In the rear definitely. I would always use one in the front too but technically you don't need one for the first ten hours before the mousse is fucked.

 

I have a 701 and have used mousses in the past and put rim locks in both wheels.

I also balanced the wheels as the rim locks weigh a ton and vibes are horrible at cruising speed on tarmac between lanes.

 

I have rim locks with mousses on my 350 husky.

Not sure about balancing as the knoblies buzz like fuck on the road.

 

I too have an FE350 with rim locks and mousses. I don't balance the wheels on that bike, but I do on my 701 because it is more of a 50/50 bike and travels faster on the road where any imbalance is more noticeable.

 

Rim lock imbalance is more like a pumping or shaking feeling, easily balanced out, just takes a lot of weight. Higher frequency vibrations might be tyres both only if under high pressure and each knob hits the ground after each other. For most off road applications you have a large number of knobs in contact with the ground at all times which should be reducing the feel of individual knobs.

 

I have just bought Mitas E12 & E13 for the 690 to still give decent fair weather trail and grass grip but better road comfort/manners. I will still be using tubes though.

Having seen this topic I just checked the bike and there is a pop rivet type thingy in what looks like a rather small diameter hole in the rim, about four spokes from the valve, which seems an unbalanced location.
No rim lock fitted and, interestingly, no rim lock shown on the KTM fiche.

The bike gets a fair hammering on the road, somewhat less off road, and the valve is still nice and straight. I’m not inclined to start bothering with a rim lock in that case.

 

I have just bought Mitas E12 & E13 for the 690 to still give decent fair weather trail and grass grip but better road comfort/manners. I will still be using tubes though.

Having seen this topic I just checked the bike and there is a pop rivet type thingy in what looks like a rather small diameter hole in the rim, about four spokes from the valve, which seems an unbalanced location.
No rim lock fitted and, interestingly, no rim lock shown on the KTM fiche.

The bike gets a fair hammering on the road, somewhat less off road, and the valve is still nice and straight. I’m not inclined to start bothering with a rim lock in that case.

Rim locks aren't specified OEM because the bike is a dual sport, with 50/50 tyres and spec'd to run tubes at much higher pressures than mousses or off-road pressures.

You only need rim locks to stop the tyre spinning when running lower pressures.

 

Motion Pro rimlocks are really light, much lighter than a std KTM one.

 

Rim locks on japanese bikes are often opposite the valve hole. Not usually the case on Euro bikes.

Motion Pro rimlock are really light, much lighter than a std KTM one.

Yes, but I couldn't get a 2.5" one for my 701 or 690 as OP has. I don't think they make them.

 

It seemed odd that the presumed rimlock hole was so close to the valve hole.
My own logic plus google implied opposite was better. The balance weights must be huge!

 

Eh, hang on, so the rim lock hole is not opposite the valve hole. That make no logical sense.
Unless it helps fitting.

 

That's exactly it. It helps fitting.

 

I’m going to ignore using one anyway thanks to your valuable advice.
I don’t know what this little pop rivet is for otherwise and I certainly won’t be fitting the tyres myself - that’s what a man with a machine is for. He can do it while I take my wife out for a nice lunch.

 

On ktm's, the rim seam/weld is 180o to the valve hole, so don't drill here for a rim lock (don't ask how l know this 🙄)

You won't see it unless you look closely as its a neat ground down weld.

Gotta love TIG.

 

P.S - l run 2 on the rear, one on the front just fyi

 

I have had my rear tire spin on the rim with a mousse fitted and I actually thought that the clutch was slipping. I use loads of mousse lube and it broke the rim lock off and the tire was spinning on the rim. I fit two rim locks now to the rear tire with a mousse and one rim lock on the front wheel with a mousse.

It doesn't happen all the time. But you want to fit rim locks with mousses. Especially if you are like me and reuse your mousses. If your tires will spin on the wheel with tubes fitted. Then what do you think the chances of it spinning on a big lump of solid rubber covered in lube is going to be.... Even though a lot of the manufactures say that you don't need rim locks with mousses. I would advise you to fit them.

 

Michelin used to say no rim locks back when the norm was not to use drilled/knackered mousses. If it span with a lock it got shredded. Now they state rim lock use.

The way we use mousses has changed. It’s still 1980s technology sponge hoops but we drill them, cut them into bits and use them well last the original working parameters. They need locks!

People are happy to use a mousse till it’s dust. They won’t do the same with pistons though.