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Managed to get out today for 60 miles on my newly rebuilt R1200 - but the front end handling was very strange. The front end really dropped in when I got past a certain angle of lean in tight corners. Good and solid in fast open bends - very planted. But horrible in really tight ones!

Steering bearings are all ok, pressure was set at 2.2bar as per handbook (33.5psi) - on closer inspection the PR3 tyre is quite worn and has distinct feathering between the tread on the tyre edges. Could this be the culprit?

Yes, could be ...

I find my 12 to be very finicky about tyres/pressures, and a badly worn front is most probably to culprit. PR3's are known to feather badly, I'm presently running PR4's good and planted if a little on the slow side steering wise, (and the 12 being a bit lazy in that department) I think I may try a Roadsmart 3 next as the profile is more angular to aid turn in.

How many miles has it done? I find all front ST tyres I have had perform well in the dry and when warmed up even if the tyre is on it`s legal limits. I tend to be harder on my rhs than the lhs. Has the front lost it`s profile ie squaring off?

Put a new one on. Try the Maxxis variant great value for money. I like these, in my experience good as anything else out there.

popsky wrote:I find my 12 to be very finicky about tyres/pressures, and a badly worn front is most probably to culprit. PR3's are known to feather badly, I'm presently running PR4's good and planted if a little on the slow side steering wise, (and the 12 being a bit lazy in that department) I think I may try a Roadsmart 3 next as the profile is more angular to aid turn in.

Phil, don't know what mileage you do per year but the 12s I got came with Pilotpower on and they are superb - not done as much on the 12s as I'd like and not sure what mileage they'd done when I bought the bike so not sure of their longevity

dave the german wrote:
Phil, don't know what mileage you do per year but the 12s I got came with Pilotpower on and they are superb - not done as much on the 12s as I'd like and not sure what mileage they'd done when I bought the bike so not sure of their longevity

Not enough Dave, last year was a bit on the low side due to other reasons, hoping to get back to our usual std this year, my last set of PR3 lasted 11k front and 7k rear with plenty of tread left but changed as a Euro trip was imminent, we're both running PR4 now but I've lost my mileage tracker notes and can't remember how many miles or when fitted doh

When the front PR4 on my KTM became worn I thought there was something really wrong with the bike, it felt really strange and I had no confidence in it at all.

A new pair of PR4s fixed it.

Archie, do you mean worn or "Llangollen"?

scottie58 wrote:Managed to get out today for 60 miles on my newly rebuilt R1200 - but the front end handling was very strange. The front end really dropped in when I got past a certain angle of lean in tight corners. Good and solid in fast open bends - very planted. But horrible in really tight ones!

Steering bearings are all ok, pressure was set at 2.2bar as per handbook (33.5psi) - on closer inspection the PR3 tyre is quite worn and has distinct feathering between the tread on the tyre edges. Could this be the culprit?

Michelin recommended for their tyres are 2.5 bar front and 2.9 bar rear, which equates to 36psi fr and 42psi rr. Some have found put another 2psi in the front on heavier bikes reduces feathering.

For example I think the recommended pressure on K1600gt, zx12r and hayabusas etc is 42psi front and rear
W

scottie58 wrote:Managed to get out today for 60 miles on my newly rebuilt R1200 - but the front end handling was very strange. The front end really dropped in when I got past a certain angle of lean in tight corners. Good and solid in fast open bends - very planted. But horrible in really tight ones!

Steering bearings are all ok, pressure was set at 2.2bar as per handbook (33.5psi) - on closer inspection the PR3 tyre is quite worn and has distinct feathering between the tread on the tyre edges. Could this be the culprit?

This is the exact issue i had with my R1200S . I changed tyres and it made no difference . I changed the wheel bearings and put on a new steering damper - same no difference , still felt it was suddenly dropping into slow corners but was fine in fast ones . Finally decided to change the top and bottom ball joints and instantly transformed the bike and slow speed handling is now a joy .

Thanks for that - I improved it by running tyres at 36F 39R.

12S is actually heavier on rear as I witnessed when MOTing it - was surprised.

Wheel bearings are new, top & bottom "bearings" were very smooth with no play when I checked them during winter rebuild.

Tyre is nearly shot, so if problem still persists when I change it I will replace steering bearings next They look okish to change so not daunted by the prospect.

Bike has done 52K miles and been well used by previous owners - maybe needs a bit of further TLC.

scottie58 wrote:Thanks for that - I improved it by running tyres at 36F 39R.

12S is actually heavier on rear as I witnessed when MOTing it - was surprised.

Wheel bearings are new, top & bottom "bearings" were very smooth with no play when I checked them during winter rebuild.

Tyre is nearly shot, so if problem still persists when I change it I will replace steering bearings next They look okish to change so not daunted by the prospect.

Bike has done 52K miles and been well used by previous owners - maybe needs a bit of further TLC.

My top and bottom ball joints looked fine with no tears or breaks in the rubber boot and the steering action seemed smooth on the bike . However when I removed them they had a noticeable "notchiness" which would likely explain the sudden falling into a corner feel . I also removed the front trailing arm axle and re- greased the bearings

Just an update - increasing tyre pressure to 36 psi, 2 more turns of preload on the shock and 4 more clicks of damping has reduced the problem massively. New tyre should sort it out completely