cranks

The Square Taper vs. External Bearing Bottom Bracket Debate

Some time ago, on our local board we had a “discussion” on the pros and cons of square taper bottom brackets vs. external bearing bottom brackets.  The mountain biking crowd has basically split into two camps.

1. Square Taper Devotees
2. External Bearing (X-Type) Riders

Others, use some of both, but I think everyone has pretty much ruled out ISIS as an option over the past couple of years.

THE PRO-EXTERNAL BEARING CROWD

198′S THOUGHTS

I am all in on the external bottom bracket technology.  I have been running this style of bottom bracket since it’s introduction for several reasons.

• Stiffer – Larger axle and bearings
• Trail-side Maintenance – You can actually get the cranks off if you have to. A friend of mine blew up a granny ring at Dupont once and it would have been a long walk back to the car if it wouldn’t have been for externals
• Cheap BB’s
• Drag is unnoticeable on the trail – For me, this is a case of what you see on the stand does not translate to the trail…just my opinion.

It all boils down to personal preference and I think the pluses of externals far outweigh the minuses. There are people that can argue either way…but the industry is going the way of externals…so all of you square taper guys better start buying up the inventory.

Manufacturers also have to produce products to the widest possible audience. The racer/pure xc riders is arguably the smallest group of riders these days due to increased bike technology and market trends. 10 years ago…that was basically all there was, but that is not the case now. XT cranks see everything from xc to dh, so why would a company manufacture several product lines when one will eventually win out due to market demand?

The AM 5″ trail bike is the fastest growing market in mtn biking. Even now we are seeing larger travel bikes marketed towards more xc oriented riders because of light weight parts/frames that can also take long term abuse. External BB’s are a better fit for these types of riding styles and frames.

Phil Wood also makes some great replacement bearings for the external cups…but like everything Phil Wood, they aren’t cheap.

Probikewrench on the local forum had this to say:

I guess I’m a technology buff. Personally, I’d rather use the newer style cranks with an outboard bearing set-up (ceramic or not) than revert back to a square taper that is over two technological generations removed. No manufacturers are spec’ing it on completes… there’s definitely a reason for that. I’ll still run ST on my single-speed beater, but not on anything else. If you are doing it with some trick cranks or just in it to be a little different, by all means, go for it. It’s your bike. You have the final decision. Good luck!

Bikephan’s Statements:

weight is a small factor when comparing st to external. external bb weight lighter but then you have to add some weight to crank due to spindle. why a bike company would switch is how the market looks. it is the what is new that sells. you can put a $300 dollar st bb on A bike and most people would not care because it is not current. unless you have a knowlegeable staff it would be a hard sell. a st is only proven in regular riding or racing xc conditions.

the true problem with st is that is a press fitting, not an interface. there will be some slight alignment issues(maybe a white industry crank to deda bb, the companies will have slightly different margins of errors) but for the most part it is not an issue. a st will never be perfectly aligned(we are talking mm) due to factors of manufactoring. it does have a smaller q factor but now we have bikes with 83-100mm shells for strength. q will help with narrow hip people etc(most racers)

the orginal design of the external was to run a larger bearing with more surface contact for strength in crank/bearing interface. a external drive crankset is a stiffer design. you are not dependent on a m12/m10 bolt. now does the strength come from just riding xc or hucking mountains. that design came about to improve the strength to weight ratio due to cranks failures in the dh scene. when running a square taper i was blowing up bearings or with a heavy impact on bashguard could and has started to move my cranks due to a 4 piont press engagement. not the cranks or bb faults, it was the fact i was on 46lb dh bike with 10 inches of rear travel. this was a new area for mtb. people went looking for solutions.

the issues with bearings on x drive is that the oe bb companies use plastic shims to “help seal bearings”. that is why i prefer the enduro bearings since they design a metal to metal interface with their bearings. ceramic bearings have been used for quite a while, it was how to cut manufactoring cost to get it where it will sell. issues i have noticed with x drive is you can get water through the seatpost etc that can get to bearings on the inside where that is not possible on standard st designs.

THE SQUARE TAPER CROWD

Duckman had this to say:

Proven design.

I use an Action Tec titanium square taper BB(Cambria) on the race XTC. I wish all my bikes had the same setup. 145gms. Been in 4 frames to date since late 02. Spins about 25 times with new bearings(yes, they are replaceable. About $20 per set every yr or so if you race alot with some mud events).

Anyone can get ST cranks off on a trail plus a decent multi tool and self extracting bolts. Why is that so hard on a ST crank? And I’ve NEVER needed to pull a crank on a ride regardless. Thats not even a concern either way.

I bet most can’t flex or detect it on a ST crank. Thats crap. Theres LOTS of super strong roadie and mtb racers that are animals that still use ST with zero “flex” issues. I think thats a non issue for 99.9% of racers. Maybe Lance.. 

XT ST BBs can be had real cheap. And last way longer then “cheap” external BBs ever dreamed of. All the while performing better as well as lighter.

Speaking of “generations removed”…one could say that the Racer X is an “old” (but proven) design(like my Spider for that matter) also…and could also be argued a couple generations removed from current tech(again, like my Spider  ) itself. Somethings just don’t need “improving” much imo. But in BB design…that apparently means going to heavier, slower, wider(Q-factor), and apparently less reliable x-cranks(unless much more $ bearings are had).

Kokopelli said:

Okay, I have been giving this a lot of thought over the last few days (obviously). I think there are pros and cons of both designs, but I still question whether the pros of external BBs outweight the cons.

Then it hit me: The manufacturers are not making external BBs for the beneift of the riders, it is for their OWN benefit. The big advantage is ONE SIZE FITS ALL. Instead of making two (or more) different shell sizes and multiple axle lengths, they just package up one unit with a bunch of spacers and let the wrench sort it all out.

Now, this does give the bike owner one small advantage in that you can move your spacers around to get the perfect chainline for your rig, and eliminate some of the vagaries of internal BB manufacturing. But I know that at least RaceFace admits in their instruction manual that the spacers might create further drag on the bearings (they suggest you move or remove spacers if your cranks are not spinning smoothly upon installation).

edited to add: I guess another advantage is that they are easier to install and remove, which is good because you have to replace them so often

Some riders wanted bigger axels, and now they have them, but so does everyone else. While 5″ trail bikes are apparently a huge market, I question how many of those owners are actually using the 5″ of travel in a way that necessitates a larger axel. I know some of them clearly are, but what percentage?

I don’t mean to sound like I’m whining, I just question whether the “new” technology is “better” technology. I have ridden bikes my whole life, and I have been riding mountain bikes for 12 years. I never gave my bottom bracket a single thought until 2004, when I bought an ISIS crankset and the BB seized up after only 6 weeks of use.

Iridetitus…

herein lies the problem…i’ve got square tapers that are over 10 yrs old that still rock. they’re the king headsets of the bb world. i’ve been through 3 or 4 isis though i am now using the crank bros that has a 5yr warranty. no true experience w/ the outboard stuff, i’ll admit, so perhaps i was a bit hasty in judgement. of course, there are those that would never run carbon cranks and i’ve been rockin the same set on the titus since oct ’03 and i’ve hit some fairly big stuff w/ them.

what exactly are the problems w/ sq t other than their being an older design? the only things i can think of are perhaps rounding them off – which i’ve never done – or possibly flex.

The square taper devotees seem to find the Turbine’s from Race Face as the holy grail of hard to find cranks these days.

198′S FINAL THOUGHTS

A solution that I think would make everyone happy is for frame builders to start building in the external bottom bracket bearings into the frame.  The roadies have seen this for awhile and we are starting to see this style move over into the custom steel mountain biking market.  Overall, I truly believe that the external sets are a step up from the older square taper design.  The advantages they have over the traditional square taper bb’s far out weigh any minuses they might have.  What do you guys think?

Powder Coated Shimano XT Cranks

Fred at Wolfhound Cycles hooked me up with a set of sandblasted and powder coated XT cranks to go on the Terremoto. The black powder coat matches the frame exactly. I really couldn’t have asked for a better crankset for this frame.

I was having issues with the spacing of the Race Face Atlas set that I was using.  Something about the bottom out bold design with the small washer spacing just wasn’t meshing well with my frame.  On top of that, I am pretty sure that I bent the spindle and that was causing a horrible creek that continued no matter which bottom bracket I was using.

So far the XT’s have been perfect, and I am glad to say that the spacing and installation is much easier.  With the axle attached to the drive side and the simple load nut on the non-drive side, the cranks come on and off easier than any other set I have tried recently.  I had been using the cranks out of the Race Face stable ever since my move to external bearings years ago.  Now…I am wondering why I didn’t just start with Shimano to begin with. I tend to wrench a lot, sometimes even when I don’t need to, so the simplicity that these cranks display for install/removal is a huge plus for my needs. Some people may be a set and forget type rider, but that just isn’t my style.

These cranks also seem to be stiffer than the Atlas cranks they replaced. This may not be completely accurate due to the problems I was having with the previous set. Those symptoms might have caused the Atlas cranks to feel flexier when in fact they weren’t.

Complete Setup

• Blackspire SuperPro Rings 2×9 24T/34T
• Gamut 34T Bash Black
• Shimano XT Cranks
• Wicked Racin Dual Chain Guide (installation finishing this weekend.)

Coming soon…
The square taper vs. external bearing debate w/198′s thoughts…
Wicked Racin Dualrailleur Guide Review

2008 Sea Otter Classic – Syncros Components

More exciting news coming out of the 2008 Sea Otter Classic.

Syncros revealed their new products for 2008.

Photos can be found here on mtbr.com.

198′S THOUGHTS

I run the Syncros Bulk bars, so I am really excited to see new products in the Syncros line.  I also think I have found the pedals that I have been looking for.  Those will work out great on the 6″ bike for DH/FR duty.  Their “grunge” graphics will take some getting used to, but they are already starting to grow on me.  It seems like a lot of manufacturers are getting into the more extreme graphics designs this year without going way overboard.

New Shimano Component Groups – SLX and LX

Say hello to the new component group from Shimano…SLX. Set to replace the Hone and LX line for mountain biking, the SLX is marketed as a heavier duty all mountain group for the Shimano line. So far from the pictures, it appears that Shimano mixed the previous LX and Hone together and added a new look along with the some features that were added to the XTR line. The rear derailleur shows some XTR-like characteristics. This line will still fall below the XT line in price and is designed around the growing popularity of 5″ and 6″ trail bikes.

SLX COMPONENT GROUP

I actually really like the look of the cranks, but a heavier bash guard would replace the plastic one shown if I ever picked up a set.

Overall, I think these moves are smart on Shimano’s part. It not only brings excitement back to their line, it also appears to bring something “new”. The LX, XT and XTR have been staples in the mountain biking world almost since the beginning. The introduction of a new line should breathe some life back into Shimano. I will still stay with SRAM for my shifting needs, but I like the way Shimano is heading. They are starting to realize how big the trail bike market is becoming. It will be interesting to see what is in the future for the company. I will also add that I really like the look of the darker components. It’s just a personal preference, but I tend to like the darker color components because they don’t overtake the look of the frame. I really like that Shimano is using this model on most of their cranks these days. Now if they would just make their XT set black so I wouldn’t have to have them powder coated…

SHIMANO 29er WHEELS

Now….I just came across this picture below. It appears to be a 29er wheelset available from Shimano. This should be an interesting introduction into the 29er market. If Shimano has improved the hubs over previous designs, this should make a lot of people happy. If the the hub design is still like last years, I would go with something else.

LX COMPONENT GROUP

The LX group will now be marketed as a trekking line. It will be seen on more of the “comfort” mountain bikes and cruisers. In the picture you can see the new rear integrated hub and the absence of disc brakes.