So I bought a Kenda K270 rear. I assumed that since the stock tire was a 4.6 that a 4.5 would be similar. WRONG!
It's much taller than stock. So much so that I wouldn't be able to put my 15 front sprocket on without the tire rubbing the plastic guard behind the shock.
Also, the bike tends to 'wobble' on gravel and on certain paved surfaces. I checked the alignment and it's good. Not a speed wobble but side to side. I'm thinking the tire height has thrown off the balance of the bike??? The rear sits slightly higher than with stock 605.
Anyways, the tire looks about the same circumference as the front....I'm sure that shouldn't be like that.

I'm going to bite the bullet and get a 4.0 18 to be sure. Less weight. Easier to spin in the dirt.

Lesson learned.

For Sale: Kenda K270 4.5 - 18. Slightly used....

 

Do the research on sizing. I have the following sites saved:

Bridgestone
Dunlop
Duro
IRC
Kenda
Shinko

They have listings of the true sizes on a specified rim width. You can actually KNOW what you're getting before you order or look. Tires may vary in looks when you look at a rack of them based on how they're "packaged" or stored. The Duros have cardboard spreaders between the beads to keep them from flattening as some without the spreaders do. Makes them look a bit wider than they normally are when mounted and inflated. Some that are pinched might look taller and narrower than when mounted.

Then there are those who have two different models that are supposedly same size based on the sidewall marking, but the reality is they might be significantly different in true size. I've seen that in some Kendas. Then there is the difference in width between same marked tires from manufacturer to manufacturer. My Duro HF904 4.10-18 shows a true 4.00", the 4.60 shows a true 4.80" - where the Kenda K270 shows the 4.10 at a true 3.80", their 4.60 shows a true 4.30" and the 4.50 shows a true 4.80". As you see, it's a freaking mess in the inch measurements. But even the metrics will have variations at times, although the only difference between the Duro and Kenda 120/80-18 tires is the Duro is .1" smaller diameter, the widths are both at 4.80".

So that is why I look up the tires first. I want to know what I'm getting, no surprises.

I am running a 4.10-18 Duro Median HF904. I run the Duro because of past experience in about every sort of terrain on the KLX650. I am going with the smaller size than stock, because of past experience (decades ago on my 125) and seeing what off road racers (MX/hare scrambles) use for tires on smaller lower powered bikes. They are lighter (less power to drive them and less unsprung weight), will spin up easier when wanted (saves clutches with less slipping), and cost less. So far I certainly have not had any traction problems when I wanted traction and in deep sand I can spin the tire to work through versus slipping the clutch, the engine didn't bog.

Then there is the fact that there is no clearance issue when going slightly smaller than OEM versus going the opposite way. That front inner fender is darn close - even with the 4.10.

Oh, I have a set of near new Kenda K761s available, I don't know that they even have 100 miles on them. They are a 90/90-21 and 120/80-18. Make an offer, not including shipping since I have no idea what shipping would be at this point. I will see Monday.

 

Thanks for that info. It's really a shame that there can't be a true standard but....
Anyways , I'm actually going to grab the Kenda 4.0 18 for this season. I appreciate the offer in the tires but I need to see for myself if these Kendas are worth anything in light trails.
I'll post once it's installed.

Thanks again! And for the links!