By Bike Friday Designer Willie Hatfield
What is Bike Friday’s “BF Boost”?
- The hub is offset 7mm to the driveside, while the rim and tire stay centered.
- BF Boost uses the existing 56mm chain-line developed for DH bikes and Super Boost Plus 157 but uses frame off-set rather than wider hubs to bring bike performance to the next level using the existing 10×135 QR hub standard.
- Boost and Super Boost are thru-axle compatible only, so those with awesome QR hubs could not use those hubs to enjoy the benefits of a wider chainline until BF Boost.
- BF Boost is a highly optimized and backwards-compatible combination of existing standards and technologies. The BF Boost idea has enabled Bike Friday to build the 2024 All-Packa with a level of performance and compatibility previously unattainable with an 20” all-terrain bicycle
Wait, isn’t this Cannondales’ Asymmetric Integration?
- Basically, except theirs is for thru-axle, and BF Boost is for QR
- Also, their offset is 6mm and BF Boost is 7mm since (157-142)/2=7.5mm
What does the All-Packa (or other bike) gain from using BF Boost?
- A massive increase in tire clearance for running up to 20” x 2.8” with incredible mud clearance.
- Increased wheel stiffness and strength with even bracing angles and spoke tensions
- Most wheel builds use equal length spokes, allowing a single length of spare spoke for repairs while traveling.
- Continued use of easily sourced 135mm QR hubs for a bike that can be serviced all around the world, while gaining benefits of Super Boost spacing
- Increased frame stiffness and braking performance due to the shortened, straighter, stiffer, disc brake-side stays
- Front Derailleur compatibility is improved, even for triples with a long enough spindle, because there is more clearance for inner chainrings.
- BF Boost produces a narrower, more compact folded bike than the previous All-Packa by 7mm. Rear derailleurs should be shifted out of the highest gears to prevent fold interference
What are the benefits of BF Boost over Super Boost?
- A 135mm hub dished 7mm builds a stiffer, stronger wheel than a centered Super Boost hub, even if the flange spacing is narrower, because the even bracing angles allow more balanced spoke tensions. Higher minimum spoke tensions reduces risk of bending, buckling, and fatigue induced spoke breakage.
- The narrower BF Boost hub is stronger than the Super Boost Hub because less bending stress is placed on the shorter axle.
- The BF Boost hub is lighter than the wider Super Boost hub.
- There are more hub options available than for Super Boost, especially excellent legacy hubs.
- With BF Boost, one hub standard can be used to create 3 different chainlines depending on frame offset. The current thru-axle standards 142, 148 Boost and 157 Super Boost standards each require a different hub width, as well as frame spacing to create 3 different chainlines.
What cranksets can be used?
- Any Super Boost crankset
- Any crankset with Q-factor over 158 that 1. has a spider that allows the chainring to be spaced outboard from the original outer chainring position (104/110/130mm BCD cranks without hidden bolts), or 2. can have its 3/6mm offset direct mount chainring reversed to reach 56mm chainline (White Industries for example)
- Most MTB direct mount cranksets can use 0mm offset direct mount chainrings to get a 56mm chainline.
- Most square taper cranksets use a 127mm (sometimes 122mm for MTB cranks) BB spindle.
If you have any questions please feel free to contact us at service@bikefriday.com
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2 Responses
As an owner of an original All-Packa along with another AP that a friend has, I am fully aware of the problem you are addressing with the “offset”. Are there any “recent” solutions for the problem on the original frames? Narrower tires and crank spacers have been installed to “sort-of solve” the problem but not an ideal solution.
Thanks,
Victor
Hi Victor, since I released the original All-Packa, Microshift has released the Advent Super Short drivetrain. The ultra short cage provides the greatest chain/tire clearance I’ve tested with a multi-speed derailleur drivetrain. Tip: The recommended cassette limit of 38T is a hard limit, unlike with Shimano derailleur limits. I chose not to offer this drivetrain because of the limited range and proprietary cable pull ratios, but it is the clear best for clearance.
Also, while a 49mm chainline provides the best shifting performance, I have successfully pushed the crankset chainline out to 52mm on the 2022 All-Packa during testing for greater tire clearance. Big/Big cross-chaining with a double is not recommended at that chainline.
Thanks for riding an All-Packa and I wish you have many great adventures,
Willie