Folding Bikes - Downtube IXFS Ultegra? Why not?

Other posts have mentioned DT drivetrain shortcomings. I have a IXFS on the way and I also have Ultegra 9sp drivetrain parts from other bike projects: A triple crank-I've removed the inner & outer chainrings, leaving only the 40T middle. I also have a brand new 9sp 12-27T cassette, and a long cage XT RD. I'm thinking I might only need an Octalink BB, chain & shifter to make this work. I haven't worked out the gear inches yet but gearing should be close to what I'm accostomed to. I would think there'd be substantial weight savings too. Anyone think I'm crazy? I'm a 50+ rider and I don't do hills well: I'm thinking of using the 30T inner chainring and trying the FD thing with it. Thanks in advance.

I think if you check the thread on the Maunakea Bike (http://www.bikeforums.net/showthread.php?t=229066) you can get some pointers.

Speedo

I'm a 50+ rider and I don't do hills well

Oh, I'm a 50 y.o. rider who doesn't do hills well either. I can assure you that those low low gears you'll get with 20 inch wheels and a 30 tooth chain ring are pretty sweet! :)

Speedo

I'm thinking of using the 30T inner chainring and trying the FD thing with it.

You are not crazy.

What is the size of the seat tube? I have this recollection that it is not a standard size.

Anyone think I'm crazy?No!

If I had Ultegra parts laying around they would be used on some bike pretty soon...

If you are at all accustomed to road bike gearing, you probably don't need the 30T inner, but maybe a larger outer chain ring.

I have only a 56T chain ring in the front of my DT. With the stock cassette that is good enough even for steep and long climbs and sometimes in the flat I wish I had a larger one.

Sorry to tell you that you're not crazy.

I did something similar, putting SRAM X.7 drivetrain with FSA carbon cranks on my IXFS last year. I didn't use a front derailleur, instead just relying on a 11-32 cassette to give me the range with the 52t front crank. The seatpost will indeed accomodate a front derailleur, by the way. I also put on a set of Velocity wheels. The result was a "portable roadie". I routinely used it on my weekend rides. No problems keeping up, only noticeable difference was the heavier weight going up hills here in the SF Bay Area. Also, I was very impressed with the handlebars holding steady when I pulled on them.

I do ride pretty hard and I eventually swapped out the suspension fork for a rigid one.

Here are 2 pictures:

I
did something similar, putting SRAM X.7 drivetrain with FSA carbon cranks on my IXFS last year. I didn't use a front derailleur, instead just relying on a 11-32 cassette to give me the range with the 52t front crank.

By FS I'm referring to full suspension not front suspension. What rigid fork did you choose? It looks like the steertube setup is the same as my "FS". I chose the Full Suspension because the rear triangle appears it will pivot to fold up more compact with the removal of one of the two pins that fasten the rear shock. Easier suitcase fit. Are your bars stock and I assume you're using the SRAM casette too? Great bike! thanks!

I

By FS I'm referring to full suspension not front suspension. What rigid fork did you choose? It looks like the steertube setup is the same as my "FS". I chose the Full Suspension because the rear triangle appears it will pivot to fold up more compact with the removal of one of the two pins that fasten the rear shock. Easier suitcase fit. Are your bars stock and I assume you're using the SRAM casette too? Great bike! thanks!
Oops, my bad, got the nomenclature wrong. Anyway, same principle. Upgrading the drivetrain was absolutely worth it.

I swapped out a front fork from the DTNS bike. Bars were stock and yes, SRAM cassette.

jondubus, yes, after removal of a rear shock bolt, the swingarm pivots down until it hits the stand (the bent wire under the BB), but to gain a real improvement in folded size, you need to remove the stand to allow the swingarm to pivot more.

Upgrading the drivetrain was absolutely worth it.

Bike arrived late yesyerday, looked & rode pretty damn nice right out of the box, but I was able to do a very short ride only. I'm hoping to pick up some weight savings from the eventual drivetrain upgrade, especially if I stick to a single front chainring. The wide range of the stock Sunrace cassette (11-32T) is looking better all the time, but I'm thinking there could be benefits from my XT RD if it can work with the Sunrace cogs. Need more rides! Any other weight saving suggestions out there? Thanks for the great help!

but to gain a real improvement in folded size, you need to remove the stand to allow the swingarm to pivot more.
Maunakea, thanks for the great tip! It looks like a cutoff whell or maybe even a hacksaw will do the trick on the stand below the BB. I was wondering what the hell I was seeing in the pics! I'll wait till the 30 day return trial period is over, but bike has arrived and seems an obvious keeper thus far. Out of the box it is vastly superior to an older Dahon Bwalk D6 I rode briefly. Vastly superior in terms of stability, rideability, and of course, gearing. Thanks again. The cockpit on your bike is especially a thing of beauty.

Any other weight saving suggestions out there?

DT stock saddles are usually very heavy. That's the biggest bang for the buck weight savings I can think of. If you have money to spend, then wheels, tires. Finally, if you don't need to fold the handlebars, the bar post weighs about 2+ lbs.

upgrade, especially if I stick to a single front chainring. The wide range of the stock Sunrace cassette (11-32T) is looking better all the time, but I'm thinking there could be benefits from my XT

Please post your experience with the removal of your bottom bracket and/or attempt at installing a new one..

I wouldn't say you're "nuts" per se, but it does seem to me like you're overthinking things a little bit.

Although the DT uses a lot of no-name parts, as long as the stock components actually work properly, I don't see much reason to swap everything out. If the gearing isn't low enough, for example, you can just get a standard 42T chainring -- $20 or so? That's all you need.

I'd keep the Ultegra parts handy either for another bike, or as spares in case something breaks.

I'm a 50+ rider and I don't do hills well: I'm thinking of using the 30T inner chainring and trying the FD thing with it. Thanks in advance.

I'm 50+ rider and love my Dahon D7. Nothing wrong at all being 50 and on the saddle of a folding bike. I get curious looks from other cyclist when I pass them and see that I am on 20" bicycle.

jondubus, if you are ever in the Islands, let me know. Riding the Mauna Kea bike back to back with a Swift is great fun .... sort of like two delicious strains of mangos with flavor differences that are hard to articulate. (There are mango factions in Hawaii, similar to BBQ factions in TX and NC.)

The biggest weight savings on an FS is also the most challenging. The steel quill/hinge is the heaviest part of the FS, heavier than the frame. In changing it out, you get a real plus, though... a threadless headset with XXX-rated sus forks .

If you only make one upgrade, I would change the BB. The other parts are much improved compared with '06 FS and earlier ... but the later bikes have a larger seattube, making a FD more difficult.

Riding the Mauna Kea bike back to back with a Swift is great fun .... sort of like two delicious strains of mangos with flavor differences that are hard to articulate. (There are mango factions in Hawaii, similar to BBQ factions in TX and NC.)

Wife spent 10 days on Kauai just this past March-didn't take ME-I literally had to mind the store (deli&wine:now you will know why I don't do hills well). I'd forgotten I rode a Swift at Trophy Bikes in Philly last year and loved it. Love your Mango & BBQ analogy applied to these bikes. In France, fist fights have broken out as to whether lobster should/not go into Bouilliabaise. Aloha. I'll be right over.

I wouldn't say you're "nuts" per se, but it does seem to me like you're overthinking things a little bit.

Bacciagalupe, your point is well taken. My name is jondubus and I too, am a bikeaholic. It may be I only want to change out a chainring and/or BB, but this thread has been much fun to look at all the possibilities and the interesting things people have done with their DT's. I too, have the "DT's" Thanks for your perspective.

jondubus, I say go for the drivetrain upgrade. You may not get a huge weight savings, but it will be smooth as butter and there is a certain bling factor involved. :) I am also planning a drivetrain switch from a sram dual drive to a Shimano 105 drivetrain on my Raleigh Twenty. I have to save money, though, because I would like to purchase a Velocity Thracian wheelset that will cut serious weight off the bike as well as be a serious upgrade in hub quality. I just saw a Thracian wheelset in person on a super fast lowrider recumbent and they look awesome. Although we are talking 2 completely different bikes ( between my folder and his need-for-speed recumbent ), I talked to the rider and he told me he had an actual increase in speed of 1 to 1.5mph after changing out his wheelset (to the Thracians). All of his friends thought he must have been putting extra training in, but he said the only difference was the wheels.

Juan

I have to save money, though, because I would like to purchase a Velocity Thracian wheelset that will cut serious weight off the bike as well as be a serious upgrade in hub quality. I just saw a Thracian wheelset in person on a super fast lowrider recumbent and they look awesome. Although we are talking 2 completely different bikes ( between my folder and his need-for-speed recumbent ), I talked to the rider and he told me he had an actual increase in speed of 1 to 1.5mph after changing out his wheelset (to the Thracians). All of his friends thought he must have been putting extra training in, but he said the only difference was the wheels.

JuanJuan,

I built a wheelset for my Swift, using the same rims (Velocity Aeroheat), American Classic hubs and 15g spokes from Gaerlan. I was able to get separate hubs off ebay, 2nd hand, but the front unused, the back with new bearings. I think my wheelset is a fair bit lighter than the Velocity Thracians, plus the 15g spoke are a better option for the small wheels, plus the Am Cl hubs are unequalled, perhaps?

The reason I am piping up here is you may be better served by going this route, money-wise, especially if you build your own.