking of changing my ISIS BB over to an outboard type. They seem better to me, and easier to service. I figure I have to change the whole crank-set if I do. Right now I'm running a Truvativ iso-flo. I also don't know where to measure to get the right size if I buy one. (Or are they all a standard size going in the frame?)

 

[mtec]

Is your bottom bracket shot or otherwise causing problems?

 

[Bataivah]

It makes a cracking and popping noise when I pedal heavy and it drives me crazy. The outboard look to have a better bearing position to me. ??

 

[mtec]

And you've made sure its not a pedal or crank creaking from lack of grease?

I mean, might as well be sure before dumping a couple hundred into a new crank setup.

 

[Bataivah]

Yeah, I know it is'nt the pedals or crank arms. I don't have the tool to take off the BB yet, and try to repack it. What do you think of the ISIS type? They seem small and whimpier.

 

[AndrwSwitch]

One of the criticisms of the ISIS type was that the bearings had to be relatively small to fit between the large, hollow spindle and the inside of the cartridge housing. Outboard bottom brackets are better for this, and good ones are a little more adjustable, which is nice. The bearings are a lot more exposed on the new bottom brackets, so it's easier for them to get dirty inside and wear out. It's a little bit of six of one, half a dozen of the other.

How many seasons did you get out of this bottom bracket?

I'd say if it was more than two and you're happy with your crank otherwise, just replace your bottom bracket with another of the same and call it good. They're still readily available.

EDIT: Oh yeah... in general, cartridge bottom brackets, like all (to my knowledge) ISIS models, aren't meant to be rebuilt. Doesn't mean you can't do it, but it's usually about a $30 part.

 

[Bataivah]

I have 2 full seasons on it with around 1000 miles. The outboard type look bigger and stonger and I got a ton of dirt and water in the ISIS anyway. I don't think there that much more protected from the elements than the out board type. They got noisey after getting submerged in a fast running creek last year and I can't get in there to grease it very much.

 

[big_papa_nuts]

Truvativ ISO-Flo cranks uses a Power Spline BB IIRC, not an ISIS. Similar, but not the same.

Otherwise AndrwSwitch nailed the pros and cons.

I would suggest pulling the BB and having a look see. I'd doubt it's wore out with 1000 miles on it and there is a good chance a proper application of Loc-tite and grease with fix you right up. But I also think that the ISO-Flo is an entry level crankset so upgrading may have other benefits.

 

[Bataivah]

Yeah, I guess I should of said internal or external type instead of ISIS. I think an upgrade would'nt hurt even if it's still good (when I get the extra cash). When I get the tool I got to take it out and lube it up, for now at least. Thanks

 

[Bataivah]

I guess I have to find a PowerSpline removal tool now. I need to make something.

 

[AndrwSwitch]

It looks like the threaded sleeves on the powerspline have the same internal splines as other cartridge bottom brackets. I'd probably just go to my shop and get the tool, though. I've learned not to assume things match an industry standard when working on bikes, and by the time you add shipping, it's likely to cost as much to order via the 'net as to buy from a shop.

These things usually go in with a massive amount of torque. So you might want a torque wrench, breaker bar, or both.

EDIT: You know about the LX crank on Jenson? I kicked my own ass for buying an SLX when I found out about that deal...

 

[frdfandc]

The cracking/popping noise is probably the BB creaking where it threads into the frame.

If the BB spins smoothly, and only the noise happens when your hammering on the pedals, then the BB needs to be removed, the threads on the BB and frame cleaned, and grease applied to the frame. Reinstall the BB.

 

[Bataivah]

After finally getting the tool, I took out the BB and found the grease is pretty much gone and there is some wear to it. I replaced it with a Stylo GXP crankset (External type BB)
and won't use an internal type again. Now I can easily clean and re-pack the thing. It's
also lighter and stronger than that Power Spline is. Thanks guys.