Ok this is messed. I went back to buy a different sized Kenda K270.....



I have the 4.50 - 18 so I thought the 4.10 would be a better fit. No problem except the tire on the Left is the 4.10 and the tire on the right is the 4.00!
So the 4.00 is as tall as the 4.50 which I have but the 4.5 is wider. The 4.10 has half the tread depth and is tiny....really.

I`m going to order a Heidenau K60 I think.....

 

ianmcdca,

The plus .10 tires (4.10, 4.60, and 5.10) are in fact actually low profile and smaller versions of the straight designated tire. i.e. 4.10 is smaller than a 4.00, 4.60 is smaller than a 4.5 etc, and you can see it in a side by side comparison like you did. Any body that was buying bike tires as an adult in the 60s would know this. You can verify this by asking an old guy like me or better yet call a tire manufacture and speak to a real knowledgeable rep. If, after you verify this, you tell someone what you learned they will think you are nuts. But you are one of a few that have noticed this sizing issue.

 

BE AN EDUCATED CONSUMER, LOOK UP THE TRUE MEASURED SIZES.

There is another tire thread that I posted manufacturer site. Here they are again:

Bridgestone
Dunlop
Duro
IRC
Kenda
Shinko

You really need to go to the site and see what the real measured sizes of the tires are. Don't guess and hold your breath hoping you get what you want. Peruse the sites they all have listings for tire sizes either on the page with the tires or in further information links on the pages for the tire model.

Seems Kenda's 4.00 is 3.8" where my Duro was an honest 4.00". Tire sizes can be all over the place. I learned this when shopping tire for supermoto rims and for my one street bike.

You benefit from my research - look and learn. And don't assume that the biggest is best. It will be heavier, as you will see in the weight, it will be more expensive when you shop for the tire, and it may have clearance issues. Know what you are fitting and if it will physically work, then think power available for the tire size.

As I have said earlier and in other threads, I used some old school knowledge from running small bore two strokes and actually went undersize (4.00 instead of the 4.8" wide 120). My 650 runs a 130 with about double the power of the 250 and it is only about .50" wider than the 120, making me think the smaller tire might just be a good thing with only about 20 hp. I did it for weight, ability to spin the tire with throttle/no clutch, and it less likely to bog the bike down in mud/saand, and there was a fair price difference. I hit the charts and learned what true size were so I could get what I wanted.

So far I found I could run deep sand able to spin the tire to keep momentum without bogging when needed with out slipping the clutch. I also found I could pretty much lean the bike in, crack the throttle and slide the rear readily to square up a turn. Next will be working in mud and such in eastern Ohio later this summer. So far looks like a good choice. Maybe not for everyone, but good for my use.


Use the charts the manufacturers put there - know what you're buying.

 

Now THATS what I was looking for! I couldn't understand why a 4.5 would be so much taller than the stock 4.6! Makes sense now.
And KLX678 I ALWAYS appreciate your experience and knowledge. I do understand why a smaller tire would be better. I wasn't trying to buy a bigger tire....just replace stock with equivilant size. That's where the confusion started. And I DID go to Kendas site but it didn't explain the reasons for the difference in sizes....
I still think that the 4.10 is too small for the kind of riding I do though.

Thanks again for the help!

 

Always read the specs. Right from the Kenda site.
K270 Dual Sport

4.00-18.....26.2"OD.....4.3"SW
4.10-18.....25.2"OD.....3.8"SW
4.50-18.....27.0"OD.....4.8"SW
4.60-18.....25.7"OD.....4.3"SW
5.10-18.....27.0"OD.....5.2"SW

Sidewalls are "typically" 100% of the width, but the low profile version are 82% of the width. Tires sizes are not accurate by any means. The 4.6-18 has a sidewall of 4.3" so if you add 2 sidewalls and the rim then you should get the OD shown. 4.3 + 4.3 + 18 = 26.6" OD... Kenda says it's 25.7. Where did the 0.9" go? It's the same for car and truck tires. They assume a certain rim width when calculating OD. If the rim width isn't listed in the specs, then your results will vary.

 

It's just the way they made them. The metric sizing is actually much better in consistency. The English not so much.

You just read what they have for actual sizing and decide what to do from there. In some cases the sidewall number seems pretty far fetched.

Use your judgement on the tire sizing based on what you think will work right, then after you get the new one think what is going on with that tire in your riding for the next time around.

There is one more bit of information there - the ply rating. The 120 has a 4 ply rating and will conform to terrain better (squish), most inch sizes (excluding the 4.60) are 6 ply - like rocks. It will affect the way the tire works. Knowing where you are at you may not want to consider the 6 ply, due to the stiffness. The 6 ply may work fine in rocky terrain where you need the sidewall to take a lot of the bashing protecting the rims a bit, but if your terrain is more dirt/mud/etc the 4 ply would be far better. They also may give better feel on the pavement. I know that is the case with street tires, no way I run six ply bias tires. The more flexible carcass will form to the terrain better when running lower pressure. Others here may have some thoughts on the stiffer 6 ply and where they are effective.

It's a shame Kenda didn't put in the tire weight. In the Duro, the 120 is 2.5 lb heavier than the 4.10 - that is roughly 20% less rotating and unsprung weight. Sport bike guys will spend several hundred to cut wheel weight by 20%.

Now you have the references to know more when you buy tires. That's good. I'm glad I could help out.


My trying the smaller tire is an experiment based on what I learned in the past. I know I'm going to encounter some gummy mud and crap along with loose dirt, the kind of stuff you want a tire to kind of knife down through, but not to bog down with too much tire. So the narrower tire is worth trying. Plus if it cuts out clutch slipping that's a saver too.