How to Convert Older MTB Wheels to Boost Spacing

Keep your old mountain bike wheels and hubs rolling on a new fork or frame with a Boost conversion kit.
This is my front hub, converted with a simple symmetrical spacer kit I found on eBay for €14. I converted the rear with a functionally identical kit, and the bike shifts flawlessly despite the imperfect chain line.

Boost spacing has been debated and appreciated throughout our community of technical-toy lovers since its industry debut roughly five years ago. Today it is difficult to find a frame or fork that has not conformed to the new standard, or been “supersized.” Let’s pause and appreciate this moment of consistency, while we wait for Super Boost or another standard to upend the bicycle frame and fork markets once again.

If for any reason you cannot replace your hubs to work with a new frame or fork, there is hope. For a standard through-axle conversion, from 100mm-front and 142mm-rear to Boost 110mm-front and 148mm-rear, there are a number of ways to fill the gap.

Asymmetrical adapter solutions

These adapters are made of spacers and end caps that take up Boost space on the non-drive side of the rear hub, and drive side of the front, requiring you to re-dish (re-center) the wheel to a new central point. In the rear, they add spacers on the non-drive side so that your chainline remains properly oriented for precise shifting on the drive side.

  • The Woolftooth Boostinator works with several hub brands, adding a 6mm spacer between the hub and the disc rotor, and replaces the stock, non-drive side end cap with one 6mm longer. The front hub is “boosted” with a drive side end cap that is 1cm longer than the stock version. Both wheels then need to be re-dished. Woolftooth says, “by shifting the hub flanges slightly, spoke bracing angles are brought closer to symmetric for a stiffer, stronger build.”
  • The Problem Solvers Booster Rear Kit functions identically to the Wolftooth option but works with any 12mm through-axle hub you may have.
  • The Problem Solvers Super Booster Kit converts a Boost rear hub to the new Super Boost rear spacing found on select bikes from brands like Devinci and Pivot. It works similarly to the above kits, with a larger amount of spacing.

Symmetrical adapter solutions

These adapters convert your hub by adding spacers equally on either side, avoiding the need to re-dish your wheel. This may be a better option for folks who don’t own a truing stand or dishing tool and want to complete the conversion on their own.

The MT Zoom front Boost adapter added a scant 29 grams to my bike, and cost less than lunch.
  • Problem Solvers’ Booster Front Kit works with any front 15mm through-axle hub,  adding a 5mm spacer to either side of the hub’s end caps, and a 5mm spacer between the hub and the disc rotor.
  • Mountain Racing Products makes a symmetrical Boost adaptor that replaces the stock end caps of DT-Swiss, Stans, Industry Nine, Hope, and Chris King hubs.
  • NOW8 adapters are essentially the same as the Problem Solvers kit and also come in a centerlock version.
  • Neatt adapters function identically to those above.
  • Hope Tech is one of the few hub manufacturers solving the Boost conversion problem in-house, with a variety of end caps to “future proof” their hubs. Many of their Boost adapters employ tool-free installation methods.
  • Roval/Specialized make a conversion kit for some of their hubs that uses a pair of replacement end caps and a disc spacer. No re-dishing required.
  • Spank Industries has adapters for all of their hubs, including a Super Boost conversion option. These are some of the most adaptable hubs on the market.
This bike has performed brilliantly, with a non-Boost fork and front hub, a symmetrically converted Boost rear hub, and non-Boost chain set. Whatever your mix-match may be, there are options to make it all work together.

In addition to the adapters listed above, eBay and Amazon both host a glut of adaptor kits to choose from. I don’t often steer folks toward these sites for quality components, but in this case, there are some solid options.

What are your tips and tricks for Boost conversion? How have you managed to keep your old “narrow” hubs rolling through another standard?

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