Belt tensioner placement

[Stumpy6Guns]

Hey, I have a question regarding where the idler wheel is most effective and why.

SmoothSpyder's idler wheel runs on the slack side of the belt. The BRP idler runs on the tension side of the belt. From a design standpoint, which placement (not product) is more better, and why?

Just a ponder.

[Roadster Renovations]

Think of the tension side of the belt as a banjo string; and BRP's damper as a finger stopping the string from vibrating.

[jcthorne]

SmoothSpyder for the F3 also rides on the top side.

[Dennis elliott]

I'm sure the Brp Engineers put a lot of thought into the placement

[Chupaca]

From the feed back on the BRP unit...it works well where they placed it. The mods made to adapt it to the RT has also worked well. So it becomes a choice cause the others have had favorable effects as well.

[Stumpy6Guns]

I'm just curious. I put the SmoothSpyder on my 2012 and the BRP on my 2016. The SmoothSpyder works well; I haven't taken the 2016 out for a ryde yet.

[2dogs]

BRP took the route of least resistance. The easiest, quickest, least expensive location to mount a belt tensioner which ended with serendipitous results.

[irvin48]

had anyone looked at mounting the brp unit on the bottom, or is it
not economically feasible ? too much angle?

[Bob Denman]

The fact that they work should be the only important point...
If you're trying to re-invent a perfectly good wheel; you might need to:

Ride MOre worry less 02.jpg

[BLUEKNIGHT911]

had anyone looked at mounting the brp unit on the bottom, or is it
not economically feasible ? too much angle?

When " Joel the Biker " made His adapter for the BRP tensioner ....I believe He tried to mount it on the bottom first but decided it wasn't feasible ...... so He went with BRP's placement ...... jmho ........ Mike

[Bob Denman]

...Which is probably a good idea anyway!
If you're going to get (pretty much) equal results from either placement: why make the job any tougher than it needs to be?

[Stumpy6Guns]

I would just leave well enough alone and stick it on the top. It works quite well up there, and the installation is easy.

[pjweimer]

This question of position of a tensioner on a belt to control slap interests me. So, as I usually do, I went searching, me and my friend Google. Well I read a bunch of things on the Gates site and came across a white paper explaining a concept called "overhung load". Has to do with the forces on the driven shaft's bearings influenced by the distance of the pulley from the bearings, size of pulley and weight on the pulley as caused by the belt's tension among other factors, at least as I understood what I read. While I found nothing specific in that white paper regarding tensioners but it seemed logical to me that a tensioner would figure into considerations regarding added weight and its negative impact on the life of the shaft's bearing. Of course these are just my thoughts, perhaps unfounded.

Continued searching turned up an interesting read. Here is a link to that bit of engineering information... http://machinedesign.com/archive/bel...ain-tensioners.

Now that seemed to address the issue of a tensioner and it recommended placement. An interesting read for any who may be curious about the subject. The last paragraph makes a most interesting suggestion on tensioner placement... "The best place for a tensioner on a belt drive is on the inside of the belt against the slack side. The idler should be located such that it provides nearly equal arcs of contact on both driver and driven pulleys."
How about that? None of the offered products are so designed!

Now to the cause of my curiosity. When we bought our current bike, the 2014 RT Limited, I installed a SmoothSpyder tensioner before many miles were logged on this bike. This I did based upon our experience with the first Spyder, a 2012 RT Limited. The SmoothSpyder unit on that bike calmed a rather disturbing belt vibration so putting one on the 2014 seemed to be a "no-brainer". But we had infrequent occasions where we felt some vibrations and accredited it to untamed belt harmonics. So when BRP introduced the belt tensioner for the F3 and then a fellow forum member offered an adapter so it could be mounted on the RTs I asked if any comments were available directly comparing the effects of the SmoothSpyder unit to BRP unit mounted with the adapter. As it turned one of the testers indeed removed a SmoothSpyder unit prior to mounting the adapter and BRP unit to test it. His experience was most positive, extreme pleasure with the later.

Yesterday I installed the new configuration, adapter and tensioner. So it seemed logical to remove the SmoothSpyder unit. Then came all questions. Fear of too much uncalculated additional weight on the belt and the potential resultant increased bearing wear and possible failure initiated this search. When the SmoothSpyder was installed I set the recommended pressure on the belt to 10 pounds as measured but the spring scale provided with the unit. So I used that spring scale to measure the pressure applied by the BRP unit on the top of the belt... 9 pounds. Individually the pressures don't seem like much, even combined it may not be much. But can one know, for sure?
So, living in central Ohio, I won't be riding the Spyder too soon. I have decided to leave both units mounted until I have weather that will permit comfortable time to compare. First with both units, then after removal of the SmothSpyder.

Meanwhile I hope there may a mechanical engineer or two here on the forum that may read this and offer comments to sooth my old mind.

Thanks for reading my ramblings.