Brake problems ?

[Doctor T]

I have a problem when turning right on a roundabout or a corner the bike seems to lean in like the front tyre is underinflated. Tyre is spot on at 36 PSI and the rear is 42 PSI. Tested with 2 pressure gauges.
I've jacked the front of the bike up to check the new wheel bearings, and they are good. I spin the wheel with the caliper on and there is a bit of drag.
Had a good look at the calipers and with the one on the left i can easily push the pistons back home but with the pistons on the right i need a bit of force to push the back. So this caliper is dragging. Would this make it feel like the tyre is underinflated?. I've noted that turning left need more pressure on the bars. Have a answered my own question?

[David.]

I'd be most surprised if the brakes have any impact on the steering. Some bikes only have a single disc brake on one side of the front wheel.

What does the tyre profile look like. They can wear unevenly due to the camber of the road.

[Doctor T]

It's the only thing i can come up with. Checked ball joints, and shock mounts and there is no play. BMW Worthing did note the front brake was sticking never had just one caliper drag before, always both.

[Steve398]

It's the only thing i can come up with. Checked ball joints, and shock mounts and there is no play. BMW Worthing did note the front brake was sticking never had just one caliper drag before, always both.

II didn’t know Worthing had a BMW dealership, or are you another ECM customer?
Have you checked the head bearings?

[Doctor T]

Dont know what ECM is. They are called BMW one now. I did a naughty to test, I strapped the calipers to the fork legs and rode up the road to the roundabout and it steered perfectly. It was hard not to use the front brakes whilst slowing down.
I noticed the righthand pistons doesn't retract as much as the lefthand side. I've ordered a caliper rebuild kit from Motorworks.
I check all the steering, ball joint, head bearing for smoothness, etc and all are fine. Nothing loose

[Stu]

First thing I would be doing is popping it a bit more pressure in the front to see if it solves the issue

2psi can make a lot of difference believe it or not

I had something similar on my fjr and it was down to tyre pressure. Running at 39psi was spot on

[David.]

The solo tyre pressures for a Hexhead are Front 32 psi & Rear 36 psi.

[Doctor T]

I've run 36psi since day one. I once overinflated the front to 38psi in error and i found the front end a bit light.
I think ive narrowed it down to the right caliper as in my previous post. Felt really strange not having front brakes

[Doctor T]

The solo tyre pressures for a Hexhead are Front 32 psi & Rear 36 psi.

But am a fat, short, hairy git

[Stu]

The solo tyre pressures for a Hexhead are Front 32 psi & Rear 36 psi.

It's only recommended pressures not you must stick with that.

You can go as high as 42 front and rear if you really want to.

When I had my tl1000s I was getting movement on the rear at 36psi I spoke to Michelin and their advice was to raise the pressure 2psi at a time till it stops but not to exceed 42psi

Anyone who has owned an fjr will probably know that yamaha couldn't decide what pressure to run in the front! There was different variations for different years even though the bike pretty much stayed the same baring cosmetics

[Doctor T]

When i bought the bike with road 4 on they were set at 32f/36r and the steering felt very heavy and dropped into corners. At 36psi on the front with over 5000 miles on the tyres ive got no cupping as some complaint about.

[David.]

The BMW weight guidelines are based on a rider or pillion being between 8st & 13st, using an average of 11st.

[David.]

At around 5,000 miles, I'm usually looking to replace the tyres as the steering goes off because the front tyre has lost its' shape.

[Doctor T]

The BMW weight guidelines are based on a rider or pillion being between 8st & 13st, using an average of 11st.

Am 17 stone.
The front tyre still has plenty of tread left and is not out of shape yet. Going by my last tyre i should get with fingers crossed at least 7-8k out of it.
The rear was changed 1000 miles ago and i got 8000 miles out of it. I was an mm over the tread marker.
The same tyres on my Tiger 1050 the rear only lasted 6000 miles. Don't know about the front as i sold the bike

[David.]

Always change my F&R tyres as a pair, they wear out pretty much the same and are designed to work together. They are both well legal but the ride isn't compliant.