Chain tensioner for forward-facing dropouts?
 

The bike I made into a fixie was once an old geared bike; the dropouts on it are horizontal, but forward-facing (like the Campy 1010 ones here).

This is possibly another stupid question, but does anyone make a chain tensioner (bmx-style, to keep the axle in place, not singlespeed style to take up slack) for that sort of dropout? The bmx-style ones (like this, for instance) only work on rear-facing dropouts; it would be possible to rig something up so that the threaded part was offset outwards so that it was out of the way of the back of the dropout, but I'd rather buy one than make one given the option.

thanks,

-- dan

these will work fine:

http://www.danscomp.com/cgi-bin/haze...IL&item=440006

have you looked into getting trackends brazed or welded to your frame instead?

my surly chain tensioner worked fine with my frankenfixie, you just need to make sure the axle is almost all the way in the back of the dropouts.

What the heck, how do you rig that up?

You're refering to the Surly Tuggnut chain tensioners right and not the Surly Singleator? Cuz I thought the Surly Singleator will not work with a fixie. According to Sheldon Brown...
You cannot use a derailer on a fixed gear bike, even as a chain tensioner, because when you resist the rotation of the pedals, you would bend the derailer. This presents a problem if you want to use a frame with vertical dropouts as a fixed gear, because there's no easy way to adjust the chain tension. This is also true of chain tensioners sold for singlespeed coasting bikes, such as the Surly Singleator.

Okay, thanks for the pointers -- I'll head along to the local BMX shop and see what they have, now I know what basic type of tensioner I'm looking for.

-- dan

Peligro, can you describe how these operate? Don't you know I just called Dan's today to ask about another tensioner I saw to ask if it would work on forward-opening dropouts. The guy said no, which I figured. If these will work it would have been nice of him to tell me about them. It was actually kind of a strange conversation. It took several tries for him to understand what I meant by forward-opening horizontal dropouts.

Basically the tensioner would go on like so.. I made it a bit transparent to see better. Just picture the axle going through the hole in the spur and tightening the bolts pulls the wheel back more. http://www.sighost.us/members/sxefbmsxe/dropout.jpg

I looked at those with the star. They have a raised part on the inside that fits in the track end slot. This pushes the whole assembly out far enough so the screws don't grab. I'm sure you could take a file or a dremel and knock it down. Maybe I'll try that this weekend.

I use a surly tugnut on my convert.
Works the same way 'sxe fbm rider' posted about the starshaped one.

OK, gang, I just got this reply back from the techs at danscomp.com:










Folder Manager
Mailbox Manager
Address Book
Calendar





CURRENT SETTINGS


Spam Blocker
Virus Protection



More E-mail Options

SEARCH THE WEB






Move to folder:
INBOX Attachments BikeStuff Draft Erin MISC SAVES OREGON PalmStuff Photography RECEIPTS Screened Mail SentMail Trash Travel stuff





From: CustomerService <CustomerService@Danscomp.com> Save Address Reminder

To: "'RainmanP@att.net'" <RainmanP@att.net>
Subject: RE: Product Issues
Date: Wed, 22 Sep 2004 18:40:21 +0000 [View Source]

I think you are talking about forward open droputs like a Mountain bike
would have. If this is the case the Bullet Spurs won't work at all.

Rats. I may try to make my own. It's not like the tensioners have to actually bear any load. Seems to me that once adjusted they just hold the wheel in postion while you tighten the axle nuts. Maybe something as simple as aluminum or steel bar bent in a hook with a hole for the axle and some set screws would do the job. Any machinists out there?

geez, sorry I meant the tug nut, not the singulator. The one with the bottle openers.

I have made my own chain tensioner before for a forward-facing dropout. All you need is a U bolt (http://www.larsonhardware.com/prod/u-bolts.html) and a bolt to go in one of the eyelets of your frame (the ones that would ordinarily be used for fenders and a rack; most road frames have two on each side). Here's what you do: First, screw a bolt into one of the eyelets from the inside (the opposite of the way you'd screw it in if you were actuallly mounting a rack); screw it in enough to fill the eyelet, but hanging out some (maybe a cm if you have room); then, on the inside of the dropout (that is, between the wheel and the frame), put the U bolt over the axle with the open part of the U facing toward the back of the bike. Now attach the flat piece of metal to the legs of the U bolt so that when you tighten the nuts of the U bolt, the flat metal will press against the bolt in the eyelet. I've fashioned a very crude drawing of this, which may be of some assistance.

Did I mention that anyone who attempts my homemade chain tug does so at his own risk and waives any and all liability arising out of any resulting injuries? Let me mention it: do this at your own risk.