OG fatgoose 170 update

[snoopy72]

I think your right, it feels the weakest under a bit of load but I haven't really forced it because I don't want to twist it out of shape, at the moment it springs back.
 I was originally worried about the crankshaft, no chance of that breaking

[oldschoolace]

If the expanding foam idea proved usefull you could drill little "weep" holes to inject it in. 

[snoopy72]

I think it'll crack where the bb meets the box the way it is under heavy load, in my opinion that's the area pedaling will stress most as power is transferred to the rear wheel via the cranks.

I'd consider increasing the size of the box.

As it would reduce the bb flexing I think this might actually reduce the stress on where the down tube and seat tube meet the bb.

Might increase the stress where the down tube meets the head tube though.

Any structural engineers on here?

The headstock on a mongoose is pretty strong with the gusset, not known a mongoose to break there.
I've known one snap at the top of the seat mast tube but that could have been caused by the seat post not in far enough. all in all mongoose did make a strong frame but can it handle my modifications ? It will certainly be a test for it
Skip Hess would probably say   your going to hurt yourself you 

[Gnarlyscoots]

I'd consider increasing the size of the box.

You boasting again    Most of us would prefer to see a smaller box but, in this case of requiring a bigger box for the extra stiffness gained, I would have to agree 

[snoopy72]

I'd consider increasing the size of the box.

You boasting again    Most of us would prefer to see a smaller box but, in this case of requiring a bigger box for the extra stiffness gained, I would have to agree 

I agree the box needs to be wider, got to be careful not to go too wide as this will in turn move the stress to the bottom stay tubes, then brace the top and bottom stays together, this moves the stress to the top stay where it meets the triangle, brace this and the top of the seat mast and the stress now moves to the bottom of the seat mast, brace this then it moves to the base of the down tube, brace this then it moves to the headstock, brace this more and now it makes the forks weak , brace these and now I have a bike that looks and feels as heavy as an Austin Allegro.

[rodriguez]

I'd consider increasing the size of the box.

You boasting again    Most of us would prefer to see a smaller box but, in this case of requiring a bigger box for the extra stiffness gained, I would have to agree 

 

 

[oldtired]

i think increasing the size of the chain stay box is the way to go ,  i would assume that goose used this method to get round the flex problem on the original goose frame , as the front end is held solid with the gusset , 

[snoopy72]

A lot of bmx's were prone in the 70's to snapping at  the headstock after big jumps and mongoose used the gusset design on theirs.

[snoopy72]

Spent all morning making cardboard templates and then cut these out of a piece of 50 x 20 rectangle box section, they fit great.
I'm going to do 2 types of strengthening and take a chance ! the next stage is paint, the only time it will be built again will be when it's finished.
I'm going to extend the cigarette box and fit a 1976 frame gusset, I think this gusset will look ok because like the 76 model my frame doesn't have a rear brake bridge.
Just waiting for the 2mm plate to arrive and then pop to the engineer and ask if he can drill a nice clean 16mm hole in it, then I can cut out the shape from a cardboard template that i've made from the original specs which Johnny goose kindly took time to take his 76 out of storage, unbox it and measure the gusset for me.
I didn't want to go too wide with the box , I don't want to transfer the problem to another place and make it look wrong to the triangle gusset above it at the top of the seatmast.

[Retrodan72]

That looks bombproof, good work. 

[snoopy72]

 

[rodriguez]

Great stuff   

[oldschoolace]

Proper job 

[oldtired]

 

with the down tube gusset i would have thought it will be solid enough , at the very least no more bendy than an og frame , comparing the update shots to the first box tube shots i think it needed to be bigger any how even without the need to overcome the flex , looking forward to the next update 

 

[snoopy72]

You'd be surprised how much more leverage 60mm has made over the standard bb, if I go too big with the box it will make it weak on the bottom stay tubing just as it leaves the box.
It was 40mm and now it's 80mm, to get the same distance between the end of the cups and the rectangle to make it visually  the same as the original it would have to be 100mm which will look like a video cassette.

[snoopy72]

with the down tube gusset i would have thought it will be solid enough , at the very least no more bendy than an og frame , comparing the update shots to the first box tube shots i think it needed to be bigger any how even without the need to overcome the flex , looking forward to the next update 

My thinking is, if the leverage could make one of the tubes crack at the weld  then joining them together it would have to crack 2 tubes which is unlikely.
I don't want to risk doing just the rectangle , painting it then wishing I had fitted the gusset , the gusset is just a precaution.
Maybe it doesn't need it.

[MartyC]

Great work, this is progressing nicely 

[snoopy72]

I do too much thinking 
I thought lets make the triangle match the rectangle.

[Retrodan72]

There's nowt wrong with thought, just keep it to a minimum and keep this thing going.

I look forward to the updated instalments mate. 

[griff]

Think SE have got wind of this project and wanted to have a go themselves

[snoopy72]

 

[snoopy72]

Wish I could TIG , i'd have it done by now
Now then, for the colour, (yellow or white)  ?? or the original blue metallic and what about the anodised parts, what colour ? any thoughts ?

[Jaymz]

I like a yellow and black motomag

[snoopy72]

I like a yellow and black motomag

I've been looking at the seat leon yellow but got to find the paint code for it, maybe I could stop someone at the lights with one and ask them to pop the hood or door shut so I can get it 
Anyway I think it's Ovni yellow S1H but the cupra I saw looked like a straight colour, if you put the colour in on the net it says it's metallic.

[Retrodan72]

I like a yellow and black motomag

I've been looking at the seat leon yellow but got to find the paint code for it, maybe I could stop someone at the lights with one and ask them to pop the hood or door shut so I can get it 
Anyone on here got a yellow 2004 FR TDI Leon ?

Onvi Yellow - S1H.