Hollowtech 2

gotta_hurt

Are they much better than the hollowtech 1's? I've got xt's all round, but just got a Scott frame with LX hollowtech 2 crank...just wanted to know if they are worth putting on and upsetting the whole drive train which run gorgeous! At least they'e silver!

ride_whenever

What exactly do you want to do?

gotta_hurt

is the new LX better than the old XT's?

andyturner28

gotta_hurt wrote:

is the new LX better than the old XT's?

It is a lot lighter as the crank arms are hollow, hence "hollowtech" External bb. Stronger. Looks better. I am assuming it would shift better.

Andy.

gotta_hurt

but surely hollowtech XT are hollow as well?

andyturner28

gotta_hurt wrote:

but surely hollowtech XT are hollow as well?

Oops didn't read it properly :oops: I thought you were talking about the old old pre hollowtech XT's.

supersonic

Hollowtech refers to the hollow crank arms. However HT2 cranks also have integrated axles and external BBs.

Are they better? Well, my LX HT1 with octalink BB is cheaper and lighter than the HT2, and the bearings will last longer...

jpembroke

I have HT1 octalink on my Inbred and quite like it but I think you are misinformed if you think the bearings on HT1 will last longer. The reasoning behind Octalink was to create a fatter, stiffer axle but this resulted in smaller, less durable bearings than the old square taper BBs. The current restrictions of narrow BB shells on Road and Mountain bikes meant this issue could only be resolved by putting the bearings on the outside of the frame. So, we now have a wider axle for stiffness and larger diameter bearings for durability.

Of course, the best solution would be to standardise on a BMX BB shell in MTB and Road frames meaning that the BB could be put back inside the frame. I'm sure that HT2 is a temporary solution to the issue of stiffness and bearing durability. Frame manufactures WILL at some point redesign their frames to take a wider BB.

This sums it up: http://en.wikipedia.org/wiki/Bottom_bracket

For the record, my Octalink BBs tend to last a year whereas my square taper BBs will last 5 or 6 years.

gotta_hurt

Damm, thats a whole lots of info!

I think i'm going to leave the XT crank on, being a sucker for the "brand", looks flash to keep it all XT!!! :oops:

So, time will tell if the Hollowtech 2 is better than the original....

rob cole

Hollowtech II bearings actually last a long time if you bother to face your bottom bracket cups before installing them, but few people bother...and then whine about short bearing life

supersonic

"I have HT1 octalink on my Inbred and quite like it but I think you are misinformed if you think the bearings on HT1 will last longer."

Compared to external bearings currently available, HT1 and octalink bearings last longer, I was not comparing to square taper, that was not mentioned.

Despite similar bearings, octalink also lasts longer than ISIS, price for price.

jpembroke

I know you weren't talking about square taper; I mentioned it merely to illustrate the relative merits of each system and put HT2 development in to context, i.e.:

Square taper: low stiffness, high durability (narrow axle, large bearings)
Octalink: high stiffness, low durability (wide axle, small bearings)
HT2: high stiffness, high durability (wide axle, large bearings)

You may of course have other experiences of all these systems but the fact remains that Shimano developed the HT2 system in order to increase the durability of the HT1 system whilst maintaining its stiffness. Don't blame me, just read up on the reasoning behind Shimano's decision.

I have all 3 systems on my bikes: Square taper on Road and Cross bikes, Octalink on MTB, and Truvativ Giga-X-Pipe on Fixed. In terms of longevity I would put Campag square taper at the top and Octalink at the bottom.

supersonic

Indeed they set out to increase the durability with HT2, but so far it hasnt been seen with the majority of people who ride them.

rob cole

Indeed they set out to increase the durability with HT2, but so far it hasnt been seen with the majority of people who ride them.

again, this is often due to people retrofitting HT2 chainsets to bikes that had ISIS, square taper or Octalink without bothering to face the shell - for the internal bearing units this was not as critical, but for X-Type and HT2 it is so critical to face the shell and get the faces parallel otherwise it accelerates wear on the bearing

supersonic

Lol, even then people are reporting shorter lifespans! The 2008 bearings are better sealed though, so lets hope this year the design goal is fulfilled and we do see sets that can last over a year of normal riding.

Totally agree on facing the shells.

jpembroke

Come back square taper all is forgiven. Lets face it, if it was good enough for Tom Boonen to win Paris Roubaix, Tour of Flanders and the World Championships; and is deemed good enough for olympic track riding, then it should be OK for the rest of us.

dave_hill

supersonic wrote:

Compared to external bearings currently available, HT1 and octalink bearings last longer, I was not comparing to square taper, that was not mentioned.

Despite similar bearings, octalink also lasts longer than ISIS, price for price.

I have to disagree entirely as far as ISIS is concerned. In the first 12 months of ownership of my VT I went through 3 ISIS bb's (two RaceFace units and and FSA). I switched to HT2 for the fourth one and eighteen months later it's still going strong. Not a hint of play and it's as smooth as the day it was installed.

I can't comment on Octalink because I've never owned one, but as they use more or less the same size bearings I would have assumed that the longevity would be about the same.

One other thing that hasn't been mentioned is thatsince the HT2 bearings (and X-type) are outside the BB shell, there is less axial loading on the bearings as they are further apart so again they should last longer.

dave_hill

jpembroke wrote:

Come back square taper all is forgiven. Lets face it, if it was good enough for Tom Boonen to win Paris Roubaix, Tour of Flanders and the World Championships; and is deemed good enough for olympic track riding, then it should be OK for the rest of us.

I take it you're not a MTBer? I think that you'll find that square taper BBs are fine for road riding because a road bike's BB isn't under anything like the amount of stress that an MTB's is.

supersonic

Its all shoulds, ifs and buts. ;-) In the real world, it has been time and time again demonstatred that octalink BBs last longer than a price eqivalent ISIS. It seems that your experience with ISIS is typical of many users with swift wearing bearings (sealing is an issue too, not just bearing size).

As I said earlier, the latest designs of external bearings are better sealed, which hopefully will improve life. You are always going to get some users who report no problems at all, but from all the research I have done and speaking to shop mechanics and riders, as well as online reviews, the potential of HT2 has not been fully realised, with bearing lifes much shorter than expected.

Splasher

I have run Square taper, Octalink, ISIS and Shimano HT2 outboard BBs and my experience (actual not theoretical) is that in order of life from best to worst they are:

Square taper - fail at natural life expiry.
Octalink - fail slightly prematurely because bearings are smaller than ideal
HT2 - fail prematurely on an MTB due to loss of lubricant - last well on a road bike
ISIS - fail increadibly early due to double whammy of lost lubricant AND small bearings.

Hopefully SKF will manufacture properly sealed HT2 cups shortly!

jpembroke

dave_hill - I'm a very keen XC MTBer who currently uses an Octalink BB (which I have to replace once a year - sigh). I am also a road rider and cyclocross racer. If you think that BBs on track bikes and the bikes used in the Paris-Roubaix are not put under as much pressure as those used in mountain biking then I think you seriously need to read up on these disciplines/races. I'm not talking about downhill or trials here (I realise that is a different kettle of fish where a snapped BB is common); I'm talking about what most of us do: cross country riding. The loads endured by bikes used on the track and in the northern classics is extraordinary; way more than what you or I put our MTBs through. Go to Youtube and search for 'Paris Roubaix A Sunday in Hell' and watch the race sections over the cobbles. It may give you some idea of what I'm on about.

Splasher

Square taper is plenty strong enough for XC. It was the ever increasing jumps and drops of DJ, FR and DH that pushed it strength wise, but there was also the desire to make BBs lighter for XC. The M12 axles were stronger than square taper, whereas the M15s were lighter.

Of course, the bigger axles meant smaller bearings and the rest is history, but for anyone riding XC wanting the ultimate life and not too fussed about weight, get a square taper BB and a Middleburn crank IMO.

As for the Hell of the North, sure it's rough for a road race, but the impact loads are not the same as someone landing a drop, particularly since the riders are seated for most of it (ouch). But anyway, let's not have a road/XC/FR p1ssing contest, it's all cycling to me.

supersonic

I have just upgraded my 97 LX chainset and BB to the 2004 LX octalink. The square taper UN52 BB performed faultlessly, surviving many 1000s of miles through some pretty nasty terrain including some drops and jumps. Eventually though it has started to loosen, with notcicable play, and the crank is past its best.

The new LX set up is MUCH stiffer - suprisingly so.

glasgowdan

The experience of everyone I talk to, and personal experience, is that square taper lasts forever, but you can't get the nice shimano cranks in square taper, so they use octalink, which lasts well enough. HT2 bearings do not not last relative to these two. This is probably because they are more exposed. Everyone I know who fits them faces their BB shell.

I wouldn't spend the cash to change from HT1/octalink to HT2 in the name of weight saving etc. A good BB with an XT HT1 crank is the same weight as the LX HT2 set-up.

ISIS doesn't factor in any equation - why does it still exist?

Matteeboy

Had LX Hollowtech 2 on my old Stumpy (the last Strongarm crank died) for a year and it's been brilliant. I do serious mileage and destroy kit quite readily.

Didn't go for XT as I was worried about durability.

My new Stumpy (2007) has Truvativ Stylo but I reckon the Hollowtech 2 is probably better.

Splasher

glasgowdan wrote:

I wouldn't spend the cash to change from HT1/octalink to HT2 in the name of weight saving etc. A good BB with an XT HT1 crank is the same weight as the LX HT2 set-up.

HT1 XT with an XT BB is actually lighter than LX HT2:

XT HT1 + ES71 = 877g
LX HT1 + ES51 = 927g
LX HT2 inc BB = 935g

All measured weights.

El Capitano

Bottom Bracket Scores this year:

Coiler - Raceface ISIS = 9 months before destruction.
XTC - XT Hollowtech II = 15 months of XC racing before destruction
Commuter - Shimano SQ Taper £10 jobby - still going strong, it raplaced the orginal one, which had done 4 year's worth of commuting.
Road - Campagnolo Record 8spd. Still smooth, fitted circa 1997.

That said, I do like the lightweightness of the Hollowtech II set I have and I'll be sending the borked bearings to BETD to be renovated with better bearings.

ride_whenever

acros bearings for HTII look pretty good as well