Smoothspyder vs Doc Humphreys belt roller assembly for F3 T

[Bruisr]

Both are excellent and supportive vendors for our forums. Any suggestions which one may have an advantage on the F3 T ?(ease of installation/ warranty etc)

 

[Bob Denman]

All that I can say is that I've had Doc's on my RT, and it does a great job! :thumbup:
I seem to recall that there have been some folks in here that have tried several of the available ones!

 

[Devious56]

I had a Sooth Spyder tensioner on my RT and it did an ok job. But now have a Doc Humphreys one on and it is doing a better job. Keep in mind, I have an RT and there are some differences in your F3.

 

[Chupaca]

Tough one...

Always hard to find those that try more than one of anything...:banghead: especially when they are expensive items (not the case here) but if they work once installed then why buy another :dontknow: I have a smoothspyder but got it when they were the better known one and Doc had not got into the fray. Unfortunately Doc does not have a model for us so will opcorn: for the F3 guys to chime in

 

[jcthorne]

I have the Smooth Spyder on my F3S and Louise has the Doc Humphreys on her F3T.

Realize that on the F3, both vendors versions install on the top of the belt.

They both work fine. The Smooth Spyder is the more polished of the two as its very nicely built and uses OEM style components and pulleys. They both look like they will last a long time and as I said, they both seem to work equally well. Have not had any problems with either of them.

The one on Louise F3T replaced a BRP tensioner that had better than 10k miles on it. It was working fine as well and had no more play in the bearings than new ones. IE it was in fine shape at 10k. Nothing wrong with it.

 

[Samson]

I had the BRP model on my F3 T and it started to fail ( was getting wobbly) at about 200 miles or so. I now have Docs, very nice piece, well made. VERY easy install. Works well.

 

[Badco149]

I have the Smoothspyder installed on mine. I found it made the ride even better if possible. I do love the way it is constructed. Looks like it will last many miles. I had the dealer install mine while it was getting a spring checkup.

All the Best
Ride Safe

 

[papanorm]

I believe both Doc's and Jim's belt rollers are high quality products and you cannot go wrong with either. I installed a Smoothspyder on my F3L when it was new and now have about 14,000 miles on it. I no longer have any belt vibration at any speed. The unit is built like a tank and will probably last as long as the bike.

 

[papanorm]

I believe both Doc's and Jim's belt rollers are high quality products and you cannot go wrong with either. I installed a Smoothspyder on my F3L when it was new and now have about 14,000 miles on it. I no longer have any belt vibration at any speed. The unit is built like a tank and will probably last as long as the bike.

 

[Dmetcalf]

Question doesn't the harmonic issue come from the bottom side of the belt ..?

Shouldn't the vibration come from the side of the belt that isn't under torque..? So shouldn't the belt tensioner be installed on the bottom side of the belt to keep that side of the belt tight so the harmonic issue isn't contributing to the imbalance..?

 

[jcthorne]

Shouldn't the vibration come from the side of the belt that isn't under torque..? So shouldn't the belt tensioner be installed on the bottom side of the belt to keep that side of the belt tight so the harmonic issue isn't contributing to the imbalance..?

I can't really tell you WHY its not that way but the higher tension in the upper belt is where the harmonic sets up and where the tensioners work to remove it. It works. Tensioners on the bottom were tried and were largely ineffective.

 

[Dmetcalf]

Could Doc & Jim give us their opinion on this issue please ..?

I can't really tell you WHY its not that way but the higher tension in the upper belt is where the harmonic sets up and where the tensioners work to remove it. It works. Tensioners on the bottom were tried and were largely ineffective.

Could Doc & Jim join in on this discussion to give us their opinion on why the tensioner works. Eat from the top side of the drive belt please ..?
Thanks

 

[Roadster Renovations]

Could Doc & Jim join in on this discussion to give us their opinion on why the tensioner works. Eat from the top side of the drive belt please ..?
Thanks

As I understand the vibration issue, the harmonics of the top side of the belt causes a guitar string-like vibration that will occur at different speeds based upon factors such as; total weight load, suspension settings, belt tension and alignment, and other factors. You would think that the vibration was on the bottom, but in BRP's research they found that it was on the top and not the bottom. They created a inexpensive idler kit for the F3 only. It was explained to me that the reason they didn't make one for the RT was due to the positioning of the gas tank. The engineers said it was not possible. In our initial testing of an extension bracket (RTBK kit) with the BRP idler it was proven that even if the rear shock totally failed (bottom bolt fallen out, etc.) there was at least 3/4" of an inch clearance with the gas tank.

We began offering the RTBK adapter kit and then began to look at the BRP idler kit. We didn't like the small bearing, nor the play that was in the pulley, so we improved on their design. We went to a double bearing roller with Japanese steel bearings. We then used an aluminum arm and a heavier duty bracket. When the BRP units started freezing from debris in the pivot point we added a gasket washer to keep the garbage out and a grease fitting for easy access to lubricate the joint. When the BRP springs (and some of ours) starting breaking, we upgraded the diameter of the wire to make it stronger and increased the coil diameter so that the arm could travel farther without binding. We are continuing to work on several other aspects of the kits, one of the first will address the buzzing noise for the outer ribbed belts of the earlier RTs.

Doc & Kathy Humphreys
AKA Roadster Renovations

 

[Dmetcalf]

Excellent explanation - Thank you

I can't really tell you WHY its not that way but the higher tension in the upper belt is where the harmonic sets up and where the tensioners work to remove it. It works. Tensioners on the bottom were tried and were largely ineffective.

As I understand the vibration issue, the harmonics of the top side of the belt causes a guitar string-like vibration that will occur at different speeds based upon factors such as; total weight load, suspension settings, belt tension and alignment, and other factors. You would think that the vibration was on the bottom, but in BRP's research they found that it was on the top and not the bottom. They created a inexpensive idler kit for the F3 only. It was explained to me that the reason they didn't make one for the RT was due to the positioning of the gas tank. The engineers said it was not possible. In our initial testing of an extension bracket (RTBK kit) with the BRP idler it was proven that even if the rear shock totally failed (bottom bolt fallen out, etc.) there was at least 3/4" of an inch clearance with the gas tank.

We began offering the RTBK adapter kit and then began to look at the BRP idler kit. We didn't like the small bearing, nor the play that was in the pulley, so we improved on their design. We went to a double bearing roller with Japanese steel bearings. We then used an aluminum arm and a heavier duty bracket. When the BRP units started freezing from debris in the pivot point we added a gasket washer to keep the garbage out and a grease fitting for easy access to lubricate the joint. When the BRP springs (and some of ours) starting breaking, we upgraded the diameter of the wire to make it stronger and increased the coil diameter so that the arm could travel farther without binding. We are continuing to work on several other aspects of the kits, one of the first will address the buzzing noise for the outer ribbed belts of the earlier RTs.

Doc & Kathy Humphreys
AKA Roadster Renovations

Thanks for explaining this in such great detail.

 

[capt.jim]

Could Doc & Jim join in on this discussion to give us their opinion on why the tensioner works. Eat from the top side of the drive belt please ..?
Thanks

There is vibration from both the top and bottom. The bottom vibration can be seen on Finless Bob's RT tensioner install video.

The bottom mount tensioners have worked reliably at 90-100% for the vibration on the GS/RS/ST and many RT's. While the RT tensioner has worked reasonably well for most and been very reliable, the fact is it works better on the top overall from the reviews on here.

The top of the belt vibration is more likely to be felt on the heavier F3's and RT's and has a lot to do with the heavier weight accrued, suspension setting and wind resistance, going up hills and anything that loads the belt, all of these will all add to the top being stretched tight and resonance felt throughout.

My F3/F3S and T/LTD both go on the top. On the F3 the bottom tensioner helped but the majority was coming from the top of the belt, upper and lower idlers were the smoothest but the top works almost as well by itself. What small residual vibration felt is likely coming from the bottom.

I had great hopes for BRP's "idler accessory" but it doesn't appear to be engineered too well overall. The few failed ones I've looked at seem like the bearing wallows out the seat in the soft idler material rather than the bearing itself failing, maybe others have seen different. The arm movement is not the best either and prone to sticking on some.

I may drop a couple tensioners from my product line to go another direction on some different products I've been working on. As long as someone is on top of the vibration issue and the product is holding up I'm good with that.