FAQs
Frame Questions
Where do I get thread taps and gages for ISIS Overdrive shells?
Please visit the Tooling page on this web site for information regarding tooling suppliers.
What issues should I look into regarding producing ISIS Overdrive frames?
The thread is a larger diameter than normal BSA threaded shells and therefore it will require more force to cut the threads.
There will potentially be more distortion during the welding process due to the larger shell diameter. Whenever possible threads should be cut after welding and heat treatment in a single fixture.
The thread pitch is different between the BSA shell and ISIS Overdrive. Therefore tapping machines will need to be reconfigured for the different thread pitch.
As always, thorough pre-production planning and samples runs are suggested prior to production.
How do I mount a chainguide onto an ISIS Overdrive frame?
By the time ISIS Overdrive bicycles hit the market we expect that both frame mounted and BB mounted chainguides will be available for ISIS Overdrive frames. Please see the following question for more information regarding frame mounts.
Is there an ISIS Overdrive chainguide mount standard for frames?
As of August, 2003, no, although there are a number of companies discussing the details of such a standard. There is a meeting to be held at Interbike 2003 in Las Vegas, USA, to discuss such a standard. Please contact Dave Weagle of e13 for more information regarding the Interbike meeting.
If I have an ISIS Overdrive frame am I stuck using an ISIS Overdrive BB?
No. You can purchase adapters from various sources to size an ISIS Overdrive frame down to the normal BSA size. In this respect the ISIS Overdrive standard is backwards compatible with existing BSA bottom brackets.
Bottom Bracket Questions
What kind of spindle should I use in an ISIS Overdrive bottom bracket?
Whatever spindle you would like. The ISIS Overdrive standard is as applicable to tapered square spindles as it is to ISIS Drive spindles. It is the bottom bracket designer’s choice as to the spindle design used in the bottom bracket.
What bearings should I use?
Again, it is up to you. Bearings for the bottom bracket may take any number of forms, including custom cartridge bearings, needle bearings, bushings, or loose balls. The purpose of this standard is not to standardize one particular bottom bracket design, but rather to standardize the interface between the bottom bracket and frame. It is up to the individual designer to determine the type and configuration of bearings in the bottom bracket.
Do I have to use the suggested tool interface?
No, although the use of a Shimano XTR tool or Truvativ X-Tool cup interface is preferred to maintain compatibility with existing tools. However, the bottom bracket designer may use any type of tool interface they choose.
Should I grease the bottom bracket cups and/or the frame prior to installing the BB?
Please follow the bottom bracket manufacturer’s suggestions.
Miscellaneous Questions
Is the ISIS Overdrive geometry compatible with any other frame/bottom bracket interface?
Not that we know of.
Does the ISIS Overdrive system infringe any existing in-force patents?
Not that we know of. However, we do not guarantee this to be the case in any way. It is up to the individual manufacturer to perform their own legal research and protect themselves from any legal repercussions of using the interface.
Is it really “free”?
Yep, use it to your heart’s content.