Is tire sizing changing?

[hahmule]

I've been shopping tires lately having cooked both on my 610. But I've noticed that some tires are no longer available in sizes that were available previously.

Specifically, there are fewer 140/80-18 rears and 90/90-21 fronts. I've been told that the 120/100-18 is the equivilant replacement for the rear and the 100/80-21 is the replacement for the front.

A little arithmatic suggests I'm getting a taller, skinnier tire in the rear while the front is about the same. Kenda in particular, mentions "new metric" sizes. What gives?

 

[Nielly]

I think it may vary somewhat by maunfacturer but I went from the Michellin and then the Pirelli rear in 140/80-18 which seemd to be the same to the Maxxis 120/100-18. The Maxxis is definitely skinnier and taller - noticeable both visually and in riding. It fits but I wouldn't call it equivilent.

 

[hahmule]

I noticed that Maxxis no longer makes the 6006 dual sport tire in the 140/80-18 size and gives the 120/100-18 as the replacement. I was wondering if there was an industry move afoot to standardize sizes along certain lines.

 

[PALMER84ONE]

I've run across the same thing. 140/80/18 is still avail for the Mich. Desert, $$$ 160.00 to the door though. The 120/100/18 gives it (08TE450) more wheel spin and works but not as beefy IMO. Running the Desert IT Maxx. I am going to try out the Mich AC10 in 110/100 or 120/90/18 and see how that goes, $$$ 70.00 AC10 works well on my XR4.

 

[Mike Kay]

IMHO the TE610 should use a 120 and not a 140.

When Team Honda raced 300lb XR650r's in Baja, they used a 120 rear.

Lots of reasons its a better choice.

Just sayin dont be concerned with using a 120.

 

[RLW]

In addition to a listed size being slightly different from mfr to mfr (or tread type to tread type), you need to be aware there is also a different sizing systems used by a couple tire manufacturers out there that causes confusion.

Michelin (& I think as mentioned above, Pirelli) go by the Alpha (European?) sizing. Most others go by Metric sizing, so for dirt tires.....Michhellin/Pirelli 140/80-18 (Alpha) = Dunlop/Maxxis 120/80-18 (Metric) = (whoever uses it anymore) 5.00/5.10 x 18


(copied from a chart)
Metric ___ Alpha ___ Inch
80/100 ___ 80/90 ___ 2.50/3.60
90/100 ___ 110/90 ___ 3.60/4.10
100/100 ___ 120/80 ___ 4.00/4.10
110/100 ___ 130/80 ___ 4.00/4.50
120/100 ___ 140/80 ___ 5.00/5.10

 

[robertaccio]

go to the michelin site they even size their different tire models differently depending on which ones they measure width from near the center carcass and on others from the widest point.

 

[desmo900]

where do street tires fit into this? I have not noticed any measured size difference in brands of 180/55-17's that my Buell Ulysses uses.


(copied from a chart)
Metric ___ Alpha ___ Inch
80/100 ___ 80/90 ___ 2.50/3.60
90/100 ___ 110/90 ___ 3.60/4.10
100/100 ___ 120/80 ___ 4.00/4.10
110/100 ___ 130/80 ___ 4.00/4.50
120/100 ___ 140/80 ___ 5.00/5.10[/QUOTE]

 

[Iceman]

Nice to see they tables. They figures has being confusing me a bit. I´m using Dunlop 756 110/100 on my TE510 and think they do work grate.

 

[RLW]

where do street tires fit into this? I have not noticed any measured size difference in brands of 180/55-17's that my Buell Ulysses uses.

Can't answer that one. I haven't had a street bike or really looked at street tires since mid '80s. If I remember right, street bike "Alpha" sizes start with something like a "MR" or "MV**" (?)
I'm guessing by the 180/55, it's just the standard metric size most use. (maybe street bikes use more standardized metric sizing like typical car/truck tires?)