Size of sidecar wheel?

I think the sidecar ride depends more on suspension stiffness and tire pressure than wheel size. With a larger diameter wheel one could increase the ground clearance if desired for off-road work.

Lonnie
Northwest Sidecars

In addition to ground clearance, I would keep a close watch on the bearings. The wheel will be spinning much faster and I've seen trailer wheels go off into outer space (I was behind one once, too. Amazing how those things can bounce!)

Trailer and automobile axles are generally larger diameter than those found on motorcycles or adapted from motorcycles to sidecars. The bearing is larger as well, providing more surface, both for carrying the load and dissipating heat. I suspect the trailer wheel you saw flying off may have come apart due to poor maintainance rather than inherent design flaw(YMMV).

VW

I had thought of the smaller wheel doing more work so to speak, and being lower to the ground, had not really thought of the passengers's ride. When one looks at the current racing machines they have small wheels, obviously a relationship between speed and roadholding so I guess my inital question was irrelevent. Recently while having so much fun chasing solo machines on the freeway the thought had occurred to me that would I have done so well had I a unit with a larger wheel. Jumping about on a unit with an empty chair at speed on a winding road broadens one's motorcycle riding enjoyment so very much. I guess the answer is obvious, the larger the wheel, the more caution required, and the more fun to be experienced if the envelope is pushed. (PS where can I borrow one for a fang?) Regards Carey

How important is the quality of the passenger ride Lonnie? Being a long term, recent convert from two wheels it still has not entered my thought process to consider anyone other than the rider. My initial thought had been how well the unit held the ground and kept stride with the solo units I was playing with as opposed to ground clearance and off-roading. I had not really considered off roading with a side car but it does sound interesting. Older BMW"s, particularly RT's are loaded down with plastic panels etc and really only suited for bitumen, I suppose there is enough fun there for a novice anyway! Regards Carey

Many of the older Beemers are used here for dual sport and off road work.
Like any other vehicle used off the pavement, many are highly modified while others depend on stiffer shocks, beefed up front suspension (or LL's) and more aggressive tire treads.

I guess the importance of passenger comfort depends upon the passenger.
Mole monkeys don't seem to mind Spartan conditions whereas your Mum inlaw might snivel a bit if the going got too rough. lol

Lonnie
Northwest Sidecars

Originally written by careyjohnson on 9/28/2007 4:39 AM
(snip)...I had not really considered off roading with a side car but it does sound interesting.(snip)

May I submit for your consideration the following links? 😉

http://adventuresidecar.com/BlackDog/BlackDog07.htm

http://adventuresidecar.com/KLRrides/killertestride.htm

At one time I really felt that a larger diameter wheel would provide a much better ride. In theory this can be true due to it going over road inperfections a little smoother. In real life practice I was convinced it isn';t that big of a deal. One of the best riding sidecars we have had, passenger wise, was a recently sold Watsonian Palma. Wheel size? 10".
Hannigan builds some very nice and luxurious sidecars. Wheel size? 12"
Wheel bearing stresses? More will be on the larger size wheel due to sideloads (leverage)and possibly more on the smaller size wheel due to spinning faster. Form your own opinion maybe on which ios best. Fact is we have sidecars out there wiht both and we are not seeing wheels flying off all over th ecountry.
The older Velorex Sidecars had a small axle and a failry large wheel. Did they have issues? More reports of 'alleged' axle problems than anything else.
Look at the Urals and oither russian irn. These rigs take a lot of abuse in many cases on and off road with large wheels pretty much in stride. Yes there are bad reports on Dnper wheels being weird and out of round but that seems ot be moreso th efault of poor maunufacturing or soemthing other than just th ewheel size question.
Off roaders do tend to do better with larger diameter wheels due to them going over bumps better but even there some are different.
Ground clearance? Yes larger whels can help in this area but so can suspension design for most practical purposes.
Verdict? I broad terms I am leaning towards it being a toss up in most all cases.

I can say your fears about bearings etc are unfounded.
AS for racing machines using smaller sidecar wheels, as a racer I can there are a number of points;
- spokes break under cornering loads
- solid rimes are much stronger
- racing tyres that are more suitable come in the smaller rim diameters
- smaller diameter less wind resistance
- smaller diameter, machine can be lower to the ground[c.o.gravity]