What do you look for when buying a used frame?

[Sevenrider]

I have a custom ti frame that was made me.I've ridden it for around 6 yrs recently refit shorter stem alittle more upright.
I'm looking to purchase another frame possibly carbon.
So I have the build sheet for my ride what should I be looking at in another frame that I could make work for me?

[Lifelover]

That is a pretty loaded question given the limited amount of information you have given.

Take some of the money that you will save buying used and find a good fitter. Take you current bike with you and ask the fitter for some guidance on any critical dimensions to look for.

ATMO, the guidance you get over the internet will be worth just a little more than you pay for it.

[dd74]

Fit. Or the potential for fit given what you know of stems, seat posts, top tube lengths, etc., and the variables within those that can work for you.

[oldpotatoe]

I have a custom ti frame that was made me.I've ridden it for around 6 yrs recently refit shorter stem alittle more upright.
I'm looking to purchase another frame possibly carbon.
So I have the build sheet for my ride what should I be looking at in another frame that I could make work for me?

Seat tube angle, top tube length and head tube length are the biggies.

[sg8357]

When buying an old frame, I like to have the original paint, even if it is pretty beat. Good to see the condition of the frame without paint and maybe bondo
hiding nasty surprises.

[veloduffer]

Seat tube angle, top tube length and head tube length are the biggies.

+1 For every degree steeper than your current your seat tube angle, you effectively lengthen the top tube by about 1cm because you need to move your saddle back to get to your current position.

For example: assuming the head tube angles are the same, these two bikes have effectively the same top tube length if your pedal position behind the bottom bracket is constant:

STA 73 degrees
TT length 57cm

STA 73.5 degrees
TT length 56.5cm

The head tube length is important to figure out how many spacers you'll need to reach your desired saddle-to-bar difference. If the steerer has already been cut, then you are trying to determine if there is enough room to raise the bars to your desired height.

A rough approximation is to take the bb to top of the saddle length and subtract the bottom bracket drop and saddle-to-bar differential. This will yield the approximate length you need for the head tube plus fork length (most are about 37cm to 37.5cm, cyclocross forks are longer at about 39cm). Add the stack height of the headset (usually about 40mm/4cm) and stack height of the stem clamp (about 36mm to 40mm). For every 5 degrees of rise in the stem, you gain about 10mm/1cm of bar height (approx.). From that addition, you can figure in the spacers to fill in the void.

Now, you might need room at the top of the stem too, particularly for carbon steerers. Lately, mechanics that I know are advocating 10mm spacer at the top so the stem clamp doesn't crush the top of the steerer or cause breakage. Some folks don't but I'm from the "safer than sad" camp.

Hope this helps. :D

[RPS]

+1 on what oldpotatoe said which should also apply to your custom frame. Can you share those dimensions? Additionally what stem length and angle are you using, along with approximate amount of spacers?

That makes a big difference because if you went from a 14 CM to a 12 CM stem and from -17 to -6 degrees then your present frame size is still within a normal range. On the other hand if you went from a 12 CM to an 8 CM stem at + 30 degrees then you’d probably want a frame with less reach and taller head tube.

[cmg]

new used frame should be as close to the custom dimensions as possible. particulary as oldpotatoe pointed out "Seat tube angle, top tube length and head tube length are the biggies."

[Sevenrider]

I'll post sizes of my frame later this evening Thanks all! Mark

+1 on what oldpotatoe said which should also apply to your custom frame. Can you share those dimensions? Additionally what stem length and angle are you using, along with approximate amount of spacers?

That makes a big difference because if you went from a 14 CM to a 12 CM stem and from -17 to -6 degrees then your present frame size is still within a normal range. On the other hand if you went from a 12 CM to an 8 CM stem at + 30 degrees then you’d probably want a frame with less reach and taller head tube.

[Sevenrider]

bike I'm thinking about is a 2010 Douglas Matrix from Colorado Cyclist
Their bike
ST 60cm
STA 73 deg
HT length190 cm
HTA 73 DEG
TT 57.9
CS length 40.6

My current ride: 90mm stem 35mm spacer on steerer
Seat tube length (cnt-cnt) 57.5cm
TT lg eff. 58.2 cm
HT angle 73 deg
ST angle 73.5
CS length 42.2 cm
HT length 20.2 cm
TT slope 3 deg
+1 on what oldpotatoe said which should also apply to your custom frame. Can you share those dimensions? Additionally what stem length and angle are you using, along with approximate amount of spacers?

That makes a big difference because if you went from a 14 CM to a 12 CM stem and from -17 to -6 degrees then your present frame size is still within a normal range. On the other hand if you went from a 12 CM to an 8 CM stem at + 30 degrees then you’d probably want a frame with less reach and taller head tube.

[RPS]

Assuming you mean the head tube is 19 CM or 190 MM:

The reach seems to be moving in the right direction but considering you are only using a 9 CM stem I’m not sure it’s enough. For a frame that size a much longer stem would be normal and you won’t get it replicating your reach.

The head tube of the proposed frame is shorter, which means you’d have to use even more spacers or else use a stem that is turned up even more; or a combination of the two. Since you are already using 35 MM I’m not sure I’d go that route either unless you can turn the stem up considerably more. You didn’t mention the angle of your present stem but I’d think about that hard before making a decision. Another factor to consider is whether you can work with the frame’s stand over height which may be higher.

There are plenty of experts on fit here and I’d listen to them more than me. Personally I’d look for something a little different if your main goal is to replicate your present position.

[Sevenrider]

yes ment 190mm Not sure about stem angle but I do have some standover theirs 82.5 My so is 85.3

Assuming you mean the head tube is 19 CM or 190 MM:

The reach seems to be moving in the right direction but considering you are only using a 9 CM stem I’m not sure it’s enough. For a frame that size a much longer stem would be normal and you won’t get it replicating your reach.

The head tube of the proposed frame is shorter, which means you’d have to use even more spacers or else use a stem that is turned up even more; or a combination of the two. Since you are already using 35 MM I’m not sure I’d go that route either unless you can turn the stem up considerably more. You didn’t mention the angle of your present stem but I’d think about that hard before making a decision. Another factor to consider is whether you can work with the frame’s stand over height which may be higher.

There are plenty of experts on fit here and I’d listen to them more than me. Personally I’d look for something a little different if your main goal is to replicate your present position.

[John H.]

Fit obviously, but also condition.
Free of dents, threads in good shape, inside of tubes in good shape, also feel toptube underneath headtube and feel underside of downtube near headtube. Sometimes there can be a subtle buckling if the bike crashed into anything or t-boned.