lelandj

I purchased a Dahon Speed TR from "Brands Cycle and Fitness" not long ago. While riding into a strong headwind this morning, I shifted into a lower gear and my pedals went limp. I stop the bike and upon inspection found that the chain had come off the chainring.

The Speed TR comes with inner and outer chainguards which protect the chain that rides on the teeth of the chainring. I also found that the inner chainguard had broken lose from the five nuts and bolts that attached it. The chainguards are circular in shape, made of plastic, and have a diameter just larger that the chainring on which the chain fits.

In order to continue my ride, I had to remove the fallen chainguard form the axle by twisting it until it broke off. The chainguard was easy to break off.

This malfunction was not a total loss, as I did learn how easy it is to mount the chain back into the teeth of the chainring, so I learned something new. <s>

When I got home I took the outer chainguard off by removing the five nuts and bolts that attached it, and found that all the attachment holes on the outer chainguard were disintegrating as well. I know chainguards are an accessory rather than a necessity. <s>

I love my Dahon Speed TR bicycle. It's incredible and the wheel has to be the greatest invention of all time, but what is a guy to do that wants a decent chainguard on his Dahon Speed TR?

Regards,

LelandJ

VT_Speed_TR

lelandj,

I also have the Speed TR (for about a year now) and have riden it extensively. I've never had an issue with the chainguards. I believe their purpose is more to protect the surface that you place the bike on when folded. That is, the bike rests on the guards/chainring if the seatpost is not place down all the way thru the frame. My guess is that at some point when the bike was folded, it was drop/place down hard on that point and that force broke the guards. Then when riding they finally let go. While riding there is nothing touching the guards. The chain should NOT be making contact in any of the gears (if it is something else is very wrong). I'd just contact Dahon and get another set if you find them useful or just do without. If mine broke, I'd most likely just do without.

Brian

jur

The chain guard is to prevent the chain from being dropped when shifting. On shifting, the chain makes a sideways oscillatory movement which can quite easily throw the chain.

There are other solutions, eg J . Gaerlan sells a kit with a flanged roller for this purpose. I made such a roller kit for my wife's Dahon.

lelandj

When I'm not using my Speed TR, I keep it folded in the house. I took a look at the folding position of the Speed TR, when the seat post is not lowered, and was able to see what you were talking about.

Although I don't recall ever dropping my Speed TR, it is possible that I folded it without adequately lowering the seat post causing the damage myself. I took a look at the Dahon website, but was unable to find a shopping cart application that would allow me to order the replacement chainguards. I'll give the Dahon folks a call and see where to go from here.

Regards,

LelandJ

lelandj

I was wondering whether the chainguards purposes included help in keeping the chain from dropping off the chainring.

On the rear wheel I have eight gears that protrude out, and the chain would not always be aligned in a complete parallel with the teeth on the front chainring and the teeth on the rear gears. The chain would be at its greatest angle when shifted into the highest or lowest gear, and it seems to me, this is when the chain would be most likely to drop off of the chainring. Also, since the folders have a shorter frame, it is possible that there is a shorter distance between the gears and chainring, which would make the angles of folders even greater, but I'm not sure whether this is true or not.

I plan on riding my Speed TR without the chainguards until a replacement solution can be found, and I will be particularily interested in whether I have anymore malfunctions with the chain dropping off the chainring.

I'm really enjoying my Speed TR. Other than this one problem, it has been a carefree bike. I particularly appreciate the Speed TR gear range (eg 21 to 113). Texas has the greatest wind production, which can be harvested for energy, of any state, and the highest wind production in the state of Texas is right here in Abilene, Texas, so the low gears on the Speed TR really come in handy around here.

Regards,

LelandJ