AT LAST a durabale ISIS BB

Back by popular demand, the general all-things Road forum!

Moderator: robbosmans

LloydP
Posts: 581
Joined: Thu Apr 08, 2004 6:19 am
Location: nr Derby, UK

by LloydP

big fellow wrote:you'd think that if cylindrical bearings were that good they would be using them right??

wonder why....


cost and ease of manufacture. there's a lot of great stuff that doesn't get made because it's not 'economically viable'

cycling's great and the technology on a lot of stuff (LW wheels, some carbon frames, the narrower indexing) is quite impressive, but it's still not F1 as far as a cost no object engineering exercise. which is why we have standards like ISIS and dropout spacings and the various clamp sizings

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

www.starbike.com



big fellow
Posts: 1288
Joined: Thu Nov 04, 2004 4:05 pm

by big fellow

true lloydy

i suppose so...having said that though, there are many cyclists out there who are willing to pay a premium for a quality product - this site is the perfect example!

i will definitely buy an SKF BB set when it comes out...

Paul_nl
Posts: 462
Joined: Sat Nov 15, 2003 4:35 pm
Location: The Netherlands
Contact:

by Paul_nl

Image

Only one side has cylindrical bearings when I look at the above image.

Because the bearing close to the chain is loaded up to seven times higher than the other bearing.

fdegrove
Tubbie Guru
Posts: 5894
Joined: Tue May 03, 2005 2:20 am
Location: Belgium

by fdegrove

Hi,

Because the bearing close to the chain is loaded up to seven times higher than the other bearing.


Exactly.....
Which makes it such a good example of well thought out engineering in the first place.

Just imagine a lightweight version sporting a Ti axle, some composites for the shells, make it watertight etc.....
Add types covering all current standards and axle lengths and you're in business.
.........Good thing dreaming out loud doesn't cost a dime..... :P

Ciao, :wink:
Being a snob is an expensive hobby.

babylou
Posts: 137
Joined: Wed May 04, 2005 2:54 am

by babylou

fdegrove wrote:Hi,

Because the bearing close to the chain is loaded up to seven times higher than the other bearing.


Exactly.....
Which makes it such a good example of well thought out engineering in the first place.

Just imagine a lightweight version sporting a Ti axle, some composites for the shells, make it watertight etc.....
Add types covering all current standards and axle lengths and you're in business.
.........Good thing dreaming out loud doesn't cost a dime..... :P

Ciao, :wink:


It appears the SKF bearings run directly on the axle and against the drive side cup and the shell on the opposite end. This allows for a decent sized bearing element which translates to long life. Though I am still confused as to how the ball bearing side can be assembled. It also appears that the spacing between bearing elements can be reduced for even more load capacity.

Anyways, it would not be good to run the bearings on a Ti axle. That axle needs to be hardened to about Rc 60 where the bearings run.

babylou
Posts: 137
Joined: Wed May 04, 2005 2:54 am

by babylou

fdegrove wrote:Hi,

Great find on the SKF BBs.
At long last someone's put some solid engineering thinking into that component.
I'm particularly pleased with their idea about using cylindrical bearings.
Particulalry so since I'd been pondering about using the same idea for hubs as well.
You can easily make them maintenance free, extremely low friction and immeasurably low torsional losses.
How about it SKF? :lol:

.......Surely someone else must have thought of that already but I've never seen it pulled of for a rear hub though....

Ciao, :wink:


A cylindrical roller bearing cannot handle any side load. Side load must be accomodated in a hub.

What do you mean when you talk of "immeasurably low torsional losses" in a cylindrical bearing? I am trying to picture what is under torsion.

User avatar
drjones96
Posts: 3717
Joined: Thu Nov 04, 2004 10:56 pm
Location: Wichita, KS

by drjones96

Superlite wrote:....ISIS is dead....


What's deader? ISIS or Octalink? :lol:

What's left? Square Taper, Tune Sixpack....what else?

User avatar
Superlite
Posts: 2325
Joined: Fri Aug 29, 2003 9:01 pm

by Superlite

Outboard and Integrated BB shells are the future. 8) e

User avatar
drjones96
Posts: 3717
Joined: Thu Nov 04, 2004 10:56 pm
Location: Wichita, KS

by drjones96

Superlite wrote:Outboard and Integrated BB shells are the future. 8)


You're most likely correct. But most of these Outboard/Integrated BB systems are heavier or no lighter than their predicessors. But I guess it's not always about weight.
The FSA K-Force w/Mega EXO..... I would have prefered the K-Force before it...very light in comparison when matched up with a DA 7700 BB or ISIS equivalent. Tis a shame they halted production on the old K-Force in favor of their new system. They were probably scared to death that the old K-Force would outsell the new one with Mega Exo BB because of it's weight.

fdegrove
Tubbie Guru
Posts: 5894
Joined: Tue May 03, 2005 2:20 am
Location: Belgium

by fdegrove

Hi,

A cylindrical roller bearing cannot handle any side load. Side load must be accomodated in a hub.


Which is why it is sitting in a hub in the first place.
Provided the BB is designed as it should be the cylindrical bearing with its wider contact surface should allow to build a BB that should not develop much play over time.

What do you mean when you talk of "immeasurably low torsional losses" in a cylindrical bearing?


See above.
The classical setup using ball bearings usually do end up developing play with use. Hence torsional stiffness is compromised due to wear and tear in the long run.
Ball bearings exhibit a line pattern of contact whereas cylindrical types are of the wide contact area type.
Cylindrical bearings usually have higher friction to overcome compared to ball bearing types, in a BB however this shouldn't be of much concern.

Using the SKF setup this problem is greatly reduced, hence my "dreaming" comment about immeasurably low torsional losses.
Granted, there's bound to be some loss at any given time but it should be noteably less compared to other types of bearings.

Ciao, :wink:
Being a snob is an expensive hobby.

User avatar
Cyco
Posts: 1875
Joined: Sat Nov 30, 2002 4:49 am

by Cyco

I was told today that they should be available from July, in almost all sizes - the rest will come in over the following couple of months.
Success is how far you you bounce back up after being knocked down

danmtchl
Posts: 9
Joined: Wed Jun 01, 2005 4:39 am

by danmtchl

I have a Spada carbon/TI ISIS bb in my MTB and have over 1200 miles on it and have not had one problem with it. It has take alot of abuse and is still going round without any problems. Oh did I mention I weighed 200 lbs. It cost alot of money but worth every penny. Just imagine how well it would work in a road bike.

ipenguinking
Posts: 743
Joined: Sun Jan 09, 2005 5:14 pm
Location: Sunny So Cal

by ipenguinking

My friend took a good look of the new SKF bb during the Taipei Show couple months ago. He said the thing is so heavy that he's almost cerntain that no weight weeneis would buy one. I guess that's why SKF has yet to disclose the weight.......

User avatar
alain
Posts: 192
Joined: Tue Oct 21, 2003 4:18 pm
Location: Sion/Switzerland

by alain

I knew it. I actually tried to contact SKF and ask them about the weight and about the lack of information on their website 2 weeks ago. No answer yet ... which may mean in other words that this thing is heavy.
Titanium rules.

User avatar
53-11
Posts: 84
Joined: Fri Apr 15, 2005 8:42 am

by 53-11

Has anyone tried one of these out yet and are they available?

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

www.starbike.com



Post Reply