Subframe

[clivegto]

What sort of thickness would you nice peoples recommend for a subframe like on this Martek. Am thinking 4mm but is that to thin?  

[TonyGee]

I tend to over engineer stuff so I would go thicker !!!!  I don't worry about the weight of things  

[clivegto]

7 minutes ago, TonyGee said:

I tend to over engineer stuff so I would go thicker !!!!  I don't worry about the weight of things  

I want to keep the weight down as much as possible for this but still be very strong. 

[clivegto]

Coz we like pictures    

[davecara]

That looks like 6 or maybe 8mm

[clivegto]

1 hour ago, davecara said:

That looks like 6 or maybe 8mm

Yea it does which makes me think it would be quite heavy. 

[dupersunc]

I'm guessing 6mm.  Drill lots of big hole in it to get the weight down.  4mm won't be stiff enough imho.

[Wagola]

4 hours ago, dupersunc said:

I'm guessing 6mm.  Drill lots of big hole in it to get the weight down.  4mm won't be stiff enough imho.

It does look thicker than 4mm which sounds a bit thin IMHO, so I'd think 6mm. But if you cut hole and 'swage' them you will add stiffness. 

[TLRS]

Look at the thickness of rearsets, caliper brackets, shock mounting hardware. Check shock travel and multiply it by the springrate. Some of these brackets look very skinny but take huge loads.

Look at the length of stock subframes and imagine the loads two up with some luggage. Hanging exhausts of the side.

If you have a very light tail section and your ass is only inches away from that already substantial bit where the tank mounts to, you could probably get away with a very svelte subframe.

Would beef stuff up around the bolt holes though, that's what you see on stock subframes too.

Edited December 14, 2022 by TLRS

[Fazz711]

At a guess I would say it 8mm 

[Ivan]

Isnt the construction more important than thickness?

[Joseph]

There are two substantial tubes welded in between the plates

There are 4 holes drilled to hold what seems to be a battery box

Those two features will totally lock the structure solid.

Judging by the last couple of photos, the plates are definitely thinner than the holes drilled to hold the battery box

An 8mm hole would realistically mean 4-5 mm of plate thickness ?

Edited December 15, 2022 by Joseph

[TonyGee]

1 hour ago, Ivan said:

Isnt the construction more important than thickness?

it does make a difference if its done right. 

[clivegto]

10 hours ago, Joseph said:

 

Judging by the last couple of photos, the plates are definitely thinner than the holes drilled to hold the battery box

An 8mm hole would realistically mean 4-5 mm of plate thickness ?

 

I was thinking along these lines.

[Joseph]

7 minutes ago, clivegto said:

 

I was thinking along these lines.

Yep i always check surroundings to see what i can estimate thanks to "known" details when it comes to this sort of thing.

4mm alu plate is quite solid, especially if you're doing a "replica" of the structure here and similar bracing points

[denisd]

I think it's 4mm plate, the strength is needed vertically so the thickness of the plate is less important than the fabrication and design of the subframe. 

[Dezza]

17 minutes ago, denisd said:

I think it's 4mm plate, the strength is needed vertically so the thickness of the plate is less important than the fabrication and design of the subframe. 

That's what i was thinking: align a plastic ruler vertically, then try and bend it. Then lay it flat and try and bend it. There is obviously a big difference here.

[clivegto]

@Ben Slabbygave me this, cheers mate. We don't know who made it but it's made of 5mm plate, so that answers my own question 

[Grove]

Where’s the best place to get rear subframes made, I’d like mine about 2 inches higher at the rear to lift the rear of the seat a bit

[BoostedRooster712]

I know the last owner of my bike went to steelheart (sp?) engineering when he picked the bike up after 12 months of it not being finished. Was meant to be 2 weeks. 

[clivegto]

8 hours ago, Grove said:

Where’s the best place to get rear subframes made, I’d like mine about 2 inches higher at the rear to lift the rear of the seat a bit

 

 

Make the subframe up yourself then take it to a welder to stick it together, it's what I do, I get Will to do my aluminium welding at Weab Motors Malton. 

[BoostedRooster712]

I don't know if this helps but this is how mine is set up and the seat fits well. 

Fucking phone.  Sorry about the rotation. I'm not sure if Walker made this or the other guy did.

 

 

[geogsxr]

On 12/14/2022 at 12:28 PM, clivegto said:

Coz we like pictures    

Shame this guy has such a bad reputation. These are stunning.

[bunk]

Im a little late to the party, but i say go 4mm and dimple die the holes. Would be plenty strong then.

[clivegto]

5 hours ago, geogsxr said:

Shame this guy has such a bad reputation. These are stunning.

Still in business as well. Always loved the Martek big tube frames back in the day.