Recumbent design

[geoffw]

Hey im new to this forum, i race recumbent trikes but im going to build a lowracer but somethings always made me ponder. see when your pedalling your leg is next to the wheel so when you turn wouldnt your leg rub on the tire? and also why doesnt the chain rub?

It would be great if someone could help me an even give me some tips on designing the frame, i really wanna get this going soon

[Low Racer]

Hi Geoff,

Welcome to the forum.

How tall are you? If you are over 175cm then the heel strike would not be an issue. LR like M5 would pose a problem to short legged people due to the low BB. So have a look at the bb height in your design too. Too high and you may get numb feet. Design like Challenge LR bike is suitable for short people due to higher BB than M5 and also smaller front wheel (406, M5's 451). Someone did a test on both wheels and he found that he was a bit faster on the 451 and more comfortable than the 406. Less tyre choices on the 451 compare to 406.

If you are not running front chain idler, the chain will strike the tyre/front when doing sharp turn. My low racer has no front idler so I learned to live with it. The idler will sap some speeds and if your intention is to race than a dropped chain will be faster.

Good luck in your bike building.

Regards

Chong

[DaveW]

G,day Geoff.

There are lots of places to find on the net that talk about this sort of thing - you just have to figure out what they mean.

I also want to build a low racer myself, and have found out heaps, but not sure what is relevant to me?

By the way, you happen to have a Delica on you would ya?

[Poiter]

If it's a really low lowracer the chain will rub on tight turns.
Medium low chain rubs but it doesn't matter so much.
Legs generally don't rub and you can splay them out when doing the tight stuff anyway.
Lowracers with dropped chains go real fast but don't do tight turns well.
See my pics under Canberra HPV Racing.
Pete

[geoffw]

hey thanks for makign me feel so welcome,

Im yer 175 so hopefully that wouldnt be a problem,

for my front wheel i was planning on using a very nice 16inch wheel i have of my trike, I reakon it would be perfect anyone disagree with that?

Yer i plan to make a really low lowracer, but thinking about where im riding wont be sharp turns so chain rub wont be an issue so i wont run chain rollers.

Peter is that a nocom is it? Anyway i was planing on building something with geometry that was very similar,

And Dave wats a delica?

[Kalgrm]

for my front wheel i was planning on using a very nice 16inch wheel i have of my trike, I reakon it would be perfect anyone disagree with that?

Trikes usually have a custom hub on them for mounting on one side only. You might find you'll need a new hub, at the very least. One that will fit into a fork.

Cheers,
Graeme

[Kalgrm]

You've probably already found it, but you might find there is a lot more information for you on the "Homebuilders'" section of BentRiderOnline.com (loath as I am to suggest another forum ....). There is a very large community of people making these things around the world, and our little forum only has a few of these wonderful people.

A Delica is a 4wd van (a bit like a loaf of white bread on steroids. )

Cheers,
Graeme

[geoffw]

yer cheers graham, i was thinking a single sided fork with a bolting system similar to taht on my trike,

oh ok thanks for that, suggestion.

A delica wouldnt happen to a mitsubishi? Dave wat did u mean by that?

Cheers Geoff

[DaveW]

A Delica is a 4wd van (a bit like a loaf of white bread on steroids. )

Cheers,
Graeme

I think I'm offended by that Graeme!

Mine is definitely a full grain loaf - none of this gutless white bread stuff here bud. (3.0 ltr 24 valve V6, superselect AWD/4WD with Low range - at least the steroids bit was right. )

Yep Geoff, it is a Mitsi Delica 4x4 Van, and there is someone on the Deli site who also ride bikes with your username - I took a punt, but was obviously wrong - sorry for the confusion

They are basically a Starwagon but with 4x4 under them - and although I got mine because I have four growing kids and the Deli fits them in with ease, but there are some guys on the site who have bought them to transport their bikes to meets and rides.

[Kalgrm]

A mate of mine has one (turbo diesel). We give him hell, stirring him about it's resemblance to the aforementioned loaf. We call his "Buttercup". Nice units though; He spent 6 months driving around Oz in his.

I took the punt you had one and I would get a rise if I put enough yeast in the mix.

Cheers,
Graeme

[geoffw]

na dave sorry to disappoint you, but its quite ironic im only 17 only jsut got my p's lol.

Also wondering if anyone knew any links to find some info and pics on low lowriders?

Cheers Geoff

[Kalgrm]

Do a search on "Nocom" (short for "no compromise"). They are well regarded as one of the ultimate speed machines.

Here's something to whet your appetite.

Cheers,
Graeme

[geoffw]

Cheers Graham thats exactly what im looking for, im currently running pictures like that thru design programs trying to get teh same angles and geometry. So im actually hoping that mine will end up being a mild steel copy of the Nocom and a 16inch front it it works out

[Kalgrm]

That's going to be VERY heavy if you make it from steel. But good luck - it's worth having a go with these things!

Cheers,
Graeme

[geoffw]

Yer i can see it being very heavy, ill just ahev to work harder. unfortuantly steel is the only material i can get for free and work with dont have facilities for anything else. An id rather bugger up some steel tahn something like cromo or composite

CHeers Geoff

[Poiter]

A 16" wheel?
Hmmm - not for a fast lowracer.
For one thing the tyres are going to be fat but there is a Stelvio in that size. Small wheel will hold back speed potential.
You should be able to build a steel bike that is fast and practical and weigh aound 14 kg.
The NoCom is great but really is a Com when you think about mixing it with the traffic or dropping off even 50mm gutters.
Pete

[Low Racer]

Hi,

Trisled made a 16 inch wheels low racer - Nitro.



I believed it is a speed machine and I was actually at one point thinking of getting the demo from Trisled.

Chong

[geoffw]

reasoning for 16inch is i have the wheel, tyre the lot from my race trike, however i was gonna have a rear 27inch wheel tho,

But woul it actually slow me down that much? i hadnt really thought about it in taht sense, the tyres are 16x1.15 i think it is, so what would you say would be best size front wheel?

[Low Racer]

Hi Geoff,
IMHO 16 inches front and a 700c rear wheel will look unbalanced and make the steering probably very twitchy. I don't think the geometry will look right or make a stable bike. All the low racers that I have sushed out are 20 inches (either a 406 or 451) and a 700c / 650 rear. If all the major manufacturers (M5, Challenge, Optima) are doing it that way, it must be saying something.

I read somewhere that even a swapped of 406 to 451 made a huge difference to the handling of the bike. Just make sure your front fork is able to accommodate bigger wheel if need be. Good luck.

Chong

[geoffw]

Oh thanks chong hadnt really thought about stabability or that, What wheel combination would you recommemd or anyone else?

[Low Racer]

Hi Geoff,
406 front - 650c rear or 451 front - 700c rear. These are the norm combination on commercially available LRs. Many other factors will affect the stability of the bike apart from wheel sizes. I am no expert. You have to do your homework to see what will work and won't.

Thanks

Chong

[geoffw]

oh ok thanks, anyone know the best places to get one and teh costs for these?

[Freddyflatfoot]

Geoff,
If it helps, I made a SWB, 700C/20"(406), out of mild steel, using sq tube as the main boom, (50mm sq x 1.6mm).
Weighed in at about 16.5 kg, before I added a front suspension fork!
But no matter, its still a quick little bike, and much quicker than a comparable weight MTB. I regularly ride with some roadies, and usually don't have trouble keeping up, but am a little slower uphill.
I personally wouldn't worry about using mild steel for your first build.
As you said, its cheap, easy to work with, and easy to change if you muck it up!
You may even find you can use some frame parts if you pick up an old steel framed bike. For my SWB, I found a ladies bike useful, as the handlebars work well for OSS, and ladies bikes usually have shorter cranks, which is also useful for a 'bent.
When I've been on this form a bit longer, I'll even be able to post some pics and links!