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Handling and track width

 
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cudgel



Joined: 12 May 2009
Posts: 42
Location: Arcadia, Fl

PostPosted: Sat Aug 08, 2009 12:19 am    Post subject: Handling and track width Reply with quote

Just got my (unfinished) rig on the road for some testing and noticed it doesn't like the rutted pavement my county has to offer. Smooth roads,if I find some are much more to its liking. Question is, has anyone noticed a SIGNIFICANT improvement by increasing track width to counteract the side to side shifting caused by the wide, square shoudered car tires? I've done changes to suspension one by one and made some improvements but have concluded the nervous handling goes away on a smooth road. Seems the tires are hitting the sides of the ruts and getting forced back and forth. I could get an easy inch or two by changing wheel offset. Would that be enough?
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sidebike



Joined: 22 Jan 2005
Posts: 157
Location: Cabot Trail, Cape Breton Island Nova Scotia

PostPosted: Sat Aug 08, 2009 1:42 pm    Post subject: Reply with quote

Need more info
what is your track width ?
what type of front end ?
what size tires all the way around ?
what tire pressure are you running in each tire ?
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zentime



Joined: 22 Jan 2005
Posts: 804
Location: Massachusetts USA

PostPosted: Sat Aug 08, 2009 2:56 pm    Post subject: Reply with quote

Congratulations on getting to the test ride stage! Can you post a link to the pictures again, I can't seem to find the link.

When you said "but have concluded the nervous handling goes away on a smooth road." the first thing that comes to mind is I wonder if you have enough caster/trail. Do you know how much trail you have? I assume you would only change the sidecar wheel offset to increase the width. Changing the front wheel offset could have a dramatic effect on how it handles if the center of the contact patch is not reasonably lined up with the steering axis.

bill
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1973 MotoGuzzi V7sport

will August ever come............
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cudgel



Joined: 12 May 2009
Posts: 42
Location: Arcadia, Fl

PostPosted: Sat Aug 08, 2009 8:43 pm    Post subject: Handling improved Reply with quote

Ok, to answer sidebike's questions in order-
Track=47 1/2
A-arm/coilover
185/60-14 fr&side,195/50-15r
35psi all

Spent a couple hours this morning rechecking everything and then did the only adjustment that made any sense-increased front caster. Maxed out the adjustments I built in and voila! Smiling now because I went the right way. Big improvement. Met a friend on my favorite road and he volunteered to ride along. Even better with a passenger. Then he drove and I rode, these things are fun! Now I need to modify the upper control arm to get additional caster and see if it gets even better. Good now but always looking for the best. Thanks. Bruce (can't seem to figure out how to put up pictures here, sorry)[/img]
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sidebike



Joined: 22 Jan 2005
Posts: 157
Location: Cabot Trail, Cape Breton Island Nova Scotia

PostPosted: Sat Aug 08, 2009 11:01 pm    Post subject: Reply with quote

Happy to hear increasing front caster worked for you. It seems that when you have wide low profile tires, you need more castor or trail than you would with narrow high profile tires. You might try running lower tire pressures, as this will allow the low profile radial tires to conform to the road surface. Also the lower pressure will allow the tires to heat to their proper operating temperatures and stick better to the road surface. 35 lbs is fine for a passenger car. I have a 185/55-15 front & rear and run 20 lbs front & 22lbs rear. The sidecar 185/55-14 and I run it at 18 lbs. Other members of this forum run anywhere from 15 lbs up to 24 lbs. The rallye racing sidecars running similar tires run with 14 lbs on all 3 tires. Try playing with the air pressure, you'll find what works best for you.
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Roger
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cudgel



Joined: 12 May 2009
Posts: 42
Location: Arcadia, Fl

PostPosted: Sat Aug 08, 2009 11:29 pm    Post subject: Reply with quote

Thanks, I will be seeking the best pressure but right now I'm making sure everything else is working right. Here in sunny Florida it's so hot we run more pressure to keep from destroying tires from overheating. Was around the tire business here for many years and know first hand heat destroys tires that are underinflated.
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zentime



Joined: 22 Jan 2005
Posts: 804
Location: Massachusetts USA

PostPosted: Sun Aug 09, 2009 1:48 am    Post subject: eye candy!! Reply with quote

Here ya go and WAY TO GO!!

















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will August ever come............
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Ralph



Joined: 27 Jan 2005
Posts: 516
Location: Lexington, Ky

PostPosted: Sun Aug 09, 2009 11:34 am    Post subject: Reply with quote

Cool How many gallons of gas will it hold?
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Paul



Joined: 27 Jan 2005
Posts: 178
Location: Utah

PostPosted: Sun Aug 09, 2009 3:44 pm    Post subject: Reply with quote

cudgel wrote:
Here in sunny Florida it's so hot we run more pressure to keep from destroying tires from overheating.


Keep in mind, a typical car on those same tyres weighs 3000 pounds - or 750 pounds per tyre. Your rig is probably 1/3 that weight, or 250 pounds per tyre. Overheating is not going to be an issue.
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cudgel



Joined: 12 May 2009
Posts: 42
Location: Arcadia, Fl

PostPosted: Sun Aug 09, 2009 8:01 pm    Post subject: Reply with quote

[quote="Ralph"]Cool How many gallons of gas will it hold?[/quote

It only holds seven gallons, may look bigger but the wedge shape is a fooler.
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docmike



Joined: 27 Jan 2005
Posts: 630
Location: Eastern NC

PostPosted: Mon Aug 10, 2009 12:36 pm    Post subject: Reply with quote

When I first got my rig the seller recommended 35 - 40 psi in all four tires. On grooved pavement it didn't feel like there was any connection between the wheels, like each one was trying to go a different direction. Lowering to 24 psi made a big difference.

(Later adding a sway bar and then CH steering also helped.)
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93 BMW K1100RS / EML Speed 2000
89 Honda GB 500 (6,700 miles, all original except tires)
67 Triumph 650 chopper
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cudgel



Joined: 12 May 2009
Posts: 42
Location: Arcadia, Fl

PostPosted: Fri Aug 14, 2009 11:23 am    Post subject: Reply with quote

Update after almost two weeks and three tanks of gas-Handling is very good now and also with a passenger. Increasing caster from +5deg to +8 1/2 deg is the only change I've made. Have carried 7 passengers including myself, 3F-4M and everyone has smiled. Thanks to those here who have offered assistance. Tire pressure remains as before and no complaints from passengers. It's not my intention to argue about tires and pressures, what works for you may not work for everyone as these rigs have their own traits. Happy motoring to all. Bruce.
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Ralph



Joined: 27 Jan 2005
Posts: 516
Location: Lexington, Ky

PostPosted: Fri Aug 14, 2009 6:09 pm    Post subject: Reply with quote

"what works for you may not work for everyone as these rigs have their own traits"
Well it does not take much time to test it now does it.
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