I am about to do my spring maintenance on my 2000 RC51. I am changing the sprockets/chain, rear tire, spark plugs and checking the valve clearances. It has 16,8XX miles. As the title suggests, I am changing the gearing and rear tire size. I know the stock chain is 104 links. And I have read somewhere on the net that a stock length chain will work with -1/+2 gearing. But will it work with a 190/55 tire? Will I need to go with a 106 link chain? I found a sweet deal on an RK 104 link x-ring chain. I already have my sprockets (Renthal with the hard anodized rear). I also have the 190/55 tire, but I work at a tire shop and ordered it through there from one of our suppliers. So a return and exchange for a 190/50 would be no problem if that's what it would take to be able to use the 104 link chain. I have no complaints with the handling with the 50 series tire. Just saw alot of RC riders on the board switch to the 55. I can save myself around $120 if I can use the 104.