I've bought a pair of wheels using Mavic XM719 rims and getting schrader valves through the drilling is proving to be a tight fit (and yes I have removed the presta adapter!).
Schrader valves seem to thicken ever so slightly in the rubber coated section as it approaches the joint with the inner tube. With my old rims I could push a scharder valve all the way through the drilling so the inner tube was in contact with the rim, with the XM719s the valves wedge at about the 3/4 point with some of the valve left in the rim section. The rims appear to get stuck in the drilling for the first section of the rim, I don't know if this is somewhat smaller or whether the drillings in the two sections are slightly out of line. Both rims are the same.
Talking about this to someone at a bike shop they suggested just working the valves through, I've applied a bit of grease to the valves but I don't want to force anything.
I've fitted the tyre and ridden without problems but am I okay doing this? Will I put undue stress on the rim? I'm assuming that the whole of the schrader valve is brass (under the rubber coating) so I don't think that the value will be cut by the rim drillings. I guess though that the tube will be held a little way away from the rim leaving an air void. Should I leave things as they are, file out the drillings or just use prestas?
I've bought a pair of wheels using Mavic XM719 rims and getting schrader valves through the drilling is proving to be a tight fit (and yes I have removed the presta adapter!).
Schrader valves seem to thicken ever so slightly in the rubber coated section as it approaches the joint with the inner tube. With my old rims I could push a scharder valve all the way through the drilling so the inner tube was in contact with the rim, with the XM719s the valves wedge at about the 3/4 point with some of the valve left in the rim section. The rims appear to get stuck in the drilling for the first section of the rim, I don't know if this is somewhat smaller or whether the drillings in the two sections are slightly out of line. Both rims are the same.
Talking about this to someone at a bike shop they suggested just working the valves through, I've applied a bit of grease to the valves but I don't want to force anything.
I've fitted the tyre and ridden without problems but am I okay doing this? Will I put undue stress on the rim? I'm assuming that the whole of the schrader valve is brass (under the rubber coating) so I don't think that the value will be cut by the rim drillings. I guess though that the tube will be held a little way away from the rim leaving an air void. Should I leave things as they are, file out the drillings or just use prestas?
Go to a bike shop that has a tapered tool with sharp edges, and a T handel, and they can make the hole a little bigger-no big deal, do it all the time.
"Qui si parla Campagnolo" wrote: (clip) a tapered tool with sharp edges, (clip) ^^^^^^^^^^^^^^^^ Ask them whether they have a *tapered reamer.* I'm surprised the people at the bike shop didn't just offer to do this for you. You could wrap some sandpaper around an old valve stem and use it as an improvised reamer. Or even use a round file. The hole doesn't have to be accurate, but should be smooth.
