rear tire selection for the 07

hey guys. just picked up a tire sponsor for this year.. dunlops. i want to get some race replicas but they dont have the original tire size of 110-90-19 for the rears. has anyone steped down to a 110-80 or a 120? if anyone has any imput on which would be best. or should i stick with the non race replicas for the rears?

I went with the 120/90-19 and cannot tell the difference.

I would not go smaller like the 100/90-19 though.....

the 110-90s are stock.. so i wouldnt be going smaller. the 110-80s would be the smaller ones.

What about front tires? I have done some searches but can't really come up with a good model of front tire. I came back from riding this afternoon and there is a huge hole on my front, so pissed, so now time for shopping


it all depends on what kind of riding you do. I have had good fortunes with the Maxxis IT front tire. It comes in an 80/100-21.

this is the standard size for most all the makes....

it all depends on what kind of riding you do. I have had good fortunes with the Maxxis IT front tire. It comes in an 80/100-21.

this is the standard size for most all the makes....

or the maxxis it rear, i had one on my kx250, had damn near 50 rides on it and it was still in good condition.

maxxis's do seem to last forever but they also seem to be a real b---h to take on and off! The rubber also seemed to get hard on them too.

yeah i love maxxis. but i decided to go with dunlop. for this season, maxxis didnt seem alittle to hard for some tracks i went to. plus it dosnt hurt that im getting killer deal on the race replicas.

A 110/80 is the same width as a 110/90, but 11mm shorter from the rim to the base of the knobs.

Dunlop 952's work much better than Maxxis IT's, cost about the same if you buy them right, and actually last longer.

If I had a Dunlop sponsorship, I think I'd run 756RR's at places like Glen Helen and Cahuilla Creek, the new 745's at the hard pack tracks, and 952's for all-around or desert stuff.

thanks grey.. so u think i should run the 110-80s, instead of the 120's. and thanks for the tire recomendation on the 952's.

I don't think I said that, really. If they're available in the tire you want, I might try one. Especially if I were setting up a pair of 745's for a really hard track. The 745 front is also available in both 80 and 90/100x21.

One of the things that Dunlop has been trying to do with some success is to widen the effect range of soil types in which their tires work. The 745 is intended to replace the 739, which many of us know as the world's best road racing knobby. The new tire works quite well on the hardest blue groove stuff you can find, but unlike the 739, it will still work well way down into softer intermediate soil, too.

I haven't tried the 745 rear yet because I've been so hung up on the 952, but I probably will eventually. I have run the front, and it's very good.

Glad to hear feedback on the 745's front. I really like the 756's, just switched over to 952 series and have to say they work really well on Cali's Central Coast.

Dunlop helps out my race team as well and I personally use the RR's all the time except deep mud (773's). The front 756RR is like glue, you will love it. The rear is great, but wears out quickly.

The new sizes for 2007 were explained to me a little differently. Dunlop told me the 120/80 was a replacement for the 110/90. They said the width is actually the same after mounting and filling with air pressure. They said to add the 120/80 = 200 as the same as 110/90 = 200. The new 110/80 is actually intended for 125's or 250F's.

The 120/90 (not an RR size available) is truly wider, but not the 120/80. The 120/80 works great on a 450F and I would not recommend the 110/80 on that stock rim or a 450F.

The way tire sizing works is different than that, and adding those numbers in the manner described will tell you that the two tires will carry the same approximate load, but not much else. Here's how it actually works.

Take a size like 110/90-19. The last number is simply the rim diameter at the bead seat. The first number is supposed to be the width of the tire body (not the tread) in millimeters. Just for fun, let's say that everyone measures the tires the same way, and they all measure from the outside or the inside so they can be directly compared.

The second number is what fouls most people up. It's the "aspect ratio". It tells you how tall the tire is from the bead seat to the top of the tire body (not the tread) in relation to it's width. So, a 100/100-19 would be 100mm wide, and 100% as tall as it is wide, or 100mm. A 110/90 is 90% as tall as wide, which makes it 99mm tall. About the same, but wider, see? A 120/80, then, should be 96mm tall...about the same, but wider, see?

But the actual width of the finished tire depends on how the blocks are set on the edges of the tread, and on whether the tire was measured from the inside or to the outside of the casing. People like Michelin make it worse by using different millimeters than anyone else. Their 130's are a lot like most 120's.

I agree with your technical explanation Gray.

I'm just sharing what my Dunlop rep. directly told me when my beloved 756RR's in 110/90 where discontinued at the end of 2006 and replaced with the 120/80 for 2007. My guys on the 125's and 250F's switched from 100/90 to 110/80's. Maybe the RR's are unique in their design, but I'm just trying to help a fellow rider by passing along what Dunlop shared with me. They said the 110/80RR would not be enough tire on the 450 being that it was similar to the 100/90 it replaced. I asked because I was worried the 120/80 would slow my starts, but they disagreed and they were right. My '07YZ450F nails a holeshot practically everytime.

Well, true enough, and one of the great things about making tires is that you can pretty much do anything you want. But seriously, one thing you can do is to look at the manufacturer's recommended rim size:

Note that, just as you said, the 100 and 110/90 are no longer available, and listed in their place are the two /80's. Looking at the recommended rim width, you see that the 110/80 is recommended for 1.85" rims, which is the size found on 125's and 250F's, and the 120/80 is recommended for the 450 sized 2.15" rims. Seems obvious what they have in mind. Also remember the point about these sizes being the size of the tire casing when mounted on the right sized rim, and are no indication of what size the tread is.

I'll also wholeheartedly agree that in their element (soils in the intermediate range), they are clearly one of the best, if not the best, tires you could hope to use....while they last.

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