Is it just me...? Quality of my ride, plunger

[Simon59]

Hi Guys! On Tuesday I got back from a 300-mile return trip on my plunger A10, to watch the MotoGP at Silverstone with my Cheshire BSAOC mates. The bike didn't break down (which was fantastic) and the MotoGP was great to see - but at times the ride was painful to say the least! The route we took was mostly B roads, but I physically bounced around far too much for my liking when I hit pot holes and similar imperfections in the road. I even broke three springs in my Lycett-style single seat (which I discovered yesterday). So my question to you is how can I improve the quality of my ride - even though the springs in my plunger units are new. Is there a more comfortable single seat that I can buy or make? Or is it just me? I weigh around 14 stone if you're wondering and I've not got much fat on my bum... 

Mod edit: title edited. Please always use a descriptive title in the tech boards.

[Butch (cb)]

Can you run the tyres with a bit less pressure?

[groily]

I think our undercarriages get more sensitive from about the age of 60. I know mine has, and it's a well-upholstered one. Doesn't matter what bike, either, moderns included.  It requires regular stops to reduce cramp, empty bladder, massage sore bits, rearrange dangling ones. Ouch. And I don't have any single seaters, having got rid of a horrible Oilfield Bullet so equipped, so can only imagine the added pain!

[berger]

i just think the roads are in a mess, i have been swapping rides between betsy beeza and urma yonda for about two weeks while trying to find out what is happening with the missfire on urma. i do find the sit up position on urma is a lot more comfy than the clip ons on betsy but the bumps still feel the same and i still find myself shouting F*****G  roads on both bikes!

[Black Sheep]

Thin oil in the front forks (I use 10-30), well greased plungers and sticking to sensible tyre pressures (22 front, 25 rear). These machines do rely on the tyres to do a bit of the suspension's job, unlike modern bikes.
I'll be riding in excess of 250 miles on my plunger A7 on Saturday. Hoping to be able to walk afterwards.

[RDfella]

Yup, run the rear tyre soft as possible without compromising handling. My rigid M21 runs 22psi front, 20 rear.

(speedmaster front, avon roadrunner universal  rear)

[Rex]

Blimey that is low, especially if they're modern tyres. That's the sort of pressures people used to run when the tyres were those horrible stiff-walled things, but I wouldn't want to run compliant tyres like Mitas etc at those pressures.

[Black Sheep]

It's not like running radial tyres on a trials bike at 2 psi on the road. Quite interesting to both do and watch. The Scottish 6 days has long bits of public road between sections and somehow they manage. 

[Greybeard]

Hi Guys! On Tuesday I got back from a 300-mile return trip on my plunger A10...

Fantastic! 👌

I now have a 4" Mitas tyre on the back. That seems to have improved the ride over potholes.

Have a search for my post about the saddle on my sickle. See below.

[Rex]

It's not like running radial tyres on a trials bike at 2 psi on the road. Quite interesting to both do and watch. The Scottish 6 days has long bits of public road between sections and somehow they manage.

Indeed they do, but I rather doubt they're ordinary road-going tyres as our bikes use. I find the bikes wallow if the tyres are down to the 20's psi level, but each to their own.

[Simon59]

Thanks guys for all your replies and suggestions!

I hadn't thought of tyre pressures before. I have new TT100's and pump them up to 30 PSI. So I will let some air out and try them again.

Grease in the plunger units - yes, I think they're full, but I will pump more grease into them through the nipple on each plunger.

Front forks - I used 15W Castrol fork oil but I will top them up and maybe change to a heavier oil.

Seat - I can definitely improve the one I have and I will look up your previous posts Neil. Can I ask you if you have the front fixing point through the frame locked tight or if yours pivots at this point? I'm trying to think through the physics of the sprung seat and wondering why three of the springs under my saddle have snapped.

All the best and thanks again, from Simon   

[groily]

I have new TT100's and pump them up to 30 PSI. So I will let some air out and try them again.

On TT100s I find 24-25psi up front and 28-ish at the rear gives a reasonably comfortable ride. Very bumpy at 30 on the front I have found. And that with swing-arms and dual seats!

I also think a bit less on the rear may lengthen the life of these modern versions. I got just 3000 miles on the rear of my A at 30-32 psi (I'm heavy) with too much of the wear on the middle bit. That's about half what trusty old Avon SMs gave. But they're doing a bit  better on a couple of other 650s at lower pressure.

To Rex' point about modern tyres, though, probably worth checking what the maker's have to say too . . . which I haven't.

[Greybeard]

...
Seat - I can definitely improve the one I have and I will look up your previous posts Neil. Can I ask you if you have the front fixing point through the frame locked tight or if yours pivots at this point? I'm trying to think through the physics of the sprung seat and wondering why three of the springs under my saddle have snapped.

A single seat must pivot on the frame.

There are alternative front fixing points for the dual seat or the saddle.

[Greybeard]

https://www.a7a10.net/forum/index.php?topic=15312.msg129089#msg129089

[Rocket Racer]

You mention it's very bouncy. std plunger forks are undamped, so adding fork damping (such as eddie dow type) will calm the front end bounce. I can't comment on your roads but over here logging trucks and other trucks have generally munted many of our roads and it pays to be vigilant and prepare to take some weight on your legs as needed, if the road surface isnt great. 
I'd likewise be reluctant to run under 30lbs on a modern thin walled tyre. Profile and width do make a difference, personally I dont think the profile of a TT100 is suitable for a plunger frame but tyres are like oil threads, everyone has a different preference, so I wont share mine beyond that. I doubt there is much you can do re rear plungers and if your seat is stock mounted and sprung ditto.