how do put on a speed sprocket?

I just got a 27 tooth front pulling sprocket (aka "speed sprocket") for christmas. i have a '95 tomos targa lx. i need help putting it on. i know how to access the current sprocket, but it dosen't want to come off. i'm guessing that the nut that holds the sporcket on is threaded backward to keep it from loosening. can anyone help me to get it on?

Re: how do put on a speed sprocket?

Its one of those flat whatsims with the two holes in it right? i do believe that those are reverse threaded. I hate taking those things off..i would recommend getting the tool for it because its a pain in the arse to do it otherwise. last time i did it i had to soak it really good with liquid wrench or wd-40 or whatever it was that i had at the time, then i took a piece of my dad's 1/4" square steel (the stuff you make fences out of) and used the grinder to make a bar with two little prongs to fit in the holes. i put the bar in the vice and turned the wheel with all my might. after about 10 tries with the 'tool' i made slipping out of the holes, it came loose.. So, in short, i suggest you get a 'proper' tool if you can..

Re: how do put on a speed sprocket?

Ataristyle /

I dont remember it being reverse threaded, but i could be wrong. To get the nut off of my '98 Tomos Targa LX I used an Airgun. Came off no problem.

Re: how do put on a speed sprocket?

Reeperette /

It's not the nut, so much as that stupid little plate under it.

When I replaced the sprocket on my bullet (due to wear, I ride a LOT, ok..) that gave me the most hassle, and I thought it looked rather insubstantial, so I made a new one out of heavier stock and replaced it...easy enough to do, a simple metal cutout, is all.

So don't let it break your heart if you mess it up, just have some sheet stock handy.

What works best to get that damn nut off, is a way humongo adjustible wrench and a rubber mallet...and don't take the pedal arm off first, cause that'll give you something to lean on/hold on to/use for leverage.

Apply that adjustible, and make ultra-sure it's as perfectly tight as you can get it, and use a RUBBER mallet, on the end, most of the way down, ole john henry bustin rock, and sooner or later it will come loose.

Once it's loose, THEN take off the pedal arm - unscrew the nut, and put a wooden dowel rod to the end of the retaining pin, and hit THAT with the rubber mallet, and that'll come out...eventually.

Then yank the pedal arm, and unscrew the nut, and get a small flat-blade screwdriver....use that to pry that damn plate off, preferably without damaging it, go one side and then the other, and have patience.

Once you get alla that done, it's a snap to replace the sprocket and smack it all back together.


Re: how do put on a speed sprocket?

Hey, thanks, but one question. Is that nut reverse threded or not?

Re: how do put on a speed sprocket?

yes it is reverse pretty sure.

Re: how do put on a speed sprocket?

Ron Brown /

Hey Matt,

I feel your pain!

I have no idea if this is a left or right hand thread, but, if the thread is visible at all, you should be able to determine if it is left or right hand.

I would not recomend trying to remove it until you know for sure.

In addition, if the crank pin mentioned by Reep is a standard bicycle type cotter pin, either buy a new one or, if you are good with a file, draw-file the flat side until the groove caused by the crank is almost gone before re-using it. You must keep the flat surface as flat as possible when filing.

After tightening the cotter pin nut, wait an hour or so and re-tighten it.

When I was a kid in England, one piece cranks were unknown and cotter pins were the bane of every cyclist's life.

Given a good spindle, good fitting crank and a good cotter pin, they worked great. If any of these three parts are bad, the other two go bad in very short order.

Good luck,


Re: how do put on a speed sprocket?

Reeperette /

I do not believe it is.

I remember when changing mine I had to block the damn sprocket cause when I turned the wrench to tighten it down, the whole cursed thing kept turning with it.

Your model may differ, however...


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