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Discussion Starter · #1 ·
Getting conflicting information. On the net most sources say the rear is a 190/50-17. But on the 2003 999s I just bought the previous owner has put 180/55-17s Continental tires on it.

What is the correct rear tire for this bike? Has the Marchinsni (spelling?) wheels on it.
 

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Saw this 03' 999 review in MOTORCYCLE USA:

"An RC51 we had along on the same day felt like a heavy pig in comparison to the 999. It was much slower turning even though it was fitted with a 180-series rear tire rather than the wider 190 on the 999. Incidentally, the Duc doesn't steer as neutral with the stock 190-series rear tire as it did on the 180s we rode at Willow. It requires a varying amount of bar pressure is required through the roll axis so, as with the old series, I'd recommend fitting a 180-series rear bun to your 999 once the OEM rubber is shagged'.
 

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The rim size should be embossed on the spokes - usually on the LHS.

If it's a 6.00 the correct tyre size is a 190/55.

If it's a 5.5 the correct size is a 180.

Fitting too large a tyre for the rim width means it will have a more pointed/triangular form.

Fitting too small for the rim size will flatten it out.

Basically you need the recommended tyre size for the rim width for it to work correctly.

A 6.00 rim refers to the width at the point where the tyre beads on the inside of the rim. It will measure almost 7" at its widest point.

A 5.5 will measure about 1/2" less at its widest point.
 

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Once you have established which size rim it is, you then have the choice of aspect ratios.

That is, the second number in the tyre's sizing.

If you have a 6.00 rim - which should be standard - your turning will be assisted by the slightly higher profile 190/55 which came out on the 1098 series, rather than the 190/50 the 999 came out with.

It should make your speedo reading more accurate also.

Be wary of fitting a 180 tyre to a 6" rim, as you can ride off the edge of it; particularly if you are tracking the bike.

PS - It is Marchesini.
 

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The 749/999 with stock wheels can use 180/55, 180/60, 190/55, 190/60 without any issues.

So yes, the tire you have is fine. When its worn out, you can replace it with something larger if you wish.
 

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190/50 vs. a 180/55 Rear Tire

Like the earlier 916, Ducati 999's were delivered with 5.5 in. rims and 190/50ZR17 tires.

When you mount a 190 tire onto a 5.5 inch rim its profile becomes slightly incorrect. The too-narrow rim forces the tire's outer edges inward into a tighter curve so that you can't use this part of the tire effectively. A correct tire profile creates a correctly shaped road contact patch essential to optimum handling, better sidewall stability with less tire flex and, and better overall tire wear.

When developing the suspension for the 916, Ducati had World Superbike racing in mind so when they sold models for the street they decided to mount 190/50 tires to 5.5 inch rims, a good combination for stable handling. It's been pointed out that WSB Ducati's then used 19/67 race tires, roughly equivalent to a 190/60 road tire.

So, we got the wide tire look without the quicker turn-in handling characteristics of the 60 section race tire.

In the 1995 916 owner's manual, Ducati specified the 180/55 as an "alternative" to the 190/50 and the bike's under-seat specification sticker also listed both sizes as recommended.

It wasn't too long before owners figured out that switching from the 190/50 to the 180/55 gave a very noticeable change in cornering feel. The 180s, mainly because of their taller, steeper profile, turn-in much quicker and easier. So eventually the word spread, and everyone who has changed to the 180s has praised its positive effects on handling.

I've run both sizes and it seems to me that the folklore about 180 tires handling better or turning-in quicker is simply describing the perceived difference between a worn 190 being replaced by a new 180. A new 190 would have handled just as well and turned-in just as quick.

The outside diameter of both size tires is the same so a switch won't require a rear ride height adjustment. The important difference is that the 180 is a 55 section meaning that its height is 55% of the width cross-section. The 190 is 50% of its width. This means that the 55-section tire has a steeper profile, it's taller.

A 180 tire is also slightly lighter. This will account for part of the subjective handling improvement experienced when moving from a 190 section tire. The weight difference between brands is greater, especially for the front tire. For example, 120/70 front Pirelli Supercorsa's (8 lb. 6 oz.) Dunlop D207RR (10 lb. 7 oz.) A two pound lighter tire will reduce rotational inertia by the same order of magnitude that you get when switching from an aluminum to a magnesium wheel.

The 190 size somewhat is stiffer because of the shorter profile. This results in increased grip and reduces the tire carcass flex (better feedback), making accelerating hard out of turns less scary. Also, if you reduce tire size, with the same horsepower you're going to stress the tire carcass more. This however hasn't been a problem, even with the most powerful street bike models.

The general rule is that a 5.5-in rim should be used with a 180 width tire and a 6-in rim should be used with a 190. However, some tire profiles are more sensitive to rim width than others. Dunlop, for example, says that their 180 slick works fine with a 6.0 to 6.25 inch wide rim.

In the past, both Michelin and Pirelli have stated that a 5.5 to 6.0 inch wheel is suitable for either a 180 or a 190 tire width. So the choice is yours.
 

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I have a 180/55/17 Dunlop Q3 on the back, and it handles and sticks incredibly. Any discussion on a 180/60, which I know some guys are fond of, should be caveated with the fact that this is an uncommon tire size that will typically only be available in race slicks. My 180/55 Q3 has been phenomenal on the track, FWIW.
 

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Discussion Starter · #8 · (Edited)
Owners manual

calls for a 190-50-17. So that's what I am going to try. Have not checked the rim size, but that's what it calls for. I cant imagine a manufacturer listing an incorrect tire size in their manual.

I just assumed the 180 was the correct tire because that's what the previous owner had on it. But in shopping for tires I discovered this bike takes the 190. Again this is a 03 999s with the Marchenisi ( Spelling?) wheels.

So going to be spooning some Michelin Pilot Power 2CT 190-50-17 soon so will see how it goes.
 

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Again this is a 03 999s with the Marchenisi ( Spelling?) wheels.

So going to be spooning some Michelin Pilot Power 2CT 190-50-17 soon so will see how it goes.
I have the same bike since '03. Over time you will appreciate the 180/55 as I did. Just saying :)
 
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