[Closed] ISIS v External BBs - are they *really* any worse?

[i]What's the inherent problem with them, and are there any good ones out there? [/i]

The bearings are too small, Yes there are good ones allegedly, but they are pricey

small bollies apparently.

FSA internal BB's last me a year if I'm lucky. Now on external BB's all round after my last internal BB went after 7 months. Thank god I stocked up in that CRC flood sale!

so (in addition to crap sealing from some of them), a similar issue to that of the external ones - trying to cram ickle bearings into too small a space?

latest Shimano and Hope external offerings are no worse than ISIS ones TBH

I changed from ISIS to external about this time last year and am still on the same bb (shimano), whereas with ISIS changing it every 3-6 months and tried FSA, Race face, Crank Bros...

ISIS by SKF lasts ages, no need to change after 4 years of using the bike as a teaching beast. HT2 seems fine but Shimano bearings ain't that good, I'll replace them with SKF ones as and when (wife wanted ceramic ones).
Truvativ, Race Face, FSA etc. can't make a decent ISIS BB, theirs last days usually. SKF can be had from Stif.

I've ridden and maintained my bikes since I was 8 or so - I'm 40 now.
I NEVER replaced a BB until ISIS came along. Suddenly I was replacing BBs every few months. I now have 6 different BB tools. IT'S A SCAM.
Here's a picture of a disintegrated Truvativ BB I took a few years ago. Marvel at the TINY TINY bearings.
[img] ?v=0[/img]

I too have gone for external, and I think the Shimano HTII stuf is good. You can replace the bearings for very little with a bit of determination and a hammer.

But, what was wrong with square taper? Nothing. At. All.

I spent a lot of money. Who won? Truvativ mostly.

al.

The SKF Isis works pretty well, it's the only one I've tried that does and I use it in preference to HT2 on a couple of bikes. The design is fundamentally flawed - big axle = small bearings - but SKF uses roller bearings on the drive side, which seem to last a lot longer than conventional Isis BBs with their tiny balls...

[i]But, what was wrong with square taper? Nothing. At. All.[/i]

For the most part, nothing, but when you start doing things on bikes that it wasn't designed for (big air), they started breaking. Big pipe don't break, but bearing life is shite. both issues more or less sorted with external.

Progression, of a sort.

Shimano Octalink was the best in my experience. I got an Octalink XT HT1 to last 5 years before it died on me. Never had a HT11 last more than 18 months

They are small balls though

I have the truvativ external isis bb - howitzer. Had the same one for three years and it's been in three different frames including a trials bike. No wobble. Heavy but lasting very well. I ate two normal isis bbs in 6 months before that....

I've tried 6 different ISIS BBs & apart from Raceface my problem wasn't the bearings but the creaking that I couldn't get rid of after a ride or two, I used grease, no grease, copperslip, different bolts, different cranks - gave up in the end & went back to square taper & all is well again.

I hope I get a few replies to this comment. I wanted to start a new post on it. I think there is a BIG fault with external BBs when used in cromolly frames.

Trouble is that external BBs use plastic spacer washers. When you torque the bb up using these plastic washers that press against a thin walled cromolly BB shell, the washers distort. this is made worse with an "actively ridden" bike e,g drops etc. This distortion puts the bb minutele out of line and damages the bearings.. Forget facing that wont help in this situation.

This doesnt happen on aluminium frames as the BB shell is thicker diameter.

Mr Shimano please could you make aluminium washers?

Radioman - would self aligning bearings be better ?

I hear what you're saying hairychested. I've got the £85 Stainless SKF Isis BB's in 3 bikes, and use Middleburn cranks (RS7's and 8's) on 2 of them. I ride a lot, usually twice a week, and there is no hint of trouble after 2, 3 and 4 years respectively. Thoroughly recommended.

I don't think 50Nm is enough to distort the plastic TBH.

Self alligning bearings may be better. Nickc The 50nm becomes relatively huge when it is pressing against a bb shell with thin walls.(The shell on my columbus cromolly frame must be just a couple of mm thick). Plastic does not distort on Aluminium frames as the shell covers the whole washer in a neat "sandwich" between the shell & bb cups.

On a cromolly frame like my Cove Handjob(Columbus) the plastic washer stands proud of the bb shell(overlaps it) all the way around.

Radioman Anyone who has access to a lathe could make you some spacers quite easily I remember a guy on this forum who said he worked as a machinist perhaps if you put a new topic on the main forum you would get someone offering to make some for beer money

[img] [/img][url= http://www.superstarcomponents.com/ISIS.html ]ISIS BB, but with big bearings[/url]