Thoughts on building up a separable frame?
Okay, this isn`t touring specific, but I know that several folks here have experience in the matter, and I feel more at home here than in other subforums, so hopefully the thread won`t get moved. Here`s what`s up:
My upcomming winter project is going to be a medium duty road bike/light tourer for 559 wheels and with demountable frame. Before I get too far into design, I need to sort out what componentry to figure on, taking packability into consideration.
Threadless? It makes sense from a convenience standpoint since it`s a little bit simpler to reassemble and it saves carrying HS wrenches. It might even be a shade lighter. On the other hand, a regular threaded steerer will be a few inches shorter and leaves me with the height adjustment that I really do use from time to time. I could do without that, but I like having it. Anybody with one type REALLY wish you had the other type for a suitcase bike?
I`m up in the air emotionally about brakes. The good points I see with straddle cable cantis are that I know them, there`s no way they are going to limit my tire sizes, and if I use the right hangers, I can instantly unhook the cable. Almost perfect. But they do stick out a ways- do ever they get in the way when you pack? Of course, it isn`t a big deal to remove them, but that`s another step and a few more pieces and bolts to keep track of. The other option that I feel tugging at my heart is long reach (47-57) sidepulls. They seem a little more compact, and they`re so sexy! It`s mostly the look that steers me towards them- I`ve never had any nice sidepulls, and this might be the bike to indulge myself on. I plan to use mostly 26 x 1.25 tires, though it would be nice to have an option for 1.5s. No fenders, so my take from reading is that they SHOULD be okay for tire fit, but that pretty much takes away any possibility of using really fat tires (which I don`t plan on, but ya never know) and I`ll probably need to use cable spliters. Any regrets from the experienced riders out there?
Crank/BB- triple for sure. I`ve used 74/110 triples with square taper BB on several bikes, so I know it and understand it, and for the most part I like the setup. But this time around I`m a little bit tempted by the new Hollowtech system. I can get a Tiagra triple for roughly the same price as Sugino or VO, and I get the feeling it might save me a few ounces. But it sounds like removing the right arm for packing might require a mallet, which would be a No-Go. Anybody know what my chances are of being able to do that sans mallet? Do you think there`s really an appreciable weight savings? Of course, I might not even need to remove them- won`t know for sure until I have the actual bike and box on hand. Apparently, they don`t need anything special as far as the frame goes, so I should be able to try it with a square taper BB and crankset borrowed from another bike, then order the fancy new stuff after I see it won`t have to be removed to go in the box. Does that sound right? FWIW, I`ll have friction shifting on the FD, so I don`t forsee any shifter compatibility problems.
Any other related thoughts or comments concerning coupled bikes or packing?
Last edited by rodar y rodar; 09-22-11 at 09:55 PM.
Bicycle Repair Man !!!
We are working on a separable tourer based on a 20 inch wheel with an IGH... the bike will pack into a 20 by 20 inch case as it breaks down into 4 pieces instead of 2.
The bike has been out on a few test rides and should have some pictures soon.
S&S couplers ( we are using our own) are a nice solution for making a full size bike packable.
Threadless stem and bar unit will be a lot smaller, for whatever increase in the size of the stem. Seems like a better system. More the most part I am still living in a frewheel, and threaded world, so I don't care what you do.
Cantis sound like a better deal to me. Just loosen the bolts, turn them in and tighten, or pop out the springs. I don't think it would be an issue. Sidepulls don't do anything for me, and they seem far and away more limited, or less effective. I haven't taken hollowtech appart. I think I had the system on a recumbent, but didn't touch it. Tapered BBS can require a puller, and I have on occasion had a lot of trouble pulling them without shop gear. Cycocomute says he has no problem pulling hollowtech if I recall. Not sure you have to remove the cranks though, or both of them. Depends on the size of your bike, and the rest of it.
I've never needed anything other than a Park BBT-9 bottom bracket wrench and a 4mm or 5mm Allen wrench. I've installed and removed Tiagra, Ultegra, Deore, XT, and SRAM Red cranks using these tools. If you need a mallet to remove the crank, I suspect you're doing something seriously wrong!
Originally Posted by rodar y rodar
Thanks for the comments. I`m also interested in hearing about things I might not have considered, so if anybody with a coupled bike has run into weird situations or anything that just didn`t work out as expected, I`d appreciate a heads up.
Yeah, good idea turning the cantis inside the blades or stays rather than taking them off to get lost. If practicality wins out over heart, I`ll pack it that way.
Park Tools info on external BBs suggests that they MAY need some help from a mallet- nice to know that they usually won`t. Except that now it doesn`t look like that would really give much advantage over the squares that I`m already familiar with. If something leans me that way though, I won`t worry about field expedient removal and instalation.
65er, that sounds tasty! Can`t wait to see what you have going on there.
I wouldn't go with a square bb axle. All you need for the newer cranks is a couple of allen wrenches. I see why they say you need a mallet, but you can muscle almost any crank out of the bb if you try.
I need to make myself a stem with a built-in front hangar for my travel bike. It's really nice to be able to totally separate the handlebars from the bike without messing around with the cables too much
Bicycle Repair Man !!!
It all started when a long time customer saw my P20 folder that is really now more of a separable touring bike and thought thay would like a bike like for their own but whereas I am five foot ten in shoes this fellow is much bigger and Raleigh 20's are not as good a fit for folks who are really tall and there would have been an issue with heel clearance.
Originally Posted by rodar y rodar
So we started building a touring bike from scratch and my partner was a little reluctant at first as he builds full sized bikes and although he has seen many a BF on tour and seen how I have ridden mine, was still not sure this was the best idea.
He is six foot 3 and weighs about 260 and said he took the new bike out for a shake down ride and laughed when he said "it rides just like a real bike" and that he soon forgot about the smaller wheels under him.
He does understand the physics of running a smaller and stronger wheel... the 36 spoke Rhynolites on my P20 are the equivalent of a 48 spoke tandem wheel and have stayed within extremely close tolerances ( > .003) since I built them and started beating the hell out of them.
We were aiming for a packed size of 25 by 25 but found that the bike could fit in a 20 by 20 case.... it needs to be back packable when it is collapsed and the break down and assembly does not take very much time at all.
The front end is thread less and needs to be removed, the rear rack is designed to have the top deck detached in minutes and stored flat, pedals need to come off while the crank stays, and then the frame breaks down into 4 pieces with the seat post being an integral part of the bike's frame like a Ritchey break away design.
Once it is complete will take tons of pictures...
Good. The description makes me think of an erector set of a 20 that Rodbikes offers. Check it out on his website if you haven`t seen it yet. I`d like to play with smaller wheels one of these days- whether or not I ever get that far remains to be seen. For this bike, I`m going to use a "Ritchey" style TT/ST union and a variation on R. Herse wedge and sleeve for the DT.
Originally Posted by Sixty Fiver
split handlebars are a packing benefit ..
FWIW, a Brompton folds down to within a 24x24x 10 volume.