Truvativ BB replacement options
 

Hi all,

I'm posting with another bottom bracket question (this time it's my bike).

I was cleaning my drivetrain last week and noticed that my bottom bracket has some play in it (when you hold the cranks they can be wobbled by 2-3mm (at the crank ends). Rotating the crank when free of chain also sounds a little grindy.

I suspect the cartridge bearings in the bottom bracket are coming to the end of their life. They will have done 6000-7000 miles with my heavy (190lb) bulk on them so I guess it is to be expected, it is funny that this has never happened to me before, all my other bikes have been stolen before I've got to this stage.

My question is what do I do now?

Can I replace the bearings? I suspect not, in which case what bottom bracket do I get to replace this one?

I'm not sure exactly what the bottom bracket model is but the crankset is truvativ elita (circa 2003-2004ish) the bike is a cannondale R600 double from around that time although differs from the spec in their archive where they have shimano BB and crankset. Looking at the truvativ website the gigapipe ones look kind of similar to what I've got when viewed from the end (I've never removed the unit from the shell – never had cause to until now). I think it is probably worth keeping the crankset, it seems in reasonable shape, chainwheels are probably a bit worn but could be replaced separately later if necessary.

Do I go for a truvativ one again and if so do you think that the gigapipe ones sound right for the elita set?

I have a Truvativ Elita crankset on my 05' Cannondale R700. BB is ISIS drive so I believe you can only use ISIS bottom brackets with that crankset. I replaced my BB with an FSA Platinum Pro (ISIS) in February and am very happy with it.

Nashbar/TH ISIS BB's are an option. I installed on with an Elita crank on my RANS 'bent. They list 3 sizes currently.

These days, bottom brackets become a "disposable item". I assume you can get new cartridge bearings and press them on, but most likely, it'll be cheaper to buy a whole new BB. (I don't like the wastefullness, but that's another story).

There are not many common BB to crank arm interfaces. Three basic choices are ISIS, Octalink, and square taper. Octalink is proprietary to Shimano and square taper is a bit old school. Chances are, you have an ISIS interface.

No need to get Truvativ brand. As long as you match 1) the spline interface, ISIS, 2) spindle length, 3) bottom bracket width, any brand will work. I am assuming you have the typical type of bottom bracket threading. You'll find plenty to choose from, in fact, you may wish you didn't have so many to choose from.

Thanks for the replies, I hadn't thought of other ISIS BBs. I'm pretty sure it is an ISIS BB as it is splined and is not shimano.

Sounds like I'm going to be bewildered by choice now.

Presumably the measurements of the present one will be written somewhere on it or do I need to get my calipers out?

Truvativ is ISIS.

Usually, the critical dimensions are on the BB. You might see a number like 73x113, which is a 73mm wide shell x 113mm long spindle. You may also see a number like 1.37x24, which is probably the most common bottom bracket thread diameter and pitch, 1.37" diam x 24 threads per inch.

Note, some bottom brackets work on either 68 or 73mm shell widths (those include a 5mm spacer).

At worst, you can measure the bottom bracket shell width of your frame with a ruler. The spindle is easiest to measure with a caliper, but you can use a big c-clamp as a contact gauge by clamping on the width of the spindle, remove the c-clamp and measure the c-clamp opening with a tape measure.

Two bearing rows or three rows?
Steel or titanium?
Cross county or downhill?
FSA, Truvative, Crank Bros, Race Face, SKF, Suntour?

Thanks mudpie.

OK, I'll have to have a close look when I have a go at extracting the bracket from the frame to see what the measurements are, failing that I get my calipers out.

I've read sheldon's articles about BBs and chainlines so feel pretty well briefed as to the crucial parameters so I should be OK but I will post back here if I have any trouble determining which one to buy.

I'm not going to think too much about that long list of other variables you list and I think my choice will be fairly limited by stock levels wherever I source the bracket from as because I have to take the thing out to see what size I need I'll be out of the saddle during that time and I'll want to be back on the road as fast as possible so cannot wait for things to be ordered. Main thing is it fits and is of good quality so I don't have to change it again for another 6000 miles or so, shouldn't be too difficult.

Cheers again

Be aware that some Truvativ cranks/BBs use a proprietary "Isoflow" interface. It looks like ISIS, but there are a different number of splines (ISIS has 10 splines; can't remember the number for ISOflow). The crank should say "Isoflow" on it if that's the case.

You can measure the bottom bracket while it's still in the frame. Measure the bike's bottom bracket shell width (measure only the frame, not any parts of the bottom bracket cups). It will be either 68 or 73mm. Then you can remove the cranks and measure the width of the spindle, assuming your calipers have the depth clearance, or use my c-clamp gauge mentioned previously. You'll have enough info to purchase a compatible BB. Also note JiveTurkey's note, about ISOFlow and check the crank for "ISOFlow" designation. I assume if it's not ISOFlow, then it will be ISIS