Manky Monkey Motors

hi ok getting to the point now where i need to start thinking of a frame so what tube size do people use i was thinking of using big tube diameter tube like 42.4 with 3mm wall buying bends of certain degrees off ebay and using 36mm 3mm wall tube as joiners anyone tried that sort of kit style frame build?  ???


ta newbie steve

Never tried it but did think about something similer a while ago on a bike frame.
I think it could look quite cool, going for a `plumbed`look, especially if used in conjunction with a steam punk theme  ;)

could be quite handy for setting up frame straightness etc almost self jigging if i work it out right! ummm

Like these.
Nicked off the Jockey Journal Forum.

(http://i471.photobucket.com/albums/rr71/reliantman/055.jpg)

(http://i471.photobucket.com/albums/rr71/reliantman/047-1.jpg)

Dam! beaten to it again.....maybe there is no such thing as an original idea any more  ;D

Yeah, Indian were doing it for years. No reason you cant do it though.

hi steve,i don't think theres any thing wrong with taking the idea of using preformed tube bends in your frame ,but i think you may find most of the tube bends on ebay will only have a 1.5 mm wall you may find 2mm but that's still not enough, but if you can find a source of tubes with a good wall thickness i think theres an advantage to using these tube bends by bending the tube your self you are weakening the outside of the bend by the stretching that happens when bending, if you can find tube bends with good wall thickness eg  ( bigger than the straight tube you use for the rest of your frame) then i think you will have good strong joints it may be a little expensive as preformed tube bends don't come cheep, but what one wants to spend is down to the individual, i think it will  also give it a kind of pleasing overall look. and as you can see from plasticpigs pics its already a proven tested idea.i have also seen this method used in the building of roll cages. go for it son.zak

banger racers. use this type as its easy to change from car to car
http://www.keyclamphandrails.co.uk/index.html

but full car racing must use fully welded and braced cage

i think the point i was making to steve, has nothing to do with the costruction of roll cages or there like, or any standards set out for the building of them,the point i was making to Steve was don't dismiss your ideas with out (constructive criticism) as to why the idea is not a good one, or why  the idea is just not going to work .zak

thats a useful link you have put up there terry

So why would a tube welded into a preformed bend be any weaker than any other welded joint?
Surely the weld would mearly be to hold the tube in the bend, and the preformed bend would itself be as strong as any tube bent in a bender, if not stronger, given the larger diameter tube needed.

well turbomangler i think to refer to some ones idea as being (the worst idea you have ever heard) is not constructive or encouraging to some one who is just starting a project,i have broad shoulders so can take none constructive criticism all day long, I'm a big believer in that politeness is no weakness, as for the comment to terrys link as being useful there was no mention of the reason i found it useful, all your doing hear is detracting away from the comment you made about some one Else's idea,and going on about things that have no relevance to that comment witch is the real point hear. zak

Gentlemen!
Keep it friendly & fluffy please.

yes m.m no prob

Just a comment.

Here is a picture of an Indian model 441 frame. Sorry it is not too detailed, but you can see the brazed in 90 degree joints. Granted the bike was only 40-odd hp, but brazing was and still is as good as any other method of joining if done properly.
I googled elbow bends from pipeline suppliers, and came up with a hell of a lot of chinese & korean ones.
Dunno what happened to good old british products.

I personally would not like to use a roll cage made of seperate pieces, and I thought there were rules against using them, but then I'm not up on scrutineering practices.

http://i471.photobucket.com/albums/rr71/reliantman/framejig.jpg

Turbo.
I don't particularly agree with you, the same as sometimes I tut over some other posts, but I have learnt my lesson from when I first started going on forums.

 I made a couple of trike frames out of sched 40, and later sched 80 pipe, and was told in no uncertain terms that I was wrong. It got to the stage where I was slagged off on every bike forum I went on, and in the end I stopped going on them. It was only when I found out that Chris Ireland, and later on Andy Mankey used the same stuff. That is why there is a gap in my membership on here and a couple of other places.

i think turbomangler, this is getting so boring,i think Steve knows the point i was making and on that note i think the decent thing to do is allow Steve to have his thread back and use it for the purpose he put it hear for in the first place, so with (my) dummy still firmlly in my mouth i think steve can make his own mind up on comments made so far.zak  

Whilst your 3mm wall thickness might be fine I suggest tube size is dependent on the size and kind of load being applied and perhaps it is dangerous, or in some cases over-the-top, to generalise on sizes.

Purely out of interest can someone tell me what a typical bike frame wall thickness might be (I've never cut into a bike frame tube)?

The few I have cut up were between 1.5 and 2mm wall. The japs have probably spent millions of yen (£2.50)
on frame design and know what to get away with.
Look up Frame design by Tony Foal. That will give you some idea.

 :-X  :-X  :-X :-X  ;D

behave yourself tbone. ::) ::)

Hi turbomangler.i dont think any one is disputing the fact about how your frames are built or andys.tbone.and any one else that have built designed and built.the point as you say to this forum is.
as you know. some one asked a question or has an idear and gets an answer back at the end of the day if they use it or not its up to them what rout to go down. and not to impose our views on then   

i think turbomangler what was intended as debate, you appear to have taken personally, my comments were not aimed at anything else but the first few words of your input to Steve's idea, as a newbie my self i put my self in Steve shoes,if this had been a posting on my thread i think the words (this is the worst idea i have ever heard) could have knocked my confidence to the point i could have felt stupid, and probably not wanted to post again or aired my project on the forum, it as nothing to do with your ability's or your work already aired on the forum I'm sure your input is valued and will continue to be valued, i think in short a little more tacked in your wording would go a long way to your advice being more appreciated, we are not all professional on hear some of us have never done any thing like this before, so we look to the more experienced amongst you for guidance. zak

With the amount of wordage this thread has generated it is obvious that there is definitely " more than one way...." to skin the proverbial! however, it might be as well to remember that successful chassis/frames, both 3 and 4 wheeled, have been constructed from large diam. tube, small diam. tube,thick wall, thin wall tube, and even marine plywood! its the attention to construction that is usually the mitigating factor, so..... you know what you have to do, 'and just be carefull out there',and guys how about using "spell-check", it makes these items so much easier to read for old 'Geezers' like me!.....Morrag

Remember amateurs built the Ark, professionals built the Titanic!!!

lol, i like that bikergran

hi thanks for all the comments i was gonna use this guys bends on ebay http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=290441737731&ssPageName=STRK:MEWAX:IT in various angles and buy 36mm tube (3mm wall)so i can cut for the joiners so a 3mm wall tube with 42.4 diameter with 3mm wall so leaves 36.4 internal size to bang the joiner in. this way i can experiment with tube and angles etc or buy a 16 (12ton) hydralic tube bender as already suggested.. just bouncing ideas off people...want the frame to be a nice feature as a lot of trikes i have seen look a bit reliant looking also toying with the idea of renault 5 gt engine converted to rwd using a mt75 transit gearbox should be interesting to build... happy new year

happy new year to you steve, and all the best with your project.zak

ok... anyone have an idea of frame width for the two bottom rails?thinking that if the bootom rails are as wide as the alternator from center line would that sound about right?????

how many inches (or mm) is that then

The front of the bottom rails is determined by the engine mounts. The MMM designed mounting varies but an inch to inch n half long will do nicely. The longer the engine mounts are, the further apart the rails will be, because of the angle they fit at.
The rear of the bottom rails can be any width you like, they can taper inwards, but will need to kick out again to attach to the axle. They can taper outward to meet the axle where you want to mount them.
The `norm` is to run them parallel, the same width apart at the back as the front, then kick outward to the axle.

Just replied to an email from Steve, saying almost exactly, word for word, Mr TBone's advice!

I`d like to think great minds and all that...... ::)

ok im sticking to the bend the heavy wall tube idea, everyone can put the hand bags down now..lol...
On another note the exhaust manifold is proving to be a complete bastard but ive solved it with some rather nice laser cutting (pic to follow..:))
also i hope my fat bob tank fits and the inlet extension dont have to be too mahoosive...

Ooh, n-i-c-e tank.

thanks for the pics that explains alot.. do i see you have the sump blocked up to 5" from the floor, on that wood? i have machined the engine mounts to 1.5inches as you say this makes the sump lower than the main tubes but looks ok to me... also how close do you run the underside of the tube to the rocker cover from the head stock any dimensions there would also be handy... ta steve... also im assuming people use 90 degree bends up to the headstock from the engine mounts??? pretty handy having the tube size the same as electric bed frame sit up tubes see pic , can you guess i work in healthcare?? lol

Mine was blocked up to 6", 3 lots of 2x2. The whole frame will drop a tad when the weight of the engine is transferred to it and the forks are in place.
90 degree bends? entirely up to you, mine were around 33 i think, the tighter the bend then the squarer the front cradle will be.
And finaly....too dam close! i fitted my top rail without having the reliant oil filler/breather in place, and only just managed to get the thing in the cover. 19" rings a bell,there are some pics on or around p7 of my build thread, the one where i realise it may be too low was later and vanished in the great site hacking of 2010!  if you like i`ll measure it when its light out.

Well I quite like the idea.

Would need some careful thought but should be fine. I like to see people take different methods and give it try.

Indian Larrys Chop with a frame built of welded chain. I'd agree it's not the prefered method of building but why do what everyone else does?






 

ok tank done not sure if its too orange??? has a sparkly laquer too... comments please..

Oooh, I have a pair of fat bobs that look that exact colour, may just be the pic though. I like it

that shade of orange would be spot on for me.zak

that be a nice colour of orange
al

Nice. Very nice.

If it's gonna be orange, how can it be TOO orange?

Really really nice, A thumbs up from me. g6.

love that and the colour too.   ;D

Re tube size, does 1 inch look a little small compared to the axle diameter aesthetically? Thinking of bigger tube.. input much appreciated :) ta Steve