BruceMetras

You also need a very straight belt line and your axles have to be parallel otherwise the belt will want to wander off the cogs, or wear the edges where it comes in contact with any type of retention.. belts are also adverse to razor blades, nicks, abrasions, and pebbles getting sandwiched between belt and cogs .. you have to plan ahead carefully for bb/rear axle center to center distance to make a selection of belt length and cogs/sprockets as the final gear ratio you might desire may not be available to you with off the shelf parts, as selection is somewhat limited (especially retrofitting small wheel bikes from chain drive) ..

Beyond that, there is the decision to either go 8mm pitch belts/cogs/sprockets (what I have done) or the more robust, and much more expensive 11mm pitch products currently available through Gates ..

All that said, I have two belt drive bikes that I ride regularly, a TSR-2 retrofitted with a SRAM P-5 hub, and a Dahon Mu Uno retrofitted with a two speed SRAM Automatix and converted to belt drive.. neither have given me any problems through the years, but it's all been street riding in good weather .. I'm contemplating a third build with a rear triangle designed to allow a belt, but am vacillating between belt and chain drive..

fietsbob

Even more money, but I read Swiss Engineer production Machine shop operator Florian Schlumpf (of the Speed/MTN drive crank company ),

has cog wheels for the belts that will clear out debris under the belt-bumps, like (I assume) , snow and dirt

BruceMetras

In addition, if you have rear suspension, you want a unified rear triangle so that belt tension doesn't change with suspension movement.. and in some cases, I've heard that belts sometimes squeak, or groan in use, defeating one of the major belt drive advantages I see, a near silent drivetrain..

mconlonx

Playing with gear ratios. Belt length and cog sizes are extremely limited; chain and cog sizes are virtually unlimited.

Noise. Not so much an issue with the newer Gates CenterTrack setup, but on the older flanged version, many people got a squeak and making it silent was always a PITA trial and error affair in tension adjustment between each side of the rear dropout tensioners.

Belt line. Need to get the belt line nearly perfect. Not as forgiving as a chain is regarding chainline from front to rear cog. And considering the width of the cogs vs. chain cogs or chainrings, tolerance, especially front cog to chainstay becomes and issue in trying to get the beltline correct.

Tension. Belt needs to be in tension to work correctly. Too loose and you get skipping, too tight and you get resistance. But because the drive side is always in tension, usually frame design has to accommodate by being beefier on that side. There are those who claim they can pull their belt system tight in a bike with horizontal dropouts, but I don't believe them, and without tensioners on both sides at the dropouts or some kind of snubber with screw adjustable tensioning, tension and alignment (noise) will be an issue.

Belt means there needs to be a break in the frame -- not an issue on elevated chainstay models like the Mu and many other folders, but on other bikes there is usually a break in the rear triangle somewhere, generally along the seatstay or at the dropout. Trek went through three different designs on their District model before dumping belt drive altogether. That break introduces a new complication, weight, and the potential for mystery frame noise.

Cost. You will pay about a $250 premium for belt over the same bike with chain setup. Might be worth it for something which was miles better than what it's replacing, but I obviously don't see it, chain vs. belt drive.

Availability. If something catastrophic happens to your chain, you get down to the LBS for a new one, same day. If the same happens with your belt or a cog, you'll be waiting days+ for replacement parts. There was an issue with aluminum 3 spline Sturmey Archer style cogs stripping the teeth and the fix is a steel replacement cog at substantial weight gain.

Now. All this said, you might thing I'm not a fan of belt drive, but you would be wrong. Silent, maintenance free once set up correctly, clean, strong. Lots to like. I just personally don't think the benefits outweigh the current drawbacks at the premium over a chain setup.

Snow accumulation is less of an issue with the centertrack design, so that's been dealt with by Gates. I wouldn't hesitate to stand up and really jump on the pedals of a belt drive bike as long as it is properly tensioned -- belt is certainly strong enough.

tcs

Bicycle shaft drive was big (in the USA), oh, around 110 years ago. It had really become a historical footnote until just the last few years, when a modern implementation began a very modest comeback, making inroads in worldwide rental bike (a.k.a. bike share) fleets.

tcs

Continental has announced a competitor belt drive system. Looks good in their marketing literature, never seen one, don't know where to buy the components &etc.

BruceMetras

Max front 50t ... smallest rear 20t 2.5:1 ratio .. problem for small wheel bikes and gearing that would like to approach 90 g/i , unless using an all overdrive hub like the Sturmey (X-RF8 W)..

tcs

The XRF8W fits a unique cog, not the std. three tab.

BruceMetras

And therein lies the rub .. you'd probably have to modify a SRAM G8 cog or similar ..

mconlonx

Y'all aren't advocating belt drive here...

fietsbob

Yea they are bigger Inside .. no smaller than 19t, regular AW3 cogs go down to 13t

martinus

I love this thread ... Quick question for the OP, do you have the means to test ride the bikes you are considering ? ... or do you base all your decisions on on line reviews ?

PS: I sometimes get caught in the rain & noticed that gray stuff that ends up all over my bike... I'm sure if it had a belt, it too would get dirty...
PSS: Check the fat bike forums, some guys are having bad luck with their belts ( breaking )...usually from sand building up between the cog and belt. ( one member even tried to make a "chain guard" to keep the sand from the rear tire, falling right on the belt. )

Good luck with your search .

fsir

I'm presuming you want gears for when you hit inclines. Instead of an internal hub, why not try to find the lightest electric motor for a bicycle?

I found this with a quick search:

https://transportevolved.com/2014/05...ghtest-market/

fwd-bwd

Late to the thread.

Montague announced a belt drive model not too long ago. It probably will become available in 2015: https://n2a.goexposoftware.com/events...2467568397.pdf

Bernds offers belt drive as an option but I don't know if you can buy one in the US: Innovations « Bernds Bikes ? Made in Germany

The now defunct Abio made a reasonably priced belt drive model. Try eBay and Craigslist to locate one. @SesameCrunch reviewed it: https://www.bikeforums.net/folding-bi...rime-time.html

Or you may convert a Brompton to belt drive: Belt-drive Brompton

washuai

What folds up better for a train than Brompton or BF tikit? Bromptons don't have belts of course. The train is why you're getting the suggestion. The more packed and less place for big bikes, luggage, or strollers that train has, the smaller you'll wish your bike folded.
Commute, performance, smaller, lighter, all this points to BF Tikit, Mezzo\Ori (belts?), Brompton (no belts), Strida (limited gearing).
Why do you want to stay away from 16" tires?
A tikit obviously can handle the gearing for the hills (like SF hills). In fact, they can handle touring, so they can handle "the full commute".
Can you test ride &\or rent for a hill length of ride challenge a Bike Friday Tikit?

The Silk suggest this isn't about touring, mountain biking, off roading, pot holes from hell, comfort concerns. Concerns that legitimize wanting larger wheels. A thudbuster isn't cheap, but it will still help a lot with comfort and doesn't care what size your wheels are.

The only thing limiting my 16" is what I'm personally capable of, USA location & I haven't upgraded the IGH. I can't throw on Big Apples, because even though Schwalbe makes them, they're too fat for my frame, but I can throw on a thud buster and scorchers. Ok, and it doesn't fold as quick or easy as the tikit or the Brompton.

tmac100

TOTALLY ticked at my SA-8. On my custom built "folder" with 20" wheels, called my Arvon2 (hello sixty-fiver) the SA-8 lasted not even 40 km (you do the math, my USA-based readers and friends).

I am sitting with a useless rear wheel - OK, OK, it turns round and round, and works in some of the gears, BUT it does NOT SHIFT reliably - and will hopefully get it repaired/replaced by SA in Canada during my Christmas break.

BUT, I am seriously looking at the Rohloff and the various ways to route/attach cables to this folder-disassemblable Arvon2.

No longer trusting the SA-8. The failure totally screwed up my Australian bike tour. And whet did the Australian SA mechanics say??

"... nurture it..."
".... we have not had good success with the SA-8..."
"... we could sell you a Shimano IGH ...
Bummer with this particular SA-8. Sheldon Brown's web site says "reliability has improved". NOT!!


Rant mode now off as I head to Kolkata on Thursday to spend time there and buy a Hero 28" wheeled single speed with "kick stand" etc ....

Jet Plus Gold 28T| Hero Cycles|India's Largest Cycle Manufacturer

The 70+ or 80+ bucks is what I call "beer money". The locals need to work MONTHS and more to pay for one. As for RT airfare?? Look at several $K bucks. Don't even start on their price (in India) and their reliability. Probably similar to my single speed 1957 CCM (I am a Canuck) single-speed. The wheels look identical, but NO coaster brakes!

fietsbob

What I actually own is a Rohloff-Bi-Fri , External shift ,, 2 cables run the length of the bike..
box separates at the hub , So in knock down, the whole cable assembly would coil up as one..

bike.gang.uk

Tikit with belt drive and disk brake.

Winfried

This one?

"Silk 8sp w/Carbon Belt drive"
https://www.bikefriday.com/bicycles/..._itikitsi/1445

smallwheeler

that's it, baby.

MAK

As for the Downtube, I did an admittedly quick Google search and found the company website, but could not find any recent reviews, photos of it folded, or videos of the folding process.

At the bottom of the response regarding the Downtube is a hot link to the bike and site. There are pictures.

The bike looks very interesting. I'm going to start a thread to request opinions and experiences with Downtube.

dezzie

Folding Style ©: Electrolyte Kosmopolit Mini Velo Series

downtube

We transferred our site a little more than a week ago. I will try to upload videos in the next couple days.

Thanks,
Yan

mconlonx

Looks much better!

downtube

Thanks we are still working on it. I hope the development will be completed in a month.

Thanks again,
Yan