I knew I would be getting large wheels even before I owned a YZ85. I googled specs and read forums to find out that a 16” rear tire fits the small wheel swing arm. Here are the parts needed to do this conversion. I also listed the parts which are optional such as the hubs and brake rotors which can be reused from your original small wheel set.
19”x1.40” front rim, 32 holes - Excel GBK404 $160
19” 70/100-19 front tube - Yamaha 942-27192-92-00 / Kenda Tuff Tube
19” front rim band - Yamaha 943-27191-11-00 $5
19” front spoke set - Excel XS0-41197 / Yamaha 4LB-25104-00-00 $80
19” front tire - 70/100-19 42M $50
16”x1.85” rear rim, 32 holes - Excel DDK404 $130
16” rear tube - Yamaha 942-09160-03-00 / Kenda Tuff Tube $15
16” rear rim band - Yamaha 943-30160-58-00 $5
16” rear spoke set - Excel XS0-41167 / Yamaha 4LB-25304-00-00 $75
16” rear tire - 90/100-16 52M
longer chain - Yamaha 9Y5-81971-21-00 or Pro Taper PT428MX
chain master link - Yamaha 946-81970-01-00
front sprocket - 14T
rear sprocket - 52T or similar size depending on your preference
large wheel swing arm - Yamaha 4LB-22110-01-00
swing arm bearing kit - Yamaha 933-17217-46-00
longer rear brake line - Yamaha 999-99030-68-00
front hub - Yamaha 4ES-25111-00-00
front hub bearings
rear hub - Yamaha 4ES-25311-00-00
rear hub bearings
front disc brake rotor - Yamaha 5PA-2582T-00-00
rear disc brake rotor - Yamaha 5PA-2582W-00-00
socket wrench set
spoke spanner wrench - Emgo 6-way
chain breaker tool
chain lube - Muc-Off All Weather
The most precise part is having the rim and spokes trued with proper spoke tension. I had mine done by the professional Mr. Lepardo at a nearby shop in Mendez, Cavite. He enjoyed using the Emgo 6-way spoke spanner wrench I had so I gave it to him as a gift.
Tire installation was done at a local vulcanizing shop. Make sure to ask the service crew nicely to keep the new rim scratch-free, while it's new at least.
There is quite a difference between the old 17 inch front wheel and the newly built 19 inch front wheel. Other than the diameter, looking at that blinged out stainless steel spoke set and fresh knobby rubber made me excited to ride the dirt.
The sprockets and chain arrived later than the rest of the wheel set.
After building the wheel, the rest of the installation is fairly straightforward by bolting in the axles through the new wheels.
For riders of all sizes, the YZ85 with the bigger wheels should be a taller but more stable ride.
- Kal Sumagui