Complete component swap advice

[MsMellie]

Hello everyone,

I am posting this as a continuation of my thread about a cracked alu headtube as someone suggested that posting pictures of the bike may be helpful. The thing is that I would like to replace the frame and use the existing components without buying new ones, if possible. I have pretty good experience with bike mechanics and I have tools but I've never done a full component swap and was hoping that I might get some advice in picking a frame and fitting everything neatly.

The photo of the bike is included in the attachment. The curent frame is aluminium and as seen it has suspension. Would it be possible to use a different type of frame ( without the shock absorber in the middle)? I am not a fan of the "broken tube" look lol. Also would I have to replace it with an alu frame or can it be steel? Asking because many of the components including the fork and the wheels are aluminium and I don't know if combining materials is a good idea.

Thank you in advance!

[Nigel]

In principle it is possible.
But, there are numerous things to get sorted out in selecting a suitable frame, they include (incomplete list):

wheel diameter, and consequently position of brake mounting bosses.
wheel clearance for tyres/mudguards.
Axle length (particularly rear).
Steering diameter to suit the steerer stem.
Bottom bracket dimensions to suit pedals and cranks
Position of derailleur on post (both height and angle) to correctly engage on front gears

In practise its probably not economic to do it, unless you do the work for free (ie. not paying a mechanic to do all the work and all the planning of the work - the planning and research is considerable ).

If the bike wheels are 26in (old mountain bike size), then an old mountain bike frame may fit the parts.


A bike without the "spring" at both the front and rear is likely to be considerably lighter, and thus easier to ride. Those springs don't look like they really add much to the ride quality, mostly just weight and more things to fail.


- Nigel

[531colin]

Find your local charity bike re-cycling place, and go and have a word with them.
Take your existing bike, they are experts at deciding what is worth using, and what isn't.
This is my local place....https://www.resurrectionbikes.org.uk/pr ... ain-bikes/

[MsMellie]

Thanks a lot for the advice!

Got a question tho: Say I obtain a steel frame. As far as I know alu tubes are thicker than steel tubes. So when measuring the headset and fork fit how do I compensate for tube thickness difference if I measure the outer diameter of the headtube on the new frame?

[mattsccm]

You don't. They could be anything in theory.
You just measure the steering column. Inside the frame. It will be either an inch or an inch and an eighth. They need to match if you want to use the old headset and forks.
Same with the seat post.
Cheap pair of Vernier calipers the best way.
To keep costs down you need a frame as near identical as possible. See above posts for variable.
I would abandon rear suspension. That currently fitted is pretty cheap and nasty and to be honest the forks are much the same.

[MsMellie]

You don't. They could be anything in theory.
You just measure the steering column. Inside the frame. It will be either an inch or an inch and an eighth. They need to match if you want to use the old headset and forks.
Same with the seat post.
Cheap pair of Vernier calipers the best way.
To keep costs down you need a frame as near identical as possible. See above posts for variable.
I would abandon rear suspension. That currently fitted is pretty cheap and nasty and to be honest the forks are much the same.

Thank you.

[rareposter]

Bluntly, there is nothing on that bike worth salvaging and transferring to a new frame.

As mentioned above you'll be running into compatibility issues immediately and if the headtube is cracked it doesn't exactly give loads of confidence that the rest of the parts on it are serviceable anyway.

Bin it, get a full bike second hand. It'll ultimately be a lot cheaper and a lot less hassle than trying to obtain a frame, trying to transfer parts over and then finding that X doesn't fit, Y is worn out, Z is not compatible...

[Stradageek]

Bluntly, there is nothing on that bike worth salvaging and transferring to a new frame.

As mentioned above you'll be running into compatibility issues immediately and if the headtube is cracked it doesn't exactly give loads of confidence that the rest of the parts on it are serviceable anyway.

Bin it, get a full bike second hand. It'll ultimately be a lot cheaper and a lot less hassle than trying to obtain a frame, trying to transfer parts over and then finding that X doesn't fit, Y is worn out, Z is not compatible...

Sadly, 'rareposter' is probably right. I have done what the OP proposes many times but have managed only because I have a perverse determination to not be beaten by the countless compatibility issues that are inevitably encountered and have a massive stock of 'alternative' secondhand spares to draw upon.

However, I have learned an awful lot about bikes in the process and have constructed one or two excellent riding, if slightly odd looking, machines

Now, back in the 60's/70's it would have been no problem at all - pretty much all components were 'standard'.