180? 190?

its the 55 profile part you will notice, it feels like the back is jacked up(good), tho with some tyres(190/55's) you will find the chain will chamfer the tyre.
Ck

if you didnt have that prob with 190's on a 6 inch rim then it says your working the edge to much on the 180/6" rim combo due less rubber on the road at that point,far more likely to overheat the tyre too and therefore go off . more likely to lose traction at rear if you ride of the edge of the tyre . (all this still depends how good a rider /racer you are or how stupid you want to be too ). the rolling radius changes on the tyre when squeezed or stretched to fit the wrong size rim . 190/6 and a 180/5.5 should by rites have the same rolling radius when in motin but a 180/6 will push the wheel out further. as for ducati's the supplied the 748 with a 5.5 rim and a 180 tyre the 916 with a 5.5 rim and a 190 tyre only reason to do this was so when racing they had a far greater range of tyres to use (once homologated you could only go smaller not larger ,this rule may now have been but at the time was correct)

not trying to offend anyone just to give insight in to what actullay happens to the carcass of tyre when put on a wrong size rim

sooooooo which models have 5.5" rims and which have 6" rims?
does the rear wheel width change with the year model or is it dependent on whether you have standard or oz wheels?

i have a 2002 rsv R with oz wheels currently on 180/55 and feels good but not taken on track yet, i'll have to wait until summer.

80kg in my riding kit unlike some of you bloaters! :biggrin

1999 has 6" rims

just been looking in the manual for it

all this does depend to a great deal on who makes the tyre as each manufacturer has different profiles

on page 100 of user manual it shows a table for tyre makes and sizes most are 190 a couple are 180 (racing compound tho)

http://www.serviceaprilia.com/public/lum/index.asp?l=RSV Mille

yup, my racetecs 190/55 did that too.( I now run 180/55's no probs now)
Diff tyres hav diff profiles, so 55's do some dont.
Ck

I think it mebbe cos I run std 108 link chain and 16/44 sproks, so wheelbase is as short as you can get it!
Ck

hi guys,
I find the fact that some 190 / 55's are touching the chain ' issue ' interesting, as I've run Metzeler, Pirelli, Dunlop's 190's on OZ rims , with 5 mm clearance to the chain. So the question is : Why do some touch, and some don't ??? I want to give a possible explanation. The front sprocket has a ' collar ' and fitting it wrong way around, will affect the alignment of the chain and also the clearance from chain to tyre. I knew this before sprocket change, courtesy of info i found on this forum. I stood by when the sprocket was changed and i believe that collar could make a 5mm difference and hence touch the chain if fitted wrong way round. Also the mis-alignment would effect pre-mature wear of sprockets and chain.

I would like to hear some responses.

hi there,

When changing tyres you can use the opportunity to change profiles to get a desired effect. ie. 50 / 55 / 60 profiles. For the un-initiated > The profile is a percentage of the width. So 190 / 55 > the height would be 55 % of 190 mm wide. It stands to reason then that a 190 / 55 would stand taller than a 180 / 55. Now most of us prefer the 190. The taller profile will result in quicker ' turn-in '. You also have a larger contact patch on full lean. The slightly larger diameter will have a small effect on pulling power. For those who have over geared, it's good, for those who still run the standard gearing of 17 / 42, it's probably bad as she will already be sluggish in 6th. Of course we can re-adjust the attitude on the suspension again if necessary.

My latest ' mistake ' was to put a Dunlop Sportmax GP 60 profile at the rear. I have not taken it to the twisties yet, but immediately i found the bike ' sluggish ' compared to the 55 profile tyre. ( running 16 / 42 gearing ). Superfast turn-in and arse to high....damn now I have to adjust everything again. All this because I was sitting at a mates' bikeshop Friday afternoon eyeing this 60 profile tyre after 3 Rum and cokes. Conveniently forgetting the effect of the higher profile as he wanted to get rid of the tyre.It was ordered for someone who did not take it. We'll I got it at a price that I could not refuse and in the process forced a sprocket change and rear suspension adjustment......so we learn.

I find the fact that some 190 / 55's are touching the chain ' issue ' interesting, as I've run Metzeler, Pirelli, Dunlop's 190's on OZ rims , with 5 mm clearance to the chain

Click to expand...

It may still be down to the tyres you used. A few years ago a Dunlop 207 180 would be as wide as a Supercorsa 190, we struggled on the RS250s because the MRO control 207GP 160 rear really needed a 5" rim. When the Dunlop 209 was released, they weren't as wide and a 160 was recomended down to a 4.5" rim (still ***** tyres mind). Assuming the same happened to the wider sizes, a Dunlop 209 or qualifier (or whetever they are called) might fit fine, but the older 207/208s might not.

For the record I use a 180/55 Supercorsa or racetec (part worn) on the road bike and the difference is barely perceivable between that and my brother's RSVR running a 190 supercorsa. On the track the RSVR seems to need more lean than any bike I've ridden so the track bike always gets a 190 racetec as I think it would be easy to run out of tyre using a 180.

List of Tyres measuring actual width Could be Useful

philandpa said:

I last got a 190/50 (ordered 190/55 but thats that bike shop for you) I know the sprockets on the right way yet my tyre rubs and the wheel alignment is showing that it needs to go further round into the chain. the tyre measures 200mm at its widest so maybe this explains things a bit.
Are different manufacturers tyres so varied in there actual width.

My tyre is a dunlop qualifier 1 190/55 and it rubs. Maybe we should start a list of tyres that do and don't rub? it could be made a sticky

Click to expand...

The answer lies in the tyre that actually measures 200mm instead of 190 as it should. A wider rim would push the wall out and ' make ' the tyre wider than intended. So my guess is that if an older make tyre was intended to be used on a 5.5 rim, but you put it on a 6.0 or wider, then that ' creates ' the wider actual measurement.

I measured a few tyres on the rack at a tyre shop with a vernier to check if the actual and indicated sizes correlates. This measurement is argueably inconsistent when a tyre is off the rim, but for the record the 180's measured +-180 and 190's measured +-190. Can't remember which makes I measured though.