Since most new cranks and bikes come with the ISIS (or Shamono splined equivalent) crank/bottom bracket set-up, I assume a fair number of these have made their way onto touring bikes and commuters. How do these hold up? Reviews of threads is mixed with the biggest complaint being durrability but most of that comes from the MTB forum. A search of the touring and commuting forum did not produce one complaint about this.

The other more bullet proof option would be to use a Phil Wood square tapered BB and crank but it is a lot more $$$ and it seems to me that most touring bikes do not go that far.

And for the record I doubt that I could tell the difference in stiffness between a square BB versus a ISIS BB. In fact I am not even sure I know what that means.

First of all, you will be able to tell the difference in stiffness between a square taper and splined b.b./crankset-it's very noticable. Splined systems are lighter, stronger, and stiffer-ultimately making them more efficient. Second: if properly installed, they're a very durable interface between bottom bracket and cranks. And third: they're all anyone sells anymore.

The reality is that, although splined BB's are an improvement in the performance department, I don't know that they're necassary for a commuter/tourer. I struggled with this choice when building my last commuter/tourer, eventually deciding to go with an ISIS system. I initially installed Shimano's Octalink Ultegra but the drive side came loose (just once) and, over the course of about a year, the splines and teeth showed noticable signs of cupping and rounding. I switched to Bontrager's Elita for Cyclo cross and they've been perfectly problem-free on my daily commute and several multi-day on/off road tours. I think the difference is that an ISIS spline continues throughout the entire length of the crank/bb interface as opposed to Shimano's partial use of splines/teeth (the 8 splines/teeth cover roughly 1/4 to 1/3 of the interface with the rest being smooth pipe billet), I never really felt confident with that system. Years ago I also had some problems with Race Face ISIS cranks installed on a mountain bike. They loosened 3 times and each time the shop mech. assured me that the problem was corrected. I finally took it to a different shop who installed them properly and I had no problems since. I do all my own work now and have realized that the critical thing when installing ISIS cranks is that you ensure that the crank and bb flange mate up perfectly, that may mean re-positioning the crank until just the right position is found between splines and teeth in the crank arm (also make sure to use plenty of grease).

That said, touring and commuting bikes are really about reliability. For the same reason I chose bar cons and cantilever brakes over STI and disk, square taper bottom brackets could be preferable. Of all the bikes I've ever owned, I've never once had an issue with a square taper system. Ultimately, with the proper installation of a quality ISIS system, you'll certainly get better performance and, most likely, get comparable reliabilty. I trust my current bb completely now on 2 of my 4 bikes and will use one of them next year for a (potential) Trans Am ride that I'm planning.

If you go ISIS, use a 4 bearing BB such as a Truvativ Gigapipe DH or a (pricy) Race Face Team. I have ridden one of these (gigapipe DH) for almost 2 years (high 4 figures km, offroad) and it is still good. The race face has replaceable cartridge bearings in a fairly common size.

The other option is one of the new external bottom bracket cranksets. Again pricy. Loctite the bolts. Get your bottom bracket faced. A bit too flash to find parts in out of the way places, but stiff, light and excellent bearing life (again, replaceable cartridge bearings).

The truvativ and the external BB cranksets require specific, but not uncommon tools. The Race Face uses a regular shimano BB tool if that helps.

If I was really riding off the beaten track internationally I would choose the Phil Wood. I ride my ISIS equipped mountain bikes to some places that would be a long long walk out so I wouldn't worry too much about an ISIS for 'civilised' touring as long it is a model known for its durability.

Thanks for the responses. With the number of LHT frames being built up I am surprised more has not been said about this subject because this is something I am really struggling with too.

As far as performance goes, you are probabley right. Its just that I never was aware of a flex problem with my square taper BB. Maybe I will notice it when I switch to ISIS.

I think I am going to go ISIS. As my part situation is it would be more conveinent and cost less. I will probably go with the FSA Platinum Pro as it seems to get enough positive reviews. I looked back over a lot of old threads on LHT builds and a lot of Shimano cranks are going on. These people are more or less in the same boat I will be in and I have not heard a lot of complaining about these failing from the non-MTB community . . . . and if there was ever a real need for the square tapered Phil Woods BB, it would be with some of the MTB guys and the problems they have had with BBs. Although I suspect as rough as these guys are with their bikes, they may break that too.

Having said all this, I thought long and hard about square tapered BBs and their reliability. The Sugino XDs go on a lot of LHTs too and the UN73 BBs are still available. I went against that for two reasons:1.) I would have to by two extra chainrings to get the gearing I want because the Sugino does not come with what I want. 2.)I kind of hesitate to put something on my bike that is clearly on the way out.

Just to let you know, I went through a similar decision in building up two LHTs recently. So I think it's just a silent struggle on most of our parts....

I went for the Suginos and UN-73's. Two big factors for this decision: cost, and the fact that all my bikes have square-taper BBs (although a few different sizes) and 110/74 chainrings. I've never had problems with square-taper, have the mechanical knowledge, have the right tools, I can swap cranks and rings, etc. As said above, square-taper BBs are no disadvantage for touring.

For me, buying all the parts for a build is like a juggling act. Before I ordered the Sugino cranksets, I found UN-73 BBs on deep discount and stocked up on 'em, so I have a couple spares for each bike. That should take me up till mid-century. Once that piece was in place, I ordered the Suginos. Lots of the build was like that: sourcing brake parts, shift housing, etc. I ended up with quality where it counts, at low cost (my primary goal, I admit).

Square-taper BBs may be harder to find in a few years, I know I have to look hard to find UN-73 or UN-53 at a good price. This doesn't faze me now since I have spares. As far as repairs on the road, if worst comes to worst and I couldn't get a BB, it would be time to go for a whole new crank. There's worse things to worry about and really, that's a pretty slim possibility.

I don't have experience with ISIS cranks, but you can't go wrong with the design. As mjw16 said above, there were early designs of splined BBs (octalink in particular) that you should stay away from. But it'd be tough to find a bike in a showroom without ISIS cranks now. Either square-taper or ISIS is a good choice for a build. It looks like you've got good criteria.

I'm curious, what gearing are you going for? The Suginos have 26/36/46, which in my mind is about as close to perfect as you can get for touring.

-- Mark

It is 48/38/28 with the Harris Cyclery 11- 28 cassette. I will be running 26 *1.25 tires, which reduces the gear inches as compared to a 700cc tire so the slightly higher gearing may compensate for that, although I have not crunched the numbers on this. Also, the bike will mainly be used for commuting with occational touring. I have nevered toured but yet, but I do commute with fairly heavly loaded Ortlieb panniers. Overall this is just a guess and it is a first step away from my MTB set up of 42/32/22, which is way too low.

Well, this is a topic that attracts a lot of opinions. But that gearing sounds a bit high for actual loaded touring ( <---- my opinion )

Lots of factors involved, so each has his/her preferences and abilities. I have 46/36/26 with a 12x32 on the back, and have only had to walk up one hill with my loaded bike. (Anyone been on the Pacific Coast trail, south of Belfair WA on the route uphill from the Hood Canal???? Arrrghhhhh!!!)

For commuting, sounds good. For touring, you might want to try out some big climbs with a full load first.

I also run 26x1.25 tires. Otherwise I'd probably want a 46/36/24 in front.

-- Mark

That could be very possible and I may need to reevaluate before going on tour.
Thanks for the feed back.