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-   -   fixed gear conversion (https://www.bikeforums.net/bicycle-mechanics/554920-fixed-gear-conversion.html)

hairnet 06-23-09 09:12 PM

fixed gear conversion
 
Hi all

So after months of procrastination, I finally ordered the hub and rim for my fixed gear conversion and I started to think of the build. The rear drop out spacing is 135mm and the hub is 120mm. I have an old steel frame and I realize I will have to compress the rear triangle to fit the hub. How do I go about doing this accurately? Is there a tool that will evenly pull both sides of the frame inward or is this a job to be done by hand and eye?

damian_ 06-24-09 02:29 AM

It's important to respace each side individually by 7.5mm, rather than just compress the rear triangle and hope that the left and right are adjusted by the same width.

Find a way to respace the left triangle, until the width is reduced to 127.5mm. Then, flip over and work on the right triangle until the gap reaches 120mm.

Sheldon Brown has instructions on exactly this: http://www.sheldonbrown.com/frame-spacing.html

dobber 06-24-09 04:14 AM


Originally Posted by hairnet (Post 9155281)
Hi all

So after months of procrastination, I finally ordered the hub and rim for my fixed gear conversion and I started to think of the build. The rear drop out spacing is 135mm and the hub is 120mm. I have an old steel frame and I realize I will have to compress the rear triangle to fit the hub. How do I go about doing this accurately? Is there a tool that will evenly pull both sides of the frame inward or is this a job to be done by hand and eye?


That's almost six tenths of an inch, quite a bit in my opinion. Not to rain on your parade, but I would have gotten a fixed hub that had 135 mm old, or at least 130.

Depending on the hub you did get, you might be able to replace the axle and add some spacers.

fuzz2050 06-24-09 07:47 AM

just do it, the steel can take it.

I don't think you have to worry about alignment either because your not compressing the stays so much as pulling them together towards a central point.

hairnet 06-30-09 06:49 PM

OYE I measured my frame incorrectly. It's 125mm

the space is so small, I'll just put spacers between the cones and the lock nuts. Does anybody have any experience with having done this?

tellyho 06-30-09 07:34 PM

Yep. It's as easy as it looks, just make sure it's symmetrical. Also, good luck finding spacers at your LBS unless they do a lot of SS conversions. I have a big box of hardware store washers in the toolbox that I use. Can't remember what size, but it's easy. Doesn't look so pretty, though.

hairnet 06-30-09 07:53 PM

I'm going to the hardware store for the 5/8" washers. If I really started to care for the look of the hub I can take the washers to a belt sander and paint it black.

Im just having a little trouble finding info on the construction of hubs. Do they go cone-> dust cap-> spacer-> inner lock nut-> outer lock nut?

stausty 06-30-09 11:55 PM

I've always gone cone -> dust cap(attached to cone or hub) -> Inner lock nut -> spacer -> outer lock nut.

hairnet 07-11-09 08:03 PM

Thank you guys for helping me on my newbie questions
Here is the final product

http://i641.photobucket.com/albums/u...t/DSC_1887.jpg

noglider 07-11-09 11:02 PM

Congratulations! Well done!

kinokokun 07-12-09 08:39 AM

Looks good! I have the same thing going up front with two brakes but only one of them connected. I lean on the other when climbing so I don't really want to take it off.


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