Belt Tension adjustments

[JRMSR]

My 2014 RT was vibrating quite bad at 3200 rpm 5th and 6th gear
Felt like I was on a road with rain grooves at that rpm

was using Manual info on 1050N (236lbs) as a setting (Krikit?)

Found a thread with 2015 Technical Service Bulletin said BRP changed to 630N (141lbs)
this is a huge change, but I tried it anyway
Bike is way better, no vibrations, smoother, feels better, has to be better for the bearings

Here is my data, taking reading with old setting rear wheel ON and OFF ground

2014 CAN AM SPYDER RT
	236 LBS - \WHEEL ON GROUND
TIRE
ROTATION	TEST 1	TEST 2	TEST 3	AVG	DIFF
0°	260	260	260	260
45°	260	260	260	260
90°	260	260	260	260
135°	270	280	260	270
AVG				263
	236 LBS – WHEEL OFF GROUND
TIRE
ROTATION	TEST 1	TEST 2	TEST 3
0°	220	240	240	233
45°	220	240	240	233
90°	230	240	220	230
135°	230	240	240	237
AVG				233	29
	150 LBS – WHEEL ON GROUND
TIRE
ROTATION	TEST 1	TEST 2	TEST 3
0°	200	220	220	213
45°	230	200	230	220
90°	220	220	230	223
135°	220	220	240	227
AVG				221
	150 LBS – WHEEL OFF GROUND
TIRE
ROTATION	TEST 1	TEST 2	TEST 3
0°	140	150	150	147
45°	150	160	150	153
90°	150	160	160	157
135°	150	150	150	150
AVG				152	69

looks like I can test ON the ground and only need to adjust when way off

[IdahoMtnSpyder]

I believe the reason BRP specs say to set the tension with the wheel off the ground is consistency. As your data shows, when the bike is pushing down on the swing arm the tension is greater. Extrapolating between the the two extremes, wheel off ground hence the shock is fully extended, and wheel on ground hence the shock is compressed, you can see that if the wheel is off the ground the every time you check it you remove the variability of differing shock compression. Offsetting that is the fact that the tension setting is given in such a wide range, the primary criteria being min and max and acceptable vibration, that varying shock compression will have minimal real impact on the end result.

The reason the tension increases with the wheel on the ground is the center of rotation of the swing arm is behind the front drive pulley. As the swing arm moves up with respect to the bike frame the center to center distance of the two pulleys increases slightly.

Check the tension with the wheel on the ground. It's good enough and a whole lot easier! If you want to be as consistent as possible between checks never have any weight on the seat and let all the air out of the air shock. And to get really anal about it, make sure the gas tank is full every time!

[Gunner3773]

Earlier this year, I put Doc's tensioner on my 2015 RT and it made a huge difference in the belt vibration. But I decided to adjust the belt on my RT down to 630N the other day using my sonic meter. That new adjustment, along with Doc's damper, has eliminated the belt vibration on my bike. I was astonished how smooth my bike ran on a 300 mile jaunt yesterday with the wife. I should have adjusted the belt down to 630N sooner.

Unfortunately, I will be putting the bikes away tomorrow for the season. Summers are way too short in MN!

Gunner

[Jetfixer]

Earlier this year, I put Doc's tensioner on my 2015 RT and it made a huge difference in the belt vibration. But I decided to adjust the belt on my RT down to 630N the other day using my sonic meter. That new adjustment, along with Doc's damper, has eliminated the belt vibration on my bike. I was astonished how smooth my bike ran on a 300 mile jaunt yesterday with the wife. I should have adjusted the belt down to 630N sooner.

Unfortunately, I will be putting the bikes away tomorrow for the season. Summers are way too short in MN!

Gunner

Did you happen to, and/or could you, recheck the tension using the sonic meter, after letting Doc's damper contact the belt again? (I assume you set the tension to 630 holding the damper off the belt.) I have the same setup and the Gates meter, but just can't quite get the vibration gone completely. I'm still running on the high side of the old tension.

[JRMSR]

Did you happen to, and/or could you, recheck the tension using the sonic meter, after letting Doc's damper contact the belt again? (I assume you set the tension to 630 holding the damper off the belt.) I have the same setup and the Gates meter, but just can't quite get the vibration gone completely. I'm still running on the high side of the old tension.

If iyour on the high side of 236lbs ( wheel off ground). That is why you have heavy vibration
go to 140-150 lbs and you should be way better

[Gunner3773]

Did you happen to, and/or could you, recheck the tension using the sonic meter, after letting Doc's damper contact the belt again? (I assume you set the tension to 630 holding the damper off the belt.) I have the same setup and the Gates meter, but just can't quite get the vibration gone completely. I'm still running on the high side of the old tension.

Sent PM.

Gunner

[Roadster Renovations]

A Tensioner for our kit is a misnomer. We call it a Vibration Damper because it does not add tension (very little) to the belt. It is more like a finger put on a vibrating guitar string to stop the vibration. With the rear wheel off of the ground, there is probably very, very little tension, if any at all.

[cptjam]

Rocky at Coyote powersports just showed me the technical bulletin about lowering the belt tension. The F3 models are destroying the front pulley like mad! If you have an F3, remove the cover and inspect the pulley. Any red dust is rust, and that means the pulley is going to fail. Replace. BRP thinks it is caused by belt being too tight. Watch it!
We use Doc’s belt tensioner/ vibration device, and have seen too many BRP models fail and ruin belts. We did 2 this weekend.

[cnl414]

What should the tension be set to for a F3? I just assumed that it would be set correctly from the factory.

Thanks,
Charlotte

[Jetfixer]

Got mine down to an average of 650N the other day. What a difference!

[Sarge707]

I adjusted mine to 120 Kricket pounds = 540 neutons.
Still going to do a New Sprocket in the Spring (Hopefully by then there will be a Bulletin and it will done for FREE like the 2015 frame support?)