Folding Bikes - 9 speed on my dahon?

Hi all,

Trying to get my danon ready for lots of road riding this year and am up to gearing. At the moment I spin out at around 35 km/h as my 7 speed rear cartridge only goes down to a 14 tooth.

I bought a bling 28 hole cassette compatible rear hub and am trying to decide between 8 and 9 speed. I am pretty sure they get the additional ring in by reducing the spacing rather than increasing the cassette width, that's why you need a narrower chain for 9 speed. I think that means the maximum chain deflection or bend to reach the extreme rings will not change.

I currently run a 53 tooth front chain ring and am looking at going to an 11-28/30 rear cassette.

Is anyone running 9 speed on their folder? Any experience with chain breakage or excessive wear? Is it worth the extra effort to go 9 speed?

Cheers
Derek

Derek,
I am running 9 speeds on a Raleigh 20" wheel (non folding) bike. Chainwheel is 52T and cassette 11/32T.
Gives a top gear of 94 and bottom of 33.
The chain looks alarmingly out of line in the extreme ratios but runs remarkably well.
The rear mech is Shimano Deore and is on the limit for sideways movement, so alignment adjustment is critical.
Also the rear mech arm is quite close to the ground, so collects lots of dirt and is vunerable to damage on rough ground or dropping off kerbs.
Les

Les,

I am guessing you are running a long cage derailleur? How many kms have you clocked up on the setup? I am hoping to run a road or a short cage derailleur to avoid damage and dirt.

I got a set of 1 1/8 stelvios yesterday and what an amazind difference compared to the 1.5" kenda slicks I was running. Faster, more responsive and actually seems stickier with the new rubber. What are you running?

Derek

I use an 8 speed on my Swift, 52T + 11-32T. If pedalling downhill, I'd say I top out around 32mph. 8th gear gets a little bit of vibes.

You won't see a huge difference between 8 and 9 speeds; I'd decide based upon component compatibility first, quality second, cost third.

You may also want to talk to Gaerlan, they do lots of aftermarket Dahon mods and may have good components for you.

I modded a Yeah (rebadged licensed Dahon Helios) from 7 to 9 speed.

I run a 11-34 in the back on XT hub. You don't need a long cage derailer if you have a single chainring. You must have a chain guard because the chain jumps off easily. It works really great. It puzzles me why Dahon do not move to 9 speed on all their 8 speed bikes; it's not really more expensive.

As long as I get the 11 tooth sprocket I think I should be OK with either 8 or 9 speed, I have an old 8 speed grip shift to get me by until I track down a rear rapid fire shifter and I think the chain on my current 7 speed set up should work with 8 speed.

8 speed stuff seems to be a bit harder to track down than 9 speed though. Thought the chain bend might have been an issue with a single chain ring.

Derek

I run a 11-34 in the back on XT hub. You don't need a long cage derailer if you have a single chainring....
FYI, I believe 11-32's don't need a chain guard.

Also, SRAM makes a bunch of 8-speed gear, it should be a snap to pick up.

FYI, I believe 11-32's don't need a chain guard.

Also, SRAM makes a bunch of 8-speed gear, it should be a snap to pick up.
I have the SRAM X.7 9 speed drivetrain on my Downtube. 11x34 cassette, long cage derailleur with an FSA carbon crankset. Works very well, except that I had a chain drop problem until I install a front derailleur.

Any comments on using rapid fire instead of grip shift? Visited the greenspeed recumbent factory yesterday and one of the techies said to use rapid fire if I could for better shifting, the only disadvantage I can see is the breakability of the levers.

It was like being in aladins cave, so many little wheels, so many shiny bits :-) . They were putting together a couple of bromptons while I was there.

As mentioned earlier, you should check the Gaerlan site (http://gaerlan.com/). He modifies both the Speed and Helios P8s to 9 speed cassettes with dual drives. He has the specs of each on the site. He is also very helpful, if you have questions.

Any comments on using rapid fire instead of grip shift? Visited the greenspeed recumbent factory yesterday and one of the techies said to use rapid fire if I could for better shifting, the only disadvantage I can see is the breakability of the levers.

I much prefer the trigger shifters over the grip. Personal preference, I guess. The SRAM X.7 stuff is very good. Shifting up is excellent, shifting down is not as crisp (don't know why). I bought all the components on eBay, didn't cost an arm and a leg.

As for levers breaking - they're tucked in under the brake levers pretty well. I can't forsee a scenario where they'd get clipped. Here's a photo of my setup...
The shifters:
http://i39.photobucket.com/albums/e157/sesamecrunch/IMG_1282.jpg
The drivetrain:
http://i39.photobucket.com/albums/e157/sesamecrunch/IMG_1286.jpg
The bike:
http://i39.photobucket.com/albums/e157/sesamecrunch/IMG_1289.jpg

That is one sweet looking drive train, how do you find the bar ends?

I have a Dahon Mu C9 with the Capreo set. It has 9 gears with the smalled one being a 9 tooth. It rides really well.

That is one sweet looking drive train, how do you find the bar ends?
The barends are setup up that way to get a more aero position. I use this bike as a "portable roadie" and to go fast on. I use the barends to simulate the drops on a full size bike. Works well, but no brake access, so I have to treat them like aerobars.

I like the SRAM stuff, pretty good performance for the buck. The wheels make a huge difference, of course. Also, I've swapped out the suspension for for a straight one recently, just to get the bike lighter. It really rolls now, but I can sure feel the road ;)

SesameCrunch,

Do you have any trouble with you chain coming off? Mine has been giving me hell recently, I run without a chaing guard on the chain ring as well. Have tried all the rear deraillure adjustments I can think of, the only thing that works for me is to completely depower and pedal really slowly for that last down change.

I used to - until I installed a front derailleur. It's a function of the relatively short chainstay of a folding bike (compared with a regular sized bike). The FD was just enough to keep the chain from "bouncing" when I shifted (particularly at the small cogs in the rear). Now, no problems at all. I normally do 40 mile rides, pretty good speed, and no problem at all. I'm very happy.

Here's a previous post on the subject, including pictures (post #888 on the Downtube thread) http://www.bikeforums.net/showthread.php?t=122760&page=30

Good luck on it. I know how frustrating this problem is.