Tyre profiles 180 versus 190

Hi Everyone

Had a phone call from my local Honda dealer letting me know that my
CBR600RR had a 190/55ZR17 on and the recommended size was 180/55ZR17.

I had an other dealer fit the tyre a few months ago and never noticed
that I either gave them the wrong size or that they fitted the wrong size.

I've not noticed any difference in handling and have only done a couple
of hundred miles on it.

Since I'm off to the Elefantentreffen next week which will put 2000 [1]
miles on a basically new tyre I told them to leave it and I'll change it
if I make it back.

Should I be extra careful and change it ?

[1] Wish I hadn't calculated that now
Edinburgh - Harwich 419 miles
http://maps.google.co.uk/maps?f=d&s...62,7.06384&sspn=3.941757,8.602295&ie=UTF8&z=6
Hook of Holland - Randersacker Germany 370 miles
http://maps.google.co.uk/maps?f=d&s...,13.160934&sspn=0.146253,0.270882&ie=UTF8&z=7
Randersacker - Elefantentreffen 192 miles
http://maps.google.co.uk/maps?f=d&s...,13.187714&sspn=0.146383,0.270882&ie=UTF8&z=8

 

No. The only difference you may notice is it's a little slower turning
in. Plenty of people (usually idiots) replace 180s with 190s.

--
Krusty

'03 Tiger 955i
'02 MV Senna (for sale) '96 Tiger (for sale)
'79 Fantic Hiro 250 (for sale) '81 Corvette (for sale)

 

190/55 shouldn't be slower than a 180/55... it's the 190/50 that has
the rounder shape.

 

I'm not. The "/55" means 55% tall as it is wide, so the shape for a
190/55 and a 180/55 will be the same, just scaled up on the 190.
Whereas a 190/50 will only be 50% as tall as it is wide, and therefore
flatter with a gentler curve.

That's the reason they developed 190/55's for the newer litre bikes,
so they tip in quickly, like the older 180/55's do but have a wider
profile for more grip.

Science, innit?

 

In other words, the 190/50 will have the *less* rounded shape then...
especially compared to a 190/55 when both are fitted to a rim designed for a
thinner tyre, which is kinda why Nige questioned your comment above?

Glad we cleared that one up.

--
JackH

98 Yamaha Fazer FZS600
03 VW Passat TDI Sport (Resting)
00 VW Golf 1.9 TDI SE Estate

 

Ahh I see.. yeah.

A /50 would be pretty much just round, but a /55 would be a bit more
'pointy' and round because of the combination of it's higher profile
and the fact it's queezed into the same width rim.

Indeed.

 

Wrong.

 

Explain why.

 

Oh, before you answer read this...

http://www.sportrider.com/tech/tires/146_0302_rear_motorcycle_tire/index.html

 

This might be true if the 600 had a rim wide enough for a 190. I'll
bet it doesn't, which means that the 190 will actually have a greater
curve, which will in put less rubber on the road, and will speed up
the steering.

 

OK, that I get. I didn't realise 600's don't use 6 inch rims.

 

'cos they're Italian and they can.

They have 190/50x17 IIRC - ask Kiran as he'll know.

 

190 / *55* same as the 10R

 

The only other test I've seen said that the 190/55 was still
marginally slower steering than a 180 but I really can't be arsed
searching around because it was probably a magazine and not online.

I don't really give a **** anyway.

 

Would anyone other than a riding god actually notice much of a
difference, without riding the same bike with the different sizes
back-to-back? I'm not sure I would.

I mean, after fitting new tyres I can tell that the bike handles
differently from before, but after a while I just get used to it.

 

Yes, but only on the same bike and *immediately* afterwards.

Once I get used to it, I couldn't really say that the bike is steering
any quicker or not.

 

I certainly notice it with the MV. A 180 makes you feel like a riding
god, but a 190 just never quite seems to work. Can't speak for other
bikes though.


--
Krusty

'03 Tiger 955i
'02 MV Senna (for sale) '96 Tiger (for sale)
'79 Fantic Hiro 250 (for sale) '81 Corvette (for sale)

 

i'm not a riding god. i replaced the 190 section rear tyre on my zx-7r with
a 180 section tyre, and it steered a little bit more easily. not much in it
though.

 

I think you're making my point for me though! You would, Champ would,
Antonye would, etc. etc. Maybe I would, but I'm not so sure for the
reasons I've already made.

 

Last time I had a rear replaced I noticed the difference because the
bike would no longer stand up on its own while stationary.