building a bike around an older kit

[kidneyboy]

for the last few months i have been building a bike frame around an older kit. this is my first try at building a frame/bike from scratch. it has been a slow and interesting process. the pic is where i am at currently. the seat needs to be trimmed yet and the handlebars are getting close to where i want them. next will be some gussets, posts for front brakes and possibly origin 8 bars.

i'm pretty happy with progress so far. the initial test ride went well. the kit made the entire process easier so far.

 

[Doug Burton]

Hi KB,

I've been watching this build with great interest. Looks like it will be a very fun ride.

The French are going nuts over MBB; there are a lot of variations on the "Speculoos" design being built in steel, aluminum and carbon fiber. A Cruzbike kit can make these easier to build because one of the more difficult engineering jobs, the drive triangle, is taken care of.

See "Traction directe (sp?culoos et consorts)" about halfway down the page:

http://velorizontal.bbfr.net/le-coin-du-constructeur-amateur-f10/table-des-matieres-t3097.htm

The Origin8 "Gary" bar appears to be out of production. This is a loss to us, because it works very well on the Silvio and conversions that need knee space between the bar ends.

An alternative is the Salsa "Woodchipper" which is a very similar design, but a tad more pricey (about $40, if I recall correctly.)

Cruzbike is also looking into having its own bars fabricated, but I don't know if we'll run enough of them to offer them as accessories. I hope we'll be able to do that.

Keep on wrenching!


Doug

 

[kidneyboy]

i didn't think there would be an update today but i trimmed the seat and tweaked the bars a bit. my position on the bike seems about right.

it would look cool with a rear fairing....

 

[kidneyboy]

after a lot of experimenting with handlebar setups i have ordered a straight stem and b37 bars from rans. i'm hoping these will resolve what are some small issues i'm having with the setup. the issues are mostly in my head, i'm sure, but i have been test riding a bit and there is a certain feel i'm trying to get. road bars, or gary bars, don't seem compatible with the components on the bike so i'm stepping outside my budget and trying these. pics will follow.

the test rides are very encouraging too.

 

[defjack]

Looks good.The B37 bar is a good choice you get a lot more adjustmet than with road bars. Jack

 

[kidneyboy]

i did a few sketches of possible fairings. drawn over a photo of the bike. i like this one and may give it a try if winter and unemployment go long.

 

[John Tolhurst]

kidneyboy wrote: i didn't think there would be an update today but i trimmed the seat and tweaked the bars a bit. my position on the bike seems about right.

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it would look cool with a rear fairing....

If I may say so, I think you look too comfortable. I want see your arms outstretched ready to give an almighty heave on the crank strip the damn teeth off the chainring.

 

[kidneyboy]

john,
if i wasn't already used to recumbents it would be disconcerting to be so comfortable. the very interesting part of this is the amount of adjustability of the kit. i have been able to move the seat and bottom bracket easily to find a sweet spot for myself and the bike. this is my first attempt at building a frame up bike and the kit has inspired a lot of confidence and new (for me) ideas. a 559/406 is on the drawing board.
i would like to ask a question about handlebar placement. this is out of curiosity. are there advantages to the different arrangements out there? some are ahead of the stearing axis, some behind, some low, some high. i'm pretty sure the answer starts with "it depends on.." but i'm asking anyway.

 

[Doug Burton]

Hi KB,

I'm hoping you'll get lots of responses to your question about handlebar placement, because a lot of thoughtful folks around here have done a lot of experimenting with it.

My $0.02:

- Handling seems to benefit from having the handgrips in line with or ahead of the steering axis. The bikes I've built with the grips farther than about 3 inches behind the steering axis have been very sensitive to all the other adjustments (grip height, for example) until I moved the grips forward. Then the bikes became very tolerant of anything else I tried. That being said, I notice many of Jack's bikes use grip points well behind the steering axis.

- You will probably realize more upper body power if your arms are straight or nearly so. I think of it a bit like doing pull-ups. Also, if your arms are under a little bit of their own "static tension", it tends to improve steering consistency in a straight line, making it a more unconcious affair rather than "thinking in" steering corrections. You'll want to balance this with shoulder stress, which will creep in if your arms are too extended.

- I prefer a grip lateral down-angle of about 45 degrees. This puts my shoulders in an un-twisted state, and allows my wrist muscles to provide small motor inputs to the steering more precisely than using my elbows and shoulders to do it with vertical grips, as with road drop bars. Also, inclined grips allow me to relax my grip tension and rest my hands on the bars, where with vertical grips, I have to apply constant energy to my fingers to keep my hands on the bars. Over a long distance (charity rides for example) this makes a big difference for me.

Hope others will chime in. That's what this forum's all about.

Hope the bike is going well for you.


Best,

Doug

 

[rearengine]

It seams we all do a lot of fiddling with bar adjustment .. Thankfully it's easy to do.. I go along with Doug, especially the rist control ,and the hands resting on top of the bar.. Pix are worth a thousand words,..

 

[John Tolhurst]

Good post, Mr rearengine.

 

[kidneyboy]

thanks for the replies. part of the fun of all of this is the large variety of approaches around a single design. the differences in the setups in the cruzbike line being a good example.
it is also interesting to work around the parameters of the build. knee clearance being the most interesting issue but also having my shoulders and hands in comfortable and effective positions. combining that with wanting to keep my hips and the bottom bracket close to the same height has been great fun.
i have had 4 different handlebars and 3 different stems on this build so far and while i hope the rans bars will be satisfactory the picture in my head of how the bike should look seems to lean towards the silvio. marias' record breaking ride and the pics and videos have much to do with that. so i will keep experimenting as i go. i mocked up a wtb-ish sort of bar that would work with the components i have on hand and may try to weld a set up this week. i hope it's obvious i have more time than money

i'm hoping to do the final cleanup of the frame in the next couple of weeks. have not decided on a paint color yet. suggestions more than welcome.

 

[John Tolhurst]

The bar type is a consequence of the seat recline. 30 degs, use a bar like on Sofrider, 45 degs, use drop bars like on Silvio, while 60 degs, you may need to cook up a little cowhorn soup. Because, roughly forward facing arms cross the thigh at different locations in each case, because the shoulders are further away.

We have some silvio type flared road drop bars.

What feels good when you are sitting on the bike is often not the position you need when you are active on the bike. It is in fact an ergonomic exersizing position, rather than a relaxation position.

 

[kidneyboy]

John Tolhurst wrote:

What feels good when you are sitting on the bike is often not the position you need when you are active on the bike. It is in fact an ergonomic exersizing position, rather than a relaxation position.

this part i understand. so i change things a little and then test ride.

this really is great fun and a new experience for me and i appreciate all the info.

 

[teacherbill]

And looking but not reading too closely I thought those handlebars were from pieces of PVC tubing. I was ready to ask how well they were functioning and what schedules pipe sizes were until I read they were a mock-up .....

 

[kidneyboy]

bill,
there have been so many mockups on and around this bike it's kind of funny. i can only imagine what tolhurst goes through.

i should take a moment to give credit to the forum members here, including john tolhurst and doug. a huge source of help, info and experience.

 

[kidneyboy]

well, the sans b37 bars are not going to work out. i would have to set them up so my knees clear underneath them. it would work with the correct long curved stem but that isn't what i'm aiming for. i have bent some older bars to match where i want my hands and shoulders to be based on the mock up handlebars pictured a few posts back and will test ride, maybe with working brakes this time out.

 

[Doug Burton]

Hey KB,

Your PVC mock-up reminds me of the Origin8 Gary and the Salsa Woodchipper...

http://www.bikepartsusa.com/cgi-bin/category.cgi?item=409&source=froogle

http://directbicycleparts.com/page.cfm?PageID=53&action=details&sku=HB8112&utm_source=froogle&utm_medium=na&utm_campaign=froogle&utm_content=HB8112

 

[kidneyboy]

doug,
that is my intent. i am going to try to make a swoopy/aero looking version around the lines of these

a friend of mine has offered to help with the trial version. probably out of wood (yes wood) with the same lines as the pvc mockup.

 

[kidneyboy]

i have managed a final geometry http://s561.photobucket.com/albums/ss51/kidneyboy1/bents/?action=view&current=004-4.jpg check out these pics to see my slow and tedious process of getting to this point.



an hour of test riding today and i am very pleased with it. i have not settled on the actual handlebars but i am happy with where my hands are. i also leaned the seat back a few degrees. now i am going to mess around with a tailbox design a little then disassembly, grinding and paint.

 

[kidneyboy]

ok, it's done.

it is a blast to ride too!!!