In this article I will review the Alugear Aero Boost Chainring for Shimano Direct Mount, which is one of the very few aero chainrings for a mountain bike. I’m riding a Rotor no-Q Aero chainring on my Canyon Ultimate CF SLX 8 and a Wolf Tooth Aero Chainring for Shimano GRX 820 on the Canyon CF SL 8 gravel bike.
TABLE OF CONTENTS
Key features Alugear Aero Boost Chainring for Shimano Direct Mount
On the product page of the Alugear Aero Boost Chainring for Shimano Direct Mount there are no key features highlighted.
- Product Description
- Technical Specifications
- Compatibility
- Information
- Recommendations
- Product Details
- Datasheet
- Review
From the Information section on the product page you can read that:
Alugear chainrings are some of the lightest chainrings on the market. Using our experience and vigorous testing, we tweaked the arm design and strategically machined the chainrings so that only minimal sacrifices were made in impact strength in exchange for large gains in weight reduction.
The chainrings are CNC machined from 7075 T6 aluminum and hard coat industrially anodized to provide protection from mechanical impacts, a good look, and an excellent tactile feel to each of the chainrings that lasts a long time.
A unique tooth profile eliminates chain noise, reduces wear, and provides smooth operation on the entire system of all the most common combinations, such as 10, 11, and 12-speed drives. The narrow wide teeth guide the chain reliably. The tooth profile is specially designed for use with MTB chains.
Alugear chainrings are the best choice if you are looking for a technologically sound chainring with a unique design and low weight.
On my kitchen scales the Alugear Aero Boost Chainring for Shimano Direct Mount shows a weight of 77 grams for a 32 tooth chainring. This is a chainring for mountain bike, where reliability and robust durability is more important to me than weight. However every gram saved is a gram. 🙂
Just like the Wolf Tooth Aero Chainring the one piece is very stiff and rigid, which is a feature I really like. Partly this is also due to the used 7075 T6 aluminum, partly this is on the structural design. On the backside of the chainring (on the bottom bracket side) you can see the five reinforcement ribs that distribute the power in a unified way and provide mechanical strength (while the material in between these ribs is optimized for minimum weight in combination with aero gains.
Installation Alugear Aero Boost Chainring for Shimano Direct Mount
Installation is as easy as removing a Shimano Hollowtech II mountain bike crankset. In order to install the Alugear Aero Boost Chainring you need to remove the Shimano Deore XT M8100 Hollowtech II crankset. There is a good work instruction from Park Tool for this: Crank Removal and Installation: Two-Piece Compression Slotted.
Removing the Hollowtech II crankset
- Loosen the M5 bolts on the non-drive side crank arm
- Loosen the Kogel Bearings Shimano Crank Arm Fixing Bolt with
- Remove the Protection Plate with product# Y1GE98050
- Remove the non-drive side Hollowtech II crank arm from the 24 mm hollow Shimano axle
- Gently remove the Shimano Hyperglide chain from the chainring, and slide the drive-side Hollowtech II crank arm through the CEMA Bearing Interlock BB86-BB92 Bottom Bracket
- Slide the Shimano TL-FC41 Tool for Direct Mount Chainring over the axle and onto the Direct Mount lockring.
- Use a Bahco 9033 adjustable wrench to loosen the lockring and remove the lockring
- Remove the old (Shimano SLX M7100) Direct Mount Chainring
Installation Alugear Aero Boost Chainring and placing Hollowtech II crankset
- Place the Alugear Aero Boost Chainring for Shimano Direct Mount over the 24 mm hollow Shimano axle
- Adjust the Alugear Aero Boost Chainring so it locks into the correct position
- Place the lockring (you might even want to put some Morgan Blue Aquaproof Paste or Weldtite TF2 Lithium Grease on the lockring thread.
- Slide the Shimano TL-FC41 Tool for Direct Mount Chainring over the axle and onto the Direct Mount lockring.
- Use a Bahco 9033 adjustable wrench to tighten the lockring
- Gently place the Shimano Hyperglide chain on the Alugear Aero Boost Chainring and slide the drive-side Hollowtech II crank arm with the 24 mm axle through the CEMA Bearing Interlock BB86-BB92 Bottom Bracket
- Gently place the non-drive side Hollowtech II crank arm onto the 24 mm hollow Shimano axle
- Place Protection Plate with product# Y1GE98050
- Place M5 bolts and Kogel Bearings Shimano Crank Arm Fixing Bolt and hand tighten these;
- Adjust the preload with the Park Tool BBT-10.2 Adjusting Cap Tool;
- Torque the crank arm bolts to specification with Stahlwille Manoskop 730N/2 Mechanical Torque Wrench 2-20 Nm
Enjoy the ride with your new chain ring.
Please note the black Prototipo Works (Ultra) Low Bidon Cage Bolts
Concluding thoughts and wrap-up
The price point of the Alugear Aero Boost Chainring for Shimano Direct Mount (32T version) is around € 64,00. As mentioned in the technical specification section the chainring sizes available vary from 26T up to 38T (7 different options) and available in 8 different colors. So this gives a lot of combinations.
And while the Aero gains might be less than on a road- or gravel-bike, it simply looks cool. And Alugear offers a rigid and stiff chainring, which I personally always appreciate when standing on the pedals. The shifting performance is good, and I think most after market chainring manufacturers have figured out the narrow-wide tooth profile.
Other Aero chainrings that I’ve reviewed on this website are:
- Wolf Tooth Aero Chainring for Shimano GRX 820 Hollowtech II Cranks
- Rotor Aero noQ Chainring for Shimano Dura Ace 9000
And another really good looking chainring for your mountain bike is the Works Components GEO Chainring for Shimano Direct Mount. Other interesting product reviews can be found in the categories below:
