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what should I go for?
Square taper IMO unless you're a regular BB snapper or don't mind forking out a chunk of cash for one of the few decent ISIS BBs.
Square taper.
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Ok then I think that answers my question! Square taper it is.
If you need more, try these threads...
http://www.singletrackworld.com/forum/topic/isis-or-square-taper-middleburn
http://www.singletrackworld.com/forum/topic/middleburns-isis-or-square-taper
http://www.singletrackworld.com/forum/topic/isis-or-square-taper
...although as per what postierich said. 😀
Put a Middleburn RS8 crankset on a Royce sq taper axle just before MM. Carried an allen key arround for the first few rides just to ease up any slack, but now nice and solid. I'm 15st and can't notice any flex.
The bike has done 4k miles at the mo - at a cost of 4-5 XT HTII BBs... I'll post again at 10k to see if the Royce BB has met expectations!!
I've got both sorts. No difference really especially if you are going to use a decent quality BB.
Square taper. Mine are 3 years old and are as great as the day i fitted them... Plus I'm only on my 2nd BB 🙂
I've got 2001 Raceface turbine LP cranks on a signature XS bottom bracket that link via ISIS. I'm only on my second set of bearings in that time. I'm happy with it and I'm known as a fussy bugga.
I've got 2003 RF Turbines on a Signature BB now on its second frame, bearings replaced at eighteen months. Running perfectly, and none of the creaking that usually dogs s/taper, or the tales of woe accompanying a wrecked crank after a bolt has worked loose allowing the crank taper to round off. Which used to crop up on here with monotonous regularity around the time I first came on here in '03.
go for square taper and if you can afford it a phil wood BB,these things have done 10,000 miles in alaska snow,sand and ice,mines smooth as silk,crank spins like a front wheel,actully too nice to hide away!
[url=
]phil wood 100mm BB[/url]
My ST set up is creaking at the moment. RS8s onto Royce ST BB. Anyone know the correct torque settings perchance for this set up. The Middleburn site doesn't seem to cover it 🙁
RS8's and square taper Royce Ti BB BB here. Very light and durable, no problems.
No idea how far they've been ridden. A lot probably.
Royce state that crank bolts should be done up to 20lbft.
From the Royce instruction leaflet:-
6. Thoroughly clean the crank arm taper and axle tapers using an air drying cleaning fluid (such as Methylated Spirits) When clean DO NOT apply oil or grease to the axle taper or crank arm taper.
7. When fitted by hand, both crank arms should sit between two-thirds and three-quarters of the way up the axle taper.
6a. STAINLESS STEEL END BOLTS: Each Royce end bolt, complete with
spring washer (Bellville) should be fitted as shown in the il/ustration and the threads greased with assembly grease. Tighten each crank arm onto axle taper to 20lbfft (27 Nm) torque.
6b. TITANIUM END BOLTS: Each Royce end bolt, complete with spring
washer (Bellville) should be fitted as shown in the illustration. Apply an anti-seize compound to the end bolt threads, then tighten each crank arm onto axle taper to 20lbfft (27 Nm) torque.
6c. ALUMINIUM END BOLTS: Aluminium end bolts should be used only to retain fully tightened
and bedded in crank arms. Only after step 7 has been completed using stainless steel or titanium end bolts, can aluminium end bolts be used. Tighten each aluminium bolt to 141bfft (19 Nm) torque.
Top of taper7. Crank end bolts should be re-tightened to 20lbfft (27 Nm) torque after each of a series of short (100 metres) rides that increase in intensity. This process should continue until the end bolts stop rotating and the cranks have fully bedded-in. When fully bedded in, the inside edge of the crank arm should not reach the start of the radius at the top of the axle taper.
Thanks. Going to do it now 🙂
Been using the SKF ISIS with Middleburns on my SS, rise it all over Scotland, Dalby, Peaks etc and with my children (both) on trailer and crossbar seats so it does get hammered.. The BB is fine but the arms keep creaking, torques all ok, no flex, basically I have to keep greasing them.
The tolerances have to be perfect cos tightening the bolts nore wont really help as there isn't a taper.
I would go SQ taper next time
Sorted now- fingers crossed.