changing sprung seat mounting

I would be liking to be changing my solo seat, Ive had enough of the cheap bates replica & would like to put on a charcoal metalflake/leather, or something similar. The rear bracket I have is set up for seats with spring mounts that are 7" centre to centre. The seat I wanna put on has studs at 6" C/C, as are many of the seats that are available (it seems mainly only ultima & larosa are among the few that are 7" C/C).
I also want to move the rear spring mounts forward (I think the seat is too far back from the tank for my liking).
I could mod the bracket, but the bracket already sits a little high for my liking, so i use very low 2" hairpin springs to counter this, but...they bottom out straightaway so I would like to use 2.5". This means I would like to mount the springs a bit lower than the height the current bracket sits.
Are you still with me in my long seat story .... anyway, I was thinking about drilling and tapping a thread into the crossbar/tube thingy that runs across between the frame tubes. Do you think a threaded hole in the top of this would work okay, to bolt a spring to? (remember Im a woodworker by trade not a metalworker I be needing help with these things)
The red x in the pic is roughly where I think I would be drilling & tapping. This would give me a lower mounting height than the existing bracket.

There wouldn't be many threads to hold it but then again, it wouldn't be under a lot of pressure. Could you not put a bolt thropugh from underneath?

a rivnut would work brett. drill the hole, riv nut, then bolt on.

Yep rivnut would be the easiest,most bike shops have them and the tool to fit them.

Thanks guys. I had never heard of a rivnut before. I gather this is a nut that is inserted & drawn up just like a rivet. Very handy! Wish I knew about it before.
Hey Andrew do you know anywhere local where I would get the tool & nuts?

Brett, that’s what I have to hold down the lid in my battery box, did you notice? Anyway orb borrowed one, so they must be around, "the bolt shop" on the shore here sell them but they may know someone who has stock, the tools are pricy...

brett7777 wrote:

Thanks guys. I had never heard of a rivnut before. I gather this is a nut that is inserted & drawn up just like a rivet. Very handy! Wish I knew about it before.
Hey Andrew do you know anywhere local where I would get the tool & nuts?

yeah. my mate has one in the panel shop. i'll see if i can steal it of him again and let you know. i'll price one up to. handy to have for your projects.

Irishjon wrote:

There wouldn't be many threads to hold it but then again, it wouldn't be under a lot of pressure. Could you not put a bolt thropugh from underneath?

yeah that's what I was thinking. Yeah drilling right thru the tube and bolting from underneath could be another way. Was tryin to avoid drilling thru top & bottom & just drill top only, it's funny tho, there's about 4 other holes from the factory in it so I guess HD weren't too worried bout holes in it!
Rivetnuts sound very good.
The only other possible hitch is that the tube is sloping down at that point, so Im wondering if that's gonna be a prob. I guess another way is to get a stud welded on there.
I would like to go and look at it more but the wind & rain is blowing all around my wee shed & I aint got a light in there etc etc yes harden up I hear you say

andrewj wrote:

brett7777 wrote:

Thanks guys. I had never heard of a rivnut before. I gather this is a nut that is inserted & drawn up just like a rivet. Very handy! Wish I knew about it before.
Hey Andrew do you know anywhere local where I would get the tool & nuts?

yeah. my mate has one in the panel shop. i'll see if i can steal it of him again and let you know. i'll price one up to. handy to have for your projects.

thanks Andrew. Im gonna have to figure out something cos I do wanna be able to put seats with 6" C/C studs on there cos it gives more choice in what seat I put on there.

I did'nt have that top bar on mine but I do have the same tube. I welded threaded bungs into that tube so I can just bolt straight through from the spring. The slope on min is the same as yours.

i just got the grinder and cut the whole thing off!

jon61 wrote:

i just got the grinder and cut the whole thing off!

BUTCHER
I think yours was a bit irrelevant at that stage

Irishjon wrote:

I did'nt have that top bar on mine but I do have the same tube. I welded threaded bungs into that tube so I can just bolt straight through from the spring. The slope on min is the same as yours.

yeah the top bar is aftermarket, bolts on where the fender bolt is
my welder friend is grumpy & non-communicative at the moment, so that's sad
I guess by welding on threaded bungs you managed to get them facing upright instead of on a slope? or doesn't it really matter?

hey. 225+gst for a riv nut kit. comes in case with shit loads of sizes.

[/quote] yeah the top bar is aftermarket, bolts on where the fender bolt is
my welder friend is grumpy & non-communicative at the moment, so that's sad
I guess by welding on threaded bungs you managed to get them facing upright instead of on a slope? or doesn't it really matter?[/quote]

Yep that made them straight. Thats a goo price fopr that kit. It would be useful to have one around.

yeah for sure. i may get one this week. i'll let you know what its like

i got a whole bunch of rivnuts 2 different sizes your welcome to have, my old lady works at ullrich aluminium so i get them free, i dont have tool but ill probably buy one soon, ill try remember to price one up tomoro

COOL

the other idea i have is to get a flat piece welded in the corners (like a gusset) between the frame tube and the crossbar tube
(drawn in red in the diagram) do you guys think that would work? I would drill holes in the gussets to mount the springs

Yup that would work fine, But its going to screw up your powder coated frame dude.