Hot rear end

[Baldini]

Knackered rear wheel bearing @ 3,000miles. Left (brake) side. Also groan from back end, sounds like brake binding. Is their some connection? Put in new bearing went for a short 8 mile run. Rear rotor was warm tho I hadn't used brake. But also the wheel hub & the caliper mount bracket were warm. Where's this heat coming from? Binding brake? Binding axle? Binding bearing? Transfered from bevel box? There was not much grease in the other side wheel bearing...but no evidence of grease having left the bearings to suggest overheating. I don't see where anything could be out of alignment. I don't see how overtightening the axle nut could cause bearing failure unless a bearing was not fully home, or one of the spacers in the hub is too short...

I know others have had bearings go & brake binding - what are your thoughts?

 

Thanks,

 

KB, Wales.

 

Thought some more. Heat must be bearing/axle. Also found, like others, that tightening axlenut to correct torque causes wheel rotation to stiffen up...

[Mike Stewart]

Perhaps a warped rear brake rotor? Both my 00 V11 Sport and 03 Rosso have the famous rear brake groan. My 03 Rosso started to groan after a high speed ride, I found the rear brake lever binding and causing the rear brake to drag causing alot of heat on the rear rotor. Now the rotor is warped and will drag when the rear wheel rotates. I removed the rear brake lever and sanded down the pivot ends to add clearence and now the rear brake pedal feels free. There is still a rear brake groan caused by the overheated warped rotor.

 

Mike

[dlaing]

I had the rear groan, my dealer lubed the caliber, groan disappeared, groan reappeared, replaced one of the rear bearings, groan disappeared, and went a long time without a problem. I may hav had to lube one more time...cant recall.

Then I heard about the brake lever clearance issue, so, tested to see if two sequential 60MPH rear brake only stops would heat the brake fluid enough to reduce the clearance, the good news, it did not.....the bad news, a week later I noticed the groan reappeared accompanied this time by disk warpage.

Anyway, that is a good point that the heat could cause premature bearing failure or the bearing failure could cause the brake to rub and for heat to build up.

Anybody got a source for aftermarket rear brake disk?

[Baldini]

The wheel starts to bind as soon as you tighten the axle nut to any decent torque...with the caliper removed. Seems to be unrelated to the brake? It's as if the bearing spacer in the hub is too short, both bearings seem fully home.

 

KB

[al_roethlisberger]

Sounds like we need a "Rear Brake Groan" FAQ

 

...any volunteers for writing one with the following info covered:

 

1) Adjusting the rear brake lever

2) Modifying/filing down the stops

3) Lubricating/cleaning the rear caliper

4) Proper torque for rear wheel

 

...etc??

 

...maybe even a note on replacement rear bearings, size, etc... so that one doesn't have to spend high $$ on the OEM unit. I think I remember someone on the list getting a good set from a bearing dealer.

 

If you write one up, I'll be happy to 'format' it and put it in the FAQ section

 

al

 

P.S.

Mine has always groaned as well, and it warm(not hot) to the touch after any ride

[Baldini]

I did a quick search in this forum & found 7 people had brake side rear bearing fail at v low miles. I don't think in my case at least that it was caused by brake. My wheel binds when torquing the axle nut without the caliper fitted. I think there's 2 seperate problems.

 

I've been told axle should be torqued at drive side, not at nut. Indeed the manual lists torque of 120Nm & specifies housing side. But WHY? I can't see why it should make any difference which end - the load is carried straight thru the spacers and inner races. Unless one of the spacers is undersized, or a bearing is not fully home I can't see how tightening can knacker a bearing.

 

The only thing that I can come up with is that the centre spacer is too short for the hub...sounds unlikely doesn't it...

 

This is doing my head in - someone out there must know what's going on here...

 

KB, Wales

[guzzi323]

Actually I've heard of a few instances where the beareing spacer in a wheel was too short. One of them happened to me on my Monza. It's easy to overlook until you've tossed a few sets of bearings in your wheel. That's when I took a closer look at everything.

I ended up having a new slightly longer spacer made.

johnk

[Baldini]

I've measured up & the bearing spacer is shorter than the distance between the bearings...

[al_roethlisberger]

I've measured up & the bearing spacer is shorter than the distance between the bearings...

 

...maybe this is one of the many mysterious reasons why some V11s make more horsepower from the factory than others... some effectively have the "brake on" from the start

 

Nuts...

 

How short was it?

 

al

[Baldini]

Bearing spacer measures 112.2mm. Distance between bearing faces is 112.8mm.

 

That's 0.6mm. It appears to me that is enough to misalign the bearing races under load from the axle nut.

 

I am no engineer, and I may be missing something, but I can see no other explanation for the wreckrd bearings.

 

KB, Wales .

[Martenni]

Hi All

I changed the rear wheel bearings on my Tenni at 2000 ish miles got replacement from local bearing factor £26 pair.I didnt tighten the nut to a specific torque just went by feel,if the spacer is too small and the wheel nut is too tight then you are pulling the inner races toward each other whilst the outer races are held by the machined housing in the wheel therefore pulling the inner and outer races out of line [not good] .If the spacer is too short i suggest fitting a shim to make it right and tighten the wheel nut to a lesser torque if there is a resistance to turning[of wheel] when you tighten the wheel nut then the spacer is too small and your bearings wont last.If the spacer was perfect[er this is a guzzi] then the bearing would stay in line and you could tighten the nut till the cows come home and the wheel would spin freely.The spacer is a cheap bit of tubing not a precision machined part maybe getting a machine shop to make up something better would be a good idea and not having those flanges on the tube would allow the bearings to be drifted out much easier.

sorry this is so long [yawn snore etc]

Regards Martin

.........................

Tenni 165

[emry]

Like Martenni said I would try a spacer. Normally I tighten the nut either till it is tight and then back it off the the wheel is stiff until it spins freely. My 1970 Ambassador does the same as yours, no problems yet.

[docc]

Evidently the short spacer is common. I remember reading about it in "Guzziology." Time to go back and see what Dave said . . . .

 

I think you guys are on the right track. I mentioned this before but while experimenting with rear braking into corners I cooked a rear bearing. The bike is just happier with LESS rear brake. It won't fix the short spacer or the drag but overbraking the rear will aggravate the bearing failure in the brake side.

[Baldini]

Thanks for all the replies.

 

It concerns me that if the bearing spacer is too small, & if the axle nut is backed off to prevent the wheel from binding, then the inner races of the bearings will not be clamped tight. They will therefore be free to spin on the axle. I don't think this is a good thing, & is not how the assembly was designed too work.

 

Do you agree?

 

Thanks again, KB, Wales.

[guzzi323]

I tried the shim approach on my wheel spacer before and found it annoying to have one more thing that needed to be aligned while assembling the rear end. If you're able to bring the old one into a machinist and say make one similar but longer they ought to be able to knock it out in no time.

 

(Now I have one more thing to check on my Scura...)

 

Cheers,

johnk