2008 GSA Rear wheel lateral play - new rear diff?

[Philiptigerrice]

Hi All - had my bike in for new tyres, discs and brakes, plus a bit of a mini service this week, its just coming up to 50,000 miles.

The mechanic spotted that, with the bike on the centre stand, when you put one hand on the top of the wheel, and one hand on the bottom - there's about 1.0mm - 1.5mm of lateral play in the wheel.

His theory is that one of the bearings is going. Could it be anything else?

He also said that swapping the bearings is a big-ish job, and that he'd rather I take it to a BMW specialist - and suggested Ray near Preston.

We got chatting, and he's not certain about the bearing - could be something else - he also explained that there's a few guys who specialise in BMW final drives, and that often its best to just replace the whole rear diff. His logic is that, a bike on 50,000 miles, hoping to do another 50,000 is likely to need it at some point... so why not swap the lump in a oner...

Anyone had anything similar? How much will a rear diff cost me (just as a one lump part?)

Also - can anyone recommend someone who does them? I'm thinking if I buy the part, re-conditioned, in the next month or so, I can then have it dropped in on the next payday. Who sells them though? I seem to remember someone on the forum was a final drive specialist?

Maybe having mine taken out, and sent off would be best?


Just interested in anyones experiences / thoughts please!


Phil

Bury
Lancs

[Philiptigerrice]

Doing some research, and apparently, cold, about 1mm of play is normal and acceptable.

Maybe keep a close eye on its best for now...?

[Nico-D]

I seem to remember someone on the forum was a final drive specialist?

Think that was Mikeyboy, based in the midlands I believe, sorry can't remember more details, sure someone else will.

[steve the grease]

When you turn the wheel a little bit , does the wheel move sideways the 1.0-1.5mm . if so this would suggest that the wheel bearings are worn and the lateral thrust from the gears pushes the crownwheel against the pinion gear and moves it sideways. All Bevel gears ( its not really a diff, its a crown whel and pinion) feed a side load into the bearings so compared with a normal chain driven bike the bearings take a hammering., due to this side loading.

When the gear teeth don't line up perfectly wear can take place quite rapidly of the pinion and less so of the crown wheel. Once the gears are worn you have no alternative but to change the whole lot. My advice would be to talk to someone who knows these bevel gear setups well. New crown wheel and pinion bearings and having it all set up properly with the correct bearing preloads and so on is not rocket science, and will not cost anywhere near as much as all new gears as well . You do however need the correct tooling to get the pinion protrusion and crownwheel clearance correct to get even tooth engagement across the crownwheel. Never done a bike , have done pleny of Bedford 4x4 trucks, just the same principle as the beemer , just larger!

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[AustinW]

I seem to remember someone on the forum was a final drive specialist?

Think that was Mikeyboy, based in the midlands I believe, sorry can't remember more details, sure someone else will.

Mikeyboy is your man for advice first and any repairs on BMW final drives and gearboxes. He can rebuild them with all new parts - expect around £400-£500 for a full rebuild of the FD, but your problem may just be the wheel bearing which is obviously waaaay cheaper. Google "Overland and Classic" and you will find him, or browse around UKGSer where you will find loads of accolades. Tel 07786 340692 based in a small farm near Melton Mowbray.

[92kk k100lt 193214]

I don't have one of these but my friend who does these said we should regard them as consumables and replace the bearings at defined intervals. I am inclined to agree with him as it was for the very same reasons in the previous post by Steve. The early wear unfortunately is not so easy to measure and many don't even check it. Do it early as in before any failure and the cost is reasonable. Wait too long and you are looking at big bills for new FD or worse still collapsed FD. I would replace the pivot bearings. The big bearing I had to do a few months back on my K100RT and its the exact same bearing in most of the final drives.

[bikenav]

as in the above post check any play you may have is not coming from the paralever pivot bearing done mine twice now its a pretty poorly sealed bearing not difficult to change and more than likley only the ball bearing on the "outside" the inner needle keeps its grease and lifespan if it is the case .

[Tonibe63]

Phil, I think you are going through the fears that many GS owners do, including myself.
A mate of mine had a definate rumble from his rear drive and a lot of movement, mine in comparison was quiet and with only half the movement but it didn't stop me worrying.
He had his rebuilt by BMW dealer and although the noise had gone it still had more movement than mine, 11 months later he got nervous and demanded they do it again under warranty which they did ....... the result was no different.
My rear seal started to leak in France due to overloading and scraping my boots around bends but once cooled down it was fine, another 2k miles later I changed the seal for peace of mind before going on another Eurotrip ............ that was 20k miles ago. The bike is on 56k miles now and I check the free play once in a while but don't worry about it anymore.
For me, if I hadn't read all the horror stories on the internet then I wouldn't have given it a second thought.

[I am spadger]

As other post re para lever bearings , do these first 50,000 is a good life on them you could check simply by loosing off the big nut on the pivot and tightening it up I recall to 7nm , the big nut is around 140 nm , it pays to heat the big nut with an air gun as it may have loctite on , I made the mistake of rebuilding my final drive first , to still have that play ,
Motorworks do the bearings ( expensive ) or an upgrade kit which is cheaper , I fitted that but jury's still out on it's life span . After all that I may be talking bollocks as yours is a later model mines a 2004

[Philiptigerrice]

Thanks folks, I’ll not panic, but will defo get an expert to have a nosey at it in the next week or two