This is a bit of a dumb question, but do I need to get bigger tubes if I get a wider tire in the front and back? I saw in the K270 post that people got new tubes but they were getting the thicker tubes, the tube size vs tire size isn't really clear to me.

 

I was about to order a tire the other day and have the same question. The tire I'm looking at is the IRC GP1 4.60-18 rear, so if I get that tire and want a heavy duty tube to go with it, is the right size this one : IRC INNER TUBE HEAVY DUTY 4.00/5.10-18 TR4?

 

You generally get a different tube for your 21 inch front vs the 18 inch back tire, but the 21 inch front can be used in the back in a pinch, i.e., you get a flat in the woods and need to fix it right there. Most tubes are sized by the rim size, though. I used a Kenda extra thick tube to help protect against flats - not for any other reason.

 

I know the rim size designation but its the widths that was bothering me, like for example 4.00/5.10-18 is this saying that it will fit a tire that is anywhere from 4-5.1 inches wide?

 

Right.