Starter rollers

[fridayflash]

has anybody made a set of starter rollers before,or have any advice
on the matter?i thought id make a small 'chassis' and mount some kind of
roller tubes (perhaps from a conveyer of some type) linked together with chain,and powered by a car starter motor.
something ive wanted for a few years now,to save having to run up and down
the road push starting 'project bikes' etc lol
also useful for 'total loss' racebikes etc
gratefull for any input,
ta

[geoffm]

A fellow Gama owner has a set - fery nice that uses a car (subie in his case IIRC) starter motor. THere is a gera on the roller (was in the mud of the wrecking yard - band unkinwn) gives around a 3-1 ratio from the starter to the roller. It has a heavy duty momentry contact switch that you can push with your foot to start it, release to stop. Bloody cleaver and works well. As I reaclal there was a stop to prevent the bike rolling off the back of the rollers. The whole thing was maybe 400x300mm + battery. The rollers were turned out of pipe with a welded in axle, then the whole lot turned up true, and running on pillow blocks.
He was showing me when I bought his old set of starting rollers from him. Mine are the ones around 1m long - put one end under car drive wehel, get whife to rev car while you futz with bike. The self contained set is so much better. I have been meaning to make a set, but never got around to it.

[Ixion]

I have contemplated making a 230v powered thingy for the workshop. Does anyone know what rpm the rollers should optimally run at ?

[fridayflash]

hmmm...not a bad idea, might be able to modify some kind of
existing plug in motor source?

[R6_kid:Me]

I have contemplated making a 230v powered thingy for the workshop. Does anyone know what rpm the rollers should optimally run at ?

1500rpm? Or just below the average idle speed?

[Ixion]

That would be 1500 ENGINE speed though? 1500rpm at the wheel would be a hit load more at the engine.

[Squiggles]

According to my gearing calculator, at idle in first for the tl, the wheel is moving at around 17km/hr (4.7m/s), so for rollers of radius 5cm, you're looking at 15revs/sec or 900rpm
(Assuming my maths/memory is right it should be frequency(in rpm) = 60*velocity/(2*pi*radius of roller )

[Ocean1]

According to my gearing calculator, at idle in first for the tl, the wheel is moving at around 17km/hr (4.7m/s), so for rollers of radius 5cm, you're looking at 15revs/sec or 900rpm
(Assuming my maths/memory is right it should be frequency(in rpm) = 60*velocity/(2*pi*radius of roller )

Sounds right.

But trying to start in 1st gear on a roller might be a good way to shred tyres. Also starting revs would ideally be more than idle, and the roller might be better at 50mm dia (2.5cm radius) so you can ride over it/them.

So I'd aim at 2000rpm. Maybe a direct drive from a 2800rpm (2 pole) motor. Or even better a decent sized air motor, (much higher rev's and far more tolerant to overload/stall).

Or you could just bung it on a centre stand and learn to hand-start it on the back wheel...

[xwhatsit]

Or you could just bung it on a centre stand and learn to hand-start it on the back wheel...

I saw some guys doing that on Youtube with an RC166. Tried it with the RS, but couldn't even make the wheel move unless it was in third gear haha. Maybe I'm just weak!

Plus, with `project bikes', I can imagine them being, er, rather stubborn at times. Let an electric motor do the hard work

[koba]

Ive got ones made to go under a car wheel.
Came with a race bike.
They work OK, the bike was a very light big single so near impossible to start without them.
These were made (by someone else) out of old driveshafts in an angleiron frame, simple and effective.
Self contained would be better but more complex.

Always apply the handbrake in the car doing the pushing and make sure it has an open diff......

[Ixion]

Old driveshafts!. What a jolly good idea. This is taking shape isn't it.

[fridayflash]

driveshaft tube? great idea! ive got an older mitsi L300 work van
that needs to be dumped so ill raid the drive shaft out of it first
...and the starter motor

[lostinflyz]

i was gonna give it a go for my race bike.

figured a wee 5hp motor and a go kart wheel would be enough. weld up a frame and bobs your uncle. seems to be what alot of the ama superbike starters are.

[F5 Dave]

Yeah but the AMA guys usually have mechanics to push the starter up to the rear wheel which it is on the stand with the rider.
Then do you build a starter to start the starter?

A self contained means one person can do it if foot starter. They advertise them in classic bike mags etc & use 2 dirty great V8 starters. Of course something more modern would likely need a sight less grunt than some groady hi comp bsa.

I didn't buy a Rotax tandem disc valve twin some years back as I figured that (after a track day by myself) that I'd travel & never be able to start the damn thing when I needed to. It started 2 out of 3 times no problem, but the 3rd time was always when you had no one to help. Didn't think of building rollers till later.