Hendo Posted December 12, 2009 Report Share Posted December 12, 2009 My bike currently runs a 160width rear tyre on a 5.75inch width rim. The wheels I'm planning on fitting are a 5.25inch width rim, but according to the specs sheet, should also run a 160width rear tyre. Can this be right? The wheel Im using now (5.75") already looks as if the tyre is too wide for it, never mind taking off another half an inch from the wheel width for the new wheel. I would have thought a 150 would have been better? Or am I missing something, can someone enlighten me about the complex world of tyre sizing!? Cheers Andy Link to comment Share on other sites More sharing options...
thefatman Posted December 12, 2009 Report Share Posted December 12, 2009 What bike is it, a 5.75" rim is 1000 territory. 5.5" or 6" both take a 180/190 tyre. Has someone fitted the wrong size tyre to it? 160 goes fine on 4.5 - 5.25. Link to comment Share on other sites More sharing options...
Hendo Posted December 12, 2009 Author Report Share Posted December 12, 2009 Its a 2005 KTM SMC 625. Just measured it again with my vernier calipers and it is definately 5.75" spoked wheel, and the tyre is a 160/60/17 BT090. And like I say my new wheel (KTM duke 2 wheel) is 5.25" wide. I think the BT090's are well known for being excessively wide mind... Andy Link to comment Share on other sites More sharing options...
thefatman Posted December 13, 2009 Report Share Posted December 13, 2009 Did you measure the outside of the rim, or the inside where the tyre bead fits? They are measured on the inside. You can fit a 160 tyre to a wide rim like that though but it makes the handling dangerous. Link to comment Share on other sites More sharing options...
Gary Posted December 14, 2009 Report Share Posted December 14, 2009 Did you measure the outside of the rim, or the inside where the tyre bead fits? They are measured on the inside. You can fit a 160 tyre to a wide rim like that though but it makes the handling dangerous. As the fatman says, a 4.5" rim is good for a 160, if you have anything over 5" then you should be running 180+ sizes of tyre, I suspect you are measuring the rim incorrectly. The size is measured on the inside flanges of the rim, where the tyre walls locate and seal to the rim, not the outside width of the rim. Remeasure the inside width of the rim where the tyre sits and tell us what it measures and we can then recomend a correct tyre size. You state the new rim is 0.5" narrower, but that doesn't mean the width actually reduced. If the original rim was a cast wheel and the new rim is a chromed steel rim, the actual width where the tyre goes could be the same even thought the outer width decreased by half an inch.. I hope I am making some sense.. Link to comment Share on other sites More sharing options...
Hendo Posted December 14, 2009 Author Report Share Posted December 14, 2009 Yep, Im a ! I was indeed measuring it from the outside of the rim, I didnt even give it a second thought to be honest, but its blatently obvious now you have mentioned to measure the inside of the rim. Anyhoo, panic over, Ive have ordered a supermoto specific 160/60/17 tyre now (as specified for the 5.25" rim) I was maybe looking into it too much. Cheers Andy Link to comment Share on other sites More sharing options...
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