SRAM’s Single Chainring

The trend in mountain and cyclocross is to drop your extra chainrings and your front derailleur to run a 1x system. The hope is that removing the front derailleur will increase reliability and decrease weight. And, frankly, it looks pretty sharp.

1x drivetrains used to require a chain guide to keep the chain on the chainring. Clutched rear derailleurs, like Shimano’s Shadow Plus and SRAM’s Type 2, keep tension on the chain to decrease chain dropping.

But, the narrow wide chainring is the final piece of the puzzle to reliably keeping the chain on without requiring a chain guide. Narrow wide is pretty descriptive – teeth of the chainring alternate between having a narrow width and a wide width. The wide teeth grip the links of the chain to hold the chain on the chainring.

After SRAM’s introduction of the XX1 mtb drivetrain, several manufacturers introduced their own narrow wides – for example, RaceFace and Wolf Tooth.

On October 21 and October 28, 2014, SRAM was awarded US design patents D715,699 and D716,191, respectively. Both design patents are drawn to narrow wide chainrings.

From D715,699:

619-2

619 4

619 5 and 6

From D716,191:

191 1

191 2

191 3 and 4

It is important to remember that it is the solid lines in the figures that define the covered, patented subject matter.

Application: 29/471, 384
Application Status: Patented – D715,699, Issued October 21, 2014
Assignee: SRAM, LLC
Related Applications: Continuation of US 13/311,735 (under final rejection)

Application: 29/473, 643
Application Status: Patented – D716,191, Issued October 28, 2014
Assignee: SRAM, LLC
Related Applications: Continuation of US 13/787,276 (under non-final rejection), which is a continuation-in-part of US 13/311,735 (under final rejection)

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Clement’s LAS Tread Design Patent

In January, the UCI announced that CrossVegas will be the first Cyclocross World Cup race for the 2015-2016 series.

With a fast, dry course, Clement’s LAS tire will be a likely choice for many riders. The LAS, named after the airport code for Las Vegas and in honor of CrossVegas, has a fast, file tread center and shoulder knobs reminiscent of Clement’s other offerings.

Clement describes the design of the LAS:

It’s unique nail-file tread is short and fine at the center of the tire and gets progressively taller and coarser as it approaches the shoulder knobs.

Screen shot 2015-02-17 at 5.00.22 PM

Image Source: Clement

You can see the size of the file treads increases from the center to the shoulders.

US Design Patent D675,976 appears to be drawn to the tread pattern of the LAS.

Screen shot 2015-02-17 at 5.10.31 PM

Screen shot 2015-02-17 at 5.10.58 PM

The increasing size of the file tread leading up to the shoulder knobs should provide solid and predictable traction for corners and off-camber sections.

Application: US 29/401,315
Application Status: Issued on February 12, 2013, as US D675,976
Assignee: Donnelly Sports, LLC
Related Patents/Applications: N/A

Trek’s Externally-Geared, Belt-Driven Mountain Bike

Conventional wisdom in the belt drive arena tells us that belt drive is only for single speed setups, and an internally geared hub or a gearbox is needed to change gear ratios.

Not so according to Trek. Trek is pursing a US patent application that shows a hardtail mountain bike with both belt drive and a rear derailleur. In March of 2012, Trek was issued a US design patent drawn to the chainring for this implementation.

Screen shot 2015-02-04 at 1.36.59 PM

One or both of the crankset and wheel hub cogs can include more than one cog having different circumferential sizes so as to alter the mechanical advantage provided between the pedals and the driven hub. … It is envisioned that, when provided in a multiple geared format, bicycle 30 be equipped with a front and/or a rear derailleur assembly to facilitate the manual lateral manipulation of the flexible drive member 80 in effectuating shifting of the gearing arrangement of bicycle 30 such that flexible drive member 80 cooperate with one of cogs 120200, or 300 as desired.”

In other words, Trek envisions belt-driven bikes to have both front and rear derailleurs.

Here’s a portion of Trek’s belt drive cassette:

Screen shot 2015-02-04 at 1.39.39 PM

In the cross-section of the cassette, you can see that the belt 80 is engaged in the largest cog and moveable to the right as indicated by arrow 434.

And, here’s a better look at the design of the cogs:

Screen shot 2015-02-04 at 1.43.50 PM

Screen shot 2015-02-04 at 1.43.22 PM

Looks like belt drive may be finding more applications soon.

Application: US 12/985,166
Application Status: Final Rejection – Early Response Due February 12, 2015
Assignee: Trek Bicycle Corp. (original assignee)
Related Patents/Applications: D655,225 (issued March 6, 2012)