if my tyre should be 19 55 17, the 55 is the height/pitch of the tyre? So a 50 should be ok, would you think?
I'm pretty sure that the 55/50 part of the sizing is the aspect ratio of tyre wall to tread width as a percentage, so a 50 aspect tyre will, effectively, alter the rolling radius of the wheel and tyre. It may, therefore, also alter, slightly, the speedometer/odometer accuracy. The possible effect of the change on the bike's handling is hard to predict but, generally, a production road motorcycle is designed with and for specific tyre sizes and it's rarely ever going to be a good thing to deviate from the manufacturer's original spec. My 2 penn'orth.
Also what's sometimes overlooked is insurance companies know the types and sizes of tyres that are supposed to be used and for them it will be an easy blame...... You crashed out because of the rubber. Not worth the risk matey.
Not a good idea on a Speed Triple as it will mean you end up overworking the outer edge of the rear tyre
Not sure about that but there’s more to it than just size, the profile of the tyre will be different. The “height “ difference is nearly 10mm (50%of 190 is 95 and 55%of 190 is 104.5) so your 50 aspect tyre will lower the rear and alter the steering geometry. Better off with the correct size. Have you found a 50 aspect that’s really cheap or something?
190mm Width 55% aspect ratio i.e. 104.5mm High 17” rim size (423mm) A 50% aspect tyre is 95mm high - an overall difference of 2x radii or 19mm in lost diameter which my fag packet calculation makes about a 3% difference in lost rolling circumference (gearing) than it does in ride height (1x 9.5mm radius) and slightly lengthened trail (slower steering) at the front. More of a ‘get you home/false economy’ than sensible switch......in my opinion. If you imagine a cross section of the tyres you are going for a flatter overall profile.....more dish, less cup!
TopBanana0 I support the insurance answer. I had a good friend had his Daytona wrecked by a pillock doing a stopie in front of him. The rear wheel came down on the front of his bike and did some damage. Because he had different tyres on there his insurer walked away. This is one time I would give Jack Lilly a lot of praise as they sourced parts and bits to put his bike back on the road for practically nothing. Ride Free Joe.
Totally agree Joe. topbanana0 Try looking for "tyre selector - triumph motorcycles" it tells you all you need to know on the matter, From manufactures to sizes that should be used.
Not sure changing the tyre sizes unless you really do know what your doing is a good idea! From a good source of mine I was told that this incident (no 34) was caused, or contributed to, by him fitting a 190 tyre over a 180 when he had been advised not to!
I did say contributes, I'd believe my source over a public video. What caused the shock to break if indeed that was the real cause? I have another friend who's shock did break whilst racing and he ended up with a snapped tib and fib but this was due to running the rear too high.
Yes fair enough Glyn The point I was making is a bit like a boy racer in his vauxhall Corsa or whatever. 3" bore exhaust sounds loads faster but in reality is it? or has he/she just wasted all the manufacturers development time? Regarding this thread tyre question riding bikes well is often a matter of confidence so try it if you think it will suit, just be careful.
I don’t need to try them anymore, that’s why i asked the question why do you want to change the profile. But what I will say we did used to run wider race tyres at at tracks with high grip levels as they dissipate heat better but significantly slow the steering, so we used to experiment with different profile shapes to try and get the grip with a similar turn in. But that’s just my opinion, take from it what you will.
