Bike Inner Tube? 26" x 2.125 to 2.35" Schrader valve bicycle inner tubes.) for Mountain Road Bicycle Replacement Tubes-Black Note? 1.Please kindly confirm the size of your bicycle tire before you buy.?If you buy tubes are not the right size, you may return the products for a full refund.? 2.Before changing the tube,please check whether have some stones or sharp things that may broke the tube that stay in your tire ,if have please clean it. 3.When changing your bicycle inner tube always be sure to add just a little air to the tube before installing. This gives it form so it doesn't get twisted or bunch up. 4.Never over inflate past the recommended tire pressure.