Handling Help

[MikePotteRR]

Morning all,
So the first track day on the S1000RR has been completed....what....a...machine.

I was having some handling issues that I'm hoping for some help with. I found the bike tended to understeer both into and out of corners. If I entered the corner with the throttle closed I would need to hold it closed to get the bike to turn but it was pushing wide. I later found this was in part due to me rushing the corner so I corrected this but the mid corner and out symptoms stayed.

I have sag set at 35mm front (6 turns of preload) and 25mm rear (8 turns of preload). Front damping was set at +3 and rear comp +1 rear reb +3. The rear has shown that I could do with lowering the rebound to +2 due to the lower round front sipe and hire rear sipe with debris.

I do now have the front 2D sensor for the next days for better set up. My fork cable tie is around 1 inch from bottom. Tyres are Supercorsa SP's set at 31 front and 26 rear off the warmers (200 rear profile)

My understanding is that the bike could have too much weight on the front off the throttle causing the push or could well be riding low in the rear due to the higher rebound setting. I was planning on tryingto lower the front compression to -1 to allow better initial turn in and reduce rear rebound to +2. This may well be more of a geometry issue so preload may need to be altered to suit?

 

[FastBike]

I'd be interested to hear how you get on with the 2D sensor, I was thinking of investing.


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[MikePotteRR]

The brakes on the bike are immense so it definitely needs setting up to cope with hard braking. My handling issue could well be that the bike needs to ride lower in the front once braking is finished and therefore opening the compression damping would be best. Of course I can only accomplish this with the 2D sensor. I've got a feeling it is going to be a question of trial and error. I back at Silverstone on the 29th May but am tempted to go again on the 24th April. I'll post a mini review of the sensor the next time I give it a go. I've taken it off for road use as the left lock stop really does reduce steering considerably and it is probably overkill for road use.

 

[MikePotteRR]

Just to add to the handling so far. The bike very much liked to go light at the front under power with a few power wheelies occurring along the straights. Could this also be a further sign of a nose high tail low character?

 

[Toan the Moan]

The best thing to do is get one of the suspension guys at the track to set the bike up for you best 40-50 quid you'll spend

 

[bananaman]

As stated, best to get set up to yr weight etc as a base setting then play from there.
Front will come up in 5th/6th under power, only needs a little nudge from the road....
2D prob overkill on the road but come into its own on track.

 

[paul_m]

What suspension is fitted?

 

[P0u1]

My money is on, to much sag on the front compared to the rear, my bike was showing the same symptoms and a bit more pre load on the front sorted it out.

 

[paul_m]

Depending on what kit used, the spring requires min of 8 turns.

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[MikePotteRR]

Hi all. I'm using the stock DDC suspension with the stock spring rates. I'm just over 13 stone without gear.

 

[paul_m]

Aah. Pass. Never used the standard gear were on KTech now but did try some Ohlins. I wouldn't like to comment but springs are springs and require pre-load.
I sent you a pm

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[MikePotteRR]

No worries Paul. Could too much compression damping in the fork cause the issue?

 

[soofsayer]

Hi all. I'm using the stock DDC suspension with the stock spring rates. I'm just over 13 stone without gear.

You need your preload setting as you are on the heavy side for the 'out of the box' setup. You can do the basics by following the manual and see how you get on from there.

 

[MikePotteRR]

You need your preload setting as you are on the heavy side for the 'out of the box' setup. You can do the basics by following the manual and see how you get on from there.

Hi Soof, is the 15 RR not sprung for someone around the 13 stone (85KG Mark)? I know the HP4 DDC was aimed at a weight of 75KG. I've set my sag at 35mm front and 25mm rear. The consensus so far seems to be that I need more front preload to may add 2/3 turns to see the effect.

 

[fast_ryan]

DDC Suspension Setup

As a guide set front and rear preload as per the Owner's Manual for DDC. You must recalibrate the DDC system if you make any changes to preload for it to function correctly. Set damping to '0' for both front and rear compression and rebound for your first session on track. This will give you a basis from which to start from. Do not change more than one variable at a time and make any changes incrementally or you will simply get lost. Make a record of each change that you make, and note what it did in terms of feeling on the bike. The beauty of the DDC system is that changes are simple and easy to make.

Just remember that there is absolutely no such thing as a perfect setup as your suspension settings will continuously change depending on a huge range of variables (circuit type, tyres, temperature, surface etc). The bike will also behave differently as your pace increases. I would strongly recommend approaching a suspension specialist to help you achieve a suitable base setting upon which to make further changes. Note that suspension setup is an evolving process and what works for one rider will generally not work for another. A good grasp of the fundamentals of compression, rebound and preload is essential. This will allow you to understand what the bike is doing beneath you and, more importantly, what it is preventing you from doing.

 

[Eddie]

I thought sag was meant to be 10-15mm front and 8-10mm rear on the DDC bikes?

 

[RacersEdge]

I thought sag was meant to be 10-15mm front and 8-10mm rear on the DDC bikes?

+1 Indeed it is.


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[soofsayer]

Hi Soof, is the 15 RR not sprung for someone around the 13 stone (85KG Mark)? I know the HP4 DDC was aimed at a weight of 75KG. I've set my sag at 35mm front and 25mm rear. The consensus so far seems to be that I need more front preload to may add 2/3 turns to see the effect.

Usually, yes. But yours is set up for someone much lighter than you based on those preload settings (your weight is not relevant, it's the effect on the bike that matters). As your current settings are beyond the recommended settings for general use I wrongly presumed you got the bike like that. I would reset the preload and recalibrate the ddc before looking at fine tuning. You sound like you know what you should expect to feel so it'll makes sense immediately I hope .

 

[MikePotteRR]

Sorry all. just to clarify, my sag is a total number so fully extended to me, in gear, on the bike. The numbers BMW talk about are only with the bike at rest vs me on the bike and not a total number, thus my numbers are much higher than the manual points to. My sag if measured via the manual does fall between their ranges.

 

[MikePotteRR]

Just been the the garage to have a look over the bike and noticed the shock eccentric is in the down/long position. Is it not better to have these in the shortest position?