It seems that the general consensus - not just on this forum but everywhere - is that a 190/55 rear tyre tips in better and gives more grip at the limit than a 190/50 rear tyre. So why, since time eternal, has Honda specced 190/50 tyres on Fireblades from the factory? They will test and test and test every aspect of the bike rigorously - it won't be a decision that's made randomly. So they must have reasons. Any insights?
I agree with you they can't be wrong can they?! I recently put a 55 profile on my 09 blade for the reasons you said, tips in quicker etc. But also it gave me a little extra ride height as well. On my new SP though I'll be leaving the 50 profile in place, I've heard the larger profile tyre can mess with the electronics. In a similar way putting larger wheels on a car can affect the speedo. Not 100% certain on this but is enough to deter me. Plus the bike handles sweet and it's harder to get rid of your chicken strips on a 55 profile haha
Yes as soon as you've got clever electronics you'd be daft to mess with tyre size - but agreed on the chicken strips! I was very disappointed to see I hadn't scrubbed to the very edge on the 190/55 at Snetterton when riding like a granny on my old bike (on 180/55s) the chicken strips were gone by the first lap! Having said that - the fact that at your maximum lean angle you're still not actually on the very edge of the tyre seems to back up the theory that you've got more tyre in contact with the tarmac on a 190/55 when riding hard. On the final session at Snett, first lap out, I came into the first right hairpin behind another rider at pretty much the same speed as him. Half way round his bike washed out and he lowsided. I missed him by inches. Many factors here why he might have run out of grip and I didn't (colder tyres, worn out tyres, sudden movement on throttle/brake (not that I noticed), subtly different line) but maybe also something as simple as too much lean for the tyre edge - given his tyre. Given such fine margins can be the difference between staying on your bike and not, I think such apparently trivial questions like tyre profile are indeed relevant.
Wise. @RC45 has covered this on the USA forum. A member had changed profiles and had a lot of messed up readings on his dash. Apparently affects the wheel rotation sensors (makes sense) and can even throw out the torque control settings. Like you, I certainly wouldn't be messing with mine.
Correct me if I'm wrong but i thought the SP came with 190/55 OE and its the standard bike that comes on 190/50? But absolutely agree with the general sentiment, I much prefer the feel of 190/55 and would always go for that size
I will correct you because you are wrong.....SP comes with 190/50/17 rear tyre as standard You did ask to be corrected
I used the 55 on my old blade, better grip at full lean than the 50, also tips in better, so great for track, i doubt you would notice any difference on the road really though, unless you ride and corner real fast? my R1 comes with 55's as std as do most suprbikes now, although I move to 200 width for track and no problem with the electronics
Let me ask this question then ref sp wheel sensors and electronics.... The bike comes from the factory with 2 completely different style tyres? Bridgestone and Pirelli with a very different profile design. I don’t believe that a change from a 50 to 55 will make any difference, so much so I’ve put my money where my mouth is and put a 55 on. Hope I ain’t wrong
And there is the point - different design, same profile. Many of us will be interested to hear your experiences of the changeover.
Same percentage of a different design tyre, stand the 2 tyres next to each other and the sp is a higher tyre with a completely different style profile, a 180/55 does not have the same profile as a 200/55 it’s a percentage not a fixed measurement
The difference between the multiple vendors tyres supplied on the SC77 SP/SP2 are within the tolerance that the Torque Management is designed to work in. The jump from 190/50 to 190/55 does take the tyre outside this range - but slower street riding may note invoke any misbehaviour by the Torque Management system - running 200/5x tyres at aggressive track speeds does not allow the entire system to operate as intended. But the higher skilled track rider may not care about this as they tend to ride around any issues the bike presents or they to turn off Torque Management features and ride the bike in an analog way. You may still experience Quick Shifter Autoblipper problems though. For the entry level rider or rider that is going to specifically try rely on the Torque Management features there is no real point in changing tyre profiles - if you need the bike to tip in, just drop the triples down the forks
I I wouldn't question @RC45 's knowledge and experience of the SP/SP2. He is widely regarded, in USA at least, as a foremost authority on the bike. If you spend some time on this thread you'll see what I mean: https://www.1000rr.net/forums/modifications-upgrades-12/246833-rc45s-sp2-track-bike-build.html
Me? No, I only ran my bike with the 190/50 before I started my Super build and it seemed to behave as expected the few times I nudged the rear tyre into misbehaving - as in it dialed back the throttle as expected. But a few of my SP2 thrashing cohorts have experienced issues. Mostly on track or during very hooligan street/canyon riding.A couple issues around autoblipper downshifts and somewhat unpredictable Traction Control intervention. As in the rear tyre spinning more than expected before intervention on higher TC settings or simply no intervention at all. But these guys are all pretty fast and often run sans TC anyway, and on the SP2 TC0 and TC1 both have Wheelie Control at 0 so the lack of intervention doesn't really bother them - except that they would prefer a more predictable platform. You may not experience anything different to the stock 190/50 behaviour - but that also assumes you have invoked Torque Management under enough varied circumstances with the 190/50 tyre that when you swap to the 190/55 you have a good point of reference when you invoke the Torque Management intervention with the 190/55 to know if it is still behaving as previously. Which s why I always frame my answer around whether someone has a point of reference to fall back on when they invoked Torque Management intervention with the stock tyre size. Because if they don't - then how will they know its working as expected after the tyre size change ?
