Shilun

I'm really curious about these. Have you actually tried them out? Is it as easy to shift as the website suggests? If so, it seems like a perfect (though expensive) solution for Folders, being able to get rid of the cables, and only needing a single chainring. If you're able to take a picture of the conversion once it's done, it would be great to see.

Shilun

14R 

Are you considering a triple front chan ring for your Halfway RS? Please let me know if this is possible. Maybe it's even cheaper than the hub option.

Rafael

Rincewind8

A not ideal but pretty cheap option would be to change the crank set to a (used to make it cheaper) dual chain ring crank set and "shift" by hand. Since you already mentioned that you think it is a little undergeared, you could use a little larger chain ring as your usual chain ring with which you still can tackle short inclines. If however you encounter a long incline you could stop and "shift" to the climbing chain ring.
I changed the crank set to a dual crankset, but never used the small chain ring. I mainly wanted a bigger front chain ring and haven't taken of the small front chain ring because the crank bolts would be too long to just attach one chain ring to the crank.

v1nce

@ Rafael. i don't own a Halfway...? Just my Twenty. And i really have not inkling of a clue whether what i want to try someday works.

As for "manual shifitng" on a dual chain ring.. That does mean a derrallieur in the back i presume, otherwise don't you totally mess with your chain tension?

14R 

@Wind8: I actually managed to switch from big chainring to small chainring using my food against the wheel in a competition before!

@V1nce: Sorry vince, I mixed your post with Shilun's, the other guy from this forum that has a halfway RS. My bad!

So far, as soon as I get back from Brazil, my options are The Dual Drive 3spd hub and Shimanos 7 or 8 speed similar.

Rafael

v1nce

That Speeddrive seems intriguing. Anyone know what kind of durability we are talking about? Also will it work with odd brackets such as the 26 TPI (rather than 24) BB shell in a Raleigh Twenty. To get a good range one must still combine the SpeedDrive with a 3 (or more) speed hub correct?

BruceMetras

I have one on a Dahon Helios XX.. I like it so much another is going on an XP.. You see them used on Recumbents and HPVs. They can be installed on steel or aluminum bottom brackets of 67-73mm widths and 33.6-34.5mm diameters. It's appears to be made really well, uses standard 110mm chainrings, and I haven't had any problems. It shifts very easily, and there are flat 'extenders' available cheap that run along the crank arm if you want it even easier. For a folder, you'd want the 'SpeedDrive' with a 1.6:1 overdrive or possibly the 'High Speed Drive" with a 2.5:1 overdrive. A 'Mountain Drive' is available, but that is a 2.5:1 underdrive. Attached are a couple of quickie pics.

Bruce

jasong

Yan, any ideas on where to find a 550mm 27.2 seatpost for the Downtube? Would a design be possible that's similar to the other telescoping models out there, so that the seatpost could be dropped all the way down and not protrude too high from the folded frame?

Or is there such a thing as an adapter onto which the seat could sit to give it a bit more height? It would have rails like a normal seat, be grabbed by the clamps on the normal seatpost, and then have clamps for the desired saddle.

Thanks,

Shilun

Thanks for the pictures. What range of gearing does that give you? [Could you use inches as I'm a little behind the times on these kind of things]

Shilun

BruceMetras

As an example, using a 490mm wheel, 44t chainring, 11-34 cassette, you would get a 509% overall range with 24 to 127 gear inches.... that's huge! About the same as a Rohloff hub or a SRAM Dual Drive. Personally, I reduce the cassette range and would jockey the chainring number to get me closer to 115 gear inches at the top.

Bruce

14R 

Bruce,

It seems that you had access to a lot of different things, so le me ask you this:

Comparing the Sram dual drive with not having anything at all (besides a rear derailleur), what is your opinion about the "dragging" factor?

I read several threads after a search in these forums and, so far, there are a few comments like "it feels like there is a full bottle of water inside my wheel" or "I will never have gear hubs again".

The main reason I started investing on upgrades is a (now gone) "dragging" feeling that I was having, mainly due to por psi and low gear range. Would be horrible to compromise the almost perfect situation that I have now with another high investment.

Still on the same topic, how much would cost the entire SRAM Dual drive mod? (derailleur, cassete, hub, shifter and instalation). Just to have an idea...

Rafael

14R 

Bump

Bruce: is US$340.00 for dual drive system (SRAM 3x9 + Megarange Cassette + shifter + Box +megarange compatible derailleur) fully installed a decent price?

My roomate got his Downtube FS today by the way...I'll see if I can put some miles on it tomorrow but so far it is a confortable ride! May get one for me.

Rafael.

BruceMetras

Sure, if all parts are new....a new wheel has to be built, so a few hours could be tied up with the whole installation..

Nice way to go, DualDrive's are really a top choice for extending gear range on small wheeled bikes, and I certainly like the one on my SpeedPro.

One cheap way (not going the used route) is to increase the chainring ($32)... I just put a 58t on my Swift to compliment the 9spd 11-34 cassette... this effectively gives me a 10t top gear (approx 105 gear inch) and is just right for me for pedaling at 30mph (conditions optimum) and this change only went from a 30" to 32" on the bottom (where I don't spend much time)..

Bruce

14R 

Thank you. I got 54T on the front and anything bigger than that will turn my "sidewalk climbing habits" into something that I need to pay more attention than I desire.

Can't wait to have it installed. Now it's time for a downtube ride.

Once again, thank you.

Rafael

downtube

I am sorry my supplier is unable to get 550mm posts. I am trying to source them, however it is difficult.

Thanks,
yan

downtube

Bruce,

Bike looks awsome!!! Tell me if you didn't get the shims.

Thanks,
Yan

downtube

Thanks for the words of encouragement!!!!

We will never change our philosophy. I own the Downtube and will never sell it....I am not doing this for the money (I teach full time at Coker College in Hartsville, SC). I created the company to help make society more efficient. Thus far I am happy with our progress, and I hope our future will be a bright one. I am currently writing a book defining our business model with a basic implementation. I hope others will carry our ideas to other markets.....we'll see

Thanks,
Yan

BruceMetras

Hi Yan!..not only is it looking good, but it is performing even better!!... latest mod was the addition of some MKS Q/R pedals and Powergrips.. this holiday weekend saw my White FS and my girlfriend's Orange FS tossed in the trunk of my Alfa sedan for a 4day trip to the beaches and bike paths of central California.. both bikes worked great.. the Orange FS really got the positive comments and attention from the other bikers we came in contact with (maybe it was the blonde girlfriend) ...anyway, we were pretty conspicuous in parking lots with bikes hanging off racks and atop cars and there we were pulling two full suspension 8spd folders out of the trunk..haha...had to demo my bike more than once! Only glitch is my gf really, really liked my Nexus hub geared bike, now I may have to build another wheel....

And yes, the parts came in!! Thanks so much!

Bruce

downtube

FYI I will have some Sturmey Archer internal 8sp bikes next year...thanks for the idea!

Yan

jasong

Yan, if you're taking requests for bike features, I'd like to see something that folds really small, ala Brompton, and still uses off the shelf parts, and has the value you've integrated into the Downtube. That would be the market killer.

14R 

Yan,

Do you have the rear rack for the full Suspension bike Available? Pictures?

I need 2 of those ASAP (going to Brazil December 19th).

v1nce

@ Yan. It would be cool if you could look into the S-Ram 7 speed hub rather than the Shimano 8 Speed.

Reasons (most subject to debate of course so guys please correct when i am wrong):

1. The S-ram may have one gear less but i gather the range is considerably greater despite this.

2. If have understood from various LBS shops i trust that the Shimano is very very complicated to repair (impossible for the person tinkering at home) and that if you want replacement parts Shimano doesn't sell little seperate parts. They only sell entire hubs or 3 or four different assemblies/units each one being about half the price of an entire new hub! Now it it true that with a little care and luck hubs rarely need service. But the contrast with the S-Ram is great, according to the LBS (and they actually sell way more Shimano units) the S-Ram can be fixed almost with your eyes closed, the parts are available seperately and affordable.

3. I think the S-Ram is (a lot) cheaper. Also Shimano is a mega-corporation while S-Ram is kindoff a old timer that got nearly wiped out but now is an upstart that is taking on the giant shimano. I like their innovation and prices. Lastly i understand from many Shimano users (even fans) that over the years Shimano's quality has suffered. Mostly in derallieurs, they seem to have build in obsolesence. I could be wrong but i think Shimano now owns and produces Sturmey Archer 3 speed hubs and people say that the old hubs (before Shimano) are (much) better quality despite being the same design.

Lastly S-Ram is coming out with a 9 speed soon (heard this on these boards) which could be a good option too.

BruceMetras

Yo Vince, good points. here's some more observations.

Yan mentioned using the Sturmey 8spd, not the Shimano on selected Downtube bikes.

The gear range of the new Shimano Nexus 8 is 307%....the SRAM 7 is 303%... the Shimano obviously has a closer gear ratio spacing in addition to wider overall gear range.

The Nexus 8 is over 150g lighter than the SRAM 7

The Nexus (locally)with shifter is $46 (US) more than the SRAM 7

Sunrace has Sturmey now, not Shimano.

I don't know anything about the parts availability of either unit in the US because I haven't needed to find out yet. My Nexus unit is performing great, but anything could happen.

The SRAM unit also has an external 'click box' for shifting which protrudes beyond the dropouts and is potentially vulnerable to impacts... on my DualDrive, I haven't seen any problems with this, but I also don't go trailing with it (which I do with my Nexus 8 hubbed Downtube FS). The Shimano unit has all shifting mechanism within the rear dropouts.

I am looking forward to any new offering in the hubgear arena, the SRAM 9 looks interesting, but for now, I'm building a second wheel with the Shimano hub.

Bruce

downtube

We are working on it, no timetable yet.

Thanks,
Yan

downtube

I have chosen to go with a Sturmey Archer on the VIII bike. We will not have any FS internal hub bikes this year. My main reason for going with Sturmey Archer is:

1. 8sp
2. 305% gear ratio (303% SRAM )
3. Made by Sun Race a great fast growing company.
4. Price!

Thanks,
Yan