I’ve been having a look at Middleburn crank arms (ISIS) as a possible upgrade; lots of people seem to rate them but at the end of the day they do seem to be a bit expensive for a couple of solid lumps of aluminium and I’m not sure that they’d compare too well (for the money) to my old hollow forged XT arms.

My only experience of Middleburn products have been their chainrings (which again people seem to rate) which I hated.

What I do like is the modular arm/spider setup which would allow me to fit them to my current 3×9 setup and then switch to a Duo spider when I go 2×10.

What are people’s experience of Middleburn crank arm; are they really something special or is it a bit of a ‘label’ thing?

I’d say it’s a bit of a label thing for most, I have some – got them because I was trying to build as British a bike as possible – and I’m not sure I could really tell the difference between them and the 2004 XTs they replaced.

They work, they’re versatile, a reasonable weight and quite pretty if you like that sort of thing. Whether they’re noticably better, or even different, to your old XTs is highly subjective.

Oh, and take square-taper over ISIS.

I have 2 pairs for sqr taper bbs, use unos and duo set up – all very good, fit and forget plus Matt is a top bloke as well.

I replaced my Middleburn’s with Shimano Hollowtech II’s. I thought the latter felt stiffer and overall lighter.

Middleburn with square taper are still my cranks of choice. I have come to loathe press fit bb’s while external BB s also underwhelm me. I like reliable kit that lasts hence Middleburn get my vote.

I run square taper UNOs on my Curtis S1. Excellent things… Going to keep an eye open for some for my Five as well… HT2 BBs are quite simply utter shite compared to square taper IMHO in terms of durability.

When I move my legs they help make the wheels turn, just like my XT ones did.

But I think that they look better

Middleburn cranks, hardcore rings + Royce square taper. Fit and forget reliability.

my RS7 non drive side snapped at the BB axle. I still remember that 6 mile one legged pedal commute home vividly even though it was 15 years ago. I expect they are better made now though.

They’re alright. Can look perfect on the right bike, which is probably the only real reason to get ’em tbh… And they have very tidy single ring options etc. Otherwise, they’re a little heavier than XT, and the Middleburn rings are pretty rotten- though obviously you can fit better rings. But by the time you’ve spent more for the crank arms than it costs for a complete XT chainset with rings and BB, then bought a bottom bracket, then bought a set of rings, you may be wondering what the hell you were thinking.

They’re light, they’re strong, and they work. What could make them better?

Ah yes, they’re a British company.

Got 3 sets.
RS8 square on UN74
RS8 X-type on Chris Bling
RS8 X-type with press fit XTR
All triples and all with Blackspire Superpro rings.
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Performance and durability excellent. Interchangable spiders also a goood thing.
Downsides are the weigh and that the colour rubs off the black ones pretty quick.
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AVOID ISIS LIKE THE PLAUGE. Square is great, either UN74 or Royce if the budget will allow.HT11 X-types allow the use of CK BBs and they are fine, Shimano HT11s less so.

+1 for square taper here. What I like is the still look really good, ever after loads of mileage.

Middleburn is good kit, fact.

Have rs7 and rs8 both taper can’t fault either i have a fair selection of spiders and UNO rings

My only issue is working out how to fit a taper bb to a pf30 carbon frame
Never found an issue with stiffness but I’m only 57kg

Light, they work, are strong, look nice

Square taper BB’s last years, what’s not to like other than the weight of a square taper BB?

UN anything is fine but 54 or 55 works and is available

Not changed my BB for years, think its a 54? But was changing external (cheese) bearings every few months.

Frames come and go but my middleburns remain eternal

Have a set of x-types that dont fit on my new bike 🙁 lovely cranks they just work cant say o notice any difference over xt apart from they look better.

I have sq taper, Isis and x type, they all do the job, but man they look so good

I’ve had a few pairs over the years, still got one set with square taper on one of my bikes. I do like them, you can fit and forget them and they look good. I much preferred them to Shimano XT HT2 but I don’t think they are the best cranks in the world.

But recently I switched to Raceface atlas. Using a ht2 ceramic bb these are the best cranks I’ve used.

Love them. Rs7 sq taper on both my bikes as UNO on ss and using a Duo inner ring on my 1×10.
Have a little bit of taper damage to one set that is causing a creak but they are still soldiering on and at 12 years old I’m not too upset as I’ve had my money’s worth out of them. Happily Middleburn will sell me an individual arm direct too so I will replace it and keep them running.

Is ISIS still that bad then? I thought that the more recent designs had improved durability (Superstar ones are meant to be pretty handy)? It’s been years since I used a square taper BB (Octalink is still my favourite) is there noticeable flex?

I think theyve discontinued producing ISIS cranks and have simplfied the product range to RS8X and to RS7 sq taper.

your probably limited to secondhand or old stock

Happily Middleburn will sell me an individual arm direct too so I will replace it and keep them running.

In comparison, when I tried to order a single arm for my X-Type RF Deus cranks when the splines died I was told no, because each arm is specific to the axle. WTF – they all come out the same machine?!

They went straight into the bin. Goodbye £250 cranks and 18 months use…

I’ve come across a site selling reduced price ISIS Middleburns and I was under the impression that current ISIS BBs were more durable than of old, but I suppose that if nobody is making ISIS cranks anymore then ISIS BBs will start to disappear. For some reason I still like old style cartridge BBs so could go square taper.