70 mph on forest track need rim locks for Sertao rear rim???

George Washington

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Searched forums and online. After testing my Karoo 3's at 15psi and having the rear tyre spin 9" on the wheel (caught a tree root in mud) (no damage to the valve tho I'm replacing the tube to be safe) I need rim locks, but can't find a size 3.00 for the rear wheel any advice, solutions to bead lock the rear wheel.

Lowering to 15 psi made the bike much softer and forgiving on rocks with firm carcass walls of the tyres still protecting the rims. At street pressure gravel is like marbles.

Video of 70mph on the forest track here..

http://youtu.be/f7EDOqLOwoI

stupid and I won't be doing that again! at my age I prefer to "potter about".

Longer video of the day..

http://youtu.be/zPIc_8zSXGo

Really appreciate any help THANKS!
 
you should be able to use a 2.5 rim lock I have in the past on a bigger tyre.
Nice day out although the faster you go the bigger the crash:eek:

I did the bmw enduro course last year and after I broke the husky they gave me one of these for a half day there wasn't anything it didn't do that the enduro bikes did and JP said at the end of the day should have had that all weekend:thumb
 
Cheers Finn, would you advise two on each wheel to balance better, the mechanic is a bit bothered about drilling holes for the bead lock bolt, should be ok though eh?

I need to do the bmw endure course proper tuition would be much better than my trial, error, fall off.

Great you like the Sertao!!!
 
George Washington said:
Cheers Finn, would you advise two on each wheel to balance better, the mechanic is a bit bothered about drilling holes for the bead lock bolt, should be ok though eh?

I need to do the bmw endure course proper tuition would be much better than my trial, error, fall off.


Great you like the Sertao!!!
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Can't see why you would need two unless you're coming to a very wet muddy wales
 
Cheers Finn… I'll see your wet Wales and raise you Cumbria, Lake district and Scottish borders never see that big yellow thing in the sky hehe.
 
You should be ok with one rim lock at 15psi, dont risk any lower though. Balancing the wheel has never been an issue for me with knobblies on, certainly on the rear.
Mark
 
earthmover said:
You should be ok with one rim lock at 15psi, dont risk any lower though. Balancing the wheel has never been an issue for me with knobblies on, certainly on the rear.
Mark
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Thanks Mark really appreciate the advice.

I'd like to err on the side of caution. My objective is to get a bit more forgiving over rocks and tree roots, but not increase the risk of tube valve damage at all.

15 psi was ideal but do you think I should give it a little margin of error and up the psi a bit?

I'm getting the 2.5 rim/bead locks in tomorrow and will post results / pics next time out.
 
I'd use 18psi min on a bike that heavy, one rim lock should be enough as it not the outright speed that spins the tyre, it's acceleration (or braking) with aggressive tyres and a Dakar's not exactly rapid in that department.

You might want one one the front too but you'll find the wheels out of balance which can be sorted with a counter weight fixed to the spokes opposite. I don't bother about balancing the rear too much. :)
 
Timolgra said:
I'd use 18psi min on a bike that heavy, one rim lock should be enough as it not the outright speed that spins the tyre, it's acceleration (or braking) with aggressive tyres and a Dakar's not exactly rapid in that department.

You might want one one the front too but you'll find the wheels out of balance which can be sorted with a counter weight fixed to the spokes opposite. I don't bother about balancing the rear too much. :)
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Cheers I'll take your advice!
 
I happily run mine down to 10 to 12psi with no rim locks and haven't had a tyre spin yet or dinged a rim - but that's not using Karoo 3s. Have Michelin T63s on at the moment and you can pretty much run them at 0psi and not notice much difference. :D As stated above, a rim lock will certainly help and I wouldn't run a those tyres anywhere near that low. :thumb2
 
Cheers Dansin.

I'd also suggest it's not only acceleration or braking that causes tyre slip but the kinetic energy in the wheel if revolving at speed in mud and then the tyre getting caught on a tree root or finding friction on a rock enough to break the friction between the rim and tyre. I believe that's what caused my tyre to move on the rim.
 
Update:

I've had 1 rim lock fitted front and back opposite valve.

I also had "ride on" sealant put in the tubes.

Been for a 10 mile test run there is a high frequency vibration through the seat and pegs that's intolerable, some of it was the "ride on" as it was more pronounced at first and then smoothed out a bit. The vibration doesn't vary with speed.


So before the wheel changing begins again what's the votes for the vibration;
a. combination of "ride on" and rim lock
b. just the rim lock
c. just the ride on
d. something else
 
Get the front wheel in the air on a stand, pries the brake pads back and see if the wheel settles in one place consistently...it'll almost certainly stop with the rim lock at the bottom.

I have a heavy bolt cable tied to the spokes opposite the rim lock on my Husaberg, it was a temporary measure ...3 years ago and still there doing the job!

Or of course it could be caused by something entirely different:D
 
Timolgra said:
Get the front wheel in the air on a stand, pries the brake pads back and see if the wheel settles in one place consistently...it'll almost certainly stop with the rim lock at the bottom.

I have a heavy bolt cable tied to the spokes opposite the rim lock on my Husaberg, it was a temporary measure ...3 years ago and still there doing the job!

Or of course it could be caused by something entirely different:D
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Cheers mate! that's a good place to start, I'll do that first. If it's just balancing I'll be very happy!!!
 
Try it but if the vibration's coming through the pegs and seat it could be the rear out of balance, tyre not seated, the shit you poured into the tyre or chain problem, etc.
 
Timolgra said:
Try it but if the vibration's coming through the pegs and seat it could be the rear out of balance, tyre not seated, the shit you poured into the tyre or chain problem, etc.
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I agree, I'll start with both wheels being balanced and if that's no good have new tubes (no "ride on" sealant) put in with the rim locks, wheels balanced again and try that.

"ride on" claims it balances wheels without weights but the local mechanic said they frequently had balancing problems with it so we shall see!
 
George Washington said:
"ride on" claims it balances wheels without weights but the local mechanic said they frequently had balancing problems with it so we shall see!
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Yes, there's a theoretical argument it 'could' self balance the wheels but not if you've got a feckin lump of metal on one side :D
 
Ahhhhh tube sealant unless you spread evenly it's horrible
Hd tubes and you will be fine
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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