extending rear dropouts

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busdennis

Veteran
hi

having problems with chain tension

below are 2 pics of my dropouts of the bike im trying to convert. with X amount of chain links the wheel axle is only just in the dropouts as seen, if i had 2 llinks you cannot get chain tension before you hit the rear or the drop outs.


question 1. is it safe to exteneded the dropout on the shortest side?

question 2. by increasing or decreasing the rear gog by 1 tooth how far dose it move the axle in the dropouts?

question 3. do i have to buy a chain where you can remove links singular instead of in pairs?
 

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Zoiders

New Member
It's certainly possible to remove more material from the drop out, it's a bit suck it and see as to if it will stand up to it - it should do though it looks like it's a simple plate steel one and not a casting.

I would make a second drilling of the same diameter as the existing and and file out the remainder to give you a slot with a rounded end to reduce stress, be careful to match the angle of the slot in the drive side plate to the other side or you will get a twisted axle.

Failing that I would pop a half link on the chain so you get a usable magic gear.
 

mangid

Guru
Location
Cambridge
hi

having problems with chain tension

below are 2 pics of my dropouts of the bike im trying to convert. with X amount of chain links the wheel axle is only just in the dropouts as seen, if i had 2 llinks you cannot get chain tension before you hit the rear or the drop outs.


question 1. is it safe to exteneded the dropout on the shortest side?

question 2. by increasing or decreasing the rear gog by 1 tooth how far dose it move the axle in the dropouts?

question 3. do i have to buy a chain where you can remove links singular instead of in pairs?

You could get a half link


http://www.hubjub.co.uk/etc/etc.htm

--
Dan
 

Fixedwheelnut

Senior Member
I have modified the drop outs with a drill and file before on this type of drop outs.
1/ Scribe a line from each flat edge to the rear.
2/ Bisect those two lines to find the centre point.
3/ Measure in from the rear where you want the end to match the other side
4/ add to this the radius of the hole [half the drop out width] and mark the point with a dot punch.
5/ drill a pilot hole approx 3mm
6/ drill the hole diameter to match the drop out width [ I actually went 0.5mm smaller and filed it to size]
7/ Cut and file the remaining excess out.
8/ Cut off that rear mech hanger while you're there, you won't want that ;)

Measure twice , Cut once
biggrin.gif
 
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