200 vs 190

Hi all.

I will be fitting some new tyres for the forthcoming season and my first trackday at Donington on the 28th March.

It is likely I will be going with Bridgstone S21's or (thanks to Alex haha) the new Michelin Power RS'.

Currently I'm on very squared off S20 Evo's with a 190/55 rear.

Since the price difference between a 190 and 200 is negligible I'm tempted to go with the "bigger" tyre.

is is worth it? If I do will a dealer have to alter the ECU for the change in tyre?

Tyre Size

Read from post #19 onwards.

http://s1000rrforum.co.uk/showthread.php?9417-Spain-track-days-what-rubber/page2

Calibration

BMW claim that you need to recalibrate the DTC if you change tyre sizes for example from a 190/55 to a 200/55. From experience I've used 200/55, 200/60 and 190/60 race tyres and never had any problems.

Cheers RyS1000RR. It would probably be wiser to go for the "smaller" 190 but spend the extra for the a grippier tyre e.g a 190 K3RR vs a 200 M7RR.

Mike is your bike fitted with forged wheels?

No, just the standard cast wheels.

Also curious about this,

Tempted to go with 200 SuperCorsas wondering if I will need to re-calibrate

Calibration

You are highly unlikely to need your DTC recalibrated when switching tyre sizes. I've not experienced any issues to date and I regularly change rear tyre sizes.

I noticed the kr slicks ive accidentally bought have a 190x65 profile would that chuck it out?

Sent from my SM-G920F using Tapatalk

Tyre Size

They should be fine. I currently have a 190/60 Metzeler Racetec Rain rear fitted to my spare wheels and whenever I've used them I've not had any issues with the DTC.

Just to update anyone interested. I spoke with my dealer this week who initially had no idea it was something that was required and even mentioned only the HP4 came with a 200 section tyre (I believe the Forged wheel option comes with the 200?). He later got back to me and informed me the service team would require a minimum 30 minutes with the bike to change the DTC and ABS calibration to the larger tyre. He stated this would be less than ?50.

From memory the User manual states that when going to the larger tyre the DTC may "hold back" the bike when exiting corners. If this is the case then I can just dial back the TC intervention to a lower level.

Which bike are you on Mike (the 2015+ now?) if so yes you can dial the DTC back on user mode.
I am going to a 200 slick at the track. Only way my Gen2 can back it off is to use Slick mode/turn it off

But all of this requires the rolling circumference to be larger on the 200/55 than the 190/55 which isn't always the case.

Hi Alex,
now on a 2015 Motorsport, I couldn't resist. I did some calculations online and the change on diameter and circumference is 1.7% from a 190/55 to a 200/55. Ryan mentioned he had no issues going from 190/60 to a 200/60 which is a 1.8% change.

Mike, plenty of track and road riders switching rear sizes without issues. The fact that the dealer had to go away to research it speaks volumes.

Tyre Size

I wouldn't bother drawing any conclusions between the tyre diameter differences between a 200/55 and 190/55. There is just too much variation between tyre manufacturers when it comes to rolling circumferences etc. For example a Metzeler 200/55 will physically differ in size to a Bridgestone 200/55 and so on, let alone that of a 190/55. The point is the measurements for a 200/55 tyre from one brand may be similar to a 190/55 of another, but completely different to a 200/55 from another.

It is only really a concern if you are racing at a high enough level that you need to program exact tyre measurements into the ECU as an unwanted DTC intervention may cost you valuable tenths/hundredths of a second each lap. For that very reason the RCK3 allows you to configure the DTC and other parameters to this level of detail. For trackday and club level racing it isn't really required as you are unlikely to be pushing hard enough to feel any significant or unwanted intervention when changing between rear tyre sizes.

My thought exactly Soof. I'm pretty sure they are just creating an opportunity to earn some money. I've just got off the phone with another dealer who swapped out a guys tyres to 190's on the Forged wheels without issue. He also looked at the service bulletin for changing to and installing the Forged wheels with a 200 tyre and it made no mention of calibration. They also stated they have never done it to any of the bikes so are not sure what is involved, they hoped the bike could be plugged in and the setting found so around 10 minutes labour.

Calibration

Calibration is done by simply plugging the bike into the BMW system via the bike's diagnostic port. The DTC parameters etc are then recoded so the ECU knows what size tyre is fitted. It doesn't take long at all if you choose to have it done.

Calibration

It's my understanding that you can only calibrate when changing between 190/55 and 200/55 rear tyre sizes and vice versa at a BMW dealership. My S1000RR came with 200/55 tyres fitted on HP Forged Wheels and I'm now predominantly using Metzeler 200/60 slicks and 190/60 wets. The only way for me to calibrate the system for use with the above tyre sizes would be to use an RCK3 and I would also need to use the Metzeler tyre datasheet to input the exact measurements in mm.

I've run 190 and 200 on mine on road and track and not had any problems or recalibration, in fact I've only ever had TC cut in in the wet, with a 200 on but I think I'd switched to rain mode by then as it was pissing down (brands GP)

I've not looked recently but is there not a section to scroll to on the dash re calibration? Didn't realise it was dealer only..