BC Sport Bikes Forum banner

1 - 10 of 10 Posts
R

·
Guest
Joined
·
0 Posts
Discussion Starter #1
Aight here goes...
Whats the pro's and con's of running a 60 or 70 series front tire of same width.
Yeah, yeah hieght, but handling is what I'm lookin for.
120/60R17 & 120/70R17.
Not goin to the track with them...
Is it even worth a bother?

Replacing the 130/70R16 on my bike, so now is the time to pick.
(Dont bring up the rim diference aight idiot...)

:rider :cheers
 
R

·
Guest
Joined
·
0 Posts
Discussion Starter #3
Aight...
I'm swappin out the 16" wheel for a 17" wheel, but indescisive as to which tire to use.
Preffer the look of the 60 series, but dunno if it'll make any difference to the handling.
I've been told its the width that makes the 130/70R16 handle 'funny'. But if its actualy the hieght, then I've done the swap for nuthin if I shell out for the lower profile tire.

So is it the width or the height that makes the 16" wheels wierd.
:cheers
 

·
???????
Joined
·
908 Posts
I'm just spitting back shit I've read in Mags, but... Allegedly it's the height of the tire that make the bike a bit "twitchy".
You need to measure the circ of the old front tire and subtract it form the circ of the new tire, then raise the fork tubes by I think half that number (better check on the measurements). I don't think you'll feel much diff if you do this right, prolly a little more stable in corners, little better braking?
 
R

·
Guest
Joined
·
0 Posts
Discussion Starter #5
If I can compensate with a tube ajustment, then I can have the best of both. The 60 series is smaller, and the 70 series is taller.
Current
1) 130/70R16 = 23.19"

Choices
2)120/60R17 = 22.83"
3)120/70R17 = 23.74"
 

·
???????
Joined
·
908 Posts
Rogue Rider said:
If I can compensate with a tube ajustment, then I can have the best of both. The 60 series is smaller, and the 70 series is taller.
Current
1) 130/70R16 = 23.19"

Choices
2)120/60R17 = 22.83"
3)120/70R17 = 23.74"

Huh? The fork tube lift will only keep the front geometry right, it's not going to change the tires profile. It's funny that the 130/70 and the 120/70 are so close is size!! I wouldn't use the 120/60.
 
R

·
Guest
Joined
·
0 Posts
Discussion Starter #7
Actualy the 120/60 is only .36" smaller, the 120/70 is .55" larger, so smaller tire is closer to what I had.

Is it the geometery that makes shit 'funny'?? If thats the case, just lifting the forks a bit would get rid of the wierd charateristics of the 16" wheel.

Its gotta be the width, wider rear steers in harder, so a wider front should/would do the same yes/no?
 

·
???????
Joined
·
908 Posts
Rogue Rider said:
Is it the geometery that makes shit 'funny'?? If thats the case, just lifting the forks a bit would get rid of the wierd charateristics of the 16" wheel.?
No, doesn't work that way. I think I've just confused the issue for you.

[/QUOTE]Its gotta be the width, wider rear steers in harder, so a wider front should/would do the same yes/no?[/QUOTE]

Well ya could be, always a bit of trade off on grip and handling. The main reason you do this mod is for convenience. 130/70 are a bit hard to find if you want to run the newest and stickyist of tires, all tires come in 120/70 and 180/55. If you want a better idea of what to expect you should post on a 900rr site to get some real feed back.
 

·
umm... yeah
Joined
·
203 Posts
hey,

I went from a 120/60r17 to a 120/70r17 on my R6. Turn in was way better and the bike felt a lot smoother in the corners. Could have been that I switched from Dunlop d208's to Pirelli Diablos, but none the less the change was good.

Matt
 

·
Premium Member
Joined
·
11,195 Posts
The 60 doesn't provide much rim protection if you run through a pothole or back crack with surface change. Also not as many compounds are available in the 60 series. Go with the 70. If the bike seems lazy to turn in or feels like it has a mind of it's own in parking lot turns then just let the forks slip up in the clamps bt .25 inch to bring your geometry back to stock.

My track bike Honda is supposed to use the 60 in street trim. But race rubber doesn't come in that size. So far it's all been nothing but good going to the 70.

Width is only part of the picture. Profile curve is at least as important. And on the fronts a 70 has a more rounded profile so the handling should be more neutral and that's what you want. A low profile 130 would be bad in this respect. So going for a more rounded 70 is even further from the badness of the 130/60 than stopping at the 120/60.
 
1 - 10 of 10 Posts
Top