Lightweight tubing (e.g. triple butted, competition etc) - is it more fragile?

[R-V]

Think we are missing the point a bit.....whilst i agree that a lightweight frame can be well built and strong for its designed use....that's not what the OP is going to do with it!

Last child seat for a top tube i fitted had a pair of "u" clamps holding it onto the top tube. An no point in the design process did anybody making a tange prestige frame consider that! Considering you can nip a frame with a front mech, a pair of u bolts done up tight enough to stop a child seat swivelling round would i guess risk seriously compromising such a thin tube.

And lgf is correct 501 has its uses.....

Yes a child seat mount is likely to damage any thinwall tube, especially when overpulled, i've seen some sad examples.
PG tubes are cheaper and more resistant to that.

 

[Oldtat]

I don't agree with avoiding aluminium. I have a Trek 4500 from about 2003 for town duties that has carried a weeride seat (only connect to the head tube and seatpost) a chariot trailer (connects at the non-drive chainstay) and a Humax seat (clamps around seat tube) and it is great. Nice and stiff for big pannier loads too.

 

[2manyoranges]

Nope we did mention original design parameters on top end tube sets.

Specific suggestions?

Claude Butler 501 MTB frames
Saracen 501 frames
Marin base models eg Palisades
Peugeot 501 sets

That’s a start….

 

[uhuru]

You can use a full 531 not the red one but the green one it will do the job. A kid is 15kg max + a tonic father 80kg . I saw people with 120 kg riding a full 531.. it is better to ride an old 531 than a chinese bike such as surly canyon create or other modern bike. At least the 531 or equivalent was made by serious frame builder and and good material. Such as reynolds vitus fuji or columbus. After it is like ice cream you pick the flavor you like. There is so many choice. If your idea is marin you have the bear valley elderidgepalissade trail....... than can do the job for price and good and strong tubes

 

[mk one]

I wouldn't get too caught up in what the frame is made of, as others have mentioned just avoid the higher end race models in the line-up, and with any tubes, tighten evenly and not overly.

 

[tweedi]

Thanks all, just got myself an eldridge grade 1993, very excited to get on the project. Hopefully this will do the trick!

 

[otherself]

The lightest steel tubing i ever rode or had in my possession was made from dedacciai EOM 16.5. It had oversized multishaped tubes but mid tube of the downtube could be pushed in with your thumbs. It felt as thin as a Pepsi can, it was that thin. I read it had a rider limit of 155lbs, so a true racing frame, i think not good for touring applications.

Anything made from 4130 with rack mounts would be a good tourer.

 

[tweedi]

That is insane Otherself. I bet it was extremely light.

Those Marin bike from 1993 are 0.9 x 0.6 x 0.9. butted or double butted, hopefully it will do what I need it to do!

 

[otherself]

Thanks all, just got myself an eldridge grade 1993, very excited to get on the project. Hopefully this will do the trick!

Good choice. Should be made from Tange MTB tubing.

That is insane Otherself. I bet it was extremely light.

Those Marin bike from 1993 are 0.9 x 0.6 x 0.9. butted or double butted, hopefully it will do what I need it to do!

The deda 16.5 frame by Olmo was 54cm size and weighed a ballpark 1.4kg. I believe the butting was 0.55mm/0.4mm/0.6mm. The weight of a Titanium frame and 350g lighter than my current Olmo project which is made from Columbus Genius steel (56cm).