Tire size conversion

[Steve Minor]

Isn't a 100/100 X 18 somewhat the same as a 4.10 x 18?

I'm putting new rubber on a 72 Six Day and want to purchase the correct size inner tube. I selected the Kenda K257D, front and rear...(4.10x18 and 3.00x21)

Steve Minor
Wilmington, NC

[Mick Milakovic]

Hi Steve,
You're correct on the size conversion.  I'm running that same size and brand tire on my Harescrambler.  It's given me real good wear life.  

Mick

[Steve Minor]

Thanks for the confirmation Mick.

PS....You couldn't have picked a better name for your bike than Black Beauty. Great job by you and your daughter. I'm sure Black Beauty will bring many smiles to both of you....

Steve Minor
Wilmington, NC

[Dwight Rudder]

ACTUALLY, NO,  a 4.10 is not a 100/100X18, which is a 400X18, it is more like a 100/90X18 or a 3.50X18.  I have found that a 4.60 is close to the 400 or 4.25 X 18. (110/100X18 the Pirelli 400X18 is same size )
A 4.60 is smaller than the 450X18.  A 5.10X18 is same as a 130/90X18, 120/100X18, and 450X18. EXCEPT when it comes to the Michelin tires which I don't like on Vintage bikes. Their sizing is way off of everyone elses.  
Confusing isn't it.
I have been selling tires many many years.
Dwight

Dwight Rudder
7 time ISDT / E medalist
8 time National Enduro Class Champion.

[Steve Minor]

I must admit Dwight....you do know your tires, and I'm sure you can help me with something.

I'm trying to buy the proper tube for a Kenda K257D 4.10x18....I have (in my parts inventory)a 4.50-5.10x18 tube, but I don't want to try to stuff all that rubber into the small 4.10 cavity. I'm trying to avoid the old "10 gals of crap in the 5 gal bucket" situation...I have a knack for pinching tubes.


Steve Minor
Wilmington, NC

[Mick Milakovic]

Sorry guys, I got my information from the XS650 Yamaha site.  They had a conversion chart that I printed off and have been using.  Maybe street bike tire metrics and dirt bike tire metrics are different ... [?]

Anyway, Steve, the tire size you stated is what I have on my 250 and I like the traction that results from it.  It spins off the line nicely and hooks up in the corners.  Finally, it looks VERY vintage, too!

Mick

[t20sl]

Steve: To answer your tube question get a 350/375/400-18 tube or second choice would be a 350/400-18.

[Dwight Rudder]

a 350/4.10X18 tube is the ideal fit. OR even a 350/400X18 or a 350X18.  But not a 400X18 or 400/450X18.  I wouldn't even mind a 325/350X18.
Dwight

quote:Originally posted by Steve Minor

I must admit Dwight....you do know your tires, and I'm sure you can help me with something.

I'm trying to buy the proper tube for a Kenda K257D 4.10x18....I have (in my parts inventory)a 4.50-5.10x18 tube, but I don't want to try to stuff all that rubber into the small 4.10 cavity. I'm trying to avoid the old "10 gals of crap in the 5 gal bucket" situation...I have a knack for pinching tubes.


Steve Minor
Wilmington, NC

Dwight Rudder
7 time ISDT / E medalist
8 time National Enduro Class Champion.

[Dwight Rudder]

Although too small for a 250 , I will admit that Helmut Clasen also uses a 4.10X18 on his 250 Hercules. I like a bit more sidewall.  I would use a 4.10 X 18 on my 125 Hercules 7 speed.
Dwight

quote:Originally posted by Mick Milakovic

Sorry guys, I got my information from the XS650 Yamaha site.  They had a conversion chart that I printed off and have been using.  Maybe street bike tire metrics and dirt bike tire metrics are different ... [?]

Anyway, Steve, the tire size you stated is what I have on my 250 and I like the traction that results from it.  It spins off the line nicely and hooks up in the corners.  Finally, it looks VERY vintage, too!

Mick

Dwight Rudder
7 time ISDT / E medalist
8 time National Enduro Class Champion.