120/60ZR17 vs. 120/70ZR17

Could anyone tell me if it is a good idea to go with a 120/60 versus the more common 120/70 for a front tire on my WR250X? I currently have Distanzias (which were on the bike when i got them). I was considering putting on a more street specific tire like the BT-003 or Pilot Powers and they offer a 120/60ZR17 front. I will be running a 150/60ZR17 rear. Also, your experiences with this tire size/combo.

Thanks!,
ej

I'm running 120/70 fronts bc theyre takeoff race tires from my 600's but I prefer the extra height and lean angle I can get out of them. I've run 140 and 150 rears and honestly didnt see much difference.
With stock suspension I wasnt using the entire side of the 150 anyway but it wasnt tuned yet.

Actually, stock is:

Front: Bridgestone / BT090F Radial G / 110/70R17M/C 54H

Rear: Bridgestone / BT090R Radial G / 140/70R17M/C 66H

motokid wrote:

Actually, stock is:

Front: Bridgestone / BT090F Radial G / 110/70R17M/C 54H

Rear: Bridgestone / BT090R Radial G / 140/70R17M/C 66H

You are correct sir - I had to go look at the tire in my garage. I hate that oem front tire.

That being said the 10mm difference in side wall height couldn't make a huge difference could it?

The narrow rim will pull the sides of the tire around a bit more and make "using the whole tire" almost impossible, but it should still work shouldn't it?

I know I'll never touch the edge of my front tire.

You'd be surprised. Normal street riding - probably wouldn't make much difference. Track/racing or even hard street riding - i get these all the way on the edge. Then again, it has a lot to do with the profile of the tire. The pirelli dot race tires that i run are somewhat steep compared to say a bridgestone or rounder profile street/enduro tire.

This is probably common knowledge to all us gearheads but for the newer riders & non-gearheads that need to figure the increase or decrease of the sidewall height when changing tire sizes, this is the breakdown of what the numbers on the sidewall means.

WR250X front tire: 110 - 70 - 17

110 = Tread section width in millimeters.

70 = Sidewall height in percentage, of the tread width. ( Example 70% of 110mm or .70 x 110mm = 77mm )

17 = Rim diameter

I need new tires soon so I've been reading alot. I noticed alot of tires will come in a 70 ratio front and only available 60 ratio rear. I would think you would want the same ratio but does it matter??? I know stocks are both 70.

Either way i wanna try out the new ContiAttack SM, but man they're pricey....but I do love my bike so.....

Mikechicago wrote:

I need new tires soon so I've been reading alot. I noticed alot of tires will come in a 70 ratio front and only available 60 ratio rear. I would think you would want the same ratio but does it matter??? I know stocks are both 70.

Either way i wanna try out the new ContiAttack SM, but man they're pricey....but I do love my bike so.....

The second number is just that, a ratio. Usually you compensate for the wider tire width by going down the same % or so in the sidewall height ratio.

I.e. You can buy a 140/70/17 rear but if you wanted to go to a 150 most manufacturers only offer it as a 150/60/17. If you put the two next to each other - they're not that much different.

It all depends on the tire profile also but either way, to make changes properly like that you really need to adjust your suspension as well.

Just my $.03

rc23 wrote:

I'm running 120/70 fronts bc theyre takeoff race tires from my 600's but I prefer the extra height and lean angle I can get out of them. I've run 140 and 150 rears and honestly didnt see much difference.
With stock suspension I wasnt using the entire side of the 150 anyway but it wasnt tuned yet.

This is good to know. I'm on power pilots 110's and I almost lost the front end yesterday at this abandoned kart track. I was shocked that it washed. being it's a PP. I NEED more lean angle