Re: Well another number 1
I'm only just starting frame number 4, so I'm not an expert. However, the last frame I built was dimensionally similar (note that this frame is built for 650b, which you might want to consider also):
http://farm6.staticflickr.com/5225/5...58657e231a.jpg
Frame 3 geometry by pruckelshaus, on Flickr
I would have the following feedback:
450mm are some pretty long stays, IMO.
Those lugs, while beautiful, might not be the best choice if you are a brazing novice. The shorelines are incredibly complex, and I think you will have a lot of frustrations not only getting good flow, but doing so without having voids, blobs, or both all along your shoreline. I'm using the same lugs for my fourth frame, used traditional medium point lugs for the first three, and I'm nervous as hell about it. I used what were once called (don't remember what the name was changed to) the Llewelyn Slant 6 lugset and it was a pleasure to work with:
http://farm6.staticflickr.com/5047/5...8fb87b7c89.jpg
Lugs by pruckelshaus, on Flickr
I believe there is a similar set without the sloping top tube. Additionally, with that small of a head tube, you're most likely going to have to do a fair bit of work on the inside points of the head tube lugs in order to get them to work on a shorter head tube. The points will prevent you from getting the lugs close enough together. Here's what I'm talking about on the head tube lugs, I removed the points and did quite a bit of reshaping on the lugs above to get them right:
http://farm7.staticflickr.com/6218/6...6ecd4bd437.jpg
Front end by pruckelshaus, on Flickr
Finally, as much as I love sending eRichie money (and I do), I'd build my first frame under the assumption that I'd somehow completely screw it up, and as such, I wouldn't use such high end (and expensive) framebuilding components, especially for a uni commuter. Go with a basic DB cro-mo tube set and a nice basic medium point lug set and mistakes will be far less costly.
Good luck, have fun, measure twice, and cut once.
Pete
Re: Well another number 1
You may want to draft it out with smaller diameter wheels. Looks like a really short stem with swept bars, a short tt and a fairly short fc. For a city/ all arounder for a smaller rider you may get similar results and fewer compromises in 26". Lots of good tires, too. Worth a second though at least.
Have fun with it!
Re: Well another number 1
Attachment 49260FF- I agree with Eric to a degree. With the tire profile you mention and the space for fenders you'll run out of HT length or have to jack up the stand over height, unless you slope the TT a bunch. Your trail dimension is in the middle ground, not too many use a mid 50mm length. Not to say that it's wrong, just not as common as 30-40mm or 60-65mm lengths. I like the longer trail. Watch your front center and toe clearance. As a city bike there will be larger steering angles with the slower speed. I'd strongly consider 559 wheels. here's a shot of my city bike I made a few years ago with 26x1.5 tires. It's a 50cm but the Tt slopes to make a 45cm ST. Andy.
Re: Well another number 1
Thanks for taking the time to look over the design and giving feedback.
I have been pondering the thought of building the frame around 650's for quite awhile but the LBS I work at and most other shops in town don't stock 650 tubes so i have been trying really hard to make the 700s work. That being said a lady rocked up on Friday with a crabon TT race bike running 650's and got me thinking again. The FC issue has also been bothering me as well as i have ridden bikes with toe overlap and hated it and have been trying to make it tolerable.......
650s are sounding better by the minute.
I'll draw it up in autocad and post up
The stem dim's were just done on the fly with no real thought but it will definitely have more height and length in the final draft.
I was also expecting to do some lug modification to get everything to work in the HT department. With a decent set of files and years of fret work experience I'd like to think that some lug modification isn't out of my depth but I'll be the first to admit that I tend to throw myself in the deep end and figure out how to swim later.
I had a feeling the lugs will very hard to braze and i really should use some simpler ones but the early Brit cycle style seems to just scream for them. If that is the set I end up with i had intended to finish them off like this..
https://lh5.googleusercontent.com/-M...6/IMG_4636.JPG
With a nice white accent on the edge of the lug. This is a pic of my 50's Repco track frame and is my number one inspiration for framebuilding. It was my only bike for many years and handled beautifully and is currently getting treated to a restoration, maybe not quite the full on resto she deserves but some well earned love none the less.
As for the chain stays, I based the geometry on the sport touring design from the back of my (free copy) of the Patreck manual. I'm aware that they are very long compared to today's standards but i though that they would aid a nice stable ride and maybe offset the large leverage form the wide upright bars. But I'll look into it and make some changes.
Thanks for all the feedback and help! your collective wisdom is greatly appreciated.
One question though, Is a super short HT something to avoid not just for esthetic reasons? I can't see it affecting handling in a negative way, right?
Re: Well another number 1
Quote:
Originally Posted by
Andrew R Stewart
FF- I agree with Eric to a degree. With the tire profile you mention and the space for fenders you'll run out of HT length or have to jack up the stand over height, unless you slope the TT a bunch. Your trail dimension is in the middle ground, not too many use a mid 50mm length. Not to say that it's wrong, just not as common as 30-40mm or 60-65mm lengths. I like the longer trail. Watch your front center and toe clearance. As a city bike there will be larger steering angles with the slower speed. I'd strongly consider 559 wheels. here's a shot of my city bike I made a few years ago with 26x1.5 tires. It's a 50cm but the Tt slopes to make a 45cm ST. Andy.
Cheers for the tip Andy, I'm going to look into both 26's and 650's
Re: Well another number 1
Quote:
Originally Posted by
Filly-fuzz
One question though, Is a super short HT something to avoid not just for esthetic reasons? I can't see it affecting handling in a negative way, right?
Right - it's a resultant measurement and won't affect handling atmo.
Re: Well another number 1
Quote:
Originally Posted by
e-RICHIE
Right - it's a resultant measurement and won't affect handling atmo.
Thanks mate, good to know.
Alright i slapped this together based around 650s and already it looks much better, but i'm off to sleep on it.
https://lh5.googleusercontent.com/-N...dims+2+650.JPG
Re: Well another number 1
FF- I would think the angle mods would prove to be more challenging then the lug carving. Both in getting the angles that you might find that you really (those lugs have deep sockets) need as well as the brazing. If the gaps grow from significant angle changing then Silver might not be the best choice. I would suggest that you practice brass brazing in addition to Silver. Either way about the lugs and filler, the drop outs often done with brass. The Repco track frame is likely done with brass, few English frames used Silver BITD. The only down side with a short HT is the headset wear and sensitivity to adjustment. With quill stems the other issue use to be how much stem insertion could you get away with before running into the butt, but with threadless stuff that's moot. Andy.
Re: Well another number 1
FF- I just looked at drawing #2. A few coments. First the tires available in 650c tend to be narrow. I believe you mentioned 33mm tires in your 1st post. Big difference from 33 to 25 wide tires. Second is the fender availability in 650c without having the fit be kind of "almost but not quite". i know you haven't mentioned fenders but a city bike calls out for them. Third is the BB drop did not change from the 700c drawing #1. With 650c tirew this means that your Bb height drops a lot. Even with 165mm arms pedal strike will be far more likely.
Overall I do like that you're expolring the design options. Andy.
Re: Well another number 1
Keep in mind that 650b's are going to be very different from the wheels on the tri bike you saw, which I guarantee are 650c. Completely different animal, and AFAIK the only readily available rubber for 650c's is race-oriented. Eric's suggestion of 26" is probably the best, though I do like 650b's (I use them on the 2nd frame I built as well as the one I built for my wife). You can find 26" streetable tires in widths from 1" on up, with 1.5" probably the sweet spot.
Re: Well another number 1
With the 650 drawing I was intending to go with 650b's as grant from Riv makes a nice selection of fat road tyres for them
650B Tires
Thanks for the input, I'll refine it over the remaining weekend.
Andrew,The main reason I have been drawn to silver brazing it due to the lower working temperatures, I can also liken it a lot more to my soldering background.
Thanks for the tip. I'll look into brass, from what i understand It creates a stronger join correct? I'm really not looking to cause an internet showdown of the brass vs silver kind.
pruckelshaus, as a fellow Aussie do you have any recommendation as far as a basic torch setup goes? After reading the thread comparing oxy to propane I came to the conclusion that porpane would be the way to for my small home workshop. Although next year we may be gearing up this Acoustic guitar company i have been working with and finally get our own workshop space. In which case a nice oxy set-up is not out of the question.
Cheers
Re: Well another number 1
I'm not an Australian?
I have access to the shop of an established builder, so I use his o-a setup, so I can't really give much advice on that.
650b should work well for your design.
Re: Well another number 1
Quote:
Originally Posted by
pruckelshaus
I'm not an Australian?
I can honestly say i have no idea what gave me that impression:confused:
sorry mate!
Re: Well another number 1
The brass can fill a larger gap vs silver, and if you're stretching/changing the angles on the lugs, you might get some gaps.
cheers
andy walker
Re: Well another number 1
Is that a 5cm headtube?
- Garro.
Re: Well another number 1
Quote:
Originally Posted by
Filly-fuzz
I can honestly say i have no idea what gave me that impression:confused:
sorry mate!
It's OK, I'm not easily offended, but you just about crossed the line there!
:laugh:
Re: Well another number 1
Thanks for all the help guys, I have an amended drawing that i believe that has addressed many of my rookie errors. I'll post up later on.
I should also make it very clear that I do plan on brazing up a quite a few practice frames with cheap tubing and pressed lugs before beginning this project (which is a loooonnnnng way away)
I was just really keen on refining the geometry.
Cheers
-Fil
Re: Well another number 1
Quote:
Originally Posted by
steve garro
Is that a 5cm headtube?
- Garro.
centre to centre By the look of the diagram.