www.recumbents.com - XStream Clone - Well not quite a clone...
www.recumbents.com
www.recumbents.com
Home | Profile | Register | Active Topics | Members | Search | FAQ
Username:
Password:
Save Password
 All Forums
 www.recumbents.com
 Technical / Bike Building
 XStream Clone - Well not quite a clone...
 New Topic  Reply to Topic
 Printer Friendly
Previous Page | Next Page
Author Previous Topic Topic Next Topic
Page: of 13

ShelGame
recumbent enthusiast

USA
254 Posts

Posted - 11/05/2015 :  08:28:17  Show Profile  Reply with Quote
quote:
Originally posted by alevand

Tight Ride Rob, I don't prefer mid-drives, added complexity, weight with lower efficiency and a lot of overlap. An idler near the seat works for me. I have enough gears with a triple chain ring. I have OSS too, besides being more aero OSS is easier to walk and hold up the bike ,the wide USS bars tend to run into things. Your legs must be shorter than mine, I usually have 43 inches from butt to toe. I envision it painted black with a nice tail box and rear wheel cover. The dual 1.5 x.035 tubes are plenty strong. There probably <40% weight on the fork. If you use v-brakes or calipers, check the crank arm interference when turning.

C:
Tony Levand



What is your x-seam? My x-seam is 42.5. I was wondering if this was maybe a bit too short now. I haven't been able to find a published correlation between x-seam and seat-to-crank length. I thought the seat-to-crank should be a little shorter than x-seam. But, I'm guessing...
Go to Top of Page

warren
human power expert

USA
6090 Posts

Posted - 11/05/2015 :  09:37:49  Show Profile  Visit warren's Homepage  Reply with Quote
The X-Seam is the seat to extended pedal length. Seated against a wall with legs extended I measure from the wall to the heel and add .5". This should correspond with sitting on the bike seat with leg straight and having a small gap between your heel and the pedal when it's farthest away from you. I'm sure you can figure out the seat to BB distance from there.
Go to Top of Page

ShelGame
recumbent enthusiast

USA
254 Posts

Posted - 11/05/2015 :  11:19:37  Show Profile  Reply with Quote
Easy enough to fix with a BB move...
Go to Top of Page

ShelGame
recumbent enthusiast

USA
254 Posts

Posted - 11/06/2015 :  07:04:58  Show Profile  Reply with Quote
Fixed the x-seam length. This made me raise the BB ~2". It's now 7" higher than the seat bottom; but only about 2" higher than the approx hip point. Seem a bit high to me, but probably not as high as some bikes. Any opinions on that?

Go to Top of Page

warren
human power expert

USA
6090 Posts

Posted - 11/06/2015 :  08:40:48  Show Profile  Visit warren's Homepage  Reply with Quote
7" is good. As Thom mentioned, for normal road use you shouldn't need a mid-drive with the full size rear wheel. If you have special needs like going really slow up a steep hill or really fast in a fairing then the additional gearing is useful. I mostly use a 53/39 road crank and a wide range MTB rear cluster and that provides a great range of gearing (for me!)
Go to Top of Page

Speedbiker
human power expert

USA
3744 Posts

Posted - 11/06/2015 :  10:18:30  Show Profile  Reply with Quote
The idea of no mid drive was Tony's, but I don't mind being mistsken for Tony! Especially since this bike is very close to what Tony builds. Why reinvent the wheel when Tony already did, and did very well.
Go to Top of Page

alevand
human power expert

USA
2910 Posts

Posted - 11/06/2015 :  11:18:12  Show Profile  Visit alevand's Homepage  Reply with Quote
My bb is 3 inches over the mesh seat frame, mesh sinks 1 to 2 inches. Make sure your steering linkage has clearance between the crank arm or front Derailleur, if you go that route.
C:
Tony Levand

Edited by - alevand on 11/06/2015 11:22:01
Go to Top of Page

PUGZCAT
recumbent enthusiast

Canada
459 Posts

Posted - 11/08/2015 :  04:32:46  Show Profile  Reply with Quote
ShelGame, nice design. On the vein of OSS, another benefit, if you build it stout enough, is to lift yourself up slightly to adjust your position on the seat while riding. I had this feature on a 'bent I built and really missed it on the next one I built.
Go to Top of Page

ShelGame
recumbent enthusiast

USA
254 Posts

Posted - 11/08/2015 :  16:36:02  Show Profile  Reply with Quote
quote:
Originally posted by warren

7" is good. As Thom mentioned, for normal road use you shouldn't need a mid-drive with the full size rear wheel. If you have special needs like going really slow up a steep hill or really fast in a fairing then the additional gearing is useful. I mostly use a 53/39 road crank and a wide range MTB rear cluster and that provides a great range of gearing (for me!)



The chain also just happens to run thru where the Rans seat mount would go. Hmm. Need to rethink it. I'd prefer to keep the mid drive. No real reason other than I just want to try it.

Finished up the jig table this afternoon.

Go to Top of Page

Speedbiker
human power expert

USA
3744 Posts

Posted - 11/08/2015 :  19:57:51  Show Profile  Reply with Quote
Just so you know, type and size of idler makes a difference in power at the rear wheel. IMHO the best idler under high power is the Terra Cycle titanium 23 tooth(I think)ceramic bearing super idler. It's amazing. but also amazingly expensive. Their 16 tooth sport idler is okay. Probably a little better than a 4 inch plastic pulley from a machinery supply(Grainger, etc). No matter the idler, be sure to to add a fence to prevent the chain from bouncing off the idler.
Go to Top of Page

ShelGame
recumbent enthusiast

USA
254 Posts

Posted - 11/09/2015 :  06:56:21  Show Profile  Reply with Quote
This is kind of a big tear up from the last revision.

I realized that the head tube for the remote steerer is the same diameter as the main tube, so that meant that there would be 2 breaks in the tube - 1 welded at the bend, and 1 where the HT went thru. So, I moved the bend to the HT to make fabrication simpler. it means that the main tube under the seat is a little higher, but it seems it will be OK with the Rans seat mount under it. It now looks much more like the Rans Xstream frame, I think. Only lower, and with a more upright HT angle.

I couldn't find a single location for the mid-drive that really worked. In the last drawing, I hadn't sketched out the chain line on the smallest rear sprocket. When I did, it hit the upper rear wheel stay. If I placed the mid-drive high enough so that both min and max chain lines cleared the upper rear wheel stay over the top, then it would run along side the Rans seat clamp - probably needing an idler to keep it from striking it. If I moved it low enough to run the chain line thru the rear triangle, the mid drive was either really far to the rear - possibly still needing an idler for the front chain, or really low to the ground.

With an idler attached to a 2nd Rans seat clamp (which I happen to already have left over from the Prone) on the bottom frame tube, it looks like it should work out fine.

Other than the (extensive) frame changes, this is the same geometry as the last drawing.

Go to Top of Page

shooky56
recumbent guru

USA
544 Posts

Posted - 11/09/2015 :  07:47:21  Show Profile  Reply with Quote
Couple questions Shel, since your vertical frame brace is so close to your steerer tube, can they all be one? Would require shifting the bends in the main frame a bit forward. Speaking of bends, have you considered bending as a construction technique?
Go to Top of Page

ShelGame
recumbent enthusiast

USA
254 Posts

Posted - 11/09/2015 :  07:59:42  Show Profile  Reply with Quote
quote:
Originally posted by shooky56

Couple questions Shel, since your vertical frame brace is so close to your steerer tube, can they all be one? Would require shifting the bends in the main frame a bit forward. Speaking of bends, have you considered bending as a construction technique?



I had it that way originally. But, that makes for a long remote steerer tube. And, I have moved the remote steer tube forward quite a bit since the first iteration.

I actually would prefer to bend the bottom tube since it will be the most stressed part. But, I don't know anywhere around me to get 1-1/2" tube mandrel bent.

I won't do it at a muffler shop. I consider exhaust-tube bends to be next to worthless, from a structural point of view.

Edited by - ShelGame on 11/09/2015 08:00:31
Go to Top of Page

Speedbiker
human power expert

USA
3744 Posts

Posted - 11/09/2015 :  10:15:39  Show Profile  Reply with Quote
While I don't have a problems with those compressed bends a muffler bender does, getting the angle perfect will be WAY easier with mitering. The design is looking very good. One point; with the low bb you will be able to straighten your arms more than on a higher bb design. I think you'll find riding with just a gentle bend in your arms to be most comfortable (and probably fastest ). Perhaps you've mapped this out already. They just look kinda close. Keep up the good work. This will be a terrific bike.
Go to Top of Page

ShelGame
recumbent enthusiast

USA
254 Posts

Posted - 11/09/2015 :  10:41:12  Show Profile  Reply with Quote
Yeah, I just estimated the handlebar position from pictures of other bikes. Most seemed to have the bars right at the front edge of the seat, about level with the seat back. I expect to have several iterations on the real bike to get them just right. I drew it in just to get the idea - and make sure I wasn't missing anything.
Go to Top of Page

PUGZCAT
recumbent enthusiast

Canada
459 Posts

Posted - 11/09/2015 :  17:36:55  Show Profile  Reply with Quote
Filling the tube with water, capping the ends with sandwich bags a elastic bands and freezing will prevent the tube from kinking at the bend. I increased the bends up by the grips of a steel BMX handlebars by around 30 degrees using this method. The tube at the bends were actually more round after the tweaking.
Go to Top of Page

Speedbiker
human power expert

USA
3744 Posts

Posted - 11/09/2015 :  19:31:08  Show Profile  Reply with Quote
I've bent many bmx bars with conduit benders. Takes about 30 seconds and I've never had a problem. That was before I went to gunners on almost everything I own.
Go to Top of Page

Speedbiker
human power expert

USA
3744 Posts

Posted - 11/09/2015 :  20:36:51  Show Profile  Reply with Quote
No, I like hanging on to a rafter while jumping on the conduit bender's foot.
Go to Top of Page

Garrie L Hill
human power supergeek

USA
1691 Posts

Posted - 11/10/2015 :  06:10:54  Show Profile  Reply with Quote
Engineering 101a

Machine to shape.
File to size.
Bash to fit.

Always make certain to use a big enough mallet!

Garrie "carbon based lifeform" Hill
HPRA Co-Dictator of the East
for pics of some of my time and money sucking projects
http://garriehill.winkflash.com/
and
http://s58.photobucket.com/albums/g277/cfbb/
and videos
http://vimeo.com/5513519


Go to Top of Page

alevand
human power expert

USA
2910 Posts

Posted - 11/10/2015 :  06:29:57  Show Profile  Visit alevand's Homepage  Reply with Quote
Ive used sand to bend tubing, either wet or dry or frozen or using a internal spring. The Blue Bike is posted on Jerry's built thread tubing was bent with a garage door spring inside. For steering I put the set of bearings at the top, have a static tube downward and one running up to the head tube, strong and stiff.

C:
Tony Levand
Go to Top of Page

ShelGame
recumbent enthusiast

USA
254 Posts

Posted - 11/10/2015 :  06:50:30  Show Profile  Reply with Quote
quote:
Originally posted by Speedbiker

I've bent many bmx bars with conduit benders. Takes about 30 seconds and I've never had a problem. That was before I went to gunners on almost everything I own.



Are there any how-to's for making the gunner's bars? I do have some TT/Tri clip-on type of bars I can probably get to the right position, but if there's a how to, I'd like to check it out...
Go to Top of Page

warren
human power expert

USA
6090 Posts

Posted - 11/10/2015 :  07:23:34  Show Profile  Visit warren's Homepage  Reply with Quote
Unless you are going to lean your seat back to under 20 degrees you probably don't need to worry about super aero steering. Your design doesn't appear to all for much lower than 40 degrees.
Go to Top of Page

ShelGame
recumbent enthusiast

USA
254 Posts

Posted - 11/10/2015 :  07:29:18  Show Profile  Reply with Quote
quote:
Originally posted by warren

Unless you are going to lean your seat back to under 20 degrees you probably don't need to worry about super aero steering. Your design doesn't appear to all for much lower than 40 degrees.



How do you usually measure the seat back angle? Tip to top? I measured across the lowest portion and set it at 25 degrees. But, maybe this isn't how everyone measures seat angle?
Go to Top of Page

shooky56
recumbent guru

USA
544 Posts

Posted - 11/10/2015 :  08:24:50  Show Profile  Reply with Quote
Looked a while in here for how our gang recommends doing it but could not find a how-to on it. It's probably here, I find brand new stuff all the time in here (that's been here for years).

Bacchetta measures their lumbar seat using the straight edge across the back. http://www.bacchettabikes.com/support/performance/

I drew two lines through your drawing (pic included) and calculated both angles. The second method tried to mimic your torso were the seat a plank. They came essentially the same.

[URL=http://s1372.photobucket.com/user/shooky56/media/Recumbent%20Postings/Jerrys%20Seat%20Angle_zpssoboutmw.png.html]
[/URL]
Go to Top of Page

Speedbiker
human power expert

USA
3744 Posts

Posted - 11/10/2015 :  10:28:36  Show Profile  Reply with Quote
Shel, gunner bars are just vertically oriented grips. If they are more than about a foot apart they aren't usually considered gunners. The ones I use mash my fingers together, but that is extreme. The good thing about gunners is how ergo they are. I suggest you prop something against the wall that approximates your seat angle (the more reclined, the most comfy, the less recumbent butt), then naturally reach forward. I like a verticle grip becauseit keep my elbow in and minimizes wrist stress. Don't over reach or your hands will get tired. You are building from scratch, make it fit you :-)
Go to Top of Page
Page: of 13 Previous Topic Topic Next Topic  
Previous Page | Next Page
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
www.recumbents.com © 2017 www.recumbents.com Go To Top Of Page
Snitz Forums 2000