Time for a belt idler?

[fulltimer]

A question to confirm what I am already thinking. Since my last rear tire change, I have picked up a vibration in the 2 highest gears (4th and 5th) between about 4200 and 4400 rpms. Smooth above and below or under hard acceleration. I have had the tension checked on the drive belt and the tech tweaked it a little but had said it was within specs. Am I probably getting the harmonic in the belt? And if so, is this mostly cleared by the belt tensioner I have heard about on this forum?

[ingramwc]

Your RPM's are too low, rev that engine higher, it is smooth as silk above 5,000 RPM... Running at those RPM you are beginning to lug the engine!!!!

[Richardv]

A question to confirm what I am already thinking. Since my last rear tire change, I have picked up a vibration in the 2 highest gears (4th and 5th) between about 4200 and 4400 rpms. Smooth above and below or under hard acceleration. I have had the tension checked on the drive belt and the tech tweaked it a little but had said it was within specs. Am I probably getting the harmonic in the belt? And if so, is this mostly cleared by the belt tensioner I have heard about on this forum?

...I have ther same vibration. You can change the RPM range by playing with the belt tension, but it remains "somewhere" in that area.

I already boughtt my F3 tensioner frrom BRP, and as soon as the Spyder will come out of storage, I will try to adapt it like Doc Humprey did for the RTs. I suspect it will fit since it is the same frame, fuel tank, and rear swing arm. (confirmed by double checking parts # in the shop manual).

But still have do try it to prove it.....to be followed..... ;-)

[sjanway]

I have a 2012 rt i dont see a belt tensioner, does that year not have one?

[fulltimer]

Your RPM's are too low, rev that engine higher, it is smooth as silk above 5,000 RPM... Running at those RPM you are beginning to lug the engine!!!!

Though the engine does indeed run as smooth as silk at 5K or above, there are 2 factors in play here.

1 in 24K miles, I have not had the vibration before.

2 that RPM range is where 55 mph sits. A not uncommon cruising speed in the midwest.

PS, sorry for not getting back on line sooner.

[Spider-man]

I have a 2012 rt i dont see a belt tensioner, does that year not have one?

It's not standard, you need to purchase one after-market.

[Roadster Renovations]

I have a 2012 rt i dont see a belt tensioner, does that year not have one?

It works for all RT's.

http://dochumphreys.wixsite.com/road...amper-products

[Roadster Renovations]

...I have ther same vibration. You can change the RPM range by playing with the belt tension, but it remains "somewhere" in that area.

I already boughtt my F3 tensioner frrom BRP, and as soon as the Spyder will come out of storage, I will try to adapt it like Doc Humprey did for the RTs. I suspect it will fit since it is the same frame, fuel tank, and rear swing arm. (confirmed by double checking parts # in the shop manual).

But still have do try it to prove it.....to be followed..... ;-)

If you can figure it out, we sure can produce the mod. One problem is the parking brake pawl on that side by the front sprocket. Not sure how we will get around that. If I had one to experiment on, I could make it work.

Good Luck! Hope you are able to do it!

[Peter Aawen]

Though the engine does indeed run as smooth as silk at 5K or above, there are 2 factors in play here.

1 in 24K miles, I have not had the vibration before.

2 that RPM range is where 55 mph sits. A not uncommon cruising speed in the midwest.

PS, sorry for not getting back on line sooner.

But you also told us this was only after you changed the rear tire, so that's at least a third factor!?! Changed from what tire to what tire?!? Any size or make change? And did the vibrations become obvious immediately after the change, or only after ryding for a while on the new tire??

That tire change could well have a bearing, if not being the sole reason that you 'now' notice vibrations when in the past you didn't?! It could even be that you always had the vibrations only they were masked by something else (a dodgy tire maybe?) & now that you have a different tire, the vibration has become obvious!! This can work both ways, an old dodgy tire masking vibrations so now that you have a good tire the vibrations are apparent; or it could be the last tire was OK & now you've got one that's not so good creating or enhancing the inherent vibrations...

So what tire did you have & what did you change to? Any balancing or bearing changes done at the same time? Belt tension changes, new shocks, anything else really?!? Vibrations can be a real pain to sort, especially if you've done a few things before they miraculously 'appear'!

[Pirate looks at --]

If your Spyder was in alignment.......it might not be now!

[fulltimer]

But you also told us this was only after you changed the rear tire, so that's at least a third factor!?! Changed from what tire to what tire?!? Any size or make change? And did the vibrations become obvious immediately after the change, or only after ryding for a while on the new tire??
I began to notice it within the first couple days.

That tire change could well have a bearing, if not being the sole reason that you 'now' notice vibrations when in the past you didn't?! It could even be that you always had the vibrations only they were masked by something else (a dodgy tire maybe?) & now that you have a different tire, the vibration has become obvious!! This can work both ways, an old dodgy tire masking vibrations so now that you have a good tire the vibrations are apparent; or it could be the last tire was OK & now you've got one that's not so good creating or enhancing the inherent vibrations...

So what tire did you have & what did you change to?

I had the stock OEM tire. I changed to a Yokohama Avid Touring S in a 215/60, a little taller tire. I can't really comment on the tire as it handles and "feels" fine in all other aspects. Running about 23 PSI.
Any balancing or bearing changes done at the same time? Belt tension changes, new shocks, anything else really?!? Vibrations can be a real pain to sort, especially if you've done a few things before they miraculously 'appear'!

No other changes. As mentioned above, the belt tension has been checked to OEM specs. I know from reading and talking to others that this "harmonic" has raised its head before or there wouldn't be aftermarket devices to correct it.