Rear dropout spreading...

[Kevan]

I need some advise here from frame builders or folk in the “know” about this procedure.

With the help from pal Mikemets, I’m embarking on upgrading my daughter’s Olmo from a 6-speed to an ergo 8-speed drive train. In order to make this happen, the rear stays and dropouts need to be stretched to adequately handle the larger hub. It is my intention to first secure the brake bridge, preventing the weld from popping, by first protecting the paint surface with duct tape, then using 2 small blocks of wood ( shaped to conform to the tubes) on the outside of each seat stay, use hose clamps to secure the bridge area. Then by using a treaded rod, with washers and wing nuts or nuts, place the rod in the dropout and turn the nuts outward, with washers in place, to bend the dropouts to the suitable 130mm distance. Here’s a website confirming my approach: http://www.vintage-trek.com/refurbish.htm#dropouts

All along, the recommendation here has been, “DON”T DO IT! GET A BIKE SHOP TO DO IT!”, but I’m thinking this can be done.

A couple questions:

- Should I really not do it?
- Is my method outlined above sound?
- Should I reinforce the chainstays at the bottom bracket (lugged) as I did the brake bridge?
- Is there a tendency that one side of the frame will bend and not the other, hence, misaligning it? Any suggestions to prevent this from happening?

Thanks in advance for your comments and suggestions.

[ChrisK]

I can not stress strongly enough what a non-issue this is. I've done it on a bunch of bikes and the "just stick the wheel in and forget about it" method works great. Eventually the stays get used to the new hub. You're only spreading 2mm per side, a bit more than 1/16". I also saw it done at a very high end old school bike shop. The mechanic but his foot on one dropout and yanked on the other: "that'll be $20".

But if you are spreading from say 110mm to 135mm, though God only knows why you would, it might be wise to follow Sheldon Brown's method: http://www.sheldonbrown.com/frame-spacing.html

[Fixed]

bro just put a washer on the outside of the cass. so the chain won't rub the drop out.
cheers

[Jeremy]

Many of the older steel frames have a "dimple" on the drive side chainstay to accomodate the chain rings. The tube is weaker at the dimpled area and if you simply spread the dropouts apart from each other, all of the bending will occur on the drive side. This will result in a rear triangle that is out of alignment. If the chainstay is dimpled, the simple method is to use a long metal tube or thick wooden shaft and bend each side seperately. You do this by bracing the leverage device at the seat tube and the inside of the dropout juncture. You will need someone to help you stabilize the frame while you use the lever arm to flex each side of the rear triangle outward. Of course, you want to protect the contact areas when you do this.

The "poor mans" alignment tool is simply a length of 1/8" stretch cord. After you have spread the frame, string some stretch cord around the head tube all the way back to the dropouts and tie it off in the middle of the dropouts. Make sure that the cord is not touching anything that would make it uneven relative to either side. Measure the distance from the seat tube to the cord on each side. They should match.

Technically, your dropouts will be out of alignment. However, it is so small that you can usually ignore this. If you really want to, you can find a set of drop-out alignment tools and fix this, or take it to a shop and have them do just that part of the job.

Jeremy

[Kevan]

using:

Duct tape to protect the paint surface

2 hose clamps

2" pvc nipple cut lenghtwise in half

Threaded rod with washers and wingnuts

Wheel fits snug, but it fits.

[CJH]

I'd say Sheldon's method is really the prefered one as you can coldset each stay individually, thus maintaining proper alignment... But hey whatever works. However I do agree this is not the big deal it's made out to be...

[BumbleBeeDave]

. . . when I first saw that thread title I thought this might be something about you and Sandy that I really did NOT want to see . . . :rolleyes: ;) :crap:

BBD

[learlove]

. . . when I first saw that thread title I thought this might be something about you and Sandy that I really did NOT want to see . . . :rolleyes: ;) :crap:

BBD

me too

"Rear dropout spreading... "

sounds like a movie made in the hangars down by the van nuys airport in CA.

[saab2000]

There is a thread on RBR dot com of a guy spreading the rear stays of a Litespeed Ti. It is insane. The guy suspended it between two trees if I am not mistaken and used some sort of winch. My recollection anyway. If anyone knows of it and can post a link it is pretty cool.

[Fivethumbs]

I spread the dropouts on my bike using the threaded rod method and the rear stays did not bend equally and the frame went out of alignment. Then I had to use the Sheldon Brown method to bring it back into alignment. I should have used Sheldon's method from the start. You should check your alignment using Sheldon's method of wrapping a string around the headtuble and attaching each end of the string to one rear dropout. Then measure the distance from the seat tube to the string.

[BumbleBeeDave]

. . .what an, ahem, pain in the @ss this looks like it would be, you could probably pick up a whole new frame off eBay pretty cheap . . .

BBD