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Downtube folding bike

Old 11-23-06, 11:39 AM
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Originally Posted by SesameCrunch
Barney: Did you ever resolve this chain drop problem? I have the same issue right now. I think my chainline is good. I'm wondering if it's a loose chain.
hi SesameCrunch, sorry to report that i never found out what caused it - it just stopped doing it, which is great but i don't know why. i actually seem to have some wobble in the chain ring which i guess maybe related, i plan to have this sorted out soon.

i commute 12 miles a day and it would happen 2/3 times a day, then it just stopped.

sorry i can't be much help, maybe your problem will disappear too.

barney
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Old 11-23-06, 03:05 PM
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Originally Posted by barneybarney
hi SesameCrunch, sorry to report that i never found out what caused it - it just stopped doing it, which is great but i don't know why. i actually seem to have some wobble in the chain ring which i guess maybe related, i plan to have this sorted out soon.

i commute 12 miles a day and it would happen 2/3 times a day, then it just stopped.

sorry i can't be much help, maybe your problem will disappear too.

barney
A front derailleur will probably solve the problem. But so will a chainguard. You can chuck that small chainring and use the extra space to install one. I'm experimenting with plastic thingys to hold the chain in place. Will post on that soon.

That is a great looking bike!
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Old 11-23-06, 10:32 PM
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Originally Posted by pm124
A front derailleur will probably solve the problem. But so will a chainguard. You can chuck that small chainring and use the extra space to install one. I'm experimenting with plastic thingys to hold the chain in place. Will post on that soon.
Great idea! I guess I could go to TAP plastics and have them cut a couple of clear acrylic rings with drill holes for the bolts. Hmmm... Do let us know what you come up with also.

Originally Posted by pm124
That is a great looking bike!
I'm very pleased with the way it turned out. I'm new to folders and it's just a blast! I've virtually rebuilt both of the DT's I just got. The silver one rolls pretty smooth. Other than the ribbing from my friends (e.g. "Hey doughnut boy!" or "What'd you do, put your bike in the dryer?" or "In this cold weather, everything shrinks ." ), the bike is very enjoyable to ride. Oh yeah, and the best part is passing people on them small wheels. I'm planning on doing a century with it some time soon. Will post a ride report.
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Old 11-23-06, 10:36 PM
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Originally Posted by barneybarney
hi SesameCrunch, sorry to report that i never found out what caused it - it just stopped doing it, which is great but i don't know why. i actually seem to have some wobble in the chain ring which i guess maybe related, i plan to have this sorted out soon.

i commute 12 miles a day and it would happen 2/3 times a day, then it just stopped.

sorry i can't be much help, maybe your problem will disappear too.

barney
Your experience probably jives with what Morgan said about dry lubes. New chains have that factory coating which is real slippery. Over time that probably wore off and your chain became less slick and the chain drop stopped.

I plan to go fast on this bike, so I want to be confident about it not dropping. I think I'll try pm124's idea of a chainguard. Should be cheap and easy. I'll let you know what happens.
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Old 11-24-06, 01:53 PM
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Originally Posted by SesameCrunch
Your experience probably jives with what Morgan said about dry lubes. New chains have that factory coating which is real slippery. Over time that probably wore off and your chain became less slick and the chain drop stopped.

I plan to go fast on this bike, so I want to be confident about it not dropping. I think I'll try pm124's idea of a chainguard. Should be cheap and easy. I'll let you know what happens.

hi there - rohloff do something: https://www.rohloff.de/en/products/sp..._cc/index.html
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Old 11-24-06, 04:26 PM
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Originally Posted by SesameCrunch
Great idea! I guess I could go to TAP plastics and have them cut a couple of clear acrylic rings with drill holes for the bolts. Hmmm... Do let us know what you come up with also.


I'm very pleased with the way it turned out. I'm new to folders and it's just a blast! I've virtually rebuilt both of the DT's I just got. The silver one rolls pretty smooth. Other than the ribbing from my friends (e.g. "Hey doughnut boy!" or "What'd you do, put your bike in the dryer?" or "In this cold weather, everything shrinks ." ), the bike is very enjoyable to ride. Oh yeah, and the best part is passing people on them small wheels. I'm planning on doing a century with it some time soon. Will post a ride report.
It really is a dream bike. You'll have the last laugh when you go for coffee and bring your bike in the shop. I sold my Kryptonite along with my full size bike. Let's see...20 pound bike plus 20 pound chain or a 20 pound bike and no chain, hmmm. The kicker is that the world speed record on an upright was set on a 20" bike. The frame is nice and stiff, no redundencies, and it's light.

Yes, I would shoot for my own solution to the chainguard thing. The stock one at Performance bike is outrageously priced and is 70 grams. The 105 chainring that I have on my Birdy has holes drilled in it that would allow one to be mounted.
Dahon puts a little plastic thingy on the seatpost that approximates the ring on the inside and a chainring on the outside. I'll take a picture when I get a chance, and post it along with my improvised ring.

Garlean puts a big funky looking orange roller over the chainring on his bikes (https://www.gaerlan.com/dahon/dahon.htm).

Finally, you can see if the plastic rings from your defunct cranks fit into the drillouts in the FSA chainring (are those drillouts?). The chainring on your wife's bike is just like the one I have on my NS.

Last edited by pm124; 11-24-06 at 04:39 PM.
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Old 11-24-06, 06:14 PM
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CE,
Yan offers a 30 day satisfaction guarantee.
If you don't like it, you're only out the shipping.
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Old 11-24-06, 07:26 PM
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SesameCrunch - one of the reasons modern bikes shift well is they have teeth on the cogs and chainrings that have been cut down to make it easy for the chain to come off for faster shifts under power. A side effect is that on a bike with no front derailleur you have a natural spot for the chain to fall off. You also have a 9-speed cassette which both means a wide side-to-side flex in the chain as you go from one extreme to the other. Cures include keeping chain tension fairly high by making your chain no longer than it needs to be, but the dummy front derailler or plastic roller (modify a skate wheel if you're cheap) work the best. You really don't want the chain falling off at even moderate speeds. You could try and find an older chainring without the pins and ramps of modern ones, but it would be a bit wide for the nine speed chain.

The plastic and metal rings that can be bolted to your chainring don't always keep the chain from falling off. They do keep it from falling off the crankset and keep the loose chain from going into your back wheel, but you may just wedge your chain between the ring and the guard. That is why the derailleur approach tends to work better.

I like your modifications and will be making similar ones soon when my VIIH gets here. It will be my first new folder in about 30 years! Last one died after damage to the crank and chainring by the airlines...
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Old 11-25-06, 03:39 PM
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Originally Posted by Pine Cone
SesameCrunch - one of the reasons modern bikes shift well is they have teeth on the cogs and chainrings that have been cut down to make it easy for the chain to come off for faster shifts under power. A side effect is that on a bike with no front derailleur you have a natural spot for the chain to fall off. You also have a 9-speed cassette which both means a wide side-to-side flex in the chain as you go from one extreme to the other. Cures include keeping chain tension fairly high by making your chain no longer than it needs to be, but the dummy front derailler or plastic roller (modify a skate wheel if you're cheap) work the best. You really don't want the chain falling off at even moderate speeds. You could try and find an older chainring without the pins and ramps of modern ones, but it would be a bit wide for the nine speed chain.

The plastic and metal rings that can be bolted to your chainring don't always keep the chain from falling off. They do keep it from falling off the crankset and keep the loose chain from going into your back wheel, but you may just wedge your chain between the ring and the guard. That is why the derailleur approach tends to work better.

I like your modifications and will be making similar ones soon when my VIIH gets here. It will be my first new folder in about 30 years! Last one died after damage to the crank and chainring by the airlines...
Thanks for the advice. It's back to the drawing board and eBay to hunt for a front derailleur. The seat tube seems to be a standard size so I should be able to find one.

Good luck on your VIIIH. I debated a long time between the hub gear and derailleurs. I chose derailleurs because I knew I wanted to tinker with the bike. Heck, it's part of the fun. I am probably going to get the VIIIH for my mother-in-law, who drives a VW convertible (at my recommendation). A decent riding folder would be just the ticket for her given the small trunk and back seat.
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Old 11-25-06, 06:43 PM
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Are there any new models coming soon?
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Old 11-25-06, 06:53 PM
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Hi all,
Just thought I'd chime in, too. The whole chain drop thing is a problem with folders in general. There is a scientific reason for this, but can't remember off hand what it is. My problem was fixed as soon as I installed a front derailler.
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Old 11-25-06, 07:32 PM
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Originally Posted by Vector
Are there any new models coming soon?
We are rolling over our 2006.5 bikes as 2007's. We will introduce 2007.5 bikes in June and they will roll over as 2008's.

Thanks,
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Old 11-26-06, 04:33 PM
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Originally Posted by downtube
We are rolling over our 2006.5 bikes as 2007's. We will introduce 2007.5 bikes in June and they will roll over as 2008's.

Thanks,
Yan

Would you be willing to share with us some of the changes you're considering with the next generation of downtubes?
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Old 11-26-06, 06:02 PM
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I would love to see a slightly lower bottom bracket and a slight change in frame geometry such that the weird coat hanger thing-o on the bottom can come off and the bottom of the seat tube can take its place.

It would also be great to see a latch to hold it together. Some simple snapping mechanism. My bungee chord has already been eaten through. (I use Velcro where the QR handles approximate, but this doesn't work well.)

I love the NS, though. (OK, it's not mine, but I ride my girlfriend's all the time.)

Oh, one other thing. The wires that hold the fenders on rust. So, I just keep it lubricated. But it would be great to change it to alloy or painted unless those are OEMs and can't be changed.
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Old 11-26-06, 06:14 PM
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Originally Posted by pm124
I would love to see a slightly lower bottom bracket and a slight change in frame geometry such that the weird coat hanger thing-o on the bottom can come off and the bottom of the seat tube can take its place.
Noooooooooooo!! The 'weird coat hanger' is so much better since many times I don't have to adjust the seat - that way it will rest on that instead of the chain ring.

It would also be great to see a latch to hold it together. Some simple snapping mechanism. My bungee chord has already been eaten through. (I use Velcro where the QR handles approximate, but this doesn't work well.)
I'm actually playing around with magnets for a make-shift fix for that - will post when I get it working right!

Good to know about the fender braces!

I just put on a Suntour shifter instead of the grip shifter. Ahhhhhhhhhh It's not indexed but I find it much easier and quicker to shift. I know some people love the grip shifters but I never did - back when they were in fashion, out, and now back in!

I also seem to remember that Yan mentioned a few pages back that they won't comment on the newer versions until they're out.
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Last edited by Air; 11-26-06 at 06:29 PM.
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Old 11-26-06, 06:35 PM
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Originally Posted by JosephLMonti
Would you be willing to share with us some of the changes you're considering with the next generation of downtubes?
I can not comment on future changes at this time.

Sorry,
Yan
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Old 11-28-06, 08:51 AM
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Hey everyone, and especially Yan. It would be good for some to make a back up of this Downtube thread. Periodically, entire threads get erased here (as happened last night during server problems). It would be a shame to lose this knowledge base about the Downtube.
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Old 11-28-06, 10:26 AM
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Old 11-28-06, 01:42 PM
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Hello everybody

Hope I haven't posted this in the wrong place.

New to folders but have been a keen cyclist for nearly thirty years. Commuting, touring, bit of racing, all on road bikes. I do own a mountain bike but it never leaves the tarmac.
I'm based in Wales, UK but travel to Lithuania about every two months. I have decided to get a DT so I can take a bike with me on the flight to use as transport when I am there. (apart from some of the winter months when it's just too damn cold!)
I have ordered a 8 speed V111 NS and am eagerly awaiting delivery.
I have found this forum to be a mine of information and accordingly the decision to get a DT was an easy one. I just need the time now to go back over the previous threads in order that I don't start asking questions that have already been dealt with.
When not in Lithuania I plan to use the bike daily. Although I am a keen motorcyclist (Suzuki Vstrom 1000) and also have a Merc Vito, I do like the concept of existing car-free (and have done so in the past) as much as possible, so I'm anticipating racking some miles on the bike. Already thinking of possible upgrades (it's very hilly around here).

One question and apologies if this has been dealt with already. I'm assuming the V111NS has vertical rear dropouts. Has it ?
If so, has anyone modified their V111NS to take hub gears and if so how have you overcome the chain tension problem ?

Cheers

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Old 11-28-06, 03:07 PM
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Originally Posted by downtube
I can not comment on future changes at this time.

Sorry,
Yan

That is completely understandable, afterall, it's only November and the next DTs are not due out until June. However, I do have a question about the current line up: why does the NS lack the support tube (running from the bottom bracket to the main tube) that is featured on all of the other DT models? Does it have to do with the NS using a rigid fork?
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Old 11-28-06, 05:46 PM
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Originally Posted by JosephLMonti
That is completely understandable, afterall, it's only November and the next DTs are not due out until June. However, I do have a question about the current line up: why does the NS lack the support tube (running from the bottom bracket to the main tube) that is featured on all of the other DT models? Does it have to do with the NS using a rigid fork?
The NS is our lightweight model, hence we use our lightest frame with the lightest fork.

Thanks,
Yan
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Old 11-28-06, 05:52 PM
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YAN - will you please confirm the size of the BB on the Mini?

Thanks!
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Old 11-30-06, 02:34 PM
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Originally Posted by Polaris43
YAN - will you please confirm the size of the BB on the Mini?

Thanks!
I spec'd it with 113mm, however the factory used 114mm spindles on at least one shipment....due to supply chain issues.

Thanks,
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Old 11-30-06, 02:43 PM
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Originally Posted by downtube
I spec'd it with 113mm, however the factory used 114mm spindles on at least one shipment....due to supply chain issues.

Thanks,
Yan

So will a 115 mm work as well or will there be a fit problem?
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Old 11-30-06, 02:52 PM
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Originally Posted by Polaris43
So will a 115 mm work as well or will there be a fit problem?
It should be fine.... however one must keep q-factor in mind when talking about any bicycle fitting.

Thanks,
Yan
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