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I'm a bit confused with the sizing of these BB's.
Changing from HTII to ISIS as I am replacing the whole crankset... and I'm struggling to understand ISIS bb sizing.
Its going in to a Mojo which has a 68mm shell... so basically what is the one to go for?
What does the ISIS 108 or 113 relate to?
Any help appreciated.
Thanks
What does the ISIS 108 or 113 relate to
Spindle length.
The 108/113 measurement is the length of the axle, not the bb shell. So you'll still need a 68mm bottom bracket and most probably a 113mm axle for a mtb.
The shorter the axle, the smaller the q factor but the chainrings may foul the chainstay.
113- mtb
108- road
You'll understand it after you've replaced it about a dozen times in the first year! Why on gods earth would you go to ISIS???
It's the axle length btw.
Why?
Why?
Why?
Get a Hope BB if you are worried about longevity.
Why?
Thanks,
Reason I am looking is that the RF cranks I have, are failing after quite a few years use. The metal spindle has worn the alloy splines on the drive side to the point where they no longer fit without wobbling and its only going to get worse.
I dont spin the gears but push higher ones so maybe the cranks get a harder time... dont know.
In the same time I have replaced quite a few HTII bearings Ms Rickmeisters Howitzer Isis and crankset has performed faultlessly....
So its either a ISIS set up or, HTII where the loose arm is on the non drive side....
I think its 113mm to clear the chainstay...
The Truvativ Howitzer ISIS is very different to normal ISIS. The Howitzer has the larger external bearing like HT11 etc, while normal ISIS have small bearings crammed into the BB shell and wear out scarily quickly. The Howitzer will also only work with Truvativ Holzfeller/Husslefelt cranks.
Of course if you've got Holzfeller/Husslefelt, then the setup is really bombproof.
Thanks Steve,
I thought that we had a Howitzer fitted to one of our bikes but its all inside the bb shell with RF cranks fitted.....
6 years of racing ss on shimano ht2 cranks.....2 sets of hope bb bearings.
Say no more:0)
Wow - I've just trashed a pair of Enduro HTII's in 4 months (100km per week in all weathers) I'm assuming the Hope BB is very well sealed by comparison?
RF cranks I have
This is your problem. Just buy some XT cranks and it will be fine. Shimano have a NDS pinch bolt and RF don't. RF external BB cranks are properly shite IMHO.
Its the way RF relies on massively preloading the bearings to keep the arms on that kills the bearings. Shimano only preload them finger tight and the pinch bolt holds it all together, this results in a much longer bearing life. I have over 3 years on original bearings on my Deore crankset.
The superstar isis bbs last a long time. I've got 2 and they have both out lasted the skf ones they replaced. One is over 3 years old and has mainly been on a single speed
ISIS was possibly one of the worst BB variations we have gone through. Avoid like the plague as others have said, you'll be replacing that BB repeatedly. Enjoy the squeaking.
The superstar isis bbs last a long time. I've got 2 and they have both out lasted the skf ones they replaced. One is over 3 years old and has mainly been on a single speed
I've also had two superstar ISIS BBs - unfortunately, both failed within six months (the second being a warranty replacement).
the sqeaking, crunching and grinding lets people know i`m coming on my ISIS equipped bike.
it really does sound like it needs love. in fact it does need love bt its pointless as the next BB will need love almost instantly too.
i put up with the noise as i`m a cheapskate.
Thanks folks.. I know from experience that RF external bb's are mince, appreciate your thoughts on ISIS vs HTII
Decisions... I did ask about the ethirteen crans as it has a NDS loose arm but no replies...
I think I will have to get over the RF brand whore that I am and look at the big S.
These seems to be a lot of folklore about problems with ISIS that is not said about it's peer, Octalink. My wife killed an Octalink BB quicker than I wore out an ISIS, but people seem to be happy to accept Shimano as being disposable. Both systems suffer the same problem of needing tiny bearings to allow a fat pipe axle. The good news with both systems is that now they are old technology they are super cheap. All the bikes in our house are square taper, Octalink or ISIS; and who cares having to swap a £10 BB every couple of years. I spend less on this than brake pads!
having to swap a £10 BB every couple of years
My Deore HT2 BB has been cheaper. a £20 BB that has lasted 3 years with no maintenance.
mmm - my ISIS BBs seem to last ages - maybe I'm doing something wrong??
Rachel