Handling Help

[Nibs]

I've had some handling issues with mine, lack of feel from the front and understeering . So I'm off to MCT on the 19th for Darren to work his magic, I can't wait he turned my K6 1000 into an absolute weapon.

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[alex]

I've had some handling issues with mine, lack of feel from the front and understeering . So I'm off to MCT on the 19th for Darren to work his magic, I can't wait he turned my K6 1000 into an absolute weapon.

Sent from my SM-G920F using Tapatalk

My '17 is going on the 2nd of May, looking forward to that! Though tbh its going pretty well already


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[MikePotteRR]

Hi all,thanks for your contributions so far. I've have started to make some changes after lots of advice and reading and testing. It seems that all the S1000RR's from 2010 onwards lack trail (distance the contact patch is behind he imaginary steering head line). Trail is massively important as it provides stability, front end grip and feel. A lack of trail can cause the front to push (under steer) and miss the Apex and continue wide.

To correct this I have swapped the shock eccentric. On the 2010 to 2014 bikes this is set with the bolt at the top. Interestingly on the 2015 it is stock with the bolt on in the lower position this making the rear higher and reducing trail. I have switched this around and the bike is much better at turning and holding a line. It also hooks up under power.

i have now lowers the forks in the clamps so they are flush (no gold showing) to further increase trail. Again a positive change.


I have also found my Sag number was out and to get back to 35mm a total of 8 turns of preload (2 extra) was required. This will increase the front height again increasing trail. I also feel that the front requires less compression damping (currently at +3 damping on the front) which I can achieve with the 2d sensor. This should reduce the steering effort required to intially urn the bike.

in essence I would recommend having the shock eccentric set to the low position (bolt to the top) and the forks flush. This should set your geometry. Interestingly this is how the AMA guys in the states set their bike up as well as Tyco BMW in super stock. Take that with a pinch as setuo is very much based on your feel. What works for me or anyone else may not work for you. No harm in trying mind.

 

[Toan the Moan]

Interesting Mike, I was told by a suspension guy at Oulton last week to drop my forks all the way through and lower the rear . With yours being a much later bike than mine and your chassis being different I didn't think it would apply to yours hence why I didn't mention it.
i best get on that tomorrow as I'm at Oulton again tomorrow

 

[MikePotteRR]

It has definitely made a large improvement and fundamentally I am happier on the bike and on the throttle much earlier and harder.

it all starts linking to normal trail rather than actual trail and stats getting all science and equations. It seems that the BMW engineers recommend lifting the front and lowering the rear as they have told AMA guys this is the way forward. Even different tyre brands will have an effect due to different diameters.

 

[Toan the Moan]

I though the revised chassis in 2102 was to solve the early models shortfalls in the handling front. I just thought I was a crap rider lol turns out it's the bike

 

[MikePotteRR]

They went a step further and reduced the trail for the 2015+ bikes. It seems
Jap bikes stick to the "convention" of wanting the rear lifting to increase the swing arm angle. The benefit of BMW's stock setup is a quick steering bike that feels great on wheels road but as soon as you hit the track and add pace a different setup is needed.

Let me know how you get on with the changes. We may end up with a good idea of a base geometry setup for the bikes

 

[MikePotteRR]

I though the revised chassis in 2102 was to solve the early models shortfalls in the handling front. I just thought I was a crap rider lol turns out it's the bike

To me it's all about confidence. Having had a 2014 and now a 2015 the evolutions in the bike are clear and have generally been brought about via feedback from the race teams. Hell they increased he wheelbase simply by going to a 120 link chain vs the 118 link. Something Dan Kyle recommended doing in the states to get a 600mm swingarm length.

 

[Toan the Moan]

Funnily enough I raised the rear the other week after setting the sag due to my current pie eating fetish , last week it handled worse I thought, but it was wet and hand dried out a little later on. So I assumed it was possibly the track conditions. I had also changed the fork oil to the maxima 15wt a recommended by Dave Moss

 

[MikePotteRR]

Give it a try tomorrow with the forks flush and and the rear dropped as low as possible then set your sag. The biggest issue is that changing one thing very often affects another.

 

[Toan the Moan]

I have jut fitted some new tyres as well ready for tomorrow. Taken off worn out Metzler racetech k3 rear and Pirelli sc1 front and fiited a d212 front scrub and a d211 rear that along with the geometry adjustments will mean many changes Just what you're not supposed to do lol

 

[MikePotteRR]

How'd you get on mate?

 

[Toan the Moan]

Not out till Wednesday Mike all loaded fuelled and ready to go

 

[MikePotteRR]

Ah my mistake mate. Hope it's a good one. The weather looks set well, enjoy.

 

[MikePotteRR]

Update for y'all. I have been speaking to a few suspension specialists about the handling issues I've experienced and what is best to resolve them. They have all pointed at the front end being far too stiff for me. The 2015 DDC forks carry a 9.5 in the left leg and an 11.0 in the right leg. Ktech actually say this is a closer average rate to 10.5 than to 10 in reality. Both Darren at MCT and Perry at HM Racing have recommended a 9.5 spring in the right forkleg to bring the correct geometry, sag and suspension performance into play. Darren stated that the geometry changes I have made have exacerbated the the problem by pitching the geometry even further back. He recommended the spring change and to return the geometry to stock. The spring has indicated its stiffness as at 36mm rider sag, the static/free sag is at 29mm. This should be closer to 29/45 (static/rider) or 20/35 rather than my ratio.

I have managed to pickup a HP4 Cartridge for the right fork leg including the spring etc (@9.5). My understanding is I can just take the old cart out as one and add the new one in and set the oil height. As there is no damping in the right leg it should not require much work (or any) to bleed etc. An air gap of 120mm is recommended for my use vs the 100mm stock.

If anyone has much experience taking apart the right fork leg I would be greatful to hear about the best way to go about it.

 

[alex]

I'm thinking they will slot a 10 in mine to make it a 9.75. As the 9.5's in my Ohlins compressed a little too much imo. Will find out when it goes there.

 

[MikePotteRR]

I thought that the 9.5 may be a touch soft but the thinking is that the altering nature of the damping in the DDC allows the suspension to better control how it dives.

 

[alex]

Yes DDC is certainly an extra feature to me, worth noting.
And I can confirm that Race mode on a lot of UK roads is bone jarring, I end up back in a more plush sport mode.

I will bow to their knowledge whatever happens - my job is to tell them what I need, what I do.

 

[Toan the Moan]

Just back from Oulton. With the dunlops fitted and the geometry altered it was a lot better. I don't have the complication of DDC on my old BM, was it the tires , was it the geometry changes, was it both , all I can say is that it was alot better, not perfect by any means just better

 

[fast_ryan]

DDC Suspension Setup

Update for y'all. I have been speaking to a few suspension specialists about the handling issues I've experienced and what is best to resolve them. They have all pointed at the front end being far too stiff for me.

This was exactly my problem which caused a few preload issues and I simply couldn't generate enough front end feel under load or mid-corner. I opted for lighter front fork springs (9.5) and I can now comfortably run some quite respectable lap times, but I don?t push anywhere near as hard as I used to as I'm no longer racing.

If anyone has much experience taking apart the right fork leg I would be greatful to hear about the best way to go about it.

The Service Manual contains assembly instructions for the DDC front forks which should be of help to you.