Cycling UK Forum

Now that my son is back with his Holdsworth 531 frame based road bike I can see what the problem is. He - someone? - has over tightened the bolt so much that it has pulled thru, widening the holes on both sides in the frame.
So has this effectively wrecked the frame, does anyone know, or can it be fixed at reasonable cost?

If a bodge fix is ok, I can only suggest that you try a nut and bolt of suitably large size, with washers. If it's a treasured frame, then the seatpost cluster can usually be replaced at some expense by a framebuilder.

Thanks Jerry

Another option - and not a bodge or an expensive frame repair - is to have an oversized clamp nut/bolt made. It should be easily done on a lathe and would look far better than a nut and bolt with washers.

There are at least three different styles of bolt arrangement on steel frames. The first is basically a large nut and bolt, the bolt head generally being round and flattish with a projection fitting into a slot in the lug. Then there were some with one side of the lug itself threaded - generally with an imperial thread so the bolt looked as though the Campag allen key would fit but it didn't. Then there were some where both parts of the fixing were a sort of cone shaped and each with a hole for an allen key. How best to fix it might depend on which it is and a shop might advise but in the end, as others have said, a bigger nut and bolt should do the job.

Not a very good description of the third type - is it called a spire nut?

Thanks guys, very helpful. G

Have a look at an old fashioned seatpin bolt. The nut is often domed on the outside. Get one like this and try putting the dome on the inside ,it should "fill the hole" provided its not too bad. If other side is an issue, try a beefy washer with a slot to pick up the "tab" ,or simply use a standard bolt that you can get a spanner on. Or get something threded all along and use 2 domed nuts (like an old school seat clamp bolt system) . Trial and error is the key. Mostly error in my case.!

One way would be to cut off the top of the seat tube level with the bottom of the clamping lugs, but with some of the cut away still there. First having got one of the clamping rings that are normally used on newer bikes. Look for one that has a step inside that sits slightly over the frame and is stepped down to the seat post diameter.
Not as nice as the original but should look quite neat and tidy.