I'm currently using some cheapo Truvativ ISIS cranks (with a decent BB). Looking to upgrade in the near future. Should I get Shimano SLX or stick with ISIS and buy some Middleburns.

Despite loving Middleburn cranks, I'd get rid of the ISIS. It just doesn't seem like it's going to last much longer. If you do get Middleburn, go for the X-type or square-taper. Otherwise, SLX are very good for the money.

Ok so assuming I rule ISIS out, is square taper still really all that?
I really like the Middleburns but the SLX's look nice too.
I have had no experience with cranks that use outboard bearings and I'm a bit dubious tbh.
Been using my ISIS BB for nearly 2 years and it's still working 😮
albeit with a slight side to side movement that's started recently…

Shimano square-taper BBs regularly last upwards of 4-5yrs, but can be heavier and are not as stiff as external types. Some people also break the axles, but this is extreme.

External seem to last about 6months-1yr on average, but this varies based on what brand and how much maintenance you're willing to give it. The system itself is stiffer and generally lighter.

I have square-taper Middleburns on one bike and have just fitted my first ever external BB to another. There is a noticable difference in stiffness, but I've never ever had a problem with square-taper. I only got the new chainset (Gravity Light double+bash) because it was an amazing deal.

I was rather hoping that Middleburn would develop an 'adpater axle' that allowed you to use their sq taper/ISIS cranks with an external BB.

I've got RS7/ISIS on two bikes and shimano cranks/external BB's on 2 more – external are stiffer but the RS7's look nicer 😉

Got RS2, RS7 and RS8, 2 on royce BB 1 on race face all Sq Taper.
Have tried King and FSA Megaexo BB external, both had issues with wear where as little wear showing on sq tapers.

Just to throw something else in….
I've killed a Shimano UN52 (square taper) in as little as 5 weeks. Used to generally get about a year out of Xt/UN72s. XT Hollowtech BB is going strong after 2 years on my current bike with zero maintainance.
I ain't seen Middleburns new crankset yet, but no doubt it'll be quality. SLX is great and hard to beat for VFM.

I get about ten months out of a UN52/72 BB – ride three times a week on average with that bike.

Ok, I can get Middleburn cranks with square taper for under 800g.
Anybody know the weight of SLX cranks & BB (without rings etc)?
BTW, the cranks will be going on my commuter, so no extreme use!

Middleburn do a crank that'll work with external BB now, I just got one and it looks the mutts

I'd like to say it feels stiffer etc but to be honest I'm a bit rubbish so probably wouldn't notice the difference, plus I opted for a shorter (170mm) crank arm and double/bash (24/34) so it's totally different to what came off. I was trying to build a bike around as many UK manufacturers as possible and always liked Middleburn.

Edit to add: I just checked the Middleburn website and they still haven't got them on there(!). Give them a call or get your LBS to contact them for you. You know it makes sense 🙂

tonyd – where did you get those from and can we get some pics?

I got them through LBS – Mountain Trax in Wokingham.

Hang on, I'll go take some pics now!

Hmmm X type is an option but quite pricey for what i need them for!

Here

Nice, but do they do the duo yet? and how much are we talking?

£173.99 at Activesport

looks a lot like the tried and tested RS7/8 look but with an external bb axle. Does it come with a BB or are we supposed to live with all the ones which keep wearing out within about a years time?

Sod it, can't seem to link to pics. They're here. Bashguard is E13 turbocharger.

http://tonydalton.smugmug.com/Random-Pics/Random/12682570_HHRqJ#912354158_TCeLq

No BB included 🙁
Back to the original decision between square taper Middleburn's or SLX for me!

And no, doesn't come with BB

Skoolshoes – Member

No BB included
Back to the original decision between square taper Middleburn's or SLX for me!

??? You can get an XT BB for 30 quid, why pay all that for new cranks and not just get a new BB too if you want to move away from square taper?

http://www.merlincycles.co.uk/chainset-bottom-brackets/xt-hollowtech-11-bottom-bracket.html

It seems a completely random comparison tbh, complete SLX with rings and BB costs less than the arms alone for Middleburn surely?

If you go for external b.b you must have your frame faced to get a good life out of the bearings, the b,b relies on parallel faces of the b.b shell, square taper b.b do not. You can still fit the b.b your self but take the frame to a bike shop for it to be faced, it will not cost much if the frame is already and stripped.

Money and weight are also factors! SLX £90 or Middleburn square taper £115 with UN54 BB.
£200+ is a bit out of my budget.
Think I'm gonna plump for the Middleburn square taper and maybe invest in a SKF square taper BB later on…

external are stiffer but the BB is just utter cheese. My SS square lasts for ever as does road bike but I am shocked at 6 mths worth from and external. I am quite light so the stifness is not that big a deal to me. Probably going to go back to square TBH.

I use Profile cranks and I know its not much use for most people but Profile Racing do the sort of external BB that last more than 6 months. Only useable with 19mm axles though.

proper bearings;
http://www.vintagebmx.com/community/lofiversion/index.php/t27037265.html