Having worn out yet another drive train, I find myself with a dilemma.

I have, until this point, always had a square taper bottom bracket, and find that they have a tendency to creep over time so that the rings seem to spin out of true.

I'm wanting to replace with either a splined or hollowtech type, both of which I think should remain true.

Now, I've watched a service video for hollowtech cranks, and was informed that "this is the bit where grass can get caught" between the crank and bearing.

Is this really a problem? I ride a lot in the grass (to avoid the mud).

Any comments? Experiences?

Remember I commute on this bike 90 miles/week, 20 of which are down a muddy byway, so I don't really want to be stripping the cranks every other day...

I would suggest that a square taper bb would wind more grass in than a HollowTech II because there's more axle exposed. On HTII the gap is minimal, so you shouldn't have an issue. I don't think splined is a good option, as the bearings are smaller to make room for the bigger axle, so won't wear as well.

My thinking was the gap is bigger so it doesn't matter if there's some grass wrapped around. I was worried a smaller gap with grass would create resistance and ultimately wear...

Does this happen, or is the gap small enough that there is no grass caught?

There should be no gap, and therefore no grass. The HTII principle is similar to doing up an a-head headset, where you pull it all together with a fixing bolt in the left hand crank until there's no side to side play on the axle, then tighten the left hand crank pinch bolts.

oer the last 3 years i have used Suare taper, ISIS and HTII.
i have to say i prefere the HTII out of all of them.
i hav had a problum with destroying the bearings in both Square and ISIS in about 3 months.
the HTII has yet to die (but i changed anyway for ceramic) after 14 Months.
i have had no issues with grass in any of them that requires a strip and rebuild.
if you have the cash, want the longer bearing life, and want some cool new tools.....go HTII. the Truvative is the same design principal as the Shimano but a different drive side Bearing.
again i have used this and had no issues....except getting ceramic spares..
my advise splash the cash...go HTII....you wont regret it.

I agree with Mark and Pat that HTII is the way to go, although I never really had many problems with square taper.

I find HTII more direct to pedal and easier to maintain. I agree with Mark's comments regarding the grass, although there was some cacky grass lodged near my bearing when I replaced it.

Go for a well sealed bearing. My XT bearing lasted ages and when it finally went I sent it away to BETD to fit new bearings - it's my spare. I bought an Aerozine bearing from Superstars Components for my Litespeed, but I suspect that is already needing replacement. Moral? Spend the money!

PT

Engineering wise a sqaure taper is stupid, as one is putting a high torque loading on a tapered stress point. ie soon er or later it is bound to enlarge the hole in the pedal crank. Standing on the pedals over bumps is really tough on square tapers. The straight splined sytems are infinitely better. HT 2 seems popular with the previous chaps. I have had good results with HT2 and the Raceface equivalent. cheers

Tom R