Ducati Monster Motorcycle Forum banner

1 - 15 of 15 Posts

·
Registered
Joined
·
1,150 Posts
Discussion Starter #1
Anyone had any adverse issues running a 120/70 on the front of their S2R in place of the stock 120/60 size? Seems like most of the latest ultra high performance tire options (Pilot Power 2CT/Dunlop GP/Bridestone 012SS) are only available in the 120/70.
 

·
Premium Member
Joined
·
892 Posts
I had the same question about my 620 which came stock with a 60 series front. My tech said that that the 70 series are probably better for the street. They're more forgiving if you should happen to hit a pot-hole. Many ducs come stock with a 70. It's such a minimal difference (10% of the 120 width) that you may not even feel the difference. My 620 tracks just as well with the 70 as with the 60.
 

·
Registered
Joined
·
917 Posts
it's a big enough difference that it will change handling characteristics. your riding style will dictace whether or not it makes a big difference for you.

you can always adjust the forks in the triples to account for the change of tire diameter.
 

·
Registered
Joined
·
1,150 Posts
Discussion Starter #4
b.h. said:
it's a big enough difference that it will change handling characteristics. your riding style will dictace whether or not it makes a big difference for you.

you can always adjust the forks in the triples to account for the change of tire diameter.
That's what I was thinking; it's a full inch difference in diameter, which is gonna affect the front end geometry enough to probably slow down the steering a bit. I would think I'd want to pull the forks up in the triple clamps a bit, but I hate to start that hunting process without a specialist like GMD.
 

·
Premium Member
Joined
·
892 Posts
The S2R 1000, S4R and S4Rs all come stock with a 70 series. It shouldn't be that much of an issue. Doesn't your 800 share the same geometry as the 1K?

*added* Tech Spec on the ducati.com website is showing a 70 series as stock on the S2R 800 for 2006. (60 for the 2007) Has your front tire been changed previously? You should be fine with a 70.
 

·
Registered
Joined
·
1,150 Posts
Discussion Starter #7
rule62 said:
The S2R 1000, S4R and S4Rs all come stock with a 70 series. It shouldn't be that much of an issue. Doesn't your 800 share the same geometry as the 1K?

*added* Tech Spec on the ducati.com website is showing a 70 series as stock on the S2R 800 for 2006. (60 for the 2007) Has your front tire been changed previously? You should be fine with a 70.
Yah, just figured out that I was looking at the 07 spec sheet, didn't have my bike in front of me. That makes things a whole lot easier. Wonder why they went to the 60 in 07 and assume they had to change the length of the fork tubes to get the same rake figures.

Now I just need to decide whether I go with the Powers or the Power 2CTs.
 

·
Premium Member
Joined
·
892 Posts
Archimedes said:
Yah, just figured out that I was looking at the 07 spec sheet, didn't have my bike in front of me. That makes things a whole lot easier. Wonder why they went to the 60 in 07 and assume they had to change the length of the fork tubes to get the same rake figures.

Now I just need to decide whether I go with the Powers or the Power 2CTs.
Honestly, I don't think they would have changed the length of the fork tubes for such a small increment. 10% of 120 = 12mm of sidewall, and the sidewall isn't exactly perpindicular to the road, so we're probably talking only 8-10 mm of overall height (if even that much) = deminimus.

As for why they changed tires between years... $$$ and sponsor contracts, most likely. ;)
 

·
Registered
Joined
·
1,150 Posts
Discussion Starter #10
rule62 said:
Honestly, I don't think they would have changed the length of the fork tubes for such a small increment. 10% of 120 = 12mm of sidewall, and the sidewall isn't exactly perpindicular to the road, so we're probably talking only 8-10 mm of overall height (if even that much) = deminimus.

As for why they changed tires between years... $$$ and sponsor contracts, most likely. ;)
If you look at the tire diameters, they're a full 1 inch difference in the Michelins. That's a lot, and from a sport riding perspective should be noticeable to a decent rider. However, now that I realized the stock set up has a 70, all is good. There are a lot of choices in 70s, not so much in 60s.
 

·
Registered
Joined
·
4,897 Posts
Archimedes said:
If you look at the tire diameters, they're a full 1 inch difference in the Michelins. That's a lot, and from a sport riding perspective should be noticeable to a decent rider. However, now that I realized the stock set up has a 70, all is good. There are a lot of choices in 70s, not so much in 60s.
wouldn't a full inch diameter difference only be half an inch of height difference? ??? which would be about 12 mm of actual height, and like rule said, it's not all exactly up and down...
 

·
Registered
Joined
·
1,150 Posts
Discussion Starter #12
hiero said:
wouldn't a full inch diameter difference only be half an inch of height difference? ??? which would be about 12 mm of actual height, and like rule said, it's not all exactly up and down...
All I'm saying is, in the world of suspension tuning an inch difference in tire diameter is a material difference and someone trying to really dial in their suspension would make an adjustment for it. Would you throw an 18 inch rim up front? It too is 'only' an inch difference.

There was an article in a motomag a few years a back about this; about how you needed to be careful when selecting tires not to change diameters materially without adjusting for it elsewhere in the geometry of the bike. And they were talking about less material differences in the actual size of similarly size marked tires across different manufacturers, not 60 v 70 aspect ratios.

Now all this said, I'm curious why Ducati chose to go to a 60 on the 800 in 07. To save $8 per tire in mfg. cost?
 

·
Registered
Joined
·
917 Posts
Archimedes said:
All I'm saying is, in the world of suspension tuning an inch difference in tire diameter is a material difference and someone trying to really dial in their suspension would make an adjustment for it. Would you throw an 18 inch rim up front? It too is 'only' an inch difference.

There was an article in a motomag a few years a back about this; about how you needed to be careful when selecting tires not to change diameters materially without adjusting for it elsewhere in the geometry of the bike. And they were talking about less material differences in the actual size of similarly size marked tires across different manufacturers, not 60 v 70 aspect ratios.

Now all this said, I'm curious why Ducati chose to go to a 60 on the 800 in 07. To save $8 per tire in mfg. cost?
+100

a 1" change in ride height is enormous
a 1/2" change in ride height is a lot
a 1/4" change in ride height is significant

if you're tuning your suspension by changing front ride height you would ideally make changes by 1 to 2 mm at a time until you find a sweet spot where you're happy with both the turn in and high speed stability. and don't forget that altering front or rear ride height can also have an effect on weight bias which in turn effects handling and traction.

$8 per bike adds up. since they'll be earning a lower profit for their marquee bike they're going to want to squeeze every penny of profit out of all the models.
 

·
Premium Member
Joined
·
892 Posts
I wasn't trying to instigate. I was just speaking of my own experience. I have since; added about 1" of height to the rear of the bike and swapped the rear shock from a 749. Dialed it all in and then added an Ohlins sd-154 damper for shits and giggles.

If the 70 series tires are easier to get a hold of, I'd say to use that as a starting point. What would be the sense of beginning to dial in your suspension with a 60 series if they're just gonna be a PITA to find?

Good luck with whichever choice you make. Once you get it dialed in it'll be all ;D ;D ;D ;D ;D ;D ;D for you!!!

Ride safe. [thumbsup]
 

·
Premium Member
Joined
·
1,988 Posts
I went up 1" in the rear and down 5/16" in the front and it works pretty good for me.

I just ordered a set of 2 CT's online for $289 total shipped (MotorcycleSuperStore). On my ex s4r I used 3 fronts and 5 or 6 rears in 15,000 mi. The guys at the shop said it's the most tires they have sold to anyone in just over a year. The same shop offered me a "deal" (NOT) on a set of 2 CT's - $450 just for the tires. I like to support the local shop, but $160 saving on one set of tires? No contest! I'm back to changing em myself.

LA
 
1 - 15 of 15 Posts
Top