I like the look of the middleburn cranks but i have no experience of either of these BBs. Which is best and what make would you recommend?

Anything but isis! Almost all isis bbs have silly small bearings and it’s not uncommon for them to die in one ride…

So what about square taper then? who makes a good one? Will i need more tools in my collecttion

Shimano square taper BBs ROCK.

Given this choice I’d go square taper and with Shimano. If you don’t have a BB tool then you’ll need one of those.

Bez beat me to it and said it better….

HTH

Not all ISIS b/b’s are cast from the same block though – I chewed through the no brand one that came with my bike in 2 dry months, an FSA platinum lasted 3 – the SKF I replaced it with has outlived 3 chains and a set of Middleburn rings

ISIS BB with large ball bearings

There are a few that last

Square taper generally last, but will be (a little) flexier (having a narrower axle)

My isis has been on my Middleburns for 3 years now since I bought them, good as gold, FSA I think.

‘I have no experience of these bb’s’
WHAT! Sorry, but square taper is the standard crank fitting for at least half a century, and is used on practically every bike you’ve ever seen, and ISIS is getting on towards a decade old. FWIW, most people will probably recommend square taper, as the bearings tend to be pretty long lasting, and they’re cheap. ISIS uses a large diameter axle, which means the bearings are smaller to fit into the BB shell, which can compromise bearing life. However, properly fitted, a good ISIS will last a long time, I have one that’s six years old and is on it’s second frame. New bearings were fitted at eighteen months. That one is a RaceFace Signature, and SKF do a really good one starting from around £35ish, going up to a totally stainless steel one. The disadvantage with S/taper is the crank can be wrecked if the bolt slackens off allowing the crank to move on the taper. ISIS is a spline which gives much greater surface contact, so if the bolt slackens the crank can move outwards but won’t ‘rock’ on the spline causing failure. Middleburn cranks are probably the best out there, and, coupled with a stainless SKF bb will be as good a set-up as you’re likely to get. It’s what I would use my self, based on personal experience.

CountZero, some good points there and it looks like SKF have a product that would change my view. My experience is based on a friend who went through 3 raceface BBs under warranty until it was replaced with the signature one you have at this point he was happy – mind you the signature was £80 then – whereas even the cheaper shimano sq taper bbs were outlasting the £45 isis bbs.

I have only been riding(properly) for about 2yrs and in that time have only used external BBs which is why i know nothing of ISIS and S/taper. That sounds like good advice zero cheers

if you go the square taper route i’ve got an unused Shimano one for sale – price negotiable.
square taper for sale

The old UN73 Shimano square taper bottom brackets were so good. Its not unknown for them to be working as good as new after 10 years of hard riding I had one 3 years and it was like new., winter riding on it also. I’m not sure about the newer UN53/54 Shimano bottom brackets for square taper. I think I have heard they are not as well made. Will not be japanese made like the old ones. If you could still get hold of the UN73, then I would go for the sqaure taper. As dont think they make them anymore then it ma be better to go for a quality ISIS bttom bracket. I agree with most about the quality o ISIS though, I did 2 BB in a month! Truvativ though, so not high end like SKF. A crank is only as good as its BB a wise man once said!

I would just prefer Shimano hollowtech 2 cranks. Cant better them in my book. Sure the BB dont last for ages but a few years of riding and then buy a new one. They are a decent price too the H2 Shimano BBs

I did over 20k miles on a bike with ISIS bottom bracket made by SKF. Never had an issue. Middleburn with ISIS is great as long as it’s by SKF.

Anything but isis! Almost all isis bbs have silly small bearings and it’s not uncommon for them to die in one ride…

Massive over-exaggeration alert!