The RM-01 chassis uses 1150 Ball Bearings on the front axles as standard but these steel axle shafts will enable installation of 1/8&rdquox5/16&rdquo ball bearings which are also widely available. The use of these axles will also allow you to use different branded wheels and tires for more tuning options. Specs & Features Front Axle x 2pcs. Spacer x 2pcs. 3mm Lock Nut (Thin) x 2pcs. Compatible with RM-01 chassis.