Author Topic: Sidecar attachment  (Read 743 times)

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RogB

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Sidecar attachment
« on: 30 December, 2019, 07:33:05 »
Hi, can anyone recommend attachment measurements for fitting my Watsonian GP Manx to my swing arm Golden Flash?

I've recently attached it and after several attempts I eventually settled on these measurements:
Axle lead 10" (254mm) which is 18% of bike's 57" (1450mm) wheelbase.
Tow-in with rider seated 3/4" (19mm).
Lean out with rider seated 1/2" (12.5mm).
Track is 47" (1194mm).

Damper is screwed down a turn from solo adjustment.

Travelling at about 30 mph my outfit tracks straight enough with a slight pull towards sidecar on acceleration and a slight pull the other way on braking.  However the steering seems heavy on left turns but better on right ones (ie at junctions).

Over the winter I'm going to fit my new 18T engine sprocket with a new Regina primary chain and change the solo fork springs for sidecar ones.  I'll be removing the sidecar to do this and I'm wondering if anyone has any recommendations for when I refit it.

Thanks.
« Last Edit: 30 December, 2019, 07:35:57 by RSB »
BSA Golden Flash, Plymouth, UK

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Re: Sidecar attachment
« Reply #1 on: 01 January, 2020, 09:26:37 »
I would suggest your axle lead is too much, reduce the distance to about 8".
The heavy side car springs should also help and make sure they are sidecar springs. I bought some side car springs recently which turned out to be stretched solo ones.

Your outfit looks good.

All the best
Rob


berniej

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Re: Sidecar attachment
« Reply #2 on: 01 January, 2020, 14:55:52 »
Yes, with that much lead it will be more difficult to 'ride round' the sidecar when pulling away to the left even though the bike is being powered and not the sidecar.
Have you seen this article? https://www.draganfly.co.uk/data/pdf/Sidecar%20article.pdf
I used it as a basis for initial setting up of my rigid M21 combo and then tweaked until I was happy with each characteristic.

Cheers,
Bernie
'49 M21/B31 hybrid
'56 M21 combination
Bantam D7
C15 project
B40 Super Star
A50CC project

RogB

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Re: Sidecar attachment
« Reply #3 on: 01 January, 2020, 19:15:46 »
Thank you both for your advice.

I bought the GP Manx (second hand) from Watsonian. It came with four arms but three were too short for an A10, so I bought new clamps and the three other arms from Watsonian.

Ben (at Watsonian) suggested 3/4" toe-in and 20% of the bikeís wheelbase for axle lead. That worked out to 11.4".  I tried that first but had a feeling it was too much and reduced it to 10".

I can only move the chassis back by about another 1/2" because the cranked arm at lower front needs to enter the block on the chassis rail at a right angle and the block can only slide forward by another 1/2Ē  before it butts up against the end of the chassis (see pic).  Whether I can move the front lower clamp back so itís on the tube in a lower and more horizontal position and twist the arm around so it will still enter the block squarely - Iím not sure, as it may then point up or down too much, depending on which way it's twisted.  Something Iíll just have to try when I tackle it again.

(Edit) Also the rear block can be seen in the pic. It's on an angle because the rear lower arm is a straight one and the block needs to be at that angle for the arm to enter it squarely, so if necessary I may be able to tilt the front one slightly for the front arm.

I'm also wondering whether I should bring the chassis a bit closer to the bike. From the end of rider's footrest to chassis is 4". Track from centre of bike's rear tyre and centre of sidecar tyre is 47".  Any thoughts on that?

The fork springs were from here - so I hope they're ok.

https://www.ebay.co.uk/itm/BSA-A10-A50-A65-SIDECAR-FORK-SPRINGS-PAIR-NEW-42-5145-UK-MADE/223106303511?hash=item33f22c0617:g:QWgAAOxyUrZSpGXo
« Last Edit: 01 January, 2020, 19:38:52 by RogB »
BSA Golden Flash, Plymouth, UK

berniej

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Re: Sidecar attachment
« Reply #4 on: 02 January, 2020, 07:45:23 »
On mine, (Briggs on rigid M21) the front lower arm is attached to the sidecar frame using the same arrangement as you have for your top front, a rotatable hinge bolted upwrd through a second hole. This probably allows a bit more flexibility in position but maybe less rigidity in the strength of the mount compared with your frame clamp.

I also have mine closer in - not saying that's better but I decided to fit a braked hub as a newbie to sidecar riding. I have the 2nd pedal mounted on the sidecar frame next to the bike brake pedal so I can vary the braking between the two just by rocking my foot slightly.

Cheers,
Bernie
'49 M21/B31 hybrid
'56 M21 combination
Bantam D7
C15 project
B40 Super Star
A50CC project

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Re: Sidecar attachment
« Reply #5 on: 03 January, 2020, 12:23:09 »
With my A65 outfit, I have about 1 1/2 inches between the footrest and the sidecar chassis. I found it gives a narrow wheelbase and is better for cornering. Although mine is an older  watsonian chassis, the front lower mounting arm is connected  via a downward facing eye bolt thorough one of the holes on the main chassis. The lower arm is then straight with a fork fitting at each end.

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Re: Sidecar attachment
« Reply #6 on: 05 January, 2020, 08:47:00 »
You may find the following website very useful for fitting your sidecar.

http://simplysidecars.co.uk/fittingguide.html

Perhaps you could let us know if the modifications have worked when you are finished.

Rob

RogB

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Re: Sidecar attachment
« Reply #7 on: 05 January, 2020, 14:25:59 »
Hi Rob & Bernie, many thanks for your responses.

The planned over the winter jobs have now turned into 'now' jobs and yesterday I disconnected the GP Manx and this morning I removed the solo 21T engine sprocket. I'm now waiting for my son to arrive later this afternoon to help me put my bike up on my work platform to make it easier to fit the 18T sprocket and new primary chain. Then I'll change the fork springs and fit new shocks from PJB Shocks with a higher 126 lb spring rating.

Then when I get my A10 back on the ground I'll tackle the GP Manx again. Looking at the chassis and the fittings I have I think I can get my axle lead down to 9" (so 16% of wheelbase) and I'm going to try 2" between footrest and chassis rail.

Regards, Roger.
BSA Golden Flash, Plymouth, UK

RogB

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Re: Sidecar attachment
« Reply #8 on: 25 January, 2020, 16:15:03 »
Reporting back on my experience of attaching a Watsonian GP Manx to my swinging arm Golden Flash, which has kept me busy in a cold garage for the past three weeks.

I've now fitted new sidecar fork springs, 18T engine sprocket, 67 pitch primary chain and original looking rear shocks but with 126 lbs/inch springs.

I managed to get the axle lead down to 9" and brought the sidecar closer to the bike so the track is now 44 1/2".  Toe-in and lean were as before.  Went for a test ride and found the left turns were still heavier than rights, otherwise ok.

So yesterday I was back in the garage again to increase in the toe-in slightly. I was aiming for 7/8" to max of 1", but when all the fixings were pulled up really tight, sidecar body fitted back on and with my wife sat on the bike it ended up as 1 3/16" (30 mm) toe-in  :-\.  Lean out was 3/8" and as it was the end of the day I decided to leave it and have another go at it another day.

So this morning, being prepared to spend another day in a cold garage, I thought maybe I should go for a test ride first - just to see what it handled like with 30 mm of toe-in.  Contrary to what I've read toe-in should be, to my surprise (and delight) it seems fine.  Left turns are much the same as right ones now, but with a smaller track I was very wary of left corners. There's no noticeable difference in pull either way on a flat road at 30 mph (with hands hovering just above the handlebar grips). Next I put my 14 kg scissor lift in the sidecar to add some weight and went for another test ride and felt far more confident when turning left.

With the damper screwed down there is still some handlebar shaking when going slowly over bumps in the road but it's not uncontrollable when expected, so I'm going to leave it at this and hope the increase in toe-in doesn't end up scrubbing the sidecar tyre too much.

Regards, Roger.

« Last Edit: 25 January, 2020, 16:16:51 by RogB »
BSA Golden Flash, Plymouth, UK

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Re: Sidecar attachment
« Reply #9 on: 27 January, 2020, 20:12:38 »
I'm pleased you have sorted everything out. The toe-in on my A65 Monza outfit is 1" and something. The MOT used to query it, but he always seemed happy with the fact it worked for me. The outfit handles well and goes round corners as it should. I would leave it be and put some miles on the outfit and just check the tyre wear every so often. Again I wouldn't worry too much about the handlebar shaking whilst going over bumps, as long as you are aware of it then you ride accordingly.

Let me know how you are getting on with riding and enjoying your outfit from time to time.

All the best

Rob






RogB

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Re: Sidecar attachment
« Reply #10 on: 29 January, 2020, 14:54:39 »
Will do Rob, and thanks for the help & advice.
I'm looking into fitting some bullet type LED indicators to the outfit now. I'm going to the Carole Nash Classic Motorcycle Show at Shepton Mallett this weekend, so I'm going to have a look at what Paul Goff has to offer. Failing that it'll be something from Alchemy Parts.
BSA Golden Flash, Plymouth, UK

RogB

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Re: Sidecar attachment
« Reply #11 on: 07 March, 2020, 20:55:02 »
For anyone that may be interested went for a good test run this afternoon (to the pasty shop  :) and back) with my wife in the sidecar.

A couple of weeks ago I ended up making even more adjustments to the alignment. Now it's 1" toe-in and 1/2" lean out (which increases by 1/8" with rider seated). Now I can say the handling is good and I don't think I could improve on it. Steering is now light, it doesn't pull excessively to either left or right and now I've screwed the damper down another turn the handlebar shake is now minimal when going over bumps, sunken manhole covers, etc. but no shake otherwise.

I've also fitted indicators with orange LED bulbs (bought from Goffy at the Bristol Classic Bike show), fitted a green Lucas indicator warning light in the nacelle just in front of the speedo fitted with a green LED bulb. So now bike and sidecar have all LEDs, except the headlight which I'll keep as British Pre Focus Quartz Halogen 35/35W. Took a lot to convince myself to drill the 1/2" hole in the nacelle for the warning light though :-\

The latest improvement, completed only this morning and of which I'm particularly happy with, is semi-western handlebars. As I had to fit an indicator switch, with grip, levers and mirrors I'd run out of straight bar and had to fit the switch just after the bend on the standard bars, which wasn't particularly easy or safe to operate. The bars I eventually settled on, after a lot of deliberation, are actually Norton ones (pt no 06-1046) by LF Harris, with a width of 32", a rise of 4 3/4" and pull back of 7" and a very useful 10" of straight bar at each end, so the indicator switch now sits between the lever and the mirror clamp and is easily reachable with my forefinger to move the knob for right indicators or my thumb for left indicators without having to take my hand of the grip. The extra 5" length of the bars also definitely helps with the steering and gives me a more upright and relaxed riding position.

So happy days.
« Last Edit: 07 March, 2020, 20:57:35 by RogB »
BSA Golden Flash, Plymouth, UK