[urbaindk]

Hi,

I'm trying to convert an old Marin frame (cromoly circa '91) into a single speed commuter beater bike. My goal is to only recycle and use parts that I have on hand so its going to be a bit tricky but should be fun. I have a couple of old cassettes. I pulled one apart to rob it of spacers and to get a cog and if fell right apart and I was able to get what I needed. I still needed more spacers so I tried pulling the other one apart and the pins that hold it together appear to be riveted in place. Is there anyway to get this thing apart? I may just try drilling the tops of the rivets out.

Speaking of spare parts, I looked closely at the front chain ring that I'm going to use. It a 38 tooth biopace. That thing should probably go into a museum of junk that should never have been invented....


Thanks. I'll send a picture when its done (entitled "Granny Porn").

D.

 

[BikeGeek]

If you're only interested in salvaging the spacers, drilling or grinding the rivet heads should do it. I actually had an old one with tiny bolts holding it together. Are you sure they're rivets?

 

[urbaindk]

No I'm not sure. The pins in the one that fell apart had threaded ends but I couldn't find what they had been screwed into, plus there was no means of unscrewing them, the ends were round and smooth. On the one that won't come apart there doesn't appear to be anything to unscrew either, which is why I assume it was riveted. How would they be screwed / bolted together if there is no screwhead or bolt head? I guess that's what I'm asking.

 

[BikeGeek]

No I'm not sure. The pins in the one that fell apart had threaded ends but I couldn't find what they had been screwed into, plus there was no means of unscrewing them, the ends were round and smooth. On the one that won't come apart there doesn't appear to be anything to unscrew either, which is why I assume it was riveted. How would they be screwed / bolted together if there is no screwhead or bolt head? I guess that's what I'm asking.

Weird, I don't know. Mine actually had small hex heads on them and screwed into the small cog. I'd say grind/drill away. I don't think the pins are necessary. I've taken the pins out of 7-speed cassettes so that I could properly fit them with a spacer on an 8-speed hub with no problems.

 

[urbaindk]

Yeah, I'm not going to use either one again so I might as well drill them.

Arlington Eh? I'm over here in Annapolis. Maybe I'll see you around the trails. Look for a guy on a black soulcycle titan or a pos Marin SS.

Thanks.

 

[riderx]

If they are rivets use a hammer and a punch and they'll come right out. Drilling will be a pain.

 

[clancy98]

well I know you are trying to go free but the gusset SS conversion spacer is really nice and it comes with two cogs, only 20 bucks and it looks killer compared to cogparts.

As for your biopace chainring... Aren't those elliptical in shape? If your going no-tensioner, I would think that would be a big problem. If you are going tensioner, then no worries.

CLancy

 

[BikeGeek]

well I know you are trying to go free but the gusset SS conversion spacer is really nice and it comes with two cogs, only 20 bucks and it looks killer compared to cogparts.

As for your biopace chainring... Aren't those elliptical in shape? If your going no-tensioner, I would think that would be a big problem. If you are going tensioner, then no worries.

CLancy

How much chainline adjustability do you have with that gusset SS thingy? It looked like it was only two spacers.

Good call on the elliptical chainring. The only way I can see that working is with a spring tensioned tensioner.

 

[urbaindk]

Crap you're right. They are elliptical. That creates an unforseen challenge. I'll probably just rig some sort of tensioner up out of an old derailleur...

 

[qualude]

You can use a dremel and grind off the mushroomed part of the rivet..then slide it apart.. You should be able to find an old chainring at your LBS for cheap...I beleive Bio-Pace's had a 110mm bolt pattern...but I really don't remeber...
Anyhow, you could use the crankarm, and put a new ring on it...that way you wouldn't need a tensioner.

 

[clancy98]

well there isn't a ton of adjustability. two sides are 5mm different. 14 and 19mm. Dont know exaclty what chainline that is but with rings that are built to shift, I dont think a perfect chainline is necessary. Get it close. Ride it. SS is so inexplicably fun.

CLancy

 

[urbaindk]

That's probably what I'll do. I need to go to the LBS for some brake cables anyway. I don't think I should recycle brake cables...

What about gear ratios? I say a link some where given the BB to axel length would give a set of gear ratios that would work. An SS computer so to speak? Anybody have the link.

Thanks.

 

[clancy98]

www.sheldonbrown.com

he has a gear calculator. Again, IMHO I dont think 100percent chain tension is necessary, especially for a beater commuter. between adding or removing links from your chain (or getting a half link) and having two different cogs (from the gusset kit) and the stack of old cogs you have you should be able to play with it. I would pick an ideal ratio based on whatever chainring you get and go with it.

 

[urbaindk]

Here's another one, Java. Thanks Google.

http://www.peak.org/~fixin/personal/fmu/php/fixmeup.php

 

[riderx]

www.sheldonbrown.com

he has a gear calculator.

Wrong type of gear calculator. He is looking for this or this

 

[clancy98]

oh damn, I thought sheldon had a SS gear calc on there too. sorry!

 

[urbaindk]

The bike is coming together nicely. I'll probably be able to ride it next week. I dremeled the cassette apart last night. It definitely was a rivet. So now I have all the spacers I need. While I had everything taken apart I cleaned and repacked the hub and freewheel - it sounds so smooth now. AH!

Just for kicks I tried the biopace ring. Its really bad. Too lose, too tight. Grind Grind. Last night right before bed I remembered that I have another whole bike to scavenge so I should be able to get rid of the oblong ring in favor of a round one. Sometimes its hard too remember what's right in front of you...

 

[clancy98]

awesome! give us some pics when ya get it runnin!

 

[urbaindk]

Hey! I finished my bike last night. I ended up running a 36/18 gearing with no tensioner. The LBS didn't have a used 110 mm chainring so I ended up buying a new one. So $35 for a chainring and new brake cables and I have a new bike to ride. Thanks Bike Doctor. Pretty sweet. The chain is pretty tight but not super tight. It probably could pop off at some point. I only rode it around the yard for a few minutes last night. Its F'in cold here today so I didn't ride to work... I noticed immediately how much more power you get with no extra parts in the way. Very responsive to your input. I also notices how my hands were always searching for a shifter (in vain) I can't wait to try it out some more. I'll get some pictures tonight. Its ugly.

Thanks for your help...

D

 

[urbaindk]

Okay - I road the bike to work last week. Its great. I could definately feel it in my thighs though. Ouch. I'll be a better climber for sure. I managed to make it to work with out vomitting up a lung...

It dropped the chain a few times so I decided to put a derailluer on it for tension. Now that I've done this it seems like there is a lot more drag than there should be. Its a lot more drag than on my non-single speed setup. It was a really old derailleur so I though maybe the cogs need lube. I did that and it didn't seem to help much. I might be using an 8 speed chain on 7 speed cogs but I can't rationallize why that would lead to so much resistance. Any ideas?

As for the pictures I promised, I have the wrong usb cable for my camera so I had to order another one... Don't worry they come eventually.

 

[will_md]

thats sweet im from that "area" somewhat as well just did a ghetto conversion about 3 months a go i love it it is so much fun im still kinda limited to were i can go and have fun without dieing but shaeffer farms in i guess it would be gaithersburg right off of 95 is single speed heaven rolling tight singletrack with no real killer undoable climbs

 

[ioscope]

If they are rivets use a hammer and a punch and they'll come right out. Drilling will be a pain.

CORRECT!

 

[urbaindk]

thats sweet im from that "area" somewhat as well just did a ghetto conversion about 3 months a go i love it it is so much fun im still kinda limited to were i can go and have fun without dieing but shaeffer farms in i guess it would be gaithersburg right off of 95 is single speed heaven rolling tight singletrack with no real killer undoable climbs

I'll have to check that out. We just moved here from NC last fall and haven't ridden anywhere but Patapsco. My wife would probably love it. She's only been riding a little over a year and she's not real happy with some of the climbs and technical sections at Patapsco. I probably wouldn't be either on the new ss...