190/50 section rear tyre

[bobh]

I happen to have a new 190/50 Dunlop Roadsmart 2, which I got for another bike that I've since got rid of, and I was wondering if it might fit the MT-09.

Looking at the OEM Dunlop 214 180/55 rear tyre there doesn't seem to be a lot of clearance to fit a wider one, so initially I thought probably not. But when I did some measurements, the tyre that's on there, nominally 180 wide, actually is 190. So I reckon the one I've got in stock, which also measures 190 unfitted, would be OK.

Right, I know that a fatter rear tyre should, in theory, give slower handling. But in fact, the one I'm proposing to fit doesn't seem to be any wider, so I think I'll go ahead when the OEM tyre is worn out (which, being a Yorkshireman, means at least down to the TWI's).

But in the meantime, I'd be interested to hear if anyone has already tried a 190 back tyre?

 

[Fulfilled-09]

Your question got me thinking so I Googled for info. I found this from Continental:

Fitting a 190 section tyre to a rear wheel designed for a 180 will not necessarily make it wider, but it will almost certainly make it taller as the rim is too narrow and pinches in the sidewalls. This is something that should be avoided at all costs, as a taller and pointier tyre actually has a smaller contact patch and it slows the steering.

 

[highlander]

Your question got me thinking so I Googled for info. I found this from Continental:

Fitting a 190 section tyre to a rear wheel designed for a 180 will not necessarily make it wider, but it will almost certainly make it taller as the rim is too narrow and pinches in the sidewalls. This is something that should be avoided at all costs, as a taller and pointier tyre actually has a smaller contact patch and it slows the steering.

But the profile is a 50. Pinching it might get it back close to 55 which is standard. I have ridden with an oversize rear tyre on another bike and never had a problem. That should have been worse - from a 130 standard size with a 140 on the rim.

Nevertheless my conscience could never let me recommend it. Your local tyre fitter might have some good advice ?

 

[bobh]

Yes, I did a bit of Googling too before contemplating it. I found one tyre manufacturer's site (doh ... didn't bookmark it) that gave compatibility of tyre section and rim width. Normally a 180 tyre goes on a 5.5 inch rim, and a 190 on a 6 inch, but it is apparently permissible to use a 190 on a 5.5 inch rim.

Anyway, I'll probably give it a try once the OEM tyre has worn out. I'll report back, but don't hold your breath - it could be this time next year!

 

[highlander]

If you're into trusting the internet, this site suggests you are within tolerance for the MT-09 rim

Tyre Size for Rim Size/Width Calculator - What's the best tyre size for my rim?

 

[bobh]

Well, the original post was a very long time ago, but here's the follow-up at last. I did fit the 190/50 rear tyre - a Dunlop Roadsmart 2, which was not noticeably wider than the OEM 180/55 Dunlop D214. I didn't notice any difference in handling, and no ABS errors, so presumably the tyre rolling diameter was within tolerance.

The only issue I had was with the matching front Roadsmart tyre, which let me down (literally) on a very wet day at Cadwell - fortunately at the hairpin so at low speed with no major damage to me or the bike. I had previously used Roadsmarts on a Fazer6, and thought they were very good, wet or dry, so that took me a bit by surprise.

In terms of life, both Roadsmarts lasted around 7000 miles, which is OK, though not as much as I got on the Fazer6.

So the conclusion is really - why would you? In my case it was because I had a spare tyre available, but otherwise I see no reason to deviate from the original 180/55 spec.

Anyway, now the bike's on PR4's, of the standard sizes. Hopefully their wet grip will a bit better than the Dunlops.