Saris H3 Discussion/Issues

Refund seems practical to me, since they can’t offer a replacement for a while.

That was my thinking too, a shame really as I really like the trainer.
Since lockdown is easing I shall make the most of the good weather!

Any thoughts on a wheel on trainer? I only have one bike so may be a better option for me.
Especially in the UK with the weather.

Wheel on can be great. Typically not as accurate as wheel off. Wheel slip can be an issue for some high power efforts, but is no deal killer.

I used one for years and it was perfectly fine.

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I suppose by the end of summer there should be some good deals to be had!

Maybe. With the shutdowns, there was a run on indoor cycling equipment, so stock may not be the usual excess rolling into Fall.

Hello All
My relation with the H3 is quite new, I am on the 3rd week of use, bought new from Chain Reaction Cycles.
I was immediately affected with the belt slipping issue, so after a few hours I was disassembling it an increasing tension ob the belt; it is strange that a device announced as a beast for dealing with 20% inclinations was slipping under a low effort.

Done increase of tension on the belt (despite I have no idea of what is the suitable tension); on that matter the Saris instruction video gives no input since the tension screw on the H3 is on the left compared to the exposed on their video.

Yesterday, again slipping while climbing in Rouvy at lower than 10% gradient; again unit open…
Quite easily was noticeable some rubber powder laying on the interior of the plastic cover and erosion on other area (to the level of melted plastic due to the heat of the belt touching it).

You aren’t supposed to sand the belt. You’re supposed to sand the pulley.

Correction, Saris should just fix this damn thing so customers can ride it instead of playing inspector gadget trying to fix their engineering fails.

Still no response from Saris about that textured pulley that one customer got, but the guy I asked had no idea it even existed. Such a disorganized place

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Thats correct…thanks…I sanded the big diameter plastic pulley, not the belt…

The unit is open and will be checked after each use until I feel trust enough to close it gain.

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Don’t bank on it. I bought a second hand one after a failed attempt with a Neo and Kickr. Applied very aggressive texture to the pulley, proper tension, 2 weeks later and it screams at 450w+.

This is after I returned 4 units directly to Saris because they each made it about 3-4 weeks

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They have two sorts of belts the one for H3 and other for Hammer and H2.
From those what is the one you adress as being textured?

The belt on mine is:

The belts aren’t the part that need texture. It’s the large upper pulley which has a flat surface which cannot grab the belt causing it to slip. Sanding the upper pulley to give it some traction only works temporarily

They seem to answer to that on one of their FAQ´s:

I’m the Alex that asked that question, and their answer is absolutely asinine, like how their trainer is special because it handles thousands of watts and not hundreds of horsepower (2000w is about 3 horsepower). If a grooved pulley causes the belt to jump, it’s not grooved right or is out of balance. No competent engineer would agree with this EVER.

I don’t buy that answer for a second, every other company uses a ribbed pulley and doesn’t have this issue. It’s an outright lie to detract attention

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I agree, fully.
The same misalignment is on that guiding roller on the lower pulley that makes no purpose as it is positioned.

Do you think there may be an application to those sort of belt anti-slipping agents, from Loctite, other from Wurth?

Yes those supposedly work. I’m just irked that not only did they make a poor design, they have been tying to weasel out of properly fixing it since the beginning. Their fixes have been similar to what I would think of doing if I was a one man company with no tooling or resources and just built a trainer in my garage. Except this is Saris, a huge company.

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I have the same issue. I’ve put the belt “back on track” and after a couple of spins the problem is here again. I contacted Saris 2 days ago, no response yet, but I’ll keep you updated if I have new Information.
Obviously, it seems to be a common problem and I have to admit, for a long time I thought “ahhh, that noise doesn’t really bother me” but the smell of burnt plastic together with my fire-alarm going off (seriously! :sweat_smile:) eventually convinced me. So I guess there are other people out there having the same issue an might not care about it or doesn’t even notice it. Nevertheless, Saris needs to fix this.

Saris: You might be surprised to learn that a grooved pulley wheel makes the belt jump across grooves in our application. With a smooth pulley wheel the belt is stretching equally to both edges of the pulley wheel. Those balanced forces help to keep the belt in correct alignment.

I don’t really understand what this means. I’ve worked on cars for so much of my life, that this makes absolutely no sense to me. I saw this when Cleanneon98 posted it way back, but it still doesn’t make sense.

I’m guessing the pulleys are not aligned, and if so, they should just align it. A correctly set up belt system will not slip or jump grooves.

The “guiding roller” is not a guiding roller. It’s a tensioner pulley. The lip is just to keep it from slipping off.

What it looks like is that the tensioner has too much play in it. If I’m seeing it correctly, the tensioner is actually the whole plate, with the dead pulley on it. Dead pulley is just a cylinder on some bearings that spin freely. It sits on a plate, that the tensioner screw pushes upwards. The whole plate might be askew.

Check the mounting bolts for the plate, and see how it slides. There might be too much play there. A plate and pulley has too much slop. Autos would use a small machined plate with springs in the pulley, or externally.

If the bolts are bending, I would see if I can source class 10.9 bolts from an industrial supplier and have a go at it.

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While there are clearly units with belt problems, I don’t think it is as simple as ‘large pulley needs grooves’. My front loading washing machine uses the exact same setup - small grooved pulley, large smooth pulley.
A quick search for “pulley design for ribbed belt” brought up two different belt design guides which both give guidance for applications just like this - using a small grooved pulley and a flat large one.
In fact, one of them states:

Something is clearly wrong on these units that are chewing up the case, but using a flat pulley in cases similar to this is reasonable based on these belt design guides.


That may he the case for a washing machine or dryer, but they’re also not ramping up and down in speed/resistance like Spanish Needle.

Also the transmission is reversed, pretty sure in a washing machine there’s a smaller pulley which is turning a belt, and the belt is turning the smooth larger drum. In the trainer The force is being applied to that smooth larger pulley and going through the belt and turning the small pulley instead. The force isn’t being applied at the same place, and I’d argue the forces are quite different.

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