Home Built
 

Hey :D

Any of you dudes build your own bents?

I've just started building one and have a question or two.

How do you measure the distance to set the BB on the boom?

Thanx

I would recommend a boom or seat that allows some adjustment. It takes a while to configure a recumbent, in my opinion. I ride a RANS Rocket and it took awhile to get it set in place.

Another option is to ride some bents and try to get the measurements once you feel comfortable.

On the Rocket, it is 13 and 3/4 inches from the front of the steering tube to the back of the bottom bracket. If that is any help.

Just my $.02

ok im lost as to what the bottom bracket is. ive made my own i bought plans on line and did things my way (normally the wrong way) i really dont know the names of every thing are.

The bottom bracket is the part that hold the crank set up and is attached to the front of the boom on a SWB bent. :)

ok now i know what you are talking about.
well i mounted a fork from another bike so it stuck out in front. then i mounted my seat and set it where i was comfortable. then measured me sitting aganst a wall, back of butt to my heal. then measured off the seat to where the pedal would be when it is furthest away from the seat. cut post that is attached to the BB then attached to the fork. now the bike i used had a funny shaped tube ( tear shaped) it it was round i would of cut it close then cut a slit up the pipe thats attached to the BB so i could use hose clamps to tighten it down yet i could make it longer or shorter. ( read about a guy doing this ) might look for another donar bike for the BB so i can still do this would make attaching chain guides easier.

I forwarded your question to a friend of mine who makes all his own bents. He does not belong to this forum (yet), so I am posting his info. His web site is www.velomobiles.net if you want to track him down.

"As for locating the BB, the important distance is that from the hip socket joint to the ball of the foot (with foot slighty extended to simulate pedaling). Take that distance and subtract crank length plus an inch or two so that the pedalers leg will be bent slightly at full extension. That seems to have worked pretty well for me, although I must say that I've had to change boom length a few times, because the type of seat used seems to effect how far foward your leg extends from where you'd expect your hip socket to be located. Probably the location of the hip socket front to rear
is different depending on the seat type.

Enjoy!

Resources for home-built bents:

http://www.wisil.recumbents.com/wisil/
(click on "HPV Projects")

http://www.bentrideronline.com/
(click on "Message Board", then "Homebuilders")

Hey thanks guys... you have been very helpful.

I currently have the basics of the frame built and have nearly completed the seat frame, guess I'm going to get the boom length sorted pretty soon huh.

One little response regarding In my entire life, and we have the main national highway running through the centre of our town, I have only ever seen one bent pass through.

That's one of the reasons I find them so appealing, It's the same deal with tandems too, only ever seen about half a dozen on the road around here so I just had to build one :D... It's cool to be on the lunatic fringe.

Your safest bet is to construct the boom so it is adjustable. In otherwords, one tube inserted into the other. The tube with the BB should be able to move in or out. The support tube is welded to the headtube. By trying to cut a tube to the exact length to weld your BB on, you're taking a chance that your riding position will never change, and that there will never be any need to adjust the BB. If this is your first one, do yourself a favor and make the BB adjustable.

Thanks for your advice.
I am going to weld the BB in place as I have made the seat adjustable.
I will however be road testing the position before it is finally welded.

Best of Luck!

Alan

WOOOOOHOOOOO it lives....it lives.

First test rides today, other than bein a bit twitchy in the steering its great.
I have set it up withh ASS until I'm sure that the chain route is correct... which it seems to be (around 20kms with no probs)... then I'll get on to the USS.

congratz

:D Out of all my bikes (4) the bent is surely my favourite.... I don't think my mtb or roadie will get much use for a while. The tandem is still pretty hot though :D
Now that I have got the uss sorted it's even better and more comfortable than it was before.
Now onto making some barend shifters and a new 30 tooth chainring:)

Great to hear about your completion of the project. Keep us posted about how well you like it.

Awesome... the bar end shifters are great, still have a couple of sticky teeth on the chainring, more filing.
I tried a little experiment today, I ended up with with a triple crank driving a 5 cog set as a jack shaft then a 6 cog set at the wheel, dude it gives ya a whole bunch of gears to play with. :)
Decided that overkill is cool but this is a little extreme even for me. :D:D:D
I gotta say I love this bike... Guess I will have to paint it soon.

now what are you going to do with, what 90 gears? i still rarely use all my gears as is.......... heck i dont use but 3 gears and i dont really shift around much...

Hey Mike :)

I didn't keep all 90 gears... I went back to just 18.
But it was kinda interesting in a mine is bigger than yours kinda way :D

lol

Awesome day today... the bent claimed 2 new victims.
Why oh why do people keep falling off it... I don't. :D

Dudes this thing is the dogs bits... 30km test ride today and no probs at all :D although I might have to add a lil more padding to the seat bottom.

lol ive still got to get another trailer built so i can haul all the kids otherwise im stuck at home. I mainly ride to and from work 8 miles all togehter then i watch my kids as the wife goes to work... need one more trailer and a way to attach it to the other and the oldest can follow on her little bike.... but till then im stuck at home.. i would love to ba able to go further then my daily commute but time isnt on my side most days.

Mike... You could always go the tandem way, my daughters aged 11 and 13 have no trouble on our tandem (also home built) even though they look the other way when I ride by on my bent :) although one of the twins is getting kind of interested in having a bent.
Maybe I should build a tandem bent and make their allowance conditional on a weekly ride :D

ive seen photos of your tandom on your web site really nice looking, you need to get photos of your bent on there so i can get a look at it.
My oldest is only 5 and she is scared silly of falling off a bike. my oldest boy just turned 2 on the 9th and i have a 3 month old boy. so for now i need trailers.
i just got the fork and BB attached to the bike im making for my wife now i need to make a seat, run the chain, figure out how i want it run and add a riser for the handle bars and it shout be ready to go well brakes also then ill start on another trailer for it

Hey Mike... Check these out for an idea for the kids.
Should be pretty easy and cheap to make.:D

This is the site that caused me to get into building a bent.

http://www.ihpva.org/people/tstrike/trailer.htm

http://www.ihpva.org/people/tstrike/rectrailer.htm

I will get some pics of the machine when I've finished it and painted it... At the moment it's as ugly as a hat full of bums. ;)