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Ride to the ride.
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I've had my Spot Longboard singlespeed with Gates Carbon Drive since August. I've had excellent experience with most everything so far. I feel I've learned some important tips for owning a belt drive bike, and thought I'd pass those along. Note that this is my opinion based on my experience with one single belt drive bike. I can't hope to speak for the variations out there or for other folks' experiences. Some of this may apply, and some of it won't. Much of this will only apply to other bikes like mine.

I'll try to avoid Belts-Are-Better/Chains-Are-Better dogma, but will explain my opinions about potential advantages and pitfalls of the belt.

Belt alignment:

The most important aspect of the belt drive that is different from a chain drive, is belt alignment. Chainline is important, too. But there's more forgiveness. A gear tooth sticking between the pins and plates of a chain is trapped in 4 directions like your finger in your nose. With the belt, the belt "tooth" is more like a hotdog in a bun; cradled, but it can still slide out the end. I don't think it actually slides, but the angles within the system can make a difference between full engagement and the hotdog only halfway in the bun.

The most obvious way to change this alignment, is with the angle of the rear hub. Imagine this: the drive system is spinning smoothly. Loosen the drive-side axle nut (if there were one) and allow that end of the axle to angle forward. The belt will begin to run off the outside rear sprocket (to the right/drive side). If the end of the axle is pulled back tighter than it was to begin with, the belt will try to run off the inside of the sprocket. In this case it will be stopped by the inner flange, and instead run off the inside of the front sprocket ("chainring") -- which has an outer flange. (So to clarify the metaphor, the hotdog can only slide out one end of the bun.)

That's the basic dynamic. To dial it in, you need to get the belt to run smoothly between the inner flange of the rear sprocket and the outer flange of the front sprocket, not running off the open side of either one, and at the right tension. None of which is as hard as it sounds.

The Spot came with tensioners on the rear axle. I'd have to guess that it would be much tougher without them. Or even with just one on the drive side. By following the instructions that came with the system, I had my dialed and tensioned in maybe 15 minutes the first time. And I tend to work very carefully the first time I do something. It's been much easier ever since. And even changing flat tires on the trail has presented no problem. though I do find it easier to pull the skewer all the way out instead of fighting the brake disc.

***

This is in the instructions, but here's a quick rundown on the method, in case you're not visualizing it: Bike in a stand. Spin the cranks backwards and look. Is the belt running off the rear or off the front. Adjust the tensioner on one side or the other until it's centered. Then spin the cranks about 15 revolutions, both ways, to make sure it stays. Adjust until it does.

Then check tension. I pressed on a scale to get the feel of 5 pounds of pressure, then just thumbed the belt to about the same pressure to get a 1/2 inch deflection. Worked okay. If it's too loose or too tight, adjust tension bolts on both sides of the hub and check again.

Then check alignment again. Adjust, check, adjust. Tighten skewer, and check all again. Adjust.

It's not tough, but if you're a careful craftsman, it may take a bit of time initially. Do make small adjustments, as it can damage the belt if you run it off under tension. (More likely if you're riding.)

***

There are other considerations that aren't mentioned in the Carbon Drive instructions. Belt alignment can be compromised in several ways, and I've found myself keeping an eye on them and have been able to avoid trouble.

First was that my original Spot rear wheel with its quick release skewer didn't seem to be very grippy in the frame. I got some minor shifting that resulted in the belt running slightly off-center, and had to make some quick adjustments on the trail. It helped to crank the skewer down pretty tightly. Easy, but good to keep an eye out for. I changed wheels to one with a DT hub and have been using the RWS 10mm "thru axle" with no further trouble.

Next I realized the importance of both the bottom bracket and the cranks to maintaining belt alignment. After several rides on my new bike, I was surprised to find my Spot cranks/BB popping a bit, like something was loose. Not good, as that could change the angles for the belt, cause it to run off, and damage or destroy it. I adjusted on the trail, then checked everything again in the shop. Since then I've had to further problems with the BB. Another piece to keep an eye on.

Before one ride, I was checking my front sprocket bolts (chainring bolts), since I realized that looseness could cause a misaligned belt. I found two that were a bit loose, and when I tightened the first one, it stripped out. Closer inspection revealed that the chainring bolts (they're the standard kind) were only grabbing a couple of threads. They were single-ring bolts, which made sense. But the spider seems to be extra thick on this Spot crank. I replaced them with double-ring bolts, and they now fit properly.

It's also important to make sure the rear sprocket remains tight on the hub, via its cassette lockring. I have had no trouble with this.

Those are my experiences and observations for keeping the drive tight and the belt aligned. The only other factor I can envision is the possible rare occurrence that a bike might have chainstays that are so flexible that they could cause alignment to change when riding rough trails. Beyond that, all these tips should help keep a belt drive system working properly and in alignment.

If there are disadvantages to the belt drive system, the first one would be this learning curve. It's a new system, and it works somewhat differently and has different basic requirements. Learning to align the belt is no harder than learning to use a chain tool, but it is new.

The next perceived disadvantage would be trail repairs. Yes, the drive system is tough and all that. But, as we all know, in mountain biking things break. Replacing a belt trailside would be pretty easy -- if you'd put it on in the first place and knew the drill. But I, for one, am unlikely to have a spare belt along. They're very light, but bulky to carry. The durability of the sprockets seems very good, but is still a bit of an unknown.

Because it's new, a lack of parts compatibility and availability can be considered a disadvantage. I'd like to see this change as acceptance moves forward, but that remains to be seen. It's good to see Trek picking up the technology for two of their bikes. And to others, including small custom builders, who are enjoying the innovation.

For the kind of riding I've been doing on my Spot, these last two items aren't much of an issue. I'm not traveling on it, or doing all day epics. I tend to hammer it hard on local trails for a couple hours at a time. In the event of damage, I could walk or coast or scooter out just fine. Just like many of us have done on "regular" bikes. If I decide to go big, I may carry a spare belt. (While realizing that it's impossible to carry replacements for everything that could possibly go wrong on this or any bike.)

Advantages?

The lightness of the belt drive system is very appealing -- I noticed it more when I upgraded the wheels. I haven't geeked out over weight, but for those that do, the belt offers definite advantages.

The belt contacts the sprocket along its full 10mm width instead of only the thickness of a gear tooth. There's no side-to-side play, unlike a chain, which you can grab and shake back-and-forth on a chainring. And the contact is not metal to metal. I think these factors contribute to a smooth, quiet feeling to the drive.

I've never felt oppressed by the need to lube my chain. So it's strange how freeing it is to not have to worry about this at all. And no oily goop to clean off and accidentally smear all over myself.

There's also a certain cool factor that comes from having the opportunity to really have fun with a new way of doing things.

The overall effect of my Spot Brand belt drive singlespeed 29er is that it is a very fun bike to ride. Because I bought the whole bike, I don't know how much of this comes from the belt drive. I'm tempted to experiment by swapping the belt drive for a regular chain system to compare.

I do hope that those of you who have been curious about the belt drive system have gotten some of your questions answered by my own experience with it. For those of you who are now gaining your own experience or are wanting to try the system, good luck, have fun, and let us know what you're finding.

--Greg

Pic below, with the original wheels.
I did a video that shows (most of) the drive in action on the trails here.
 

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Good to see some real life feedback instead of the opinionated anti-belt theoretical dribble.

In the early days of belts on Harleys, we used to carry spare belts, and also there was a belt that split with a number of joining pins. Turned out to be pretty pointless, the belt system is very reliable.

I am eagerly waiting for my belt drive components to arrive.

(I'm talking about the toothed belts, even I am not old enough to have had a V-belt Harley:) )
 

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Single Speed Junkie
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Bikeabout said:
A gear tooth sticking between the pins and plates of a chain is trapped in 4 directions like your finger in your nose.
Accurately disgusting. Friend just converted an old vintage yeti over to the belt drive via splicing the seat stay. It has worked out well and have noticed little noise coming from his ride where as if my chain goes with out cleaning between rides you can hear it.
 

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skillz to pay billz
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nice, I have the same bike. no problems so far.

i do get that same popping occasionally. What did you you adjust on the BB/Cranks to solve it?
 

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i call it a kaiser blade
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fascinating.

if it wasn't for pioneers like you to figure out the bugs, we'd never have cool/alternative techonlogy.
 

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Out spokin'
In cog? Neato!
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16,544 Posts
Cool writeup, cool bike.

Living in the Pacific NorthWet, I wonder how well a belt drive would work in wet, muddy conditions. No implication in my question, I sincerely have no idea. Here's a photo that General Coonskins posted following a ride he and his wife did the day after Christmas.
 

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I have heard it does very well in mud and snow, I should know more in a couple months when my new custom frame is finished I get to go play on my new belt drive bike
 

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Sparticus said:
...Living in the Pacific NorthWet, I wonder how well a belt drive would work in wet, muddy conditions...
That's not mud, that's liquid patina...:thumbsup:
 

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KrisRayner said:
Informative post. What about gear ratios? Is there much adjustment to, say, drop or increase a couple teeth on the rear, or would that require a different belt?
Anyone? I don't think anyone answered this yet. Please? :D

I'm interested in the belt setup... not sure how to make it work easily on a SS with "regular" chainstays/seatstays, but interested nonetheless.
 

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I think I would like it very much with a Rolhoff also, but seems like to much work for my everyday SS. All i have to do is lube chain, check tire pressure, skewers and pedal.

Who doesn't like light, clean and quiet? but is it worth taking the simplicity out of SSing?

Trek has a track bike with 135 spacing, would be cool to have 2 bikes and share one great wheelset, but don't like the 9 speed only hub for belt drive also.

Thanks for the great write-up, E
 

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trail rat
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KrisRayner said:
Informative post. What about gear ratios? Is there much adjustment to, say, drop or increase a couple teeth on the rear, or would that require a different belt?
This may or may not help, from this thread. It may be way more than you wanted to know. :D

See this thread as well.
 

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skillz to pay billz
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racerdave said:
Anyone? I don't think anyone answered this yet. Please? :D

I'm interested in the belt setup... not sure how to make it work easily on a SS with "regular" chainstays/seatstays, but interested nonetheless.
swapping a cog for a slightly smaller or larger shouldn't be a problem if you have room to move your wheel forward or back in a horz dropout.
 

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nOOby said:
swapping a cog for a slightly smaller or larger shouldn't be a problem if you have room to move your wheel forward or back in a horz dropout.
The problem is the cogs are only available in 4 tooth increments, so the change is substantial.

Mark
 

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skillz to pay billz
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not so much when you look at the size of the cogs(more) and teeth of the belt(smaller interval). Definitely not one to one to a chain set up.

also the question was whether a diff. belt was required to make small changes in the cog size. Not really unless you don't have a horz. dropout.
 
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