Single seat v double seat on a plunger, ?

[dave55]

Hello, i was reading an old post which ended with Greybeard showing in detail how he fit his single seat, now i must admit i love the look of your bike Greybeard.  My bike has a dual one which i think must be a replica and i am still not sure if i like it so i am asking what was the deciding bit for you , or in fact anyone who has one or tried one. Are they more comfy and what is the comfort like for a passenger ?
There are some on ebay and chap also sells matching sprung rear one   All answers welcomed  Thanks Dave

[beezermacc]

I had a plunger with a dual seat and it was very comfortable. I also have a swinging arm with a single seat and that is comfortable too. My mate had a plunger with a single seat and i think the single seat suits the plunger, looks more appropriate for the period look of the bike.

[RDfella]

Can't speak for plungers, but a single seat is way more comfy that a double on a rigid. Given the plunger's limited travel, I'd guess they're a tad more comfortable than a rigid but not markedly so. If that is so, I'd opt for single seat with a separate pillion pad.

[Greybeard]

My bike came to me with a dual seat. While I was restoring the bike my wife told me that she would never go on a motorbike again so I fitted a sprung replica single saddle. As Andrew says, they look more appropriate than the dual seat. That replica seat was horribly uncomfortable for me. It had a metal edge at the back that the springs hook on to. The edge stuck into my gluteus maximus. On a long run I'd have to stop about every half hour to get the blood flowing again in my butt-ocks. I bought a modern design single seat that has dense foam with a metal base. It's much more comfortable. I had to manufacture fitting brackets for the modern seat.

[dave55]

Hello, after searching for single seat options they appear to be 15 to 16 inches at widest point at the back , i know ive got a big idiot but is that correct or could it be a misprint in the listings ?
The seats seem to come with springs , is there something else needed to fit the springs like on Greybeards i can see what looks like white nylon or plastic inserts on the ends ?  Anybody know / Thanks Dave

[Swarfcut]

 One of the important dimensions is the distance across the seat between the spring mounting studs on the underside of the seat, which should match the frame mounting points.  Measure the frame with the rear wheel and spindle in place...the frames spread an inch or so in the raw.  If the mounts are not directly in line, the springs will lean, and look a little ungainly from the rear, and tend to move the seat sideways as it deflects.

  Another slight problem is the front frame seat mount is a pivot point, and if worn will allow the seat to wiggle sideways at the rear, which feels a bit strange. Further disappointment comes with the first pothole or speed bump, as the underside of the unchecked seat rail makes firm contact with your newly refinished rear mudguard, a precision dent if ever there was one.  Some sort of bump stop within the springs is something BSA never considered.

  The lower mounting for the spring was originally a threaded stud into the mudguard mounting lug, length and adjustment allowed to suit seat spring height and rider's weight.  Homespun spacers for the springs may be required to end up with something that suits the ensemble.

 While a single seat certainly offers a period look, I prefer the versatility of a dual seat, which offers a chance to move around a bit to keep the blood flowing on longer runs.

 Swarfy.

[Greybeard]

The seats seem to come with springs , is there something else needed to fit the springs like on Greybeards i can see what looks like white nylon or plastic inserts on the ends ?

What you can see is bright washers either side of the spring eye. The pivoting bracket was made from a piece of ex BT cable bearer. I have plenty of it left if you need to make your own bracket. You can see what that looks like in my original post about fitting this seat. If that bracket is well fitted the seat will not wobble, (much) laterally. I had to make a tricky bracket for the spring attachment at the back of the seat. I'm not entirely happy with it but it works.

[Greybeard]

I'd better mention that I am not able to remove the petrol tank without first removing the saddle. It's a pain in the wossname but I don't have to do it very often.

[Rex]

I started with a bare seat frame so was able to drill the seat frame at the correct centres to prevent the "leaning spring" look, plus I made up the front mounting brackets and welded them on to get the front-to-back diension right.
A proper close-fitting bolt or stud is needed for the nose mounting to prevent sideways movement, and on the springs I had (from Feked) I had to turn up some mounts to get the seat to sit level, and they also prevented the seat frame kissing the rear mudguard going over a large bump in the road.
A pro recover by Leightons and I'm more than happy with the result. 
 

[dave55]

Greybeard thank you for the pictures, aand yes i have trouble taking seat and tank off , cant do one without other even after slotting holes in front bracket of seat. Both now off and on the hunt for bits.
Thanks to everybody who replied. Dave