Isis B.b

[sharn]

Hey guys,

Just looking for a little advice or sharing of experiences regarding Isis B.b's

I remember that the conventional internal bearing b.b's never used to have much good said about them however I still see them used and sold for trials.. aswell as the newer Spanish press fit bearing which seems to more common now which is cool.

My question (before asking the inevitable question of.. what's the best isis b.b out there?) is has anyone ever tried putting sram gxp (22/24mm) external bearing, threaded b.b cups with one of the 22mm axles from a trial tech Spanish isis b.b?

I spoke to tartybikes about and they kindly responded with some advice that it 'may' be possible but may be difficult to do considering the 'real estate' for bearing contact face on the axle. It seems the amount of room one would have to play with is essentially the width of the black spacer that comes with the Spanish bb kit. 

So what im wondering is.. Would a (thin as possible.. such as the 'prime gxp' b.b available at wiggle) threaded,external bearing b.b for GXP cranks (24/22mm.. 24mm side can be reduced down with an available shim) work with the trial tech axle.. Or..

Not?

[AdamR28]

Doable but needs some 'engineering'. Would obviously not be able to use a FFW.

[sharn]

Okay, Im thinking the 'engineering' might be something like angle grinding a few mm off the inside, b.b inter-face section of the crank arms?

SO naturally my second question would then be, For £50 and a bit of faff does anyone have an opinion about whether that might be of any benefit compared to buying a relatively priced internal bearing b.b?

If not, which is the best isis b.b to go for for that kind of price? There are Fsa platinums in clearance at crc.. Or Tensile have theirs going at rock n roll bikes for £20. Or are any of the b.b's from trials specific brands actually any better?

I remember SKF's were always the recommended choice before, or the superstar loose bearing but I think that's discontinued now.

Appreciate any advice or input  Cheers

 

[DYAKOV]

I remember back in the day lots of people spoke highly of truvativ givapipe. Think they’re a bit heavier than trials specific bb’s but I haven’t seen a broken one (they’re intended for downhill, so must be good quality). Also trialtech bb’s are good.

I remember that echo first bb axles used to snap a lot. Also I’m not a massive fan of the press fit bb’s.

Lastly, you could try and find external adapters for BB30 bearings and run a BB30 bb like clean or crewkerz.

What kind of a bike is it going on?

Edited December 8, 2021 by DYAKOV

[monkeyseemonkeydo]

Just to add a bit of info, I've been running SRAM GXP BB's on my mountainbike for a few years and am lucky if they last 6 months of fairly light use. I've been thoroughly unimpressed by them. My most recent one is a Wheels Manufacturing one with Enduro bearings which hopefully will do a bit better but worth keeping in mind.

[sharn]

Thanks for your reply,,

Yes I remember the gigapipe being well regarded but wondered is that in comparison- like best of a bad bunch? Ive heard many people just wrote off isis (with a threaded bb) due to the bearing issue. Now ive been out the loop some, and mostly only ever ran square taper or 48 spline with press fit for any length of time. Ive never really used isis for very long but I remember hearing that the bearings are so small that they don't last. Albeit this is more from mtb'ing.. which I suppose it could be argued that trials Is quite different in that we don't actually 'cycle' half as much and likely to avoid bad weather more often.

Im not concerned in terms of snapping b.b as such, more about bearing life. Saying that, im only just getting back into riding so Im hardly going to be putting the thing through its paces at the moment.

To be honest I may be trying to make a 'solution without a problem' if people have found conventional b.b's sufficient.

If so, what have people found is the best option? I don't mind trying a few but thought might swell ask before spending my hard earned! Currently threw a cheap nicco one in there while I weigh up my options. 

Its going on a stock trials bike (currently a Zona Zenith), with fixed front sprocket- king rear hub. Frame may change but its likely to be with another threaded b.b as I prefer geometry from days of old to be honest! Plus I don't have the money to buy newer stuff with all the newer fitments ( tapered forks, new freewheels etc etc)

 

 

 

 

[AdamR28]

Face drive side of BB shell, fit Trialtech Sport Lite BB, job done.

[sharn]

Sounds simple, obviously im worrying over nothing here. Two single sets of bearings but with extra balls? Website says 'durable enough for trials'.. I wonder how that would stand up for the Mtb'rs also? 

Perhaps the bearing issue was more with that discipline. Perhaps the idea would benefit some over in that scene more..  perhaps not everyone will be aware there's a trials specific Spanish b.b with isis axle that could be used? 

I notice that only the trial tech one has the 22mm diameter all the way to the start of the splines before it steps down a fraction.. The Echo and the ZTTO ones ive seen only have the 22mm section where the internal Spanish bearing would sit (inside the b.b) Looks like the same axle as on the trial tech sport lite.

MonkeyseeMonkeydo.. I Wasn't necessarily going to use the actual Sram GXP b.b, but a gxp compatable one. Even a 30mm could be shimmed down I guess?

Just a thought if anyone has Isis cranks they particularly like and having b.b trouble. But sounds like the trial tech it is then! 

Cheers guys