Bicycle Mechanics - dropout spacing

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poetjem
12-12-03, 05:36 AM
i am building a bike from nothing but an older french steel frame and believe it to have 120mm spacing (i lack calipers but am pretty sure). a few questions:
1) can this be changed to 130mm?
2) if it can't, am i limited to 5 and 6 spd cassettes? or are there larger cassettes that can be made to fit a 120mm spacing?
thanks for any help.
john
Don Cook
12-12-03, 07:22 AM
i am building a bike from nothing but an older french steel frame and believe it to have 120mm spacing (i lack calipers but am pretty sure). a few questions:
1) can this be changed to 130mm?
2) if it can't, am i limited to 5 and 6 spd cassettes? or are there larger cassettes that can be made to fit a 120mm spacing?
thanks for any help.
john
Spreading the dropouts 10-12 mm is more than is usually done. I did the same thing that you're getting ready to do, I restored an older Italian frame with 126mm dropouts. However, I did take the frame to a shop that had the correct frame jig for spreading the dropouts while maintaining the parrallel relationship between the dropouts. Check with a GOOD LBS mechanic. If you not sure that you're getting a good answer from the LBS then email Sheldon Brown: CaptBike@SheldonBrown.com
MichaelW
12-12-03, 11:25 AM
With 126, you can fit a 7spd freewheel. You can re-space a freehub to fit, my LBS offered to do it, but I use a screw-on freewheel for now.
BTW the frame probably has a French-threaded bottom bracket. Just so you know.
This is doable, I did it with a '72 Peugeot PX10 frame. Spreading a steel frame results in the rear fork ends being a little bit at an angle. Frame builders have tools allowing the fork ends to be bent parallel. It is not a biggy if you don't do this but I can tell you that pulling and replacing the rear wheel on a non-spread bike required that I sit down, put a foot against the L fork end, pull with much of my strength on the R fork end and use the other hand to maneuver the wheel in place. As MichailW says the French
threading is a challenge. Sheldon Brown's shop www.harriscyclery.com
(a branch of www.sheldonbrown.com) has French threaded BB, Shimano
actually makes French thread BB but getting them in the US ......
The seat post may have an odd diameter and the front fork will have odd threads so replacing the headset may require Sheldon's help. One Fr thread you can easily fix is the R der hanger thread: It is easily tapped out to the standard thread of 10.x1.0M with a $4-8 tap. OEM thread is odd. If you are changing the cranks then Fr thread pedals won't be a problem. Steve
you can have the rear professionally widened. check with your LBS if they can do this for you, or if not, ask them if they know a local frame builder..
This is minor work that can be done in less than an hour by a qualified builder with the right tools.
I have two bikes that were built as 126mm that currently have 130mm hubs and 8sp cassetes in them. Both are older lugged frames with horizontal dropouts and seem to do fine. Going from a 120mm (track?) spacing to 130 is a bit much but could probably be done. I watched the guys in my local shop do it once. They attach bars to the dropouts which point forward and proceed to pull the stays apart while making sure that the bars stay equidistant and perpendicular to the bottom bracket shell. Must admit it made me cringe a bit watching them tweak the frame like that but steel tubes are amazingly strong.
-s
I spread the Capo from 120 to 127 with no problem. CyclArt later fine-tuned the dropouts a bit as part of the painting service. I use 7-speed conventional freewheels on all bikes except the Peugeots; the UO-8 has an ultra-6, and the PKN-10 has a standard 6.
miamijim
12-15-03, 04:41 PM
120 to 130 on a steel frame is OK...its only 5mm per side. If your going to go to 127, 3.5mm per side) you might as well make the jump to 130mm.
jfmckenna
12-17-03, 02:31 PM
Just a few weeks ago I spread the frame of my old Nashbar touring bike made of Lugged Tange 2 from 126 to 135 with absolutly no problem using the sheldonbrown method as suggested above. Now I have an 8 speed cross bike set up. It was very scarry at first but if you go really slow and increase the pressure and measure carefully after each try you will get the gist of it. Check out http://www.bikeschool.com/ in there technical forum its a great website and that is where I made posts for help and got some great tips. BTW tie a string from the dropouts around the head tube to the other droupout very tightly and measure your frame allignment from the seat tube to the string on each side so that they are even on each side everytime you try to bend the frame
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